https://github.com/montanaflynn/golang-docker-cache

Improved docker Golang module dependency cache for faster builds.
https://github.com/montanaflynn/golang-docker-cache

benchmark build devops docker golang performance

Last synced: 13 days ago
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Improved docker Golang module dependency cache for faster builds.

• Host: GitHub
• URL: https://github.com/montanaflynn/golang-docker-cache
• Owner: montanaflynn
• Created: 2020-06-29T07:23:34.000Z (over 4 years ago)
• Default Branch: main
• Last Pushed: 2021-02-06T01:22:05.000Z (almost 4 years ago)
• Last Synced: 2024-10-14T11:31:40.400Z (27 days ago)
• Topics: benchmark, build, devops, docker, golang, performance
• Language: Dockerfile
• Homepage: https://github.com/golang/go/issues/27719
• Size: 7.81 KB
• Stars: 68
• Watchers: 4
• Forks: 3
• Open Issues: 2
• Metadata Files:
  • Readme: README.md

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README

        
# Golang Docker Dependency Cache

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. 

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. 

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.

## Usage

```

COPY go.mod go.sum ./

# Add this line before `go build`

RUN go mod graph | awk '{if ($1 !~ "@") print $2}' | xargs go get

```

Full Dockerfile example: [./Dockerfile](./Dockerfile)

## Benchmarks

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. 

#### With `go mod graph | awk '{if ($1 !~ "@") print $2}' | xargs go get` dependency cache:

```

# Fresh build with no cache:

$ time docker build --no-cache -t golang-docker-cache .

...

13.54 real         0.12 user         0.07 sys

# Add comment to main.go:

$ time docker build -t golang-docker-cache .

2.74 real         0.12 user         0.10 sys

```

#### With `go mod download` dependency cache:

```

# Fresh build with no cache:

$ time docker build --no-cache -t golang-docker-cache .

15.13 real         0.13 user         0.09 sys

# Add comment to main.go:

$ time docker build -t golang-docker-cache .

9.03 real         0.12 user         0.10 sys

```

#### Without any dependency cache:

```

# Fresh build with no cache:

$ time docker build --no-cache -t golang-docker-cache .

12.12 real         0.12 user         0.08 sys

# Add comment to main.go:

$ time docker build -t golang-docker-cache .

12.19 real         0.12 user         0.10 sys

```