nextcloud-docs/golang/README.md

Note: this is the "per-architecture" repository for the arm32v5 builds of the golang official image -- for more information, see "Architectures other than amd64?" in the official images documentation and "An image's source changed in Git, now what?" in the official images FAQ.

Quick reference

• Maintained by:
  the Docker Community

• Where to get help:
  the Docker Community Slack, Server Fault, Unix & Linux, or Stack Overflow

Supported tags and respective Dockerfile links

WARNING: THIS IMAGE IS NOT SUPPORTED ON THE arm32v5 ARCHITECTURE

Quick reference (cont.)

• Where to file issues:
  https://github.com/docker-library/golang/issues

• Supported architectures: (more info)
  amd64, arm32v6, arm32v7, arm64v8, i386, mips64le, ppc64le, riscv64, s390x, windows-amd64

• Published image artifact details:
  repo-info repo's repos/golang/ directory (history)
  (image metadata, transfer size, etc)

• Image updates:
  official-images repo's library/golang label
  official-images repo's library/golang file (history)

• Source of this description:
  docs repo's golang/ directory (history)

What is Go?

Go (a.k.a., Golang) is a programming language first developed at Google. It is a statically-typed language with syntax loosely derived from C, but with additional features such as garbage collection, type safety, some dynamic-typing capabilities, additional built-in types (e.g., variable-length arrays and key-value maps), and a large standard library.

wikipedia.org/wiki/Go_(programming_language)

How to use this image

Note: /go is world-writable to allow flexibility in the user which runs the container (for example, in a container started with --user 1000:1000, running go get github.com/example/... into the default $GOPATH will succeed). While the 777 directory would be insecure on a regular host setup, there are not typically other processes or users inside the container, so this is equivalent to 700 for Docker usage, but allowing for --user flexibility.

Start a Go instance in your app

The most straightforward way to use this image is to use a Go container as both the build and runtime environment. In your Dockerfile, writing something along the lines of the following will compile and run your project (assuming it uses go.mod for dependency management):

FROM arm32v5/golang:1.25

WORKDIR /usr/src/app

# pre-copy/cache go.mod for pre-downloading dependencies and only redownloading them in subsequent builds if they change
COPY go.mod go.sum ./
RUN go mod download

COPY . .
RUN go build -v -o /usr/local/bin/app ./...

CMD ["app"]

You can then build and run the Docker image:

$ docker build -t my-golang-app .
$ docker run -it --rm --name my-running-app my-golang-app

Compile your app inside the Docker container

There may be occasions where it is not appropriate to run your app inside a container. To compile, but not run your app inside the Docker instance, you can write something like:

$ docker run --rm -v "$PWD":/usr/src/myapp -w /usr/src/myapp arm32v5/golang:1.25 go build -v

This will add your current directory as a volume to the container, set the working directory to the volume, and run the command go build which will tell go to compile the project in the working directory and output the executable to myapp. Alternatively, if you have a Makefile, you can run the make command inside your container.

$ docker run --rm -v "$PWD":/usr/src/myapp -w /usr/src/myapp arm32v5/golang:1.25 make

Cross-compile your app inside the Docker container

If you need to compile your application for a platform other than linux/amd64 (such as windows/386):

$ docker run --rm -v "$PWD":/usr/src/myapp -w /usr/src/myapp -e GOOS=windows -e GOARCH=386 arm32v5/golang:1.25 go build -v

Alternatively, you can build for multiple platforms at once:

$ docker run --rm -it -v "$PWD":/usr/src/myapp -w /usr/src/myapp arm32v5/golang:1.25 bash
$ for GOOS in darwin linux; do
>   for GOARCH in 386 amd64; do
>     export GOOS GOARCH
>     go build -v -o myapp-$GOOS-$GOARCH
>   done
> done

Git LFS

If downloading your dependencies results in an error like "checksum mismatch", you should check whether they are using Git LFS (and thus need it installed for downloading them and calculating correct go.sum values).

License

View license information for the software contained in this image.

As with all Docker images, these likely also contain other software which may be under other licenses (such as Bash, etc from the base distribution, along with any direct or indirect dependencies of the primary software being contained).

Some additional license information which was able to be auto-detected might be found in the repo-info repository's golang/ directory.

As for any pre-built image usage, it is the image user's responsibility to ensure that any use of this image complies with any relevant licenses for all software contained within.