├── CONTRIBUTORS
├── LICENSE
├── README.md
├── client.go
├── doc.go
├── handlers.go
├── tcp.go
├── tcp_config.go
├── tcp_handlers_test.go
└── tcp_test.go


/CONTRIBUTORS:
--------------------------------------------------------------------------------
 1 | # This is the official list of people who can contribute
 2 | # (and typically have contributed) code to the gotraining repository.
 3 | #
 4 | # Names should be added to this file only after verifying that
 5 | # the individual or the individual's organization has agreed to
 6 | # the appropriate Contributor License Agreement, found here:
 7 | #
 8 | #     http://code.google.com/legal/individual-cla-v1.0.html
 9 | #     http://code.google.com/legal/corporate-cla-v1.0.html
10 | #
11 | # The agreement for individuals can be filled out on the web.
12 | 
13 | # Names should be added to this file like so:
14 | #     Name <email address>
15 | #
16 | # An entry with two email addresses specifies that the
17 | # first address should be used in the submit logs and
18 | # that the second address should be recognized as the
19 | # same person when interacting with Rietveld.
20 | 
21 | # Please keep the list sorted.
22 | 
23 | William Kennedy <bill@ardanlabs.com>


--------------------------------------------------------------------------------
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/README.md:
--------------------------------------------------------------------------------
  1 | 
  2 | 
  3 | # tcp
  4 | `import "github.com/ardanlabs/tcp"`
  5 | 
  6 | * [Overview](#pkg-overview)
  7 | * [Index](#pkg-index)
  8 | 
  9 | ## <a name="pkg-overview">Overview</a>
 10 | Package tcp provides the boilerpale code for working with TCP based data. The package
 11 | allows you to establish a TCP listener that can accept client connections on a specified IP address
 12 | and port. It also provides a function to send data back to the client.
 13 | 
 14 | There are three interfaces that need to be implemented to use the package. These
 15 | interfaces provide the API for processing data.
 16 | 
 17 | ConnHandler
 18 | 
 19 | 
 20 | 	type ConnHandler interface {
 21 | 	    Bind(conn net.Conn) (io.Reader, io.Writer)
 22 | 	}
 23 | 
 24 | The ConnHandler interface is implemented by the user to bind the client connection
 25 | to a reader and writer for processing.
 26 | 
 27 | ReqHandler
 28 | 
 29 | 
 30 | 	type ReqHandler interface {
 31 | 	    Read(ipAddress string, reader io.Reader) ([]byte, int, error)
 32 | 	    Process(r *Request)
 33 | 	}
 34 | 	
 35 | 	type Request struct {
 36 | 	    TCP       *TCP
 37 | 	    TCPAddr   *net.TCPAddr
 38 | 	    Data      []byte
 39 | 	    Length    int
 40 | 	}
 41 | 
 42 | The ReqHandler interface is implemented by the user to implement the processing
 43 | of request messages from the client. Read is provided an ipaddress and the user-defined
 44 | reader and must return the data read off the wire and the length. Returning io.EOF or a non
 45 | temporary error will show down the listener.
 46 | 
 47 | RespHandler
 48 | 
 49 | 
 50 | 	type RespHandler interface {
 51 | 	    Write(r *Response, writer io.Writer) error
 52 | 	}
 53 | 	
 54 | 	type Response struct {
 55 | 	    TCPAddr   *net.TCPAddr
 56 | 	    Data      []byte
 57 | 	    Length    int
 58 | 	}
 59 | 
 60 | The RespHandler interface is implemented by the user to implement the processing
 61 | of the response messages to the client. Write is provided the user-defined
 62 | writer and the data to write.
 63 | 
 64 | ### Sample Application
 65 | After implementing the interfaces, the following code is all that is needed to
 66 | start processing messages.
 67 | 
 68 | 
 69 | 	func main() {
 70 | 	    log.Println("Starting Test App")
 71 | 	
 72 | 	    cfg := tcp.Config{
 73 | 	        NetType:      "tcp4",
 74 | 	        Addr:         ":9000",
 75 | 	        WorkRoutines: 2,
 76 | 	        WorkStats:    time.Minute,
 77 | 	        ConnHandler:  tcpConnHandler{},
 78 | 	        ReqHandler:   udpReqHandler{},
 79 | 	        RespHandler:  udpRespHandler{},
 80 | 	    }
 81 | 	
 82 | 	    t, err := tcp.New(&cfg)
 83 | 	    if err != nil {
 84 | 	        log.Println(err)
 85 | 	         return
 86 | 	    }
 87 | 	
 88 | 	    if err := t.Start(); err != nil {
 89 | 	        log.Println(err)
 90 | 	         return
 91 | 	    }
 92 | 	
 93 | 	    // Wait for a signal to shutdown.
 94 | 	    sigChan := make(chan os.Signal, 1)
 95 | 	    signal.Notify(sigChan, os.Interrupt)
 96 | 	    <-sigChan
 97 | 	
 98 | 	    t.Stop()
 99 | 	    log.Println("down")
100 | 	}
101 | 
102 | 
103 | 
104 | 
105 | ## <a name="pkg-index">Index</a>
106 | * [Constants](#pkg-constants)
107 | * [Variables](#pkg-variables)
108 | * [type CltError](#CltError)
109 |   * [func (ce CltError) Error() string](#CltError.Error)
110 | * [type Config](#Config)
111 |   * [func (cfg *Config) Event(evt, typ int, ipAddress string, format string, a ...interface{})](#Config.Event)
112 |   * [func (cfg *Config) Validate() error](#Config.Validate)
113 | * [type ConnHandler](#ConnHandler)
114 | * [type OptEvent](#OptEvent)
115 | * [type OptRateLimit](#OptRateLimit)
116 | * [type ReqHandler](#ReqHandler)
117 | * [type Request](#Request)
118 | * [type RespHandler](#RespHandler)
119 | * [type Response](#Response)
120 | * [type Stat](#Stat)
121 | * [type TCP](#TCP)
122 |   * [func New(name string, cfg Config) (*TCP, error)](#New)
123 |   * [func (t *TCP) Addr() net.Addr](#TCP.Addr)
124 |   * [func (t *TCP) ClientStats() []Stat](#TCP.ClientStats)
125 |   * [func (t *TCP) Clients() int](#TCP.Clients)
126 |   * [func (t *TCP) Connections() int](#TCP.Connections)
127 |   * [func (t *TCP) Drop(tcpAddr *net.TCPAddr) error](#TCP.Drop)
128 |   * [func (t *TCP) DropConnections(drop bool)](#TCP.DropConnections)
129 |   * [func (t *TCP) Groom(d time.Duration)](#TCP.Groom)
130 |   * [func (t *TCP) Send(ctx context.Context, r *Response) error](#TCP.Send)
131 |   * [func (t *TCP) SendAll(ctx context.Context, r *Response) error](#TCP.SendAll)
132 |   * [func (t *TCP) Start() error](#TCP.Start)
133 |   * [func (t *TCP) Stop() error](#TCP.Stop)
134 | 
135 | 
136 | #### <a name="pkg-files">Package files</a>
137 | [client.go](/src/github.com/ardanlabs/tcp/client.go) [doc.go](/src/github.com/ardanlabs/tcp/doc.go) [handlers.go](/src/github.com/ardanlabs/tcp/handlers.go) [tcp.go](/src/github.com/ardanlabs/tcp/tcp.go) [tcp_config.go](/src/github.com/ardanlabs/tcp/tcp_config.go) 
138 | 
139 | 
140 | ## <a name="pkg-constants">Constants</a>
141 | ``` go
142 | const (
143 |     EvtAccept = iota + 1
144 |     EvtJoin
145 |     EvtRead
146 |     EvtRemove
147 |     EvtDrop
148 |     EvtGroom
149 | )
150 | ```
151 | Set of event types.
152 | 
153 | ``` go
154 | const (
155 |     TypError = iota + 1
156 |     TypInfo
157 |     TypTrigger
158 | )
159 | ```
160 | Set of event sub types.
161 | 
162 | 
163 | ## <a name="pkg-variables">Variables</a>
164 | ``` go
165 | var (
166 |     ErrInvalidConfiguration = errors.New("invalid configuration")
167 |     ErrInvalidNetType       = errors.New("invalid net type configuration")
168 |     ErrInvalidConnHandler   = errors.New("invalid connection handler configuration")
169 |     ErrInvalidReqHandler    = errors.New("invalid request handler configuration")
170 |     ErrInvalidRespHandler   = errors.New("invalid response handler configuration")
171 | )
172 | ```
173 | Set of error variables for start up.
174 | 
175 | 
176 | 
177 | 
178 | ## <a name="CltError">type</a> [CltError](/src/target/tcp.go?s=795:816#L32)
179 | ``` go
180 | type CltError []error
181 | ```
182 | CltError provides support for multi client operations that might error.
183 | 
184 | 
185 | 
186 | 
187 | 
188 | 
189 | 
190 | 
191 | 
192 | 
193 | ### <a name="CltError.Error">func</a> (CltError) [Error](/src/target/tcp.go?s=871:904#L35)
194 | ``` go
195 | func (ce CltError) Error() string
196 | ```
197 | Error implments the error interface for CltError.
198 | 
199 | 
200 | 
201 | 
202 | ## <a name="Config">type</a> [Config](/src/target/tcp_config.go?s=470:1102#L7)
203 | ``` go
204 | type Config struct {
205 |     NetType string // "tcp", tcp4" or "tcp6"
206 |     Addr    string // "host:port" or "[ipv6-host%zone]:port"
207 | 
208 |     ConnHandler ConnHandler // Support for binding new connections to a reader and writer.
209 |     ReqHandler  ReqHandler  // Support for handling the specific request workflow.
210 |     RespHandler RespHandler // Support for handling the specific response workflow.
211 | 
212 |     OptRateLimit
213 |     OptEvent
214 | }
215 | ```
216 | Config provides a data structure of required configuration parameters.
217 | 
218 | 
219 | 
220 | 
221 | 
222 | 
223 | 
224 | 
225 | 
226 | 
227 | ### <a name="Config.Event">func</a> (\*Config) [Event](/src/target/tcp_config.go?s=1626:1715#L49)
228 | ``` go
229 | func (cfg *Config) Event(evt, typ int, ipAddress string, format string, a ...interface{})
230 | ```
231 | Event fires events back to the user for important events.
232 | 
233 | 
234 | 
235 | 
236 | ### <a name="Config.Validate">func</a> (\*Config) [Validate](/src/target/tcp_config.go?s=1160:1195#L24)
237 | ``` go
238 | func (cfg *Config) Validate() error
239 | ```
240 | Validate checks the configuration to required items.
241 | 
242 | 
243 | 
244 | 
245 | ## <a name="ConnHandler">type</a> [ConnHandler](/src/target/handlers.go?s=485:609#L20)
246 | ``` go
247 | type ConnHandler interface {
248 | 
249 |     // Bind is called to set the reader and writer.
250 |     Bind(conn net.Conn) (io.Reader, io.Writer)
251 | }
252 | ```
253 | ConnHandler is implemented by the user to bind the connection
254 | to a reader and writer for processing.
255 | 
256 | 
257 | 
258 | 
259 | 
260 | 
261 | 
262 | 
263 | 
264 | 
265 | ## <a name="OptEvent">type</a> [OptEvent](/src/target/tcp_config.go?s=293:394#L2)
266 | ``` go
267 | type OptEvent struct {
268 |     Event func(evt, typ int, ipAddress string, format string, a ...interface{})
269 | }
270 | ```
271 | OptEvent defines an handler used to provide events.
272 | 
273 | 
274 | 
275 | 
276 | 
277 | 
278 | 
279 | 
280 | 
281 | 
282 | ## <a name="OptRateLimit">type</a> [OptRateLimit](/src/target/tcp_config.go?s=128:236#L1)
283 | ``` go
284 | type OptRateLimit struct {
285 |     RateLimit func() time.Duration // Connection rate limit per single connection.
286 | }
287 | ```
288 | OptRateLimit declares fields for the user to provide configuration
289 | for connection rate limit.
290 | 
291 | 
292 | 
293 | 
294 | 
295 | 
296 | 
297 | 
298 | 
299 | 
300 | ## <a name="ReqHandler">type</a> [ReqHandler](/src/target/handlers.go?s=720:1356#L28)
301 | ``` go
302 | type ReqHandler interface {
303 | 
304 |     // Read is provided an ipaddress and the user-defined reader and must return
305 |     // the data read off the wire and the length. Returning io.EOF or a non
306 |     // temporary error will show down the listener.
307 |     Read(ipAddress string, reader io.Reader) ([]byte, int, error)
308 | 
309 |     // Process is used to handle the processing of the request.
310 |     Process(r *Request)
311 | }
312 | ```
313 | ReqHandler is implemented by the user to implement the processing
314 | of request messages from the client.
315 | 
316 | 
317 | 
318 | 
319 | 
320 | 
321 | 
322 | 
323 | 
324 | 
325 | ## <a name="Request">type</a> [Request](/src/target/handlers.go?s=107:253#L1)
326 | ``` go
327 | type Request struct {
328 |     TCP     *TCP
329 |     TCPAddr *net.TCPAddr
330 |     IsIPv6  bool
331 |     ReadAt  time.Time
332 |     Context context.Context
333 |     Data    []byte
334 |     Length  int
335 | }
336 | ```
337 | Request is the message received by the client.
338 | 
339 | 
340 | 
341 | 
342 | 
343 | 
344 | 
345 | 
346 | 
347 | 
348 | ## <a name="RespHandler">type</a> [RespHandler](/src/target/handlers.go?s=1471:1619#L46)
349 | ``` go
350 | type RespHandler interface {
351 | 
352 |     // Write is provided the response to write and the user-defined writer.
353 |     Write(r *Response, writer io.Writer) error
354 | }
355 | ```
356 | RespHandler is implemented by the user to implement the processing
357 | of the response messages to the client.
358 | 
359 | 
360 | 
361 | 
362 | 
363 | 
364 | 
365 | 
366 | 
367 | 
368 | ## <a name="Response">type</a> [Response](/src/target/handlers.go?s=301:376#L12)
369 | ``` go
370 | type Response struct {
371 |     TCPAddr *net.TCPAddr
372 |     Data    []byte
373 |     Length  int
374 | }
375 | ```
376 | Response is message to send to the client.
377 | 
378 | 
379 | 
380 | 
381 | 
382 | 
383 | 
384 | 
385 | 
386 | 
387 | ## <a name="Stat">type</a> [Stat](/src/target/tcp.go?s=8518:8623#L376)
388 | ``` go
389 | type Stat struct {
390 |     IP       string
391 |     Reads    int
392 |     Writes   int
393 |     TimeConn time.Time
394 |     LastAct  time.Time
395 | }
396 | ```
397 | Stat represents a client statistic.
398 | 
399 | 
400 | 
401 | 
402 | 
403 | 
404 | 
405 | 
406 | 
407 | 
408 | ## <a name="TCP">type</a> [TCP](/src/target/tcp.go?s=1084:1384#L45)
409 | ``` go
410 | type TCP struct {
411 |     Config
412 |     Name string
413 |     // contains filtered or unexported fields
414 | }
415 | ```
416 | TCP contains a set of networked client connections.
417 | 
418 | 
419 | 
420 | 
421 | 
422 | 
423 | 
424 | ### <a name="New">func</a> [New](/src/target/tcp.go?s=1435:1482#L68)
425 | ``` go
426 | func New(name string, cfg Config) (*TCP, error)
427 | ```
428 | New creates a new manager to service clients.
429 | 
430 | 
431 | 
432 | 
433 | 
434 | ### <a name="TCP.Addr">func</a> (\*TCP) [Addr](/src/target/tcp.go?s=8106:8135#L352)
435 | ``` go
436 | func (t *TCP) Addr() net.Addr
437 | ```
438 | Addr returns the listener's network address. This may be different than the values
439 | provided in the configuration, for example if configuration port value is 0.
440 | 
441 | 
442 | 
443 | 
444 | ### <a name="TCP.ClientStats">func</a> (\*TCP) [ClientStats](/src/target/tcp.go?s=8679:8713#L385)
445 | ``` go
446 | func (t *TCP) ClientStats() []Stat
447 | ```
448 | ClientStats return details for all active clients.
449 | 
450 | 
451 | 
452 | 
453 | ### <a name="TCP.Clients">func</a> (\*TCP) [Clients](/src/target/tcp.go?s=9132:9159#L410)
454 | ``` go
455 | func (t *TCP) Clients() int
456 | ```
457 | Clients returns the number of active clients connected.
458 | 
459 | 
460 | 
461 | 
462 | ### <a name="TCP.Connections">func</a> (\*TCP) [Connections](/src/target/tcp.go?s=8350:8381#L363)
463 | ``` go
464 | func (t *TCP) Connections() int
465 | ```
466 | Connections returns the number of client connections.
467 | 
468 | 
469 | 
470 | 
471 | ### <a name="TCP.Drop">func</a> (\*TCP) [Drop](/src/target/tcp.go?s=6106:6152#L269)
472 | ``` go
473 | func (t *TCP) Drop(tcpAddr *net.TCPAddr) error
474 | ```
475 | Drop will close the socket connection.
476 | 
477 | 
478 | 
479 | 
480 | ### <a name="TCP.DropConnections">func</a> (\*TCP) [DropConnections](/src/target/tcp.go?s=7797:7837#L341)
481 | ``` go
482 | func (t *TCP) DropConnections(drop bool)
483 | ```
484 | DropConnections sets a flag to tell the accept routine to immediately
485 | drop connections that come in.
486 | 
487 | 
488 | 
489 | 
490 | ### <a name="TCP.Groom">func</a> (\*TCP) [Groom](/src/target/tcp.go?s=9343:9379#L422)
491 | ``` go
492 | func (t *TCP) Groom(d time.Duration)
493 | ```
494 | Groom drops connections that are not active for the specified duration.
495 | 
496 | 
497 | 
498 | 
499 | ### <a name="TCP.Send">func</a> (\*TCP) [Send](/src/target/tcp.go?s=6659:6717#L291)
500 | ``` go
501 | func (t *TCP) Send(ctx context.Context, r *Response) error
502 | ```
503 | Send will deliver the response back to the client.
504 | 
505 | 
506 | 
507 | 
508 | ### <a name="TCP.SendAll">func</a> (\*TCP) [SendAll](/src/target/tcp.go?s=7237:7298#L314)
509 | ``` go
510 | func (t *TCP) SendAll(ctx context.Context, r *Response) error
511 | ```
512 | SendAll will deliver the response back to all connected clients.
513 | 
514 | 
515 | 
516 | 
517 | ### <a name="TCP.Start">func</a> (\*TCP) [Start](/src/target/tcp.go?s=2178:2205#L102)
518 | ``` go
519 | func (t *TCP) Start() error
520 | ```
521 | Start creates the accept routine and begins to accept connections.
522 | 
523 | 
524 | 
525 | 
526 | ### <a name="TCP.Stop">func</a> (\*TCP) [Stop](/src/target/tcp.go?s=5082:5108#L221)
527 | ``` go
528 | func (t *TCP) Stop() error
529 | ```
530 | Stop shuts down the manager and closes all connections.
531 | 
532 | 
533 | 
534 | 
535 | 
536 | 
537 | 
538 | 
539 | - - -
540 | Generated by [godoc2md](http://godoc.org/github.com/davecheney/godoc2md)
541 | 


--------------------------------------------------------------------------------
/client.go:
--------------------------------------------------------------------------------
  1 | package tcp
  2 | 
  3 | import (
  4 | 	"bytes"
  5 | 	"context"
  6 | 	"io"
  7 | 	"net"
  8 | 	"strconv"
  9 | 	"sync"
 10 | 	"time"
 11 | )
 12 | 
 13 | // client represents a single networked connection.
 14 | type client struct {
 15 | 	t         *TCP
 16 | 	conn      net.Conn
 17 | 	ipAddress string
 18 | 	isIPv6    bool
 19 | 	reader    io.Reader
 20 | 	writer    io.Writer
 21 | 	wg        sync.WaitGroup
 22 | 
 23 | 	timeConn time.Time
 24 | 	lastAct  time.Time
 25 | 	nReads   int
 26 | 	nWrites  int
 27 | }
 28 | 
 29 | // newClient creates a new client for an incoming connection.
 30 | func newClient(t *TCP, conn net.Conn) *client {
 31 | 	now := time.Now().UTC()
 32 | 	ipAddress := conn.RemoteAddr().String()
 33 | 
 34 | 	// Ask the user to bind the reader and writer they want to
 35 | 	// use for this connection.
 36 | 	r, w := t.ConnHandler.Bind(conn)
 37 | 
 38 | 	c := client{
 39 | 		t:         t,
 40 | 		conn:      conn,
 41 | 		ipAddress: ipAddress,
 42 | 		reader:    r,
 43 | 		writer:    w,
 44 | 		timeConn:  now,
 45 | 		lastAct:   now,
 46 | 	}
 47 | 
 48 | 	// Check to see if this connection is ipv6.
 49 | 	if raddr := conn.RemoteAddr().(*net.TCPAddr); raddr.IP.To4() == nil {
 50 | 		c.isIPv6 = true
 51 | 	}
 52 | 
 53 | 	// Launch a goroutine for this connection.
 54 | 	c.wg.Add(1)
 55 | 	go c.read()
 56 | 
 57 | 	return &c
 58 | }
 59 | 
 60 | // drop closes the client connection and read operation.
 61 | func (c *client) drop() {
 62 | 
 63 | 	// Close the connection.
 64 | 	c.conn.Close()
 65 | 	c.wg.Wait()
 66 | 
 67 | 	c.t.Event(EvtDrop, TypInfo, c.ipAddress, "connect dropped")
 68 | }
 69 | 
 70 | // read waits for a message and sends it to the user for procesing.
 71 | func (c *client) read() {
 72 | 	c.t.Event(EvtRead, TypTrigger, c.ipAddress, "ready")
 73 | 
 74 | close:
 75 | 	for {
 76 | 
 77 | 		// Wait for a message to arrive.
 78 | 		data, length, err := c.t.ReqHandler.Read(c.ipAddress, c.reader)
 79 | 		c.lastAct = time.Now().UTC()
 80 | 		c.nReads++
 81 | 
 82 | 		if err != nil {
 83 | 
 84 | 			// temporary is declared to test for the existence of
 85 | 			// the method coming from the net package.
 86 | 			type temporary interface {
 87 | 				Temporary() bool
 88 | 			}
 89 | 
 90 | 			if e, ok := err.(temporary); ok {
 91 | 				if !e.Temporary() {
 92 | 					break close
 93 | 				}
 94 | 			}
 95 | 
 96 | 			if err == io.EOF {
 97 | 				break close
 98 | 			}
 99 | 
100 | 			continue
101 | 		}
102 | 
103 | 		// Convert the IP:socket for populating TCPAddr value.
104 | 		parts := bytes.Split([]byte(c.ipAddress), []byte(":"))
105 | 		ipAddress := string(parts[0])
106 | 		port, _ := strconv.Atoi(string(parts[1]))
107 | 
108 | 		// Create the request.
109 | 		r := Request{
110 | 			TCP: c.t,
111 | 			TCPAddr: &net.TCPAddr{
112 | 				IP:   net.ParseIP(ipAddress),
113 | 				Port: port,
114 | 				Zone: c.t.tcpAddr.Zone,
115 | 			},
116 | 			IsIPv6:  c.isIPv6,
117 | 			ReadAt:  c.lastAct,
118 | 			Context: context.Background(),
119 | 			Data:    data,
120 | 			Length:  length,
121 | 		}
122 | 
123 | 		// Process the request on this goroutine that is
124 | 		// handling the socket connection.
125 | 		c.t.ReqHandler.Process(&r)
126 | 	}
127 | 
128 | 	// Remove from the list of connections and report we are done.
129 | 	c.t.remove(c.conn)
130 | 	c.wg.Done()
131 | 	c.t.Event(EvtDrop, TypTrigger, c.ipAddress, "dropped connection")
132 | }
133 | 


--------------------------------------------------------------------------------
/doc.go:
--------------------------------------------------------------------------------
 1 | // Package tcp provides the boilerpale code for working with TCP based data. The package
 2 | // allows you to establish a TCP listener that can accept client connections on a specified IP address
 3 | // and port. It also provides a function to send data back to the client.
 4 | //
 5 | // There are three interfaces that need to be implemented to use the package. These
 6 | // interfaces provide the API for processing data.
 7 | //
 8 | // ConnHandler
 9 | //
10 | //     type ConnHandler interface {
11 | //         Bind(conn net.Conn) (io.Reader, io.Writer)
12 | //     }
13 | //
14 | // The ConnHandler interface is implemented by the user to bind the client connection
15 | // to a reader and writer for processing.
16 | //
17 | // ReqHandler
18 | //
19 | //     type ReqHandler interface {
20 | //         Read(ipAddress string, reader io.Reader) ([]byte, int, error)
21 | //         Process(r *Request)
22 | //     }
23 | //
24 | //     type Request struct {
25 | //         TCP       *TCP
26 | //         TCPAddr   *net.TCPAddr
27 | //         Data      []byte
28 | //         Length    int
29 | //     }
30 | //
31 | // The ReqHandler interface is implemented by the user to implement the processing
32 | // of request messages from the client. Read is provided an ipaddress and the user-defined
33 | // reader and must return the data read off the wire and the length. Returning io.EOF or a non
34 | // temporary error will show down the listener.
35 | //
36 | // RespHandler
37 | //
38 | //     type RespHandler interface {
39 | //         Write(r *Response, writer io.Writer) error
40 | //     }
41 | //
42 | //     type Response struct {
43 | //         TCPAddr   *net.TCPAddr
44 | //         Data      []byte
45 | //         Length    int
46 | //     }
47 | //
48 | // The RespHandler interface is implemented by the user to implement the processing
49 | // of the response messages to the client. Write is provided the user-defined
50 | // writer and the data to write.
51 | //
52 | // Sample Application
53 | //
54 | // After implementing the interfaces, the following code is all that is needed to
55 | // start processing messages.
56 | //
57 | //     func main() {
58 | //         log.Println("Starting Test App")
59 | //
60 | //         cfg := tcp.Config{
61 | //             NetType:      "tcp4",
62 | //             Addr:         ":9000",
63 | //             WorkRoutines: 2,
64 | //             WorkStats:    time.Minute,
65 | //             ConnHandler:  tcpConnHandler{},
66 | //             ReqHandler:   udpReqHandler{},
67 | //             RespHandler:  udpRespHandler{},
68 | //         }
69 | //
70 | //         t, err := tcp.New(&cfg)
71 | //         if err != nil {
72 | //             log.Println(err)
73 | //              return
74 | //         }
75 | //
76 | //         if err := t.Start(); err != nil {
77 | //             log.Println(err)
78 | //              return
79 | //         }
80 | //
81 | //         // Wait for a signal to shutdown.
82 | //         sigChan := make(chan os.Signal, 1)
83 | //         signal.Notify(sigChan, os.Interrupt)
84 | //         <-sigChan
85 | //
86 | //         t.Stop()
87 | //         log.Println("down")
88 | //     }
89 | package tcp
90 | 


--------------------------------------------------------------------------------
/handlers.go:
--------------------------------------------------------------------------------
 1 | package tcp
 2 | 
 3 | import (
 4 | 	"context"
 5 | 	"io"
 6 | 	"net"
 7 | 	"time"
 8 | )
 9 | 
10 | // Request is the message received by the client.
11 | type Request struct {
12 | 	TCP     *TCP
13 | 	TCPAddr *net.TCPAddr
14 | 	IsIPv6  bool
15 | 	ReadAt  time.Time
16 | 	Context context.Context
17 | 	Data    []byte
18 | 	Length  int
19 | }
20 | 
21 | // Response is message to send to the client.
22 | type Response struct {
23 | 	TCPAddr *net.TCPAddr
24 | 	Data    []byte
25 | 	Length  int
26 | }
27 | 
28 | // ConnHandler is implemented by the user to bind the connection
29 | // to a reader and writer for processing.
30 | type ConnHandler interface {
31 | 
32 | 	// Bind is called to set the reader and writer.
33 | 	Bind(conn net.Conn) (io.Reader, io.Writer)
34 | }
35 | 
36 | // ReqHandler is implemented by the user to implement the processing
37 | // of request messages from the client.
38 | type ReqHandler interface {
39 | 
40 | 	// Read is provided a request and a user-defined reader for each client
41 | 	// connection on its own routine. Read must read a full request and return
42 | 	// the populated request value.
43 | 	// Returning io.EOF or a non temporary error will show down the connection.
44 | 
45 | 	// Read is provided an ipaddress and the user-defined reader and must return
46 | 	// the data read off the wire and the length. Returning io.EOF or a non
47 | 	// temporary error will show down the listener.
48 | 	Read(ipAddress string, reader io.Reader) ([]byte, int, error)
49 | 
50 | 	// Process is used to handle the processing of the request.
51 | 	Process(r *Request)
52 | }
53 | 
54 | // RespHandler is implemented by the user to implement the processing
55 | // of the response messages to the client.
56 | type RespHandler interface {
57 | 
58 | 	// Write is provided the response to write and the user-defined writer.
59 | 	Write(r *Response, writer io.Writer) error
60 | }
61 | 


--------------------------------------------------------------------------------
/tcp.go:
--------------------------------------------------------------------------------
  1 | package tcp
  2 | 
  3 | import (
  4 | 	"bytes"
  5 | 	"context"
  6 | 	"errors"
  7 | 	"fmt"
  8 | 	"net"
  9 | 	"strconv"
 10 | 	"sync"
 11 | 	"sync/atomic"
 12 | 	"time"
 13 | )
 14 | 
 15 | // Set of error variables for start up.
 16 | var (
 17 | 	ErrInvalidConfiguration = errors.New("invalid configuration")
 18 | 	ErrInvalidNetType       = errors.New("invalid net type configuration")
 19 | 	ErrInvalidConnHandler   = errors.New("invalid connection handler configuration")
 20 | 	ErrInvalidReqHandler    = errors.New("invalid request handler configuration")
 21 | 	ErrInvalidRespHandler   = errors.New("invalid response handler configuration")
 22 | )
 23 | 
 24 | // Set of event types.
 25 | const (
 26 | 	EvtAccept = iota + 1
 27 | 	EvtJoin
 28 | 	EvtRead
 29 | 	EvtRemove
 30 | 	EvtDrop
 31 | 	EvtGroom
 32 | )
 33 | 
 34 | // Set of event sub types.
 35 | const (
 36 | 	TypError = iota + 1
 37 | 	TypInfo
 38 | 	TypTrigger
 39 | )
 40 | 
 41 | // CltError provides support for multi client operations that might error.
 42 | type CltError []error
 43 | 
 44 | // Error implments the error interface for CltError.
 45 | func (ce CltError) Error() string {
 46 | 	var b bytes.Buffer
 47 | 	for _, err := range ce {
 48 | 		b.WriteString(err.Error())
 49 | 		b.WriteString("\n")
 50 | 	}
 51 | 	return b.String()
 52 | }
 53 | 
 54 | // TCP contains a set of networked client connections.
 55 | type TCP struct {
 56 | 	Config
 57 | 	Name string
 58 | 
 59 | 	ipAddress string
 60 | 	port      int
 61 | 	tcpAddr   *net.TCPAddr
 62 | 
 63 | 	listener   *net.TCPListener
 64 | 	listenerMu sync.Mutex
 65 | 
 66 | 	clients   map[string]*client
 67 | 	clientsMu sync.Mutex
 68 | 
 69 | 	wg sync.WaitGroup
 70 | 
 71 | 	dropConns    int32
 72 | 	shuttingDown int32
 73 | 
 74 | 	lastAcceptedConnection time.Time
 75 | }
 76 | 
 77 | // New creates a new manager to service clients.
 78 | func New(name string, cfg Config) (*TCP, error) {
 79 | 
 80 | 	// Validate the configuration.
 81 | 	if err := cfg.Validate(); err != nil {
 82 | 		return nil, err
 83 | 	}
 84 | 
 85 | 	// Resolve the addr that is provided.
 86 | 	tcpAddr, err := net.ResolveTCPAddr(cfg.NetType, cfg.Addr)
 87 | 	if err != nil {
 88 | 		return nil, err
 89 | 	}
 90 | 
 91 | 	// Create a TCP for this ipaddress and port.
 92 | 	t := TCP{
 93 | 		Config: cfg,
 94 | 		Name:   name,
 95 | 
 96 | 		ipAddress: tcpAddr.IP.String(),
 97 | 		port:      tcpAddr.Port,
 98 | 		tcpAddr:   tcpAddr,
 99 | 
100 | 		clients: make(map[string]*client),
101 | 	}
102 | 
103 | 	return &t, nil
104 | }
105 | 
106 | // join takes an IP and port values and creates a cleaner string.
107 | func join(ip string, port int) string {
108 | 	return net.JoinHostPort(ip, strconv.Itoa(port))
109 | }
110 | 
111 | // Start creates the accept routine and begins to accept connections.
112 | func (t *TCP) Start() error {
113 | 	t.listenerMu.Lock()
114 | 	{
115 | 		// If the listener has been started already, return an error.
116 | 		if t.listener != nil {
117 | 			t.listenerMu.Unlock()
118 | 			return errors.New("this TCP has already been started")
119 | 		}
120 | 	}
121 | 	t.listenerMu.Unlock()
122 | 
123 | 	// We need to wait for the goroutine we are about to
124 | 	// create to initialize itself.
125 | 	var waitStart sync.WaitGroup
126 | 	waitStart.Add(1)
127 | 
128 | 	// Start the connection accept routine.
129 | 	t.wg.Add(1)
130 | 	go func() {
131 | 		var listener *net.TCPListener
132 | 
133 | 		for {
134 | 			t.listenerMu.Lock()
135 | 			{
136 | 				// Start a listener for the specified addr and port is one
137 | 				// does not exist.
138 | 				if t.listener == nil {
139 | 					var err error
140 | 					listener, err = net.ListenTCP(t.NetType, t.tcpAddr)
141 | 					if err != nil {
142 | 						panic(err)
143 | 					}
144 | 
145 | 					t.listener = listener
146 | 					waitStart.Done()
147 | 
148 | 					t.Event(EvtAccept, TypInfo, join(t.ipAddress, t.port), "waiting")
149 | 				}
150 | 			}
151 | 			t.listenerMu.Unlock()
152 | 
153 | 			// Listen for new connections.
154 | 			conn, err := listener.Accept()
155 | 			if err != nil {
156 | 				shutdown := atomic.LoadInt32(&t.shuttingDown)
157 | 
158 | 				if shutdown == 0 {
159 | 					t.Event(EvtAccept, TypError, conn.RemoteAddr().String(), err.Error())
160 | 				} else {
161 | 					t.listenerMu.Lock()
162 | 					{
163 | 						t.listener = nil
164 | 					}
165 | 					t.listenerMu.Unlock()
166 | 					break
167 | 				}
168 | 
169 | 				// temporary is declared to test for the existence of
170 | 				// the method coming from the net package.
171 | 				type temporary interface {
172 | 					Temporary() bool
173 | 				}
174 | 
175 | 				if e, ok := err.(temporary); ok && !e.Temporary() {
176 | 					t.listenerMu.Lock()
177 | 					{
178 | 						t.listener.Close()
179 | 						t.listener = nil
180 | 					}
181 | 					t.listenerMu.Unlock()
182 | 
183 | 					// Don't want to add a flag. So setting this back to
184 | 					// 1 so when the listener is re-established, the call
185 | 					// to Done does not fail.
186 | 					waitStart.Add(1)
187 | 				}
188 | 
189 | 				continue
190 | 			}
191 | 
192 | 			// Check if we are being asked to drop all new connections.
193 | 			if drop := atomic.LoadInt32(&t.dropConns); drop == 1 {
194 | 				t.Event(EvtAccept, TypInfo, "", "dropping new connection")
195 | 				conn.Close()
196 | 				continue
197 | 			}
198 | 
199 | 			// Check if rate limit is enabled.
200 | 			if t.RateLimit != nil {
201 | 				now := time.Now().UTC()
202 | 
203 | 				// We will only accept 1 connection per duration. Anything
204 | 				// connection above that must be dropped.
205 | 				if t.lastAcceptedConnection.Add(t.RateLimit()).After(now) {
206 | 					t.Event(EvtAccept, TypError, conn.RemoteAddr().String(), "rate limit drop : Local[ %v ] Limit[ %v ]", conn.LocalAddr(), t.RateLimit())
207 | 					conn.Close()
208 | 					continue
209 | 				}
210 | 
211 | 				// Since we accepted connection, mark the time.
212 | 				t.lastAcceptedConnection = now
213 | 			}
214 | 
215 | 			// Add this new connection to the manager map.
216 | 			t.join(conn)
217 | 		}
218 | 
219 | 		// Shutting down the routine.
220 | 		t.wg.Done()
221 | 		t.Event(EvtAccept, TypError, join(t.ipAddress, t.port), "shutdown")
222 | 	}()
223 | 
224 | 	// Wait for the goroutine to initialize itself.
225 | 	waitStart.Wait()
226 | 
227 | 	return nil
228 | }
229 | 
230 | // Stop shuts down the manager and closes all connections.
231 | func (t *TCP) Stop() error {
232 | 	t.listenerMu.Lock()
233 | 	{
234 | 		// If the listener has been stopped already, return an error.
235 | 		if t.listener == nil {
236 | 			t.listenerMu.Unlock()
237 | 			return errors.New("this TCP has already been stopped")
238 | 		}
239 | 	}
240 | 	t.listenerMu.Unlock()
241 | 
242 | 	// Mark that we are shutting down.
243 | 	atomic.StoreInt32(&t.shuttingDown, 1)
244 | 
245 | 	// Don't accept anymore client connections.
246 | 	t.listenerMu.Lock()
247 | 	{
248 | 		t.listener.Close()
249 | 	}
250 | 	t.listenerMu.Unlock()
251 | 
252 | 	// Make a copy of all the connections. We need to do this
253 | 	// since we have to lock the map to read it. Dropping a
254 | 	// connection requires locks as well.
255 | 	var clients map[string]*client
256 | 	t.clientsMu.Lock()
257 | 	{
258 | 		clients = make(map[string]*client)
259 | 		for k, v := range t.clients {
260 | 			clients[k] = v
261 | 		}
262 | 	}
263 | 	t.clientsMu.Unlock()
264 | 
265 | 	// Drop all the existing connections.
266 | 	for _, c := range clients {
267 | 
268 | 		// This waits for each routine to terminate.
269 | 		c.drop()
270 | 	}
271 | 
272 | 	// Wait for the accept routine to terminate.
273 | 	t.wg.Wait()
274 | 
275 | 	return nil
276 | }
277 | 
278 | // Drop will close the socket connection.
279 | func (t *TCP) Drop(tcpAddr *net.TCPAddr) error {
280 | 
281 | 	// Find the client connection for this IPAddress.
282 | 	var c *client
283 | 	t.clientsMu.Lock()
284 | 	{
285 | 		// Validate this ipaddress and socket exists first.
286 | 		var ok bool
287 | 		if c, ok = t.clients[tcpAddr.String()]; !ok {
288 | 			t.clientsMu.Unlock()
289 | 			return fmt.Errorf("IP[ %s ] : disconnected", tcpAddr.String())
290 | 		}
291 | 	}
292 | 	t.clientsMu.Unlock()
293 | 
294 | 	// Drop the connection using a goroutine since we are on the
295 | 	// socket goroutine most likely.
296 | 	go c.drop()
297 | 	return nil
298 | }
299 | 
300 | // Send will deliver the response back to the client.
301 | func (t *TCP) Send(ctx context.Context, r *Response) error {
302 | 
303 | 	// Find the client connection for this IPAddress.
304 | 	var c *client
305 | 	t.clientsMu.Lock()
306 | 	{
307 | 		// Validate this ipaddress and socket exists first.
308 | 		var ok bool
309 | 		if c, ok = t.clients[r.TCPAddr.String()]; !ok {
310 | 			t.clientsMu.Unlock()
311 | 			return fmt.Errorf("IP[ %s ] : disconnected", r.TCPAddr.String())
312 | 		}
313 | 
314 | 		// Increment the number of writes.
315 | 		c.nWrites++
316 | 	}
317 | 	t.clientsMu.Unlock()
318 | 
319 | 	// Send the response.
320 | 	return t.RespHandler.Write(r, c.writer)
321 | }
322 | 
323 | // SendAll will deliver the response back to all connected clients.
324 | func (t *TCP) SendAll(ctx context.Context, r *Response) error {
325 | 	var clts []*client
326 | 	t.clientsMu.Lock()
327 | 	{
328 | 		for _, c := range t.clients {
329 | 			clts = append(clts, c)
330 | 			c.nWrites++
331 | 		}
332 | 	}
333 | 	t.clientsMu.Unlock()
334 | 
335 | 	// TODO: Consider doing this in parallel.
336 | 	var errors CltError
337 | 	for _, c := range clts {
338 | 		if err := t.RespHandler.Write(r, c.writer); err != nil {
339 | 			errors = append(errors, err)
340 | 		}
341 | 	}
342 | 
343 | 	if errors != nil {
344 | 		return errors
345 | 	}
346 | 	return nil
347 | }
348 | 
349 | // DropConnections sets a flag to tell the accept routine to immediately
350 | // drop connections that come in.
351 | func (t *TCP) DropConnections(drop bool) {
352 | 	if drop {
353 | 		atomic.StoreInt32(&t.dropConns, 1)
354 | 		return
355 | 	}
356 | 
357 | 	atomic.StoreInt32(&t.dropConns, 0)
358 | }
359 | 
360 | // Addr returns the listener's network address. This may be different than the values
361 | // provided in the configuration, for example if configuration port value is 0.
362 | func (t *TCP) Addr() net.Addr {
363 | 
364 | 	// We are aware this read is not safe with the
365 | 	// goroutine accepting connections.
366 | 	if t.listener == nil {
367 | 		return nil
368 | 	}
369 | 	return t.listener.Addr()
370 | }
371 | 
372 | // Connections returns the number of client connections.
373 | func (t *TCP) Connections() int {
374 | 	var l int
375 | 
376 | 	t.clientsMu.Lock()
377 | 	{
378 | 		l = len(t.clients)
379 | 	}
380 | 	t.clientsMu.Unlock()
381 | 
382 | 	return l
383 | }
384 | 
385 | // Stat represents a client statistic.
386 | type Stat struct {
387 | 	IP       string
388 | 	Reads    int
389 | 	Writes   int
390 | 	TimeConn time.Time
391 | 	LastAct  time.Time
392 | }
393 | 
394 | // ClientStats return details for all active clients.
395 | func (t *TCP) ClientStats() []Stat {
396 | 	var clts []*client
397 | 	t.clientsMu.Lock()
398 | 	{
399 | 		for _, v := range t.clients {
400 | 			clts = append(clts, v)
401 | 		}
402 | 	}
403 | 	t.clientsMu.Unlock()
404 | 
405 | 	stats := make([]Stat, len(clts))
406 | 	for i, c := range clts {
407 | 		stats[i] = Stat{
408 | 			IP:       c.ipAddress,
409 | 			Reads:    c.nReads,
410 | 			Writes:   c.nWrites,
411 | 			TimeConn: c.timeConn,
412 | 			LastAct:  c.lastAct,
413 | 		}
414 | 	}
415 | 
416 | 	return stats
417 | }
418 | 
419 | // Clients returns the number of active clients connected.
420 | func (t *TCP) Clients() int {
421 | 	var count int
422 | 	t.clientsMu.Lock()
423 | 	{
424 | 		count = len(t.clients)
425 | 	}
426 | 	t.clientsMu.Unlock()
427 | 
428 | 	return count
429 | }
430 | 
431 | // Groom drops connections that are not active for the specified duration.
432 | func (t *TCP) Groom(d time.Duration) {
433 | 	var clts []*client
434 | 	t.clientsMu.Lock()
435 | 	{
436 | 		for _, v := range t.clients {
437 | 			clts = append(clts, v)
438 | 		}
439 | 	}
440 | 	t.clientsMu.Unlock()
441 | 
442 | 	now := time.Now().UTC()
443 | 	for _, c := range clts {
444 | 		sub := now.Sub(c.lastAct)
445 | 		if sub >= d {
446 | 
447 | 			// TODO
448 | 			// This is a blocking call that waits for the socket goroutine
449 | 			// to report its done. This parallel call should work well since
450 | 			// there is no error handling needed.
451 | 			t.Event(EvtGroom, TypInfo, c.ipAddress, "Last[ %v ] Dur[ %v ]", c.lastAct.Format(time.RFC3339), sub)
452 | 			go c.drop()
453 | 		}
454 | 	}
455 | }
456 | 
457 | // join takes a new connection and adds it to the manager.
458 | func (t *TCP) join(conn net.Conn) {
459 | 	ipAddress := conn.RemoteAddr().String()
460 | 	t.Event(EvtJoin, TypTrigger, ipAddress, "new connection")
461 | 
462 | 	t.clientsMu.Lock()
463 | 	{
464 | 		// Validate this has not been joined already.
465 | 		if _, ok := t.clients[ipAddress]; ok {
466 | 			t.Event(EvtJoin, TypError, ipAddress, "already connected")
467 | 			conn.Close()
468 | 
469 | 			t.clientsMu.Unlock()
470 | 			return
471 | 		}
472 | 
473 | 		// Add the client connection to the map.
474 | 		t.clients[ipAddress] = newClient(t, conn)
475 | 	}
476 | 	t.clientsMu.Unlock()
477 | }
478 | 
479 | // remove deletes a connection from the manager.
480 | func (t *TCP) remove(conn net.Conn) {
481 | 	ipAddress := conn.RemoteAddr().String()
482 | 
483 | 	t.clientsMu.Lock()
484 | 	{
485 | 		// Validate this has not been removed already.
486 | 		if _, ok := t.clients[ipAddress]; !ok {
487 | 			t.Event(EvtRemove, TypError, ipAddress, "already removed")
488 | 			t.clientsMu.Unlock()
489 | 			return
490 | 		}
491 | 
492 | 		// Remove the client connection from the map.
493 | 		delete(t.clients, ipAddress)
494 | 	}
495 | 	t.clientsMu.Unlock()
496 | 
497 | 	// Close the connection for safe keeping.
498 | 	conn.Close()
499 | }
500 | 


--------------------------------------------------------------------------------
/tcp_config.go:
--------------------------------------------------------------------------------
 1 | package tcp
 2 | 
 3 | import "time"
 4 | 
 5 | // OptRateLimit declares fields for the user to provide configuration
 6 | // for connection rate limit.
 7 | type OptRateLimit struct {
 8 | 	RateLimit func() time.Duration // Connection rate limit per single connection.
 9 | }
10 | 
11 | // OptEvent defines an handler used to provide events.
12 | type OptEvent struct {
13 | 	Event func(evt, typ int, ipAddress string, format string, a ...interface{})
14 | }
15 | 
16 | // Config provides a data structure of required configuration parameters.
17 | type Config struct {
18 | 	NetType string // "tcp", tcp4" or "tcp6"
19 | 	Addr    string // "host:port" or "[ipv6-host%zone]:port"
20 | 
21 | 	ConnHandler ConnHandler // Support for binding new connections to a reader and writer.
22 | 	ReqHandler  ReqHandler  // Support for handling the specific request workflow.
23 | 	RespHandler RespHandler // Support for handling the specific response workflow.
24 | 
25 | 	// *************************************************************************
26 | 	// ** Not Required, optional                                              **
27 | 	// *************************************************************************
28 | 
29 | 	OptRateLimit
30 | 	OptEvent
31 | }
32 | 
33 | // Validate checks the configuration to required items.
34 | func (cfg *Config) Validate() error {
35 | 	if cfg == nil {
36 | 		return ErrInvalidConfiguration
37 | 	}
38 | 
39 | 	if cfg.NetType != "tcp" && cfg.NetType != "tcp4" && cfg.NetType != "tcp6" {
40 | 		return ErrInvalidNetType
41 | 	}
42 | 
43 | 	if cfg.ConnHandler == nil {
44 | 		return ErrInvalidConnHandler
45 | 	}
46 | 
47 | 	if cfg.ReqHandler == nil {
48 | 		return ErrInvalidReqHandler
49 | 	}
50 | 
51 | 	if cfg.RespHandler == nil {
52 | 		return ErrInvalidRespHandler
53 | 	}
54 | 
55 | 	return nil
56 | }
57 | 
58 | // Event fires events back to the user for important events.
59 | func (cfg *Config) Event(evt, typ int, ipAddress string, format string, a ...interface{}) {
60 | 	if cfg.OptEvent.Event != nil {
61 | 		cfg.OptEvent.Event(evt, typ, ipAddress, format, a...)
62 | 	}
63 | }
64 | 


--------------------------------------------------------------------------------
/tcp_handlers_test.go:
--------------------------------------------------------------------------------
 1 | package tcp_test
 2 | 
 3 | import (
 4 | 	"bufio"
 5 | 	"io"
 6 | 	"net"
 7 | 	"sync/atomic"
 8 | 	"time"
 9 | 
10 | 	"github.com/ardanlabs/tcp"
11 | )
12 | 
13 | // tcpConnHandler is required to process data.
14 | type tcpConnHandler struct{}
15 | 
16 | // Bind is called to init to reader and writer.
17 | func (tch tcpConnHandler) Bind(conn net.Conn) (io.Reader, io.Writer) {
18 | 	return bufio.NewReader(conn), bufio.NewWriter(conn)
19 | }
20 | 
21 | // tcpReqHandler is required to process client messages.
22 | type tcpReqHandler struct{}
23 | 
24 | // Read implements the udp.ReqHandler interface. It is provided a request
25 | // value to popular and a io.Reader that was created in the Bind above.
26 | func (tcpReqHandler) Read(ipAddress string, reader io.Reader) ([]byte, int, error) {
27 | 	bufReader := reader.(*bufio.Reader)
28 | 
29 | 	// Read a small string to keep the code simple.
30 | 	line, err := bufReader.ReadString('\n')
31 | 	if err != nil {
32 | 		return nil, 0, err
33 | 	}
34 | 
35 | 	return []byte(line), len(line), nil
36 | }
37 | 
38 | var dur int64
39 | 
40 | // Process is used to handle the processing of the message.
41 | func (tcpReqHandler) Process(r *tcp.Request) {
42 | 	resp := tcp.Response{
43 | 		TCPAddr: r.TCPAddr,
44 | 		Data:    []byte("GOT IT\n"),
45 | 		Length:  7,
46 | 	}
47 | 
48 | 	r.TCP.Send(r.Context, &resp)
49 | 
50 | 	d := int64(time.Since(r.ReadAt))
51 | 	atomic.StoreInt64(&dur, d)
52 | }
53 | 
54 | type tcpRespHandler struct{}
55 | 
56 | // Write is provided the user-defined writer and the data to write.
57 | func (tcpRespHandler) Write(r *tcp.Response, writer io.Writer) error {
58 | 	bufWriter := writer.(*bufio.Writer)
59 | 	if _, err := bufWriter.WriteString(string(r.Data)); err != nil {
60 | 		return err
61 | 	}
62 | 
63 | 	return bufWriter.Flush()
64 | }
65 | 


--------------------------------------------------------------------------------
/tcp_test.go:
--------------------------------------------------------------------------------
  1 | package tcp_test
  2 | 
  3 | import (
  4 | 	"bufio"
  5 | 	"bytes"
  6 | 	"net"
  7 | 	"os"
  8 | 	"sync/atomic"
  9 | 	"testing"
 10 | 	"time"
 11 | 
 12 | 	"github.com/ardanlabs/tcp"
 13 | )
 14 | 
 15 | // TestTCP provide a test of listening for a connection and
 16 | // echoing the data back.
 17 | func TestTCP(t *testing.T) {
 18 | 	resetLog()
 19 | 	defer displayLog()
 20 | 
 21 | 	t.Log("Given the need to listen and process TCP data.")
 22 | 	{
 23 | 		// Create a configuration.
 24 | 		cfg := tcp.Config{
 25 | 			NetType: "tcp4",
 26 | 			Addr:    ":0",
 27 | 
 28 | 			ConnHandler: tcpConnHandler{},
 29 | 			ReqHandler:  tcpReqHandler{},
 30 | 			RespHandler: tcpRespHandler{},
 31 | 		}
 32 | 
 33 | 		// Create a new TCP value.
 34 | 		u, err := tcp.New("TEST", cfg)
 35 | 		if err != nil {
 36 | 			t.Fatal("\tShould be able to create a new TCP listener.", failed, err)
 37 | 		}
 38 | 		t.Log("\tShould be able to create a new TCP listener.", success)
 39 | 
 40 | 		// Start accepting client data.
 41 | 		if err := u.Start(); err != nil {
 42 | 			t.Fatal("\tShould be able to start the TCP listener.", failed, err)
 43 | 		}
 44 | 		t.Log("\tShould be able to start the TCP listener.", success)
 45 | 
 46 | 		defer u.Stop()
 47 | 
 48 | 		// Let's connect back and send a TCP package
 49 | 		conn, err := net.Dial("tcp4", u.Addr().String())
 50 | 		if err != nil {
 51 | 			t.Fatal("\tShould be able to dial a new TCP connection.", failed, err)
 52 | 		}
 53 | 		t.Log("\tShould be able to dial a new TCP connection.", success)
 54 | 
 55 | 		// Setup a bufio reader to extract the response.
 56 | 		bufReader := bufio.NewReader(conn)
 57 | 		bufWriter := bufio.NewWriter(conn)
 58 | 
 59 | 		// Send some know data to the tcp listener.
 60 | 		if _, err := bufWriter.WriteString("Hello\n"); err != nil {
 61 | 			t.Fatal("\tShould be able to send data to the connection.", failed, err)
 62 | 		}
 63 | 		t.Log("\tShould be able to send data to the connection.", success)
 64 | 
 65 | 		bufWriter.Flush()
 66 | 
 67 | 		// Let's read the response.
 68 | 		response, err := bufReader.ReadString('\n')
 69 | 		if err != nil {
 70 | 			t.Fatal("\tShould be able to read the response from the connection.", failed, err)
 71 | 		}
 72 | 		t.Log("\tShould be able to read the response from the connection.", success)
 73 | 
 74 | 		if response == "GOT IT\n" {
 75 | 			t.Log("\tShould receive the string \"GOT IT\".", success)
 76 | 		} else {
 77 | 			t.Error("\tShould receive the string \"GOT IT\".", failed, response)
 78 | 		}
 79 | 
 80 | 		d := atomic.LoadInt64(&dur)
 81 | 		duration := time.Duration(d)
 82 | 
 83 | 		if duration <= 2*time.Second {
 84 | 			t.Log("\tShould be less that 2 seconds.", success)
 85 | 		} else {
 86 | 			t.Error("\tShould be less that 2 seconds.", failed, duration)
 87 | 		}
 88 | 	}
 89 | }
 90 | 
 91 | // Test tcp.Addr works correctly.
 92 | func TestTCPAddr(t *testing.T) {
 93 | 	resetLog()
 94 | 	defer displayLog()
 95 | 
 96 | 	t.Log("Given the need to listen on any open port and know that bound address.")
 97 | 	{
 98 | 		// Create a configuration.
 99 | 		cfg := tcp.Config{
100 | 			NetType: "tcp4",
101 | 			Addr:    ":0", // Defer port assignment to OS.
102 | 
103 | 			ConnHandler: tcpConnHandler{},
104 | 			ReqHandler:  tcpReqHandler{},
105 | 			RespHandler: tcpRespHandler{},
106 | 		}
107 | 
108 | 		// Create a new TCP value.
109 | 		u, err := tcp.New("TEST", cfg)
110 | 		if err != nil {
111 | 			t.Fatal("\tShould be able to create a new TCP listener.", failed, err)
112 | 		}
113 | 		t.Log("\tShould be able to create a new TCP listener.", success)
114 | 
115 | 		// Addr should be nil before Start.
116 | 		if addr := u.Addr(); addr != nil {
117 | 			t.Fatalf("\tAddr() should be nil before Start; Addr() = %q. %s", addr, failed)
118 | 		}
119 | 		t.Log("\tAddr() should be nil before Start.", success)
120 | 
121 | 		// Start accepting client data.
122 | 		if err := u.Start(); err != nil {
123 | 			t.Fatal("\tShould be able to start the TCP listener.", failed, err)
124 | 		}
125 | 		defer u.Stop()
126 | 
127 | 		// Addr should be non-nil after Start.
128 | 		addr := u.Addr()
129 | 		if addr == nil {
130 | 			t.Fatal("\tAddr() should be not be nil after Start.", failed)
131 | 		}
132 | 		t.Log("\tAddr() should be not be nil after Start.", success)
133 | 
134 | 		// The OS should assign a random open port, which shouldn't be 0.
135 | 		_, port, err := net.SplitHostPort(addr.String())
136 | 		if err != nil {
137 | 			t.Fatalf("\tSplitHostPort should not fail. failed %v. %s", err, failed)
138 | 		}
139 | 		if port == "0" {
140 | 			t.Fatalf("\tAddr port should not be %q. %s", port, failed)
141 | 		}
142 | 		t.Logf("\tAddr() should be not be 0 after Start (port = %q). %s", port, success)
143 | 	}
144 | }
145 | 
146 | // TestDropConnections tests we can drop connections when configured.
147 | func TestDropConnections(t *testing.T) {
148 | 	resetLog()
149 | 	defer displayLog()
150 | 
151 | 	t.Log("Given the need to drop TCP connections.")
152 | 	{
153 | 		// Create a configuration.
154 | 		cfg := tcp.Config{
155 | 			NetType:     "tcp4",
156 | 			Addr:        ":0",
157 | 			ConnHandler: tcpConnHandler{},
158 | 			ReqHandler:  tcpReqHandler{},
159 | 			RespHandler: tcpRespHandler{},
160 | 		}
161 | 
162 | 		// Create a new TCP value.
163 | 		u, err := tcp.New("TEST", cfg)
164 | 		if err != nil {
165 | 			t.Fatal("\tShould be able to create a new TCP listener.", failed, err)
166 | 		}
167 | 		t.Log("\tShould be able to create a new TCP listener.", success)
168 | 
169 | 		// Set the drop connection flag to true.
170 | 		t.Log("\tSet the drop connections flag to TRUE.", success)
171 | 		u.DropConnections(true)
172 | 
173 | 		// Start accepting client data.
174 | 		if err := u.Start(); err != nil {
175 | 			t.Fatal("\tShould be able to start the TCP listener.", failed, err)
176 | 		}
177 | 		t.Log("\tShould be able to start the TCP listener.", success)
178 | 
179 | 		defer u.Stop()
180 | 
181 | 		// Let's connect to the host:port.
182 | 		conn, err := net.Dial("tcp4", u.Addr().String())
183 | 		if err != nil {
184 | 			t.Fatal("\tShould be able to dial a new TCP connection.", failed, err)
185 | 		}
186 | 		t.Log("\tShould be able to dial a new TCP connection.", success)
187 | 
188 | 		// An attempt to read should result in an EOF.
189 | 		b := make([]byte, 1)
190 | 		if _, err = conn.Read(b); err == nil {
191 | 			t.Fatal("\tShould not be able to read the response from the connection.", failed, err)
192 | 		}
193 | 		t.Log("\tShould not be able to read the response from the connection.", success)
194 | 	}
195 | }
196 | 
197 | // TestRateLimit tests we can drop connections when they come in too fast.
198 | func TestRateLimit(t *testing.T) {
199 | 	resetLog()
200 | 	defer displayLog()
201 | 
202 | 	const ratelimit = 1 * time.Second
203 | 
204 | 	t.Log("Given the need to drop TCP connections.")
205 | 	{
206 | 		// Create a configuration.
207 | 		cfg := tcp.Config{
208 | 			NetType:     "tcp4",
209 | 			Addr:        ":0",
210 | 			ConnHandler: tcpConnHandler{},
211 | 			ReqHandler:  tcpReqHandler{},
212 | 			RespHandler: tcpRespHandler{},
213 | 
214 | 			OptRateLimit: tcp.OptRateLimit{
215 | 				RateLimit: func() time.Duration { return ratelimit },
216 | 			},
217 | 		}
218 | 
219 | 		// Create a new TCP value.
220 | 		u, err := tcp.New("TEST", cfg)
221 | 		if err != nil {
222 | 			t.Fatal("\tShould be able to create a new TCP listener.", failed, err)
223 | 		}
224 | 		t.Log("\tShould be able to create a new TCP listener.", success)
225 | 
226 | 		// Start accepting client data.
227 | 		if err := u.Start(); err != nil {
228 | 			t.Fatal("\tShould be able to start the TCP listener.", failed, err)
229 | 		}
230 | 		t.Log("\tShould be able to start the TCP listener.", success)
231 | 
232 | 		defer u.Stop()
233 | 
234 | 		newconn := func() (*bufio.Writer, *bufio.Reader, net.Conn, error) {
235 | 			// Let's connect to the host:port.
236 | 			conn, err := net.Dial("tcp4", u.Addr().String())
237 | 			if err != nil {
238 | 				return nil, nil, nil, err
239 | 			}
240 | 			return bufio.NewWriter(conn), bufio.NewReader(conn), conn, nil
241 | 		}
242 | 
243 | 		// Make a successful connection
244 | 		successfulTest := func(Context interface{}) {
245 | 			w, r, c, err := newconn()
246 | 			if err != nil {
247 | 				t.Fatal("\tShould be able to dial a new TCP connection.", Context, failed, err)
248 | 			}
249 | 			t.Log("\tShould be able to dial a new TCP connection.", Context, success)
250 | 
251 | 			defer c.Close()
252 | 
253 | 			if _, err := w.WriteString("Hello\n"); err != nil {
254 | 				t.Fatal("\tShould be able to send data to the connection.", Context, failed, err)
255 | 			}
256 | 			t.Log("\tShould be able to send data to the connection.", Context, success)
257 | 
258 | 			if err := w.Flush(); err != nil {
259 | 				t.Fatal("\tShould be able to flush the writer.", Context, failed, err)
260 | 			}
261 | 			t.Log("\tShould be able to flush the writer.", Context, success)
262 | 
263 | 			// Let's read the response.
264 | 			response, err := r.ReadString('\n')
265 | 			if err != nil {
266 | 				t.Fatal("\tShould be able to read the response from the connection.", Context, failed, err)
267 | 			}
268 | 			t.Log("\tShould be able to read the response from the connection.", Context, success)
269 | 
270 | 			t.Log(response)
271 | 		}
272 | 
273 | 		successfulTest("PRE-LIMIT")
274 | 
275 | 		// The next 100 connections should fail (assuming it's all under rateLimit amount of time).
276 | 		for i := 0; i < 100; i++ {
277 | 			//  Apparently, even though the connection should not exist, we are still allowed
278 | 			//  to connect to the remote socket and write to it.  The error is exhibited
279 | 			//  only when it's time to perform a read on that connection.
280 | 			w, r, c, err := newconn()
281 | 			if err != nil {
282 | 				t.Fatal("\tShould be able to dial a non-first TCP connection.", failed, err)
283 | 			}
284 | 			t.Log("\tShould be able to dial a non-first TCP connection", c.LocalAddr(), success)
285 | 
286 | 			defer c.Close()
287 | 
288 | 			if _, err := w.WriteString("Hello\n"); err != nil {
289 | 				t.Fatal("\tShould be able to send data to the connection.", failed, err)
290 | 			}
291 | 			t.Log("\tShould be able to send data to the connection.", success)
292 | 
293 | 			if err := w.Flush(); err != nil {
294 | 				t.Fatal("\tShould be able to flush the writer.", failed, err)
295 | 			}
296 | 			t.Log("\tShould be able to flush the writer.", success)
297 | 
298 | 			// Let's read the response.
299 | 			_, err = r.ReadString('\n')
300 | 			if err == nil {
301 | 				t.Fatal("\tShould have failed to read from the connection.", failed)
302 | 			}
303 | 			t.Log("\tShould have failed to read from the connection", success, err)
304 | 		}
305 | 
306 | 		// Sleep for rateLimit to perform another successful test.
307 | 		time.Sleep(ratelimit)
308 | 		successfulTest("POST-LIMIT")
309 | 
310 | 		// NOTE If you call another 'successfulTest' here, we will fail because we expect
311 | 		// the test to fail due to the limit.
312 | 	}
313 | }
314 | 
315 | // =============================================================================
316 | 
317 | // Success and failure markers.
318 | var (
319 | 	success = "\u2713"
320 | 	failed  = "\u2717"
321 | )
322 | 
323 | // logdash is the central buffer where all logs are stored.
324 | var logdash bytes.Buffer
325 | 
326 | // resetLog resets the contents of Logdash.
327 | func resetLog() {
328 | 	logdash.Reset()
329 | }
330 | 
331 | // displayLog writes the Logdash data to standand out, if testing in verbose mode
332 | // was turned on.
333 | func displayLog() {
334 | 	if !testing.Verbose() {
335 | 		return
336 | 	}
337 | 
338 | 	logdash.WriteTo(os.Stdout)
339 | }
340 | 


--------------------------------------------------------------------------------