├── .github
├── assets
│ └── banner.jpg
└── workflows
│ └── build.yaml
├── .gitignore
├── 00-hello-world
├── main.go
└── main.py
├── 01-constants-and-variables
└── main.go
├── 02-calculation
└── main.go
├── 03-conditions
└── main.go
├── 04-loops
└── main.go
├── 05-strings
└── main.go
├── 06-arrays
└── main.go
├── 07-slices
└── main.go
├── 08-arrays-and-slices
└── main.go
├── 09-map
└── main.go
├── 10-structs
└── main.go
├── 11-interfaces
└── main.go
├── 12-pointers
└── main.go
├── 13-structs-with-pointer
└── main.go
├── 14-strconv
└── main.go
├── 15-functions-with-multiple-return
└── main.go
├── 16-errors
└── main.go
├── 17-concurrency
└── main.go
├── 18-function-type
└── main.go
├── 19-channels-1
└── main.go
├── 19-channels-2
└── main.go
├── 20-pipeline
└── main.go
├── 21-select
└── main.go
├── 22-json
└── main.go
├── 23-sharding
└── main.go
├── 24-types
└── main.go
├── 25-defer
└── main.go
├── 26-variadic
└── main.go
├── 27-regex
└── main.go
├── 28-once
└── main.go
├── 29-panic
└── main.go
├── 30-utf
└── main.go
├── 31-interface-is-nil
└── main.go
├── 32-type-alias
└── main.go
├── LICENSE
├── README.md
├── go.mod
├── httpserver
├── handler
│ └── hello.go
├── main.go
├── model
│ └── student.go
└── request
│ └── hello.go
├── justfile
└── mutex
├── ch_mutex.go
├── ch_mutex_test.go
└── mutex.go
/.github/assets/banner.jpg:
--------------------------------------------------------------------------------
https://raw.githubusercontent.com/1995parham-teaching/go-lecture/346727db1eb53a5064102d3ea3f16ed9a42ee3d0/.github/assets/banner.jpg
--------------------------------------------------------------------------------
/.github/workflows/build.yaml:
--------------------------------------------------------------------------------
1 | ---
2 | name: build
3 | on:
4 | - push
5 | jobs:
6 | build:
7 | name: test
8 | runs-on: ubuntu-latest
9 | steps:
10 | - uses: extractions/setup-just@v2
11 | - uses: actions/checkout@v4
12 | - uses: actions/setup-go@v5
13 | with:
14 | go-version: 'stable'
15 | - run: just build
16 |
--------------------------------------------------------------------------------
/.gitignore:
--------------------------------------------------------------------------------
1 | # Created by https://www.toptal.com/developers/gitignore/api/go
2 | # Edit at https://www.toptal.com/developers/gitignore?templates=go
3 |
4 | ### Go ###
5 | # Binaries for programs and plugins
6 | *.exe
7 | *.exe~
8 | *.dll
9 | *.so
10 | *.dylib
11 |
12 | # Test binary, built with `go test -c`
13 | *.test
14 |
15 | # Output of the go coverage tool, specifically when used with LiteIDE
16 | *.out
17 |
18 | # Dependency directories (remove the comment below to include it)
19 | # vendor/
20 |
21 | ### Go Patch ###
22 | /vendor/
23 | /Godeps/
24 |
25 | # End of https://www.toptal.com/developers/gitignore/api/go
26 |
--------------------------------------------------------------------------------
/00-hello-world/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import "fmt"
4 |
5 | func main() {
6 | fmt.Printf("Hello, دنیا\n")
7 | }
8 |
--------------------------------------------------------------------------------
/00-hello-world/main.py:
--------------------------------------------------------------------------------
1 | """
2 | Just a sample program to show that the UTF-8 string
3 | exists in other languages too. Here is python.
4 | """
5 |
6 | if __name__ == "__main__":
7 | print("سلام دنیا")
8 |
--------------------------------------------------------------------------------
/01-constants-and-variables/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import "fmt"
4 |
5 | // these are global variables which are accessible from functions.
6 | const (
7 | c1 = 10.1
8 | c2 int64 = 11
9 | )
10 |
11 | var (
12 | v1 = 10
13 | v2 uint64 = 10
14 | )
15 |
16 | /*
17 | var (
18 | v1 = 10
19 | v2 uint64 = 10
20 | )
21 | */
22 |
23 | func main() {
24 | x := 10 // var x = 10
25 |
26 | var y int
27 |
28 | var z float64 = 10.3
29 |
30 | fmt.Println(x)
31 | fmt.Printf("%d\n", y)
32 | fmt.Println(c1)
33 | fmt.Println(c2)
34 | fmt.Printf("%d %d\n", v1, v2)
35 | fmt.Printf("z = %f\n", z)
36 | fmt.Printf("z = %.10f\n", z)
37 | fmt.Printf("z = %g\n", z)
38 | // printf allows you to specify the precision using a parameter
39 | // (that precedes the value) if you use a .* as the precision
40 | // in the format tag.
41 | fmt.Printf("z = %.*f", 12, z)
42 |
43 | // %v is a Go unique way to print variable,
44 | // it behaves like fmt.Println.
45 | fmt.Printf("z = %v", z)
46 | }
47 |
--------------------------------------------------------------------------------
/02-calculation/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import (
4 | "fmt"
5 | "math"
6 | )
7 |
8 | func main() {
9 | fmt.Println(1 + 2 + 3)
10 |
11 | var d float64
12 |
13 | d = math.Abs(12.2)
14 | fmt.Println(d)
15 |
16 | d = math.Abs(-1 * d)
17 | fmt.Println(d)
18 |
19 | fmt.Printf("%g\n", math.Sin(math.Pi))
20 | fmt.Printf("%f\n", math.Sin(math.Pi*0.5))
21 | }
22 |
--------------------------------------------------------------------------------
/03-conditions/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import "fmt"
4 |
5 | func main() {
6 | const n = 10
7 |
8 | fmt.Printf("%d\n", Fibonacci(n))
9 |
10 | switch n {
11 | case 10:
12 | fmt.Printf("n is equal to 10!\n")
13 | // uncomment the following line to see what happen
14 | // fallthrough
15 | case 11:
16 | fmt.Printf("in c this statement will be run but here?\n")
17 | // fallthrough
18 | default:
19 | fmt.Println("this should not happen")
20 | }
21 |
22 | const name = "Parham"
23 |
24 | switch name {
25 | case "Parham":
26 | fmt.Println("Yooohoo")
27 | default:
28 | fmt.Println("Noooo")
29 | }
30 | }
31 |
32 | func Fibonacci(n int) int {
33 | if n == 0 || n == 1 {
34 | return 1
35 | }
36 |
37 | return Fibonacci(n-1) + Fibonacci(n-2)
38 | }
39 |
--------------------------------------------------------------------------------
/04-loops/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import "fmt"
4 |
5 | func GCD(n, m int) int {
6 | for n%m != 0 {
7 | n, m = m, n%m
8 | // a, b = b, a
9 | }
10 |
11 | return m
12 | }
13 |
14 | func NthPrime(n int) int {
15 | i := 2
16 | counter := 0
17 |
18 | for {
19 | if IsPrime(i) {
20 | counter++
21 |
22 | if counter == n {
23 | return i
24 | }
25 | }
26 |
27 | i++
28 | }
29 | }
30 |
31 | func IsPrime(n int) bool {
32 | for i := 2; i < n; i++ {
33 | if n%i == 0 {
34 | return false
35 | }
36 | }
37 |
38 | return true
39 | }
40 |
41 | func main() {
42 | var n int
43 |
44 | fmt.Print("please enter n: ")
45 | fmt.Scanf("%d", &n)
46 |
47 | fmt.Printf("is %d prime? %t\n", n, IsPrime(n))
48 |
49 | fmt.Printf("%dth prime is %d\n", n, NthPrime(n))
50 |
51 | fmt.Println("gcd", 10, 20, "is", GCD(10, 20))
52 | fmt.Println("gcd", 13, 15, "is", GCD(13, 15))
53 | }
54 |
--------------------------------------------------------------------------------
/05-strings/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import "fmt"
4 |
5 | // https://en.wikipedia.org/wiki/UTF-8
6 |
7 | // g defined as a global constant variable,
8 | // which is added into binary output .rodata section.
9 | // $ strings 05-strings | grep "Global"
10 | const g = "Global string is which defined"
11 |
12 | func main() {
13 | var s1 string = "Hello World"
14 |
15 | s2 := "Parham Alvani"
16 | s3 := "سلام دنیا"
17 |
18 | fmt.Printf("%d (len(s3)) != 9\n", len(s3))
19 | fmt.Println([]byte(s3))
20 |
21 | fmt.Println(s1[0])
22 | fmt.Println(s2)
23 | // 11011000 (216) means it needs another byte to be a valid UTF-8.
24 | fmt.Println(s3[0])
25 | fmt.Println(s3[1])
26 | fmt.Printf("%c\n", s3[1])
27 |
28 | for i, c := range s3 {
29 | fmt.Printf("[%d]: %c ", i, c)
30 | }
31 |
32 | // you can assign a new string
33 | // into a string variable.
34 | s1 = "New Hello World"
35 |
36 | // s3[1] = 10
37 | // cannot assign to s3[1] (value of type byte)
38 |
39 | fmt.Println()
40 |
41 | // comment out the following line and then you cannot find
42 | // the string into the compiled binary.
43 | fmt.Println(g)
44 | }
45 |
--------------------------------------------------------------------------------
/06-arrays/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import "fmt"
4 |
5 | func main() {
6 | // if you remember in C: int a[10]
7 | var a [10]int
8 | b := [...]int{1, 2, 3, 4}
9 | c := [4]int{2, 4, 6, 8}
10 | d := [4]int{1}
11 |
12 | for index, value := range a {
13 | fmt.Printf("a[%d] = %d\n", index, value)
14 | }
15 |
16 | for index, value := range b {
17 | fmt.Printf("b[%d] = %d\n", index, value)
18 | }
19 |
20 | fmt.Println("c:", c)
21 | fmt.Println("d:", d)
22 |
23 | // a = c
24 | // compile error, cannot use c (type [4]int) as type [10]int in assignment
25 | b = c
26 |
27 | fmt.Println("b:", b)
28 |
29 | b[0] = 10
30 |
31 | fmt.Println("c after chaning b", c)
32 | fmt.Println("b:", b)
33 |
34 | // n := 10
35 | // var c [n]int
36 | // compile error, arrays' length must be constant
37 |
38 | // b[10] = 1
39 | // invalid argument: array index 10 out of bounds [0:4]
40 | }
41 |
--------------------------------------------------------------------------------
/07-slices/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import "fmt"
4 |
5 | /*
6 | working with slice s:
7 |
8 | capacity: 5
9 | array: [ | | | | ]
10 | size: 2
11 | s[0] = 0, s[1] = 1
12 | array: [0|1| | | ]
13 |
14 | s = append(s, 10)
15 | size: 3
16 | array: [0|1|10| | ]
17 |
18 | s = append(s, 20)
19 | capacity: 10
20 | size: 4
21 | array: [0|1|10|20| | | | | ..]
22 |
23 | */
24 |
25 | func main() {
26 | s1 := make([]int, 10)
27 |
28 | s1[0] = 10
29 | s1[1] = 20
30 | s1[2] = 30
31 |
32 | fmt.Printf("s1: %+v, len(s1): %d, cap(s1): %d\n", s1, len(s1), cap(s1))
33 |
34 | s1 = append(s1, 10)
35 |
36 | fmt.Printf("s1: %+v, len(s1): %d, cap(s1): %d\n", s1, len(s1), cap(s1))
37 |
38 | for index, value := range s1 {
39 | fmt.Printf("s1[%d]: %d,", index, value)
40 | }
41 | fmt.Println()
42 |
43 | s2 := make([]int, 0, 10)
44 |
45 | s2 = append(s2, 10)
46 |
47 | fmt.Printf("s2: %+v, len(s2): %d, cap(s2): %d\n", s2, len(s2), cap(s2))
48 |
49 | // expanding slice with append in action
50 | s := make([]int, 10, 10)
51 |
52 | fmt.Println("before appending a new variable into s")
53 | fmt.Printf("address of s is %p\n", &s)
54 | fmt.Printf("address of s[0] is %p\n", &s[0])
55 |
56 | s = append(s, 15)
57 |
58 | fmt.Println("after appending a new variable into s")
59 | fmt.Printf("address of s is %p\n", &s)
60 | fmt.Printf("address of s[0] is %p\n", &s[0])
61 | }
62 |
--------------------------------------------------------------------------------
/08-arrays-and-slices/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import "fmt"
4 |
5 | func main() {
6 | // create a slice with length equals to 10.
7 | s1 := make([]int, 10)
8 |
9 | s1[0] = 1
10 | s1[1] = 2
11 |
12 | fmt.Printf("s1: %v\n", s1)
13 |
14 | // create a slice from a slice by slice operator.
15 | // a newly created slice points to base slice.
16 | s2 := s1[0:2]
17 | s2[0] = 10
18 |
19 | fmt.Printf("s2: %v\n", s2)
20 | fmt.Printf("s1 after \"s2[0] = 10\": %v\n", s1)
21 |
22 | // append a new element into our newly created slice.
23 | s2 = append(s2, 120)
24 | fmt.Printf("s2: %v\n", s2)
25 | fmt.Printf("s1 after \"append(s2, 120)\": %v\n", s1)
26 |
27 | // create another slice from middle of s1
28 | s3 := s1[2:4]
29 | fmt.Printf("s3: %v, cap(s3): %d, len(s3): %d\n", s3, cap(s3), len(s3))
30 |
31 | a1 := [3]int{1, 2, 3}
32 |
33 | s4 := a1[1:3]
34 | s4[0] = 20
35 |
36 | fmt.Printf("s4: %v, cap(s4): %d, len(s4): %d\n", s4, cap(s4), len(s4))
37 | fmt.Printf("a1 after \"s3[0] = 20\": %v\n", a1)
38 |
39 | s5 := s4
40 |
41 | // compile error: slice can only be compared to nil
42 | // fmt.Printf("s5 ? s4: %v\n", s5 == s4)
43 | fmt.Printf("s5: %v\n", s5)
44 |
45 | // panic: runtime error: index out of range [3] with length 2
46 | // fmt.Printf("invalid access to slice \"s5[3]\": %d", s5[3])
47 |
48 | // compile error: invalid array index 3 (out of bounds for 3-element array)
49 | // fmt.Printf("invalid access to array \"a1[3]\": %d", a1[3])
50 |
51 | fmt.Printf("s5[1:]: %v\n", s5[1:])
52 | }
53 |
--------------------------------------------------------------------------------
/09-map/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import "fmt"
4 |
5 | func main() {
6 | var m map[int]string
7 | m = make(map[int]string)
8 | // m := make(map[int]string)
9 |
10 | m[10] = "Hello"
11 | m[1373] = "Parham"
12 |
13 | for key, value := range m {
14 | fmt.Println(key, value)
15 | }
16 |
17 | var v string
18 |
19 | v = m[10]
20 | fmt.Printf("m[%d] = %s\n", 10, v)
21 |
22 | v = m[25]
23 | fmt.Printf("m[%d] = %s\n", 25, v)
24 |
25 | s := make(map[int]bool)
26 |
27 | for i := 0; i < 3; i++ {
28 | var n int
29 | fmt.Scanf("%d", &n)
30 |
31 | if s[n] {
32 | fmt.Printf("%d is already exist\n", n)
33 | } else {
34 | s[n] = true
35 | fmt.Printf("%d saved\n", n)
36 | }
37 | }
38 |
39 | opinions := make(map[string]bool)
40 |
41 | opinions["Parham"] = true
42 | opinions["Sepehr"] = false
43 |
44 | opinion, ok := opinions["Hesam"]
45 | if ok {
46 | fmt.Printf("opinions[%s] = %v\n", "Hesam", opinion)
47 | }
48 |
49 | delete(opinions, "Parham")
50 | delete(opinions, "Parham")
51 |
52 | _, ok = opinions["Parham"]
53 | if !ok {
54 | fmt.Printf("opinions[%s] does not exist\n", "Parham")
55 | }
56 | }
57 |
--------------------------------------------------------------------------------
/10-structs/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import "fmt"
4 |
5 | type Student struct {
6 | Name string
7 | Family string
8 | age int
9 |
10 | // uncomment the following line to remove the comparablity.
11 | // justForFun []int
12 | }
13 |
14 | // New is a popular pattern to create types
15 | func New(name, family string, age int) Student {
16 | return Student{
17 | Name: name,
18 | Family: family,
19 | age: age,
20 | }
21 | }
22 |
23 | func (Student) Nothing() {}
24 |
25 | func (Student) nothing() {}
26 |
27 | // String returns the string for printing by %v or Println.
28 | func (s Student) String() string {
29 | return fmt.Sprintf("Name: %s, Family: %s, age: %d", s.Name, s.Family, s.age)
30 | }
31 |
32 | func (s Student) Hello(to Student) string {
33 | return fmt.Sprintf("Hello %s, I am %s %s (%d)", to.Name, s.Name, s.Family, s.age)
34 | }
35 |
36 | func main() {
37 | s := Student{
38 | Name: "Parham",
39 | Family: "Alvani",
40 | age: 27,
41 | }
42 |
43 | newS := s
44 | if newS == s {
45 | fmt.Println("we can compare student structs")
46 | }
47 |
48 | fmt.Println(s)
49 |
50 | s.nothing()
51 |
52 | fmt.Printf("student, %s %s\n", s.Name, s.Family)
53 |
54 | fmt.Println(s.Hello(Student{
55 | Name: "Torvalds",
56 | }))
57 | }
58 |
--------------------------------------------------------------------------------
/11-interfaces/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import "fmt"
4 |
5 | type Printer interface {
6 | Print() string
7 | }
8 |
9 | type Person struct {
10 | Name string
11 | }
12 |
13 | func (p Person) Print() string {
14 | return fmt.Sprintf("Person %s", p.Name)
15 | }
16 |
17 | type Student struct {
18 | Name string
19 | }
20 |
21 | func (s Student) Print() string {
22 | return s.Name
23 | }
24 |
25 | func (s Student) Hello() string {
26 | return "Hello"
27 | }
28 |
29 | type Any interface{}
30 |
31 | func main() {
32 | var p Printer
33 | s := Student{
34 | Name: "Linus Torvalds",
35 | }
36 |
37 | s.Hello()
38 |
39 | p = s
40 |
41 | fmt.Println(p.Print())
42 |
43 | // cast from interface to concrete type with panic
44 | s = p.(Student)
45 |
46 | // cast from interface to concrete type without panic
47 | _, ok := p.(Person)
48 | if !ok {
49 | fmt.Println("p is not a person")
50 | }
51 |
52 | // type switch
53 | switch v := p.(type) {
54 | case Person:
55 | fmt.Printf("I am a person with name equals to %s\n", v.Name)
56 | case Student:
57 | fmt.Println(v.Hello())
58 | default:
59 | fmt.Println("unknown")
60 | }
61 | }
62 |
--------------------------------------------------------------------------------
/12-pointers/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import "fmt"
4 |
5 | // invalid swap because it cannot change its arguments.
6 | func swap(a, b int) {
7 | a, b = b, a
8 | }
9 |
10 | // valid swap because of call by reference.
11 | func swapWithPointer(a, b *int) {
12 | *a, *b = *b, *a
13 | }
14 |
15 | func main() {
16 | x, y := 10, 12
17 | fmt.Printf("before \"swap(%d, %d)\": %d, %d\n", x, y, x, y)
18 | swap(x, y)
19 | fmt.Printf("after \"swap(%d, %d)\": %d, %d\n", x, y, x, y)
20 |
21 | fmt.Printf("before \"swapWithPointer(%d, %d)\": %d, %d\n", x, y, x, y)
22 | swapWithPointer(&x, &y)
23 | fmt.Printf("after \"swapWithPointer(%d, %d)\": %d, %d\n", x, y, x, y)
24 |
25 | var a int
26 | a = 10
27 | fmt.Printf("%d\n", a)
28 |
29 | b := new(int)
30 | *b = 12
31 | fmt.Printf("b = %p, *b = %d\n", b, *b)
32 |
33 | b = &a
34 | fmt.Printf("b = %p, *b = %d\n", b, *b)
35 |
36 | var c *int
37 | fmt.Printf("c: %v\n", c)
38 | }
39 |
--------------------------------------------------------------------------------
/13-structs-with-pointer/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import "fmt"
4 |
5 | type Older interface {
6 | BeOlder(int)
7 | }
8 |
9 | type Person struct {
10 | Name string
11 | Age int
12 | }
13 |
14 | func New(name string, age int) *Person {
15 | return &Person{
16 | Name: name,
17 | Age: age,
18 | }
19 | }
20 |
21 | // BeOlder uses reference to Person
22 | func (p *Person) BeOlder(increase int) {
23 | // there is no ->
24 | p.Age += increase
25 | }
26 |
27 | func (p Person) String() string {
28 | return fmt.Sprintf("%s (%d)", p.Name, p.Age)
29 | }
30 |
31 | func main() {
32 | p := Person{
33 | Name: "Parham Alvani",
34 | Age: 27,
35 | }
36 |
37 | fmt.Println(p)
38 |
39 | p.BeOlder(1)
40 |
41 | fmt.Println(p)
42 |
43 | var bo Older
44 | // compile error: cannot use p (type Person) as type Older in assignment:
45 | // Person does not implement Older (BeOlder method has pointer receiver)
46 | // bo = p
47 |
48 | bo = &p
49 |
50 | bo.BeOlder(10)
51 |
52 | fmt.Println(p)
53 |
54 | var _ fmt.Stringer = p
55 | var _ fmt.Stringer = &p
56 |
57 | fmt.Printf("String on Person: %v\n", p)
58 | fmt.Printf("String on *Person: %v\n", &p)
59 | }
60 |
--------------------------------------------------------------------------------
/14-strconv/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import (
4 | "fmt"
5 | "strconv"
6 | )
7 |
8 | func main() {
9 | s := "1230"
10 | a := 10
11 |
12 | // second argument indicates base and it doesn't
13 | // accept 0x even when you have 16 as base.
14 | i, _ := strconv.ParseInt(s, 10, 32)
15 |
16 | // compile error: mismatched types int64 and int
17 | // a = i + a
18 |
19 | a = int(i) + a
20 |
21 | fmt.Println(i)
22 | fmt.Println(a)
23 |
24 | // print multiple return values with println
25 | fmt.Println(strconv.Atoi("123"))
26 |
27 | // Generic ParseInt which is written by me!
28 | y, _ := ParseInt[int]("562", 16)
29 | fmt.Println(y)
30 | fmt.Println(y + a)
31 | }
32 |
33 | type Number interface {
34 | int | int32 | int64 | int16 | int8
35 | }
36 |
37 | func ParseInt[T Number](s string, b int) (T, error) {
38 | v, err := strconv.ParseInt(s, b, 64)
39 | if err != nil {
40 | return 0, err
41 | }
42 |
43 | return T(v), nil
44 | }
45 |
--------------------------------------------------------------------------------
/15-functions-with-multiple-return/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import "fmt"
4 |
5 | func swap(a, b int) (int, int) {
6 | return b, a
7 | }
8 |
9 | func complexFunction(a int) (int, string) {
10 | c := a + 10
11 |
12 | return c, fmt.Sprintf("%X", a)
13 | }
14 |
15 | func main() {
16 | a, b := swap(10, 2)
17 | fmt.Println(a)
18 | fmt.Println(b)
19 |
20 | _, c := swap(20, 1)
21 | fmt.Println(c)
22 |
23 | // compile error: cannot initialize 1 variables with 2 value
24 | // d := swap(10, 20)
25 |
26 | fmt.Println(complexFunction(10))
27 | }
28 |
--------------------------------------------------------------------------------
/16-errors/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import (
4 | "errors"
5 | "fmt"
6 | "strconv"
7 | )
8 |
9 | //
10 | // type error interface {
11 | // Error() string
12 | // }
13 | //
14 | // when there is no implementation behind an interface, it will be nil.
15 | // so we will check err with nil.
16 |
17 | type My3Error struct {
18 | LastError error
19 | }
20 |
21 | func (me My3Error) Unwrap() error {
22 | return me.LastError
23 | }
24 |
25 | type My1Error struct {
26 | Message string
27 | Number int
28 | }
29 |
30 | func (me My1Error) Error() string {
31 | return fmt.Sprintf("%s: %d", me.Message, me.Number)
32 | }
33 |
34 | // errors should prefix with Err when they are created with
35 | // errors.New() and they are not structure.
36 | var ErrMy2 = errors.New("i am error 2")
37 |
38 | func toNumber(s string) int {
39 | i, err := strconv.ParseInt(s, 10, 32)
40 | if err != nil {
41 | fmt.Printf("error: %s\n", err.Error())
42 | }
43 |
44 | return int(i)
45 | }
46 |
47 | func iReturnError(n int) (int, error) {
48 | if n%2 == 0 {
49 | return 0, My1Error{
50 | Message: "Hello, I am error number 1",
51 | Number: n,
52 | }
53 | }
54 |
55 | return 1, ErrMy2
56 | }
57 |
58 | // iReturnErrorError calls iReturnError and wraps its error.
59 | func iReturnErrorError(n int) error {
60 | _, err := iReturnError(n)
61 | if err != nil {
62 | return fmt.Errorf("from iReturnErrorError %w", err)
63 | }
64 |
65 | return nil
66 | }
67 |
68 | func main() {
69 | fmt.Println(toNumber("123"))
70 | fmt.Println(toNumber("abc"))
71 | fmt.Println(toNumber("123abc"))
72 |
73 | // why MyError2 without {} but MyError1 with {}.
74 | // also pay attention to the error parameters because they also must be equal.
75 | // the reason behind this is because of the way that we write Error method.
76 | fmt.Printf("iReturnErrorError(1) is MyError2? %t\n", errors.Is(iReturnErrorError(1), ErrMy2))
77 | fmt.Printf("iReturnErrorError(0) is MyError1? %t\n", errors.Is(iReturnErrorError(0), My1Error{
78 | Message: "Hello, I am error number 1",
79 | Number: 0,
80 | }))
81 | fmt.Printf("iReturnErrorError(2) is MyError1? %t\n", errors.Is(iReturnErrorError(2), My1Error{
82 | Message: "Hello, I am error number 1",
83 | Number: 0,
84 | }))
85 |
86 | // parses the returned error from iReturnErrorError as MyError1
87 | // so we can get access to its details.
88 | // myError1 := &MyError1{}
89 | myError1 := new(My1Error)
90 | if ok := errors.As(iReturnErrorError(0), myError1); ok {
91 | fmt.Printf("we have MyError1 from iReturnErrorError (%s, %d)\n", myError1.Message, myError1.Number)
92 | }
93 | }
94 |
--------------------------------------------------------------------------------
/17-concurrency/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import "fmt"
4 |
5 | func main() {
6 |
7 | go func() {
8 | fmt.Println("goroutine-2")
9 | }()
10 |
11 | fmt.Println("goroutine-1")
12 |
13 | // block until goroutine execuation
14 | // everything will be killed when main died
15 | for {
16 | }
17 | }
18 |
--------------------------------------------------------------------------------
/18-function-type/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import "fmt"
4 |
5 | func insertIntoFunc(a int, b int) func(int) int {
6 | return func(i int) int {
7 | return a + b + i
8 | }
9 | }
10 |
11 | func logBeforeRun(f func(int) int) func(int) int {
12 | return func(i int) int {
13 | fmt.Println("hello, I am log")
14 | r := f(i)
15 | fmt.Printf("result: %d\n", r)
16 | return r
17 | }
18 | }
19 |
20 | func main() {
21 | f := func(x int) int {
22 | return x * x
23 | }
24 |
25 | fmt.Println(f(1))
26 | fmt.Println(f(2))
27 |
28 | functiosMap := make(map[string]func(int) int)
29 |
30 | functiosMap["square"] = f
31 |
32 | logBeforeRun(f)(10)
33 |
34 | fmt.Println(insertIntoFunc(10, 20)(10))
35 | }
36 |
--------------------------------------------------------------------------------
/19-channels-1/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import "fmt"
4 |
5 | func main() {
6 | // make(chan int, 10) with 10 rooms (buffered channel)
7 | ch := make(chan int) // with 0 room (unbuffered channel)
8 |
9 | go func() {
10 | for i := 0; i < 10; i++ {
11 | ch <- i
12 | }
13 |
14 | // if you forget to close the channel it causes deadlock.
15 | // by closing the channel you let Golang to garbage collect it
16 | // so it if there is anything remaining in the buffered channel it could be
17 | // removed soon.
18 | close(ch)
19 | }()
20 | // you can read from a channel with
21 | // i := <-ch
22 |
23 | for i := range ch {
24 | fmt.Println(i)
25 | }
26 | }
27 |
--------------------------------------------------------------------------------
/19-channels-2/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import (
4 | "fmt"
5 | "time"
6 | )
7 |
8 | func main() {
9 | ch := make(chan int)
10 |
11 | go func() {
12 | fmt.Println("I am going to write on channel")
13 | fmt.Println("I am still going to write on channel")
14 | time.Sleep(time.Second)
15 | ch <- 10
16 | fmt.Println("I am done")
17 | close(ch)
18 | }()
19 |
20 | time.Sleep(time.Second)
21 | <-ch
22 | }
23 |
--------------------------------------------------------------------------------
/20-pipeline/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import (
4 | "fmt"
5 | "math/rand"
6 | "os"
7 | "os/signal"
8 | "sync"
9 | "syscall"
10 | "time"
11 | )
12 |
13 | const processRoutines = 2
14 |
15 | func main() {
16 | var ch chan int
17 | ch = make(chan int)
18 |
19 | var wg sync.WaitGroup
20 |
21 | // create 2 process to process data from the channel
22 | for id := 0; id < processRoutines; id++ {
23 | wg.Add(1)
24 | go func(id int) {
25 | // each processor prints the data besides its id
26 | for {
27 | i, ok := <-ch
28 | if !ok {
29 | // if channel is closed, we will close the processor
30 | fmt.Printf("closed the processosr %d\n", id)
31 | wg.Done()
32 | return
33 | }
34 | fmt.Printf("process %d in %d\n", i, id)
35 | }
36 | }(id)
37 | }
38 |
39 | shutdown := make(chan int)
40 |
41 | // produce data evey 1 second into the channel
42 | go func() {
43 | for {
44 | time.Sleep(1 * time.Second)
45 | fmt.Println("we have a new input")
46 | // if we have any data in shutdonw channel then
47 | // close ch or write new data to it.
48 | select {
49 | case <-shutdown:
50 | close(ch)
51 | default:
52 | ch <- rand.Intn(10)
53 | }
54 | }
55 | }()
56 |
57 | // wait for termination signal
58 | quit := make(chan os.Signal, 1)
59 | signal.Notify(quit, syscall.SIGTERM, syscall.SIGINT)
60 | <-quit
61 |
62 | close(shutdown)
63 |
64 | wg.Wait()
65 | }
66 |
--------------------------------------------------------------------------------
/21-select/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import (
4 | "log"
5 | "math/rand"
6 | "time"
7 | )
8 |
9 | func wait() chan int {
10 | ch := make(chan int)
11 |
12 | go func() {
13 | r := rand.Intn(10)
14 | time.Sleep(time.Duration(r) * time.Second)
15 |
16 | close(ch)
17 | }()
18 |
19 | return ch
20 | }
21 |
22 | func main() {
23 | ch1 := wait()
24 | ch2 := wait()
25 | ch3 := wait()
26 |
27 | select {
28 | case <-ch1:
29 | log.Println(1)
30 | case <-ch2:
31 | log.Println(2)
32 | case <-ch3:
33 | log.Println(3)
34 | default:
35 | // other cases must have results in the moment or the default case will be exectued
36 | log.Println("failed")
37 | return
38 | }
39 |
40 | log.Println("success")
41 | }
42 |
--------------------------------------------------------------------------------
/22-json/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import (
4 | "encoding/json"
5 | "fmt"
6 | )
7 |
8 | type Student struct {
9 | Name string `json:"name"`
10 | Family string `json:"family"`
11 | // use the following definition for age to see what happens.
12 | // Age *int `json:"age"`
13 | Age int `json:"age"`
14 | }
15 |
16 | func main() {
17 | s := Student{
18 | Name: "Parham",
19 | Family: "Alvani",
20 | }
21 |
22 | b, err := json.Marshal(s)
23 | if err != nil {
24 | fmt.Println(err)
25 | }
26 | fmt.Println(string(b))
27 |
28 | str1 := "{\"name\": \"parham\"}"
29 | var s1 Student
30 |
31 | if err := json.Unmarshal([]byte(str1), &s1); err != nil {
32 | fmt.Println(err)
33 | }
34 | fmt.Println(s1)
35 |
36 | str2 := "{\"name\": \"parham\", \"family\": \"\", \"age\": 0}"
37 | var s2 Student
38 |
39 | if err := json.Unmarshal([]byte(str2), &s2); err != nil {
40 | fmt.Println(err)
41 | }
42 | fmt.Println(s2)
43 | }
44 |
--------------------------------------------------------------------------------
/23-sharding/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import (
4 | "crypto/sha1"
5 | "fmt"
6 | "sync"
7 | )
8 |
9 | type Key interface {
10 | comparable
11 | fmt.Stringer
12 | }
13 |
14 | type Shard[K Key, V interface{}] struct {
15 | sync.RWMutex
16 | data map[K]V
17 | }
18 |
19 | type ShardedMap[K Key, V interface{}] []*Shard[K, V]
20 |
21 | func NewShardedMap[K Key, V interface{}](nshards int) ShardedMap[K, V] {
22 | shards := make([]*Shard[K, V], nshards)
23 |
24 | for i := 0; i < nshards; i++ {
25 | data := make(map[K]V)
26 | shards[i] = &Shard[K, V]{data: data}
27 | }
28 |
29 | return shards
30 | }
31 |
32 | func (m ShardedMap[K, V]) GetShardIndex(key K) int {
33 | checksum := sha1.Sum([]byte(key.String()))
34 | hash := int(checksum[17])
35 |
36 | return hash % len(m)
37 | }
38 |
39 | func (m ShardedMap[K, V]) GetShard(key K) *Shard[K, V] {
40 | index := m.GetShardIndex(key)
41 |
42 | return m[index]
43 | }
44 |
45 | func (m ShardedMap[K, V]) Get(key K) V {
46 | shard := m.GetShard(key)
47 | shard.RLock()
48 |
49 | defer shard.RUnlock()
50 |
51 | return shard.data[key]
52 | }
53 |
54 | func (m ShardedMap[K, V]) Set(key K, value V) {
55 | shard := m.GetShard(key)
56 | shard.Lock()
57 | defer shard.Unlock()
58 |
59 | shard.data[key] = value
60 | }
61 |
62 | func (m ShardedMap[K, V]) Keys() []K {
63 | keys := make([]K, 0)
64 |
65 | var mutex sync.Mutex
66 |
67 | var wg sync.WaitGroup
68 | wg.Add(len(m))
69 |
70 | for _, shard := range m {
71 | go func(s *Shard[K, V]) {
72 | s.RLock()
73 |
74 | for key := range s.data {
75 | mutex.Lock()
76 | keys = append(keys, key)
77 | mutex.Unlock()
78 | }
79 |
80 | s.RUnlock()
81 | wg.Done()
82 | }(shard)
83 | }
84 |
85 | wg.Wait()
86 |
87 | return keys
88 | }
89 |
90 | type String string
91 |
92 | func (s String) String() string {
93 | return string(s)
94 | }
95 |
96 | func main() {
97 | shardedMap := NewShardedMap[String, int](5)
98 |
99 | shardedMap.Set("Parham", 20)
100 | shardedMap.Set("Ahmad", 18)
101 | shardedMap.Set("Ali", 10)
102 |
103 | fmt.Println(shardedMap.Get("Parham"))
104 | fmt.Println(shardedMap.GetShardIndex("Parham"))
105 |
106 | fmt.Println(shardedMap.Get("Ahmad"))
107 | fmt.Println(shardedMap.GetShardIndex("Ahmad"))
108 |
109 | fmt.Println(shardedMap.Get("Ali"))
110 | fmt.Println(shardedMap.GetShardIndex("Ali"))
111 | }
112 |
--------------------------------------------------------------------------------
/24-types/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import "fmt"
4 |
5 | // define new types based on current types
6 |
7 | type String string
8 |
9 | func (s String) String() string {
10 | return string(s)
11 | }
12 |
13 | type Person struct{}
14 |
15 | // define type aliases (just like typedef in c programming language)
16 |
17 | type P = Person
18 |
19 | type Int = int
20 |
21 | func main() {
22 | var ii Int = 10
23 | var i int = ii
24 |
25 | fmt.Println(i)
26 |
27 | var ss String = "hello"
28 |
29 | // uncomment the following lines to see:
30 | // cannot use ss (variable of type String) as string value in assignment
31 | // var s string
32 | // s = ss
33 |
34 | fmt.Println(ss)
35 | }
36 |
--------------------------------------------------------------------------------
/25-defer/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import (
4 | "fmt"
5 | "os"
6 | )
7 |
8 | func main() {
9 | f := createFile("/tmp/defer.txt")
10 | defer closeFile(f)
11 | writeFile(f)
12 | }
13 |
14 | func createFile(p string) *os.File {
15 | fmt.Println("creating...")
16 |
17 | f, err := os.Create(p)
18 | if err != nil {
19 | panic(err)
20 | }
21 |
22 | return f
23 | }
24 |
25 | func writeFile(f *os.File) {
26 | fmt.Println("writing...")
27 | fmt.Fprintln(f, "data")
28 | }
29 |
30 | func closeFile(f *os.File) {
31 | fmt.Println("closing...")
32 | f.Close()
33 | }
34 |
--------------------------------------------------------------------------------
/26-variadic/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import "fmt"
4 |
5 | func sums(nums ...int) {
6 | fmt.Printf("these are your numbers: %v\n", nums)
7 |
8 | total := 0
9 | for _, num := range nums {
10 | total += num
11 | }
12 |
13 | fmt.Println(total)
14 | }
15 |
16 | func main() {
17 | sums(1, 2, 3)
18 | sums(2, 3, 4)
19 |
20 | nums := []int{1, 2, 3, 4}
21 | sums(nums...)
22 | }
23 |
--------------------------------------------------------------------------------
/27-regex/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import (
4 | "log"
5 | "regexp"
6 | )
7 |
8 | func main() {
9 | r := regexp.MustCompile("[abcd]+")
10 | str := "aa bb c dd de f"
11 |
12 | log.Printf("replaced: %v\n", r.ReplaceAllString(str, "-"))
13 | }
14 |
--------------------------------------------------------------------------------
/28-once/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import (
4 | "fmt"
5 | "sync"
6 | )
7 |
8 | type LazyInit struct {
9 | once sync.Once
10 | value int
11 | }
12 |
13 | func (s *LazyInit) Value() int {
14 | s.init()
15 |
16 | return s.value
17 | }
18 |
19 | func (s *LazyInit) init() {
20 | s.once.Do(func() { s.value = 1820 })
21 | }
22 |
23 | func (s *LazyInit) SetValue(v int) {
24 | s.value = v
25 | }
26 |
27 | func main() {
28 | const v = 12
29 |
30 | var l LazyInit
31 | /*
32 | * if you use SetValue() berfore getting the value (initiation happens on Value())
33 | * your setted value is replaced by initiation value.
34 | * l.SetValue(13)
35 | * l.Value() --> 1820
36 | */
37 | fmt.Printf("%d\n", l.Value())
38 | l.SetValue(v)
39 | fmt.Printf("%d\n", l.Value())
40 | }
41 |
--------------------------------------------------------------------------------
/29-panic/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import "fmt"
4 |
5 | const (
6 | manualPanic = 1
7 | runtimePanic = 2
8 | )
9 |
10 | func badFunction() {
11 | fmt.Printf("Select Panic type (0=no panic, 1=int, 2=runtime panic)\n")
12 |
13 | var choice int
14 |
15 | fmt.Scanf("%d", &choice)
16 |
17 | switch choice {
18 | case manualPanic:
19 | panic(0)
20 | case runtimePanic:
21 | // The following code will panic
22 | var invalid func(int) int
23 |
24 | invalid(0)
25 | }
26 | }
27 |
28 | func main() {
29 | defer func() {
30 | if x := recover(); x != nil {
31 | switch x.(type) {
32 | default:
33 | panic(x)
34 | case int:
35 | fmt.Printf("Function panicked with a very unhelpful error: %d\n", x)
36 | }
37 | }
38 | }()
39 | badFunction()
40 | fmt.Printf("Program exited normally\n")
41 | }
42 |
--------------------------------------------------------------------------------
/30-utf/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import (
4 | "fmt"
5 | "unicode/utf8"
6 | )
7 |
8 | func main() {
9 | str := "ماهرپ"
10 | runes := make([]byte, 0, 4)
11 |
12 | for i := 0; i < len(str); i++ {
13 | runes = append(runes, str[i])
14 | if utf8.FullRune(runes) {
15 | char, _ := utf8.DecodeRune(runes)
16 |
17 | fmt.Printf("%c", char)
18 |
19 | runes = runes[0:0]
20 | }
21 | }
22 | fmt.Println()
23 | }
24 |
--------------------------------------------------------------------------------
/31-interface-is-nil/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import "fmt"
4 |
5 | type Helloer interface {
6 | SayHello()
7 | }
8 |
9 | type Hello struct{}
10 |
11 | func (Hello) SayHello() {
12 | }
13 |
14 | func main() {
15 | var h *Hello
16 | var he Helloer = h
17 |
18 | if he != nil {
19 | fmt.Println("he is not nil")
20 | }
21 | }
22 |
--------------------------------------------------------------------------------
/32-type-alias/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import "fmt"
4 |
5 | type t1 = int
6 |
7 | type t2 int
8 |
9 | func main() {
10 | var h1 t2 = 10
11 | fmt.Println(h1)
12 | // typecheck: cannot use h1 (variable of type hi) as int value in variable declaration
13 | // var _ int = h1
14 |
15 | var h2 t1 = 10
16 | fmt.Println(h2)
17 | var _ int = h2
18 | }
19 |
--------------------------------------------------------------------------------
/LICENSE:
--------------------------------------------------------------------------------
1 | GNU GENERAL PUBLIC LICENSE
2 | Version 3, 29 June 2007
3 |
4 | Copyright (C) 2007 Free Software Foundation, Inc.
5 | Everyone is permitted to copy and distribute verbatim copies
6 | of this license document, but changing it is not allowed.
7 |
8 | Preamble
9 |
10 | The GNU General Public License is a free, copyleft license for
11 | software and other kinds of works.
12 |
13 | The licenses for most software and other practical works are designed
14 | to take away your freedom to share and change the works. By contrast,
15 | the GNU General Public License is intended to guarantee your freedom to
16 | share and change all versions of a program--to make sure it remains free
17 | software for all its users. We, the Free Software Foundation, use the
18 | GNU General Public License for most of our software; it applies also to
19 | any other work released this way by its authors. You can apply it to
20 | your programs, too.
21 |
22 | When we speak of free software, we are referring to freedom, not
23 | price. Our General Public Licenses are designed to make sure that you
24 | have the freedom to distribute copies of free software (and charge for
25 | them if you wish), that you receive source code or can get it if you
26 | want it, that you can change the software or use pieces of it in new
27 | free programs, and that you know you can do these things.
28 |
29 | To protect your rights, we need to prevent others from denying you
30 | these rights or asking you to surrender the rights. Therefore, you have
31 | certain responsibilities if you distribute copies of the software, or if
32 | you modify it: responsibilities to respect the freedom of others.
33 |
34 | For example, if you distribute copies of such a program, whether
35 | gratis or for a fee, you must pass on to the recipients the same
36 | freedoms that you received. You must make sure that they, too, receive
37 | or can get the source code. And you must show them these terms so they
38 | know their rights.
39 |
40 | Developers that use the GNU GPL protect your rights with two steps:
41 | (1) assert copyright on the software, and (2) offer you this License
42 | giving you legal permission to copy, distribute and/or modify it.
43 |
44 | For the developers' and authors' protection, the GPL clearly explains
45 | that there is no warranty for this free software. For both users' and
46 | authors' sake, the GPL requires that modified versions be marked as
47 | changed, so that their problems will not be attributed erroneously to
48 | authors of previous versions.
49 |
50 | Some devices are designed to deny users access to install or run
51 | modified versions of the software inside them, although the manufacturer
52 | can do so. This is fundamentally incompatible with the aim of
53 | protecting users' freedom to change the software. The systematic
54 | pattern of such abuse occurs in the area of products for individuals to
55 | use, which is precisely where it is most unacceptable. Therefore, we
56 | have designed this version of the GPL to prohibit the practice for those
57 | products. If such problems arise substantially in other domains, we
58 | stand ready to extend this provision to those domains in future versions
59 | of the GPL, as needed to protect the freedom of users.
60 |
61 | Finally, every program is threatened constantly by software patents.
62 | States should not allow patents to restrict development and use of
63 | software on general-purpose computers, but in those that do, we wish to
64 | avoid the special danger that patents applied to a free program could
65 | make it effectively proprietary. To prevent this, the GPL assures that
66 | patents cannot be used to render the program non-free.
67 |
68 | The precise terms and conditions for copying, distribution and
69 | modification follow.
70 |
71 | TERMS AND CONDITIONS
72 |
73 | 0. Definitions.
74 |
75 | "This License" refers to version 3 of the GNU General Public License.
76 |
77 | "Copyright" also means copyright-like laws that apply to other kinds of
78 | works, such as semiconductor masks.
79 |
80 | "The Program" refers to any copyrightable work licensed under this
81 | License. Each licensee is addressed as "you". "Licensees" and
82 | "recipients" may be individuals or organizations.
83 |
84 | To "modify" a work means to copy from or adapt all or part of the work
85 | in a fashion requiring copyright permission, other than the making of an
86 | exact copy. The resulting work is called a "modified version" of the
87 | earlier work or a work "based on" the earlier work.
88 |
89 | A "covered work" means either the unmodified Program or a work based
90 | on the Program.
91 |
92 | To "propagate" a work means to do anything with it that, without
93 | permission, would make you directly or secondarily liable for
94 | infringement under applicable copyright law, except executing it on a
95 | computer or modifying a private copy. Propagation includes copying,
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97 | public, and in some countries other activities as well.
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111 |
112 | 1. Source Code.
113 |
114 | The "source code" for a work means the preferred form of the work
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122 |
123 | The "System Libraries" of an executable work include anything, other
124 | than the work as a whole, that (a) is included in the normal form of
125 | packaging a Major Component, but which is not part of that Major
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134 | The "Corresponding Source" for a work in object code form means all
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139 | programs which are used unmodified in performing those activities but
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146 |
147 | The Corresponding Source need not include anything that users
148 | can regenerate automatically from other parts of the Corresponding
149 | Source.
150 |
151 | The Corresponding Source for a work in source code form is that
152 | same work.
153 |
154 | 2. Basic Permissions.
155 |
156 | All rights granted under this License are granted for the term of
157 | copyright on the Program, and are irrevocable provided the stated
158 | conditions are met. This License explicitly affirms your unlimited
159 | permission to run the unmodified Program. The output from running a
160 | covered work is covered by this License only if the output, given its
161 | content, constitutes a covered work. This License acknowledges your
162 | rights of fair use or other equivalent, as provided by copyright law.
163 |
164 | You may make, run and propagate covered works that you do not
165 | convey, without conditions so long as your license otherwise remains
166 | in force. You may convey covered works to others for the sole purpose
167 | of having them make modifications exclusively for you, or provide you
168 | with facilities for running those works, provided that you comply with
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171 | for you must do so exclusively on your behalf, under your direction
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174 |
175 | Conveying under any other circumstances is permitted solely under
176 | the conditions stated below. Sublicensing is not allowed; section 10
177 | makes it unnecessary.
178 |
179 | 3. Protecting Users' Legal Rights From Anti-Circumvention Law.
180 |
181 | No covered work shall be deemed part of an effective technological
182 | measure under any applicable law fulfilling obligations under article
183 | 11 of the WIPO copyright treaty adopted on 20 December 1996, or
184 | similar laws prohibiting or restricting circumvention of such
185 | measures.
186 |
187 | When you convey a covered work, you waive any legal power to forbid
188 | circumvention of technological measures to the extent such circumvention
189 | is effected by exercising rights under this License with respect to
190 | the covered work, and you disclaim any intention to limit operation or
191 | modification of the work as a means of enforcing, against the work's
192 | users, your or third parties' legal rights to forbid circumvention of
193 | technological measures.
194 |
195 | 4. Conveying Verbatim Copies.
196 |
197 | You may convey verbatim copies of the Program's source code as you
198 | receive it, in any medium, provided that you conspicuously and
199 | appropriately publish on each copy an appropriate copyright notice;
200 | keep intact all notices stating that this License and any
201 | non-permissive terms added in accord with section 7 apply to the code;
202 | keep intact all notices of the absence of any warranty; and give all
203 | recipients a copy of this License along with the Program.
204 |
205 | You may charge any price or no price for each copy that you convey,
206 | and you may offer support or warranty protection for a fee.
207 |
208 | 5. Conveying Modified Source Versions.
209 |
210 | You may convey a work based on the Program, or the modifications to
211 | produce it from the Program, in the form of source code under the
212 | terms of section 4, provided that you also meet all of these conditions:
213 |
214 | a) The work must carry prominent notices stating that you modified
215 | it, and giving a relevant date.
216 |
217 | b) The work must carry prominent notices stating that it is
218 | released under this License and any conditions added under section
219 | 7. This requirement modifies the requirement in section 4 to
220 | "keep intact all notices".
221 |
222 | c) You must license the entire work, as a whole, under this
223 | License to anyone who comes into possession of a copy. This
224 | License will therefore apply, along with any applicable section 7
225 | additional terms, to the whole of the work, and all its parts,
226 | regardless of how they are packaged. This License gives no
227 | permission to license the work in any other way, but it does not
228 | invalidate such permission if you have separately received it.
229 |
230 | d) If the work has interactive user interfaces, each must display
231 | Appropriate Legal Notices; however, if the Program has interactive
232 | interfaces that do not display Appropriate Legal Notices, your
233 | work need not make them do so.
234 |
235 | A compilation of a covered work with other separate and independent
236 | works, which are not by their nature extensions of the covered work,
237 | and which are not combined with it such as to form a larger program,
238 | in or on a volume of a storage or distribution medium, is called an
239 | "aggregate" if the compilation and its resulting copyright are not
240 | used to limit the access or legal rights of the compilation's users
241 | beyond what the individual works permit. Inclusion of a covered work
242 | in an aggregate does not cause this License to apply to the other
243 | parts of the aggregate.
244 |
245 | 6. Conveying Non-Source Forms.
246 |
247 | You may convey a covered work in object code form under the terms
248 | of sections 4 and 5, provided that you also convey the
249 | machine-readable Corresponding Source under the terms of this License,
250 | in one of these ways:
251 |
252 | a) Convey the object code in, or embodied in, a physical product
253 | (including a physical distribution medium), accompanied by the
254 | Corresponding Source fixed on a durable physical medium
255 | customarily used for software interchange.
256 |
257 | b) Convey the object code in, or embodied in, a physical product
258 | (including a physical distribution medium), accompanied by a
259 | written offer, valid for at least three years and valid for as
260 | long as you offer spare parts or customer support for that product
261 | model, to give anyone who possesses the object code either (1) a
262 | copy of the Corresponding Source for all the software in the
263 | product that is covered by this License, on a durable physical
264 | medium customarily used for software interchange, for a price no
265 | more than your reasonable cost of physically performing this
266 | conveying of source, or (2) access to copy the
267 | Corresponding Source from a network server at no charge.
268 |
269 | c) Convey individual copies of the object code with a copy of the
270 | written offer to provide the Corresponding Source. This
271 | alternative is allowed only occasionally and noncommercially, and
272 | only if you received the object code with such an offer, in accord
273 | with subsection 6b.
274 |
275 | d) Convey the object code by offering access from a designated
276 | place (gratis or for a charge), and offer equivalent access to the
277 | Corresponding Source in the same way through the same place at no
278 | further charge. You need not require recipients to copy the
279 | Corresponding Source along with the object code. If the place to
280 | copy the object code is a network server, the Corresponding Source
281 | may be on a different server (operated by you or a third party)
282 | that supports equivalent copying facilities, provided you maintain
283 | clear directions next to the object code saying where to find the
284 | Corresponding Source. Regardless of what server hosts the
285 | Corresponding Source, you remain obligated to ensure that it is
286 | available for as long as needed to satisfy these requirements.
287 |
288 | e) Convey the object code using peer-to-peer transmission, provided
289 | you inform other peers where the object code and Corresponding
290 | Source of the work are being offered to the general public at no
291 | charge under subsection 6d.
292 |
293 | A separable portion of the object code, whose source code is excluded
294 | from the Corresponding Source as a System Library, need not be
295 | included in conveying the object code work.
296 |
297 | A "User Product" is either (1) a "consumer product", which means any
298 | tangible personal property which is normally used for personal, family,
299 | or household purposes, or (2) anything designed or sold for incorporation
300 | into a dwelling. In determining whether a product is a consumer product,
301 | doubtful cases shall be resolved in favor of coverage. For a particular
302 | product received by a particular user, "normally used" refers to a
303 | typical or common use of that class of product, regardless of the status
304 | of the particular user or of the way in which the particular user
305 | actually uses, or expects or is expected to use, the product. A product
306 | is a consumer product regardless of whether the product has substantial
307 | commercial, industrial or non-consumer uses, unless such uses represent
308 | the only significant mode of use of the product.
309 |
310 | "Installation Information" for a User Product means any methods,
311 | procedures, authorization keys, or other information required to install
312 | and execute modified versions of a covered work in that User Product from
313 | a modified version of its Corresponding Source. The information must
314 | suffice to ensure that the continued functioning of the modified object
315 | code is in no case prevented or interfered with solely because
316 | modification has been made.
317 |
318 | If you convey an object code work under this section in, or with, or
319 | specifically for use in, a User Product, and the conveying occurs as
320 | part of a transaction in which the right of possession and use of the
321 | User Product is transferred to the recipient in perpetuity or for a
322 | fixed term (regardless of how the transaction is characterized), the
323 | Corresponding Source conveyed under this section must be accompanied
324 | by the Installation Information. But this requirement does not apply
325 | if neither you nor any third party retains the ability to install
326 | modified object code on the User Product (for example, the work has
327 | been installed in ROM).
328 |
329 | The requirement to provide Installation Information does not include a
330 | requirement to continue to provide support service, warranty, or updates
331 | for a work that has been modified or installed by the recipient, or for
332 | the User Product in which it has been modified or installed. Access to a
333 | network may be denied when the modification itself materially and
334 | adversely affects the operation of the network or violates the rules and
335 | protocols for communication across the network.
336 |
337 | Corresponding Source conveyed, and Installation Information provided,
338 | in accord with this section must be in a format that is publicly
339 | documented (and with an implementation available to the public in
340 | source code form), and must require no special password or key for
341 | unpacking, reading or copying.
342 |
343 | 7. Additional Terms.
344 |
345 | "Additional permissions" are terms that supplement the terms of this
346 | License by making exceptions from one or more of its conditions.
347 | Additional permissions that are applicable to the entire Program shall
348 | be treated as though they were included in this License, to the extent
349 | that they are valid under applicable law. If additional permissions
350 | apply only to part of the Program, that part may be used separately
351 | under those permissions, but the entire Program remains governed by
352 | this License without regard to the additional permissions.
353 |
354 | When you convey a copy of a covered work, you may at your option
355 | remove any additional permissions from that copy, or from any part of
356 | it. (Additional permissions may be written to require their own
357 | removal in certain cases when you modify the work.) You may place
358 | additional permissions on material, added by you to a covered work,
359 | for which you have or can give appropriate copyright permission.
360 |
361 | Notwithstanding any other provision of this License, for material you
362 | add to a covered work, you may (if authorized by the copyright holders of
363 | that material) supplement the terms of this License with terms:
364 |
365 | a) Disclaiming warranty or limiting liability differently from the
366 | terms of sections 15 and 16 of this License; or
367 |
368 | b) Requiring preservation of specified reasonable legal notices or
369 | author attributions in that material or in the Appropriate Legal
370 | Notices displayed by works containing it; or
371 |
372 | c) Prohibiting misrepresentation of the origin of that material, or
373 | requiring that modified versions of such material be marked in
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375 |
376 | d) Limiting the use for publicity purposes of names of licensors or
377 | authors of the material; or
378 |
379 | e) Declining to grant rights under trademark law for use of some
380 | trade names, trademarks, or service marks; or
381 |
382 | f) Requiring indemnification of licensors and authors of that
383 | material by anyone who conveys the material (or modified versions of
384 | it) with contractual assumptions of liability to the recipient, for
385 | any liability that these contractual assumptions directly impose on
386 | those licensors and authors.
387 |
388 | All other non-permissive additional terms are considered "further
389 | restrictions" within the meaning of section 10. If the Program as you
390 | received it, or any part of it, contains a notice stating that it is
391 | governed by this License along with a term that is a further
392 | restriction, you may remove that term. If a license document contains
393 | a further restriction but permits relicensing or conveying under this
394 | License, you may add to a covered work material governed by the terms
395 | of that license document, provided that the further restriction does
396 | not survive such relicensing or conveying.
397 |
398 | If you add terms to a covered work in accord with this section, you
399 | must place, in the relevant source files, a statement of the
400 | additional terms that apply to those files, or a notice indicating
401 | where to find the applicable terms.
402 |
403 | Additional terms, permissive or non-permissive, may be stated in the
404 | form of a separately written license, or stated as exceptions;
405 | the above requirements apply either way.
406 |
407 | 8. Termination.
408 |
409 | You may not propagate or modify a covered work except as expressly
410 | provided under this License. Any attempt otherwise to propagate or
411 | modify it is void, and will automatically terminate your rights under
412 | this License (including any patent licenses granted under the third
413 | paragraph of section 11).
414 |
415 | However, if you cease all violation of this License, then your
416 | license from a particular copyright holder is reinstated (a)
417 | provisionally, unless and until the copyright holder explicitly and
418 | finally terminates your license, and (b) permanently, if the copyright
419 | holder fails to notify you of the violation by some reasonable means
420 | prior to 60 days after the cessation.
421 |
422 | Moreover, your license from a particular copyright holder is
423 | reinstated permanently if the copyright holder notifies you of the
424 | violation by some reasonable means, this is the first time you have
425 | received notice of violation of this License (for any work) from that
426 | copyright holder, and you cure the violation prior to 30 days after
427 | your receipt of the notice.
428 |
429 | Termination of your rights under this section does not terminate the
430 | licenses of parties who have received copies or rights from you under
431 | this License. If your rights have been terminated and not permanently
432 | reinstated, you do not qualify to receive new licenses for the same
433 | material under section 10.
434 |
435 | 9. Acceptance Not Required for Having Copies.
436 |
437 | You are not required to accept this License in order to receive or
438 | run a copy of the Program. Ancillary propagation of a covered work
439 | occurring solely as a consequence of using peer-to-peer transmission
440 | to receive a copy likewise does not require acceptance. However,
441 | nothing other than this License grants you permission to propagate or
442 | modify any covered work. These actions infringe copyright if you do
443 | not accept this License. Therefore, by modifying or propagating a
444 | covered work, you indicate your acceptance of this License to do so.
445 |
446 | 10. Automatic Licensing of Downstream Recipients.
447 |
448 | Each time you convey a covered work, the recipient automatically
449 | receives a license from the original licensors, to run, modify and
450 | propagate that work, subject to this License. You are not responsible
451 | for enforcing compliance by third parties with this License.
452 |
453 | An "entity transaction" is a transaction transferring control of an
454 | organization, or substantially all assets of one, or subdividing an
455 | organization, or merging organizations. If propagation of a covered
456 | work results from an entity transaction, each party to that
457 | transaction who receives a copy of the work also receives whatever
458 | licenses to the work the party's predecessor in interest had or could
459 | give under the previous paragraph, plus a right to possession of the
460 | Corresponding Source of the work from the predecessor in interest, if
461 | the predecessor has it or can get it with reasonable efforts.
462 |
463 | You may not impose any further restrictions on the exercise of the
464 | rights granted or affirmed under this License. For example, you may
465 | not impose a license fee, royalty, or other charge for exercise of
466 | rights granted under this License, and you may not initiate litigation
467 | (including a cross-claim or counterclaim in a lawsuit) alleging that
468 | any patent claim is infringed by making, using, selling, offering for
469 | sale, or importing the Program or any portion of it.
470 |
471 | 11. Patents.
472 |
473 | A "contributor" is a copyright holder who authorizes use under this
474 | License of the Program or a work on which the Program is based. The
475 | work thus licensed is called the contributor's "contributor version".
476 |
477 | A contributor's "essential patent claims" are all patent claims
478 | owned or controlled by the contributor, whether already acquired or
479 | hereafter acquired, that would be infringed by some manner, permitted
480 | by this License, of making, using, or selling its contributor version,
481 | but do not include claims that would be infringed only as a
482 | consequence of further modification of the contributor version. For
483 | purposes of this definition, "control" includes the right to grant
484 | patent sublicenses in a manner consistent with the requirements of
485 | this License.
486 |
487 | Each contributor grants you a non-exclusive, worldwide, royalty-free
488 | patent license under the contributor's essential patent claims, to
489 | make, use, sell, offer for sale, import and otherwise run, modify and
490 | propagate the contents of its contributor version.
491 |
492 | In the following three paragraphs, a "patent license" is any express
493 | agreement or commitment, however denominated, not to enforce a patent
494 | (such as an express permission to practice a patent or covenant not to
495 | sue for patent infringement). To "grant" such a patent license to a
496 | party means to make such an agreement or commitment not to enforce a
497 | patent against the party.
498 |
499 | If you convey a covered work, knowingly relying on a patent license,
500 | and the Corresponding Source of the work is not available for anyone
501 | to copy, free of charge and under the terms of this License, through a
502 | publicly available network server or other readily accessible means,
503 | then you must either (1) cause the Corresponding Source to be so
504 | available, or (2) arrange to deprive yourself of the benefit of the
505 | patent license for this particular work, or (3) arrange, in a manner
506 | consistent with the requirements of this License, to extend the patent
507 | license to downstream recipients. "Knowingly relying" means you have
508 | actual knowledge that, but for the patent license, your conveying the
509 | covered work in a country, or your recipient's use of the covered work
510 | in a country, would infringe one or more identifiable patents in that
511 | country that you have reason to believe are valid.
512 |
513 | If, pursuant to or in connection with a single transaction or
514 | arrangement, you convey, or propagate by procuring conveyance of, a
515 | covered work, and grant a patent license to some of the parties
516 | receiving the covered work authorizing them to use, propagate, modify
517 | or convey a specific copy of the covered work, then the patent license
518 | you grant is automatically extended to all recipients of the covered
519 | work and works based on it.
520 |
521 | A patent license is "discriminatory" if it does not include within
522 | the scope of its coverage, prohibits the exercise of, or is
523 | conditioned on the non-exercise of one or more of the rights that are
524 | specifically granted under this License. You may not convey a covered
525 | work if you are a party to an arrangement with a third party that is
526 | in the business of distributing software, under which you make payment
527 | to the third party based on the extent of your activity of conveying
528 | the work, and under which the third party grants, to any of the
529 | parties who would receive the covered work from you, a discriminatory
530 | patent license (a) in connection with copies of the covered work
531 | conveyed by you (or copies made from those copies), or (b) primarily
532 | for and in connection with specific products or compilations that
533 | contain the covered work, unless you entered into that arrangement,
534 | or that patent license was granted, prior to 28 March 2007.
535 |
536 | Nothing in this License shall be construed as excluding or limiting
537 | any implied license or other defenses to infringement that may
538 | otherwise be available to you under applicable patent law.
539 |
540 | 12. No Surrender of Others' Freedom.
541 |
542 | If conditions are imposed on you (whether by court order, agreement or
543 | otherwise) that contradict the conditions of this License, they do not
544 | excuse you from the conditions of this License. If you cannot convey a
545 | covered work so as to satisfy simultaneously your obligations under this
546 | License and any other pertinent obligations, then as a consequence you may
547 | not convey it at all. For example, if you agree to terms that obligate you
548 | to collect a royalty for further conveying from those to whom you convey
549 | the Program, the only way you could satisfy both those terms and this
550 | License would be to refrain entirely from conveying the Program.
551 |
552 | 13. Use with the GNU Affero General Public License.
553 |
554 | Notwithstanding any other provision of this License, you have
555 | permission to link or combine any covered work with a work licensed
556 | under version 3 of the GNU Affero General Public License into a single
557 | combined work, and to convey the resulting work. The terms of this
558 | License will continue to apply to the part which is the covered work,
559 | but the special requirements of the GNU Affero General Public License,
560 | section 13, concerning interaction through a network will apply to the
561 | combination as such.
562 |
563 | 14. Revised Versions of this License.
564 |
565 | The Free Software Foundation may publish revised and/or new versions of
566 | the GNU General Public License from time to time. Such new versions will
567 | be similar in spirit to the present version, but may differ in detail to
568 | address new problems or concerns.
569 |
570 | Each version is given a distinguishing version number. If the
571 | Program specifies that a certain numbered version of the GNU General
572 | Public License "or any later version" applies to it, you have the
573 | option of following the terms and conditions either of that numbered
574 | version or of any later version published by the Free Software
575 | Foundation. If the Program does not specify a version number of the
576 | GNU General Public License, you may choose any version ever published
577 | by the Free Software Foundation.
578 |
579 | If the Program specifies that a proxy can decide which future
580 | versions of the GNU General Public License can be used, that proxy's
581 | public statement of acceptance of a version permanently authorizes you
582 | to choose that version for the Program.
583 |
584 | Later license versions may give you additional or different
585 | permissions. However, no additional obligations are imposed on any
586 | author or copyright holder as a result of your choosing to follow a
587 | later version.
588 |
589 | 15. Disclaimer of Warranty.
590 |
591 | THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
592 | APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
593 | HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
594 | OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
595 | THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
596 | PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
597 | IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
598 | ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
599 |
600 | 16. Limitation of Liability.
601 |
602 | IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
603 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
604 | THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
605 | GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
606 | USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
607 | DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
608 | PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
609 | EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
610 | SUCH DAMAGES.
611 |
612 | 17. Interpretation of Sections 15 and 16.
613 |
614 | If the disclaimer of warranty and limitation of liability provided
615 | above cannot be given local legal effect according to their terms,
616 | reviewing courts shall apply local law that most closely approximates
617 | an absolute waiver of all civil liability in connection with the
618 | Program, unless a warranty or assumption of liability accompanies a
619 | copy of the Program in return for a fee.
620 |
621 | END OF TERMS AND CONDITIONS
622 |
623 | How to Apply These Terms to Your New Programs
624 |
625 | If you develop a new program, and you want it to be of the greatest
626 | possible use to the public, the best way to achieve this is to make it
627 | free software which everyone can redistribute and change under these terms.
628 |
629 | To do so, attach the following notices to the program. It is safest
630 | to attach them to the start of each source file to most effectively
631 | state the exclusion of warranty; and each file should have at least
632 | the "copyright" line and a pointer to where the full notice is found.
633 |
634 |
635 | Copyright (C)
636 |
637 | This program is free software: you can redistribute it and/or modify
638 | it under the terms of the GNU General Public License as published by
639 | the Free Software Foundation, either version 3 of the License, or
640 | (at your option) any later version.
641 |
642 | This program is distributed in the hope that it will be useful,
643 | but WITHOUT ANY WARRANTY; without even the implied warranty of
644 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
645 | GNU General Public License for more details.
646 |
647 | You should have received a copy of the GNU General Public License
648 | along with this program. If not, see .
649 |
650 | Also add information on how to contact you by electronic and paper mail.
651 |
652 | If the program does terminal interaction, make it output a short
653 | notice like this when it starts in an interactive mode:
654 |
655 | Copyright (C)
656 | This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
657 | This is free software, and you are welcome to redistribute it
658 | under certain conditions; type `show c' for details.
659 |
660 | The hypothetical commands `show w' and `show c' should show the appropriate
661 | parts of the General Public License. Of course, your program's commands
662 | might be different; for a GUI interface, you would use an "about box".
663 |
664 | You should also get your employer (if you work as a programmer) or school,
665 | if any, to sign a "copyright disclaimer" for the program, if necessary.
666 | For more information on this, and how to apply and follow the GNU GPL, see
667 | .
668 |
669 | The GNU General Public License does not permit incorporating your program
670 | into proprietary programs. If your program is a subroutine library, you
671 | may consider it more useful to permit linking proprietary applications with
672 | the library. If this is what you want to do, use the GNU Lesser General
673 | Public License instead of this License. But first, please read
674 | .
675 |
--------------------------------------------------------------------------------
/README.md:
--------------------------------------------------------------------------------
1 | 🐼 Learning Go 🤓
2 | Learn to develop cloud-native programs with Go!
3 |
4 |
5 |
6 | 
7 |
8 | 
9 |
10 |
11 | ## Introduction
12 |
13 | The Golang programming language is very similar to the C programming language,
14 | and its purpose is to reduce complexity in program development.
15 | This language is widely used to implement web servers, applications, and container management tools.
16 | Among the tools that have been developed with this language are:
17 |
18 | - [Kubernetes](https://github.com/kubernetes/kubernetes)
19 | - [Docker](https://github.com/moby/moby)
20 | - [NATS](https://github.com/nats-io/nats-server)
21 | - [Prometheus](https://github.com/prometheus/prometheus)
22 |
23 | In the last few years, this language has opened its place in Iranian companies,
24 | and it is used for the development of backend services.
25 |
26 | > [!NOTE]
27 | > C background is **required** for learning Go.
28 |
29 | ## Outline (As a separate course)
30 |
31 | - History
32 | - Variables and constants
33 | - Calculation
34 | - Conditions
35 | - Loops
36 | - Functions
37 | - Strings
38 | - Arrays and slices
39 | - `map`
40 | - `struct`
41 | - `interface`
42 | - Pointers
43 | - Errors
44 | - Concurrency and channels
45 | - `select`
46 | - `go mod` and using packages
47 | - An overview of advanced features
48 | - Introduction to HTTP protocol
49 | - HTTP server implementation
50 | - Settings management paragraph
51 | - Metric, Log and Tracing
52 | - connection with the database using PostgreSQL and GORM
53 | - Introduction to Docker and containerization
54 |
55 | At the beginning of the course, an introduction to the Go language is made and students implement simple programs with it.
56 | Since the implementation of web servers is one of the important uses of the Go programming language,
57 | we will review the structure of the HTTP protocol and then implement a simple web server in Go.
58 | In this implementation, we try to familiarize ourselves with the structure of large programs created in Go and review details such as
59 | Configuration or Metrics, which are of great value in real systems.
60 | Finally, a MongoDB and PostgreSQL databases are added to this web server,
61 | the purpose of which is to familiarize students with database interfaces in the Go.
62 |
63 | ## Outline (As a part of internet engineering course)
64 |
65 | Using Go for design and implementing servers contains two major steps.
66 | First is about learning Go itself and another step is learning an HTTP framework (here we go with Echo).
67 | Reviewing these source codes are useful for learning Go but there aren't enough.
68 |
69 | ### Go
70 |
71 | 0. Hello World
72 | 1. Constants and Variables
73 | 2. Calculation
74 | 3. Conditions
75 | 4. Loops
76 | 5. Strings
77 | 6. Arrays
78 | 7. Slices
79 | 8. Arrays and Slices
80 | 9. Maps
81 | 10. Structs
82 | 11. Interfaces
83 | 12. Pointers
84 | 13. Structs with Pointers
85 | 14. `strconv`
86 | 15. Function with multiple-return
87 | 16. Errors
88 | 17. Concurrency
89 | 18. Function Type
90 | 19. Channels
91 | 20. Pipelines
92 | 21. Select
93 | 22. JSON
94 | 23. `go.mod`
95 | 24. Packages
96 |
97 | ### Echo
98 |
99 | 0. Say hello to Echo
100 | 1. HTTP Handlers
101 | 2. Request Binding
102 | 3. Path Parameters
103 | 4. Query Strings
104 |
105 | ## Continue your journey 🧳
106 |
107 | You can visit [Go101](https://github.com/1995parham-learning/go101) which contains
108 | some more advance concepts of Golang.
109 |
110 | ## Review Me
111 |
112 | One of the main steps in learning new language and its best practices is reviewing
113 | written projects:
114 |
115 | - :
116 |
117 | - In the first step, you need to review the project structure and find out how modules are related
118 | - Then we continue with running the docker-compose to have the requirements
119 | - And in the final step, we lunch the application and trying it with curl based on its swagger
120 | - This project use zap as a logger and pass it into its modules also each module
121 | has its metrics based on [otel](https://github.com/open-telemetry/).
122 |
123 | - :
124 |
125 | - This example containing the migration and how we store things on the [MongoDB](https://www.mongodb.com/) database.
126 |
127 | - :
128 |
129 | - This example shows tracing in action with [NATS](https://nats.io/) as a message queue.
130 | - Also, We can use profiler to see how replacing [Echo](https://echo.labstack.com/) with [GoFiber](https://gofiber.io/) increase the performance.
131 | - This project has Helm chart and after knowing Kubernetes basis we can lunch it on the cloud with its Helm.
132 |
133 | - :
134 | - In the first step, we review the server structure. The server is stateless and only returns simple responses.
135 | - We it on the cloud with its manifests
136 | - using server and ingress to send requests and see how they distributed between instances
137 | - We also see how we can mount configuration on Kubernetes with [configmap](https://kubernetes.io/docs/concepts/configuration/configmap/).
138 |
--------------------------------------------------------------------------------
/go.mod:
--------------------------------------------------------------------------------
1 | module github.com/1995parham-teaching/go-lecture
2 |
3 | go 1.22
4 |
--------------------------------------------------------------------------------
/httpserver/handler/hello.go:
--------------------------------------------------------------------------------
1 | package handler
2 |
3 | import (
4 | "encoding/json"
5 | "fmt"
6 | "log/slog"
7 | "net/http"
8 |
9 | "github.com/1995parham-teaching/go-lecture/httpserver/request"
10 | )
11 |
12 | type Hello struct {
13 | From string
14 | Logger *slog.Logger
15 | }
16 |
17 | func (h Hello) User(w http.ResponseWriter, r *http.Request) {
18 | value := r.PathValue("username")
19 |
20 | h.Logger.Info("read username from path parameter", "username", value)
21 |
22 | w.WriteHeader(http.StatusNoContent)
23 | }
24 |
25 | func (h Hello) Get(w http.ResponseWriter, r *http.Request) {
26 | if value := r.FormValue("hello"); value != "" {
27 | h.Logger.Info("read hello from query parameter", "hello", value)
28 | }
29 |
30 | enc, err := json.Marshal(fmt.Sprintf("Hello World from %s", h.From))
31 | if err != nil {
32 | w.WriteHeader(http.StatusInternalServerError)
33 | return
34 | }
35 |
36 | w.WriteHeader(http.StatusOK)
37 | _, _ = w.Write(enc)
38 | }
39 |
40 | func (h Hello) Post(w http.ResponseWriter, r *http.Request) {
41 | ct := r.Header.Get("Content-Type")
42 |
43 | if ct != "application/json" {
44 | w.WriteHeader(http.StatusBadRequest)
45 | return
46 | }
47 |
48 | var req request.Name
49 |
50 | if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
51 | w.WriteHeader(http.StatusBadRequest)
52 | _, _ = w.Write([]byte(err.Error()))
53 | }
54 |
55 | if req.Count == nil {
56 | h.Logger.Info("There is no count")
57 | } else {
58 | h.Logger.Info("There is a count", "count", *req.Count)
59 | }
60 |
61 | enc, err := json.Marshal(fmt.Sprintf("Hello to %s from %s", req.Name, h.From))
62 | if err != nil {
63 | w.WriteHeader(http.StatusInternalServerError)
64 | return
65 | }
66 |
67 | w.Header().Add("Content-Type", "application/json")
68 |
69 | w.WriteHeader(http.StatusOK)
70 | _, _ = w.Write(enc)
71 | }
72 |
--------------------------------------------------------------------------------
/httpserver/main.go:
--------------------------------------------------------------------------------
1 | package main
2 |
3 | import (
4 | "log/slog"
5 | "net/http"
6 | "os"
7 |
8 | "github.com/1995parham-teaching/go-lecture/httpserver/handler"
9 | )
10 |
11 | func main() {
12 | logger := slog.New(slog.NewTextHandler(os.Stderr, nil))
13 |
14 | h := handler.Hello{
15 | From: "Golang",
16 | Logger: logger.With("handler", "hello"),
17 | }
18 |
19 | mux := http.NewServeMux()
20 |
21 | mux.HandleFunc("GET /hello", h.Get)
22 | mux.HandleFunc("POST /hello", h.Post)
23 | mux.HandleFunc("GET /hello/{username}", h.User)
24 |
25 | if err := http.ListenAndServe("0.0.0.0:1373", mux); err != nil {
26 | logger.Error("http server failed", "error", err.Error())
27 | }
28 | }
29 |
--------------------------------------------------------------------------------
/httpserver/model/student.go:
--------------------------------------------------------------------------------
1 | package model
2 |
3 | import "fmt"
4 |
5 | type Student struct {
6 | FirstName string
7 | LastName string
8 | ID int64
9 | }
10 |
11 | func (s Student) String() string {
12 | return fmt.Sprintf("FirstName: %s, LastName: %s, ID: %d", s.FirstName, s.LastName, s.ID)
13 | }
14 |
--------------------------------------------------------------------------------
/httpserver/request/hello.go:
--------------------------------------------------------------------------------
1 | package request
2 |
3 | type Name struct {
4 | Name string `json:"name,omitempty"`
5 | Count *int `json:"count,omitempty"`
6 | }
7 |
--------------------------------------------------------------------------------
/justfile:
--------------------------------------------------------------------------------
1 | default:
2 | @just --list
3 |
4 | # build all the examples
5 | build:
6 | #!/usr/bin/env bash
7 | set -euo pipefail
8 | for step in $(find . -maxdepth 1 -type d -name '[!.]*'); do
9 | echo "*** $step ***"
10 | echo "*************"
11 | cd $step &> /dev/null
12 | go build -o main.out || true
13 | go test
14 | cd - &> /dev/null
15 | done
16 |
--------------------------------------------------------------------------------
/mutex/ch_mutex.go:
--------------------------------------------------------------------------------
1 | package mutex
2 |
3 | type channelMutex struct {
4 | ch chan int
5 | }
6 |
7 | // NewChannelMutex creates new channel mutex implementation of mutex.
8 | func NewChannelMutex() Mutex {
9 | return &channelMutex{
10 | ch: make(chan int, 1),
11 | }
12 | }
13 |
14 | func (cm *channelMutex) Release() {
15 | <-cm.ch
16 | }
17 |
18 | func (cm *channelMutex) Acquire() {
19 | cm.ch <- 1
20 | }
21 |
--------------------------------------------------------------------------------
/mutex/ch_mutex_test.go:
--------------------------------------------------------------------------------
1 | package mutex_test
2 |
3 | import (
4 | "testing"
5 |
6 | "github.com/1995parham-teaching/go-lecture/mutex"
7 | )
8 |
9 | func TestOne(t *testing.T) {
10 | t.Parallel()
11 |
12 | m := mutex.NewChannelMutex()
13 | f := 0
14 |
15 | t.Log(t.Name())
16 |
17 | go func() {
18 | m.Acquire()
19 | t.Log("Thread-1")
20 |
21 | f = 1
22 |
23 | m.Release()
24 | }()
25 |
26 | for {
27 | m.Acquire()
28 | t.Log("Thread-2")
29 |
30 | if f == 1 {
31 | m.Release()
32 |
33 | break
34 | } else {
35 | m.Release()
36 | }
37 | }
38 | }
39 |
--------------------------------------------------------------------------------
/mutex/mutex.go:
--------------------------------------------------------------------------------
1 | package mutex
2 |
3 | // Mutex interface provides acquire and release functions
4 | // as a basis for mutex locks.
5 | type Mutex interface {
6 | Acquire()
7 | Release()
8 | }
9 |
--------------------------------------------------------------------------------