├── go.mod ├── main.go ├── Dockerfile ├── README.md └── go.sum /go.mod: -------------------------------------------------------------------------------- 1 | module github.com/montanaflynn/golang-docker-cache 2 | 3 | go 1.14 4 | 5 | require github.com/dgraph-io/badger/v2 v2.0.3 6 | -------------------------------------------------------------------------------- /main.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import ( 4 | "log" 5 | 6 | badger "github.com/dgraph-io/badger/v2" 7 | ) 8 | 9 | func main() { 10 | db, err := badger.Open(badger.DefaultOptions("").WithInMemory(true)) 11 | if err != nil { 12 | log.Fatal(err) 13 | } 14 | defer db.Close() 15 | } 16 | -------------------------------------------------------------------------------- /Dockerfile: -------------------------------------------------------------------------------- 1 | FROM golang:1.14-alpine AS build 2 | WORKDIR /go/src/app 3 | ENV CGO_ENABLED=0 4 | 5 | COPY go.mod go.sum ./ 6 | RUN go mod graph | awk '{if ($1 !~ "@") print $2}' | xargs go get 7 | 8 | COPY main.go ./ 9 | RUN go build -o /go/bin/app 10 | 11 | FROM scratch 12 | COPY --from=build /go/bin/app / 13 | ENTRYPOINT ["/app"] -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # Golang Docker Dependency Cache 2 | 3 | If you've switched to go modules you might have found your docker builds have slowed down due `go build` needing to recompile all the dependencies even if they have already been downloaded or vendored. 4 | 5 | For the simple program in this repo with a single dependency I was able to get 4x improvement over doing no dependency caching and 3x compared to using `go mod download` as the dependency cache. 6 | 7 | There is an [open issue](https://github.com/golang/go/issues/27719) but until it's built into the `go` cli this could make your builds much faster. 8 | 9 | ## Usage 10 | 11 | ``` 12 | COPY go.mod go.sum ./ 13 | 14 | # Add this line before `go build` 15 | RUN go mod graph | awk '{if ($1 !~ "@") print $2}' | xargs go get 16 | ``` 17 | 18 | Full Dockerfile example: [./Dockerfile](./Dockerfile) 19 | 20 | ## Benchmarks 21 | 22 | I used `time` to measure how long it took to build a fresh docker image with `--no-cache` and then changed the main.go file by adding a comment so Docker would run the `go build` step again while keeping the preceeding cached docker layers. 23 | 24 | #### With `go mod graph | awk '{if ($1 !~ "@") print $2}' | xargs go get` dependency cache: 25 | 26 | ``` 27 | # Fresh build with no cache: 28 | $ time docker build --no-cache -t golang-docker-cache . 29 | ... 30 | 13.54 real 0.12 user 0.07 sys 31 | 32 | # Add comment to main.go: 33 | $ time docker build -t golang-docker-cache . 34 | 2.74 real 0.12 user 0.10 sys 35 | ``` 36 | 37 | #### With `go mod download` dependency cache: 38 | 39 | ``` 40 | # Fresh build with no cache: 41 | $ time docker build --no-cache -t golang-docker-cache . 42 | 15.13 real 0.13 user 0.09 sys 43 | 44 | # Add comment to main.go: 45 | $ time docker build -t golang-docker-cache . 46 | 9.03 real 0.12 user 0.10 sys 47 | ``` 48 | 49 | #### Without any dependency cache: 50 | 51 | ``` 52 | # Fresh build with no cache: 53 | $ time docker build --no-cache -t golang-docker-cache . 54 | 12.12 real 0.12 user 0.08 sys 55 | 56 | # Add comment to main.go: 57 | $ time docker build -t golang-docker-cache . 58 | 12.19 real 0.12 user 0.10 sys 59 | ``` 60 | -------------------------------------------------------------------------------- /go.sum: -------------------------------------------------------------------------------- 1 | github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU= 2 | github.com/DataDog/zstd v1.4.1 h1:3oxKN3wbHibqx897utPC2LTQU4J+IHWWJO+glkAkpFM= 3 | github.com/DataDog/zstd v1.4.1/go.mod h1:1jcaCB/ufaK+sKp1NBhlGmpz41jOoPQ35bpF36t7BBo= 4 | github.com/OneOfOne/xxhash v1.2.2 h1:KMrpdQIwFcEqXDklaen+P1axHaj9BSKzvpUUfnHldSE= 5 | github.com/OneOfOne/xxhash v1.2.2/go.mod h1:HSdplMjZKSmBqAxg5vPj2TmRDmfkzw+cTzAElWljhcU= 6 | github.com/armon/consul-api v0.0.0-20180202201655-eb2c6b5be1b6/go.mod h1:grANhF5doyWs3UAsr3K4I6qtAmlQcZDesFNEHPZAzj8= 7 | github.com/cespare/xxhash v1.1.0 h1:a6HrQnmkObjyL+Gs60czilIUGqrzKutQD6XZog3p+ko= 8 | github.com/cespare/xxhash v1.1.0/go.mod h1:XrSqR1VqqWfGrhpAt58auRo0WTKS1nRRg3ghfAqPWnc= 9 | github.com/coreos/etcd v3.3.10+incompatible/go.mod h1:uF7uidLiAD3TWHmW31ZFd/JWoc32PjwdhPthX9715RE= 10 | github.com/coreos/go-etcd v2.0.0+incompatible/go.mod h1:Jez6KQU2B/sWsbdaef3ED8NzMklzPG4d5KIOhIy30Tk= 11 | github.com/coreos/go-semver v0.2.0/go.mod h1:nnelYz7RCh+5ahJtPPxZlU+153eP4D4r3EedlOD2RNk= 12 | github.com/cpuguy83/go-md2man v1.0.10/go.mod h1:SmD6nW6nTyfqj6ABTjUi3V3JVMnlJmwcJI5acqYI6dE= 13 | github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38= 14 | github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c= 15 | github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38= 16 | github.com/dgraph-io/badger/v2 v2.0.3 h1:inzdf6VF/NZ+tJ8RwwYMjJMvsOALTHYdozn0qSl6XJI= 17 | github.com/dgraph-io/badger/v2 v2.0.3/go.mod h1:3KY8+bsP8wI0OEnQJAKpd4wIJW/Mm32yw2j/9FUVnIM= 18 | github.com/dgraph-io/ristretto v0.0.2-0.20200115201040-8f368f2f2ab3 h1:MQLRM35Pp0yAyBYksjbj1nZI/w6eyRY/mWoM1sFf4kU= 19 | github.com/dgraph-io/ristretto v0.0.2-0.20200115201040-8f368f2f2ab3/go.mod h1:KPxhHT9ZxKefz+PCeOGsrHpl1qZ7i70dGTu2u+Ahh6E= 20 | github.com/dgryski/go-farm v0.0.0-20190423205320-6a90982ecee2 h1:tdlZCpZ/P9DhczCTSixgIKmwPv6+wP5DGjqLYw5SUiA= 21 | github.com/dgryski/go-farm v0.0.0-20190423205320-6a90982ecee2/go.mod h1:SqUrOPUnsFjfmXRMNPybcSiG0BgUW2AuFH8PAnS2iTw= 22 | github.com/dustin/go-humanize v1.0.0 h1:VSnTsYCnlFHaM2/igO1h6X3HA71jcobQuxemgkq4zYo= 23 | 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