Golang Mac OSX build for Docker machine - linux

Question

I need to run Golang application on Docker machine.
I'm working on Mac OSX and Docker is working on top of Linux virtual machine, so binaries builded on Mac are not runnable on Docker.
I see two ways here:
cross-compile binaries on Mac for linux OS
copy project sources to docker, run 'go get' and 'go build' on it
First one is hard because of CGO (it is used in some imported libraries).
Second is very slow because of 'go get' operation.
Can you please tell me, which way is the most common in that situation? Or maybe I'm doing something wrong?

Answer 1

Here a solution to make cross-compile super easy even with CGO.
I stumbled upon it recently after wasting a lot of time getting a new windows build server to build my Go app.
Now I just compile it on my Mac and will create a Linux build server with it:
https://github.com/karalabe/xgo
Many thanks to Péter Szilágyi alias karalabe for this really great package!
How to use:
have Docker running
go get github.com/karalabe/xgo
xgo --targets=windows/amd64 ./
There are lots more options!
-- edit --
Almost 3 Years later I'm not using this any more, but my docker image to build my application in a linux based CD pipeline is still based on the docker images used in xgo.

Answer 2

I use the first approach. Here its a gulp task the build go code. If the production flag is set, it runs GOOS=linux CGO_ENABLED=0 go build instead go build. So the binary will work inside a docker container
gulp.task('server:build', function () {
var build;
let options = {
env: {
'PATH': process.env.PATH,
'GOPATH': process.env.GOPATH
}
}
if (argv.prod) {
options.env['GOOS'] = 'linux'
options.env['CGO_ENABLED'] = '0'
console.log("Compiling go binarie to run inside Docker container")
}
var output = argv.prod ? conf.paths.build + '/prod/bin' : conf.paths.build + '/dev/bin';
build = child.spawnSync('go', ['build', '-o', output, "src/backend/main.go"], options);
if (build.stderr.length) {
var lines = build.stderr.toString()
.split('\n').filter(function(line) {
return line.length
});
for (var l in lines)
util.log(util.colors.red(
'Error (go install): ' + lines[l]
));
notifier.notify({
title: 'Error (go install)',
message: lines
});
}
return build;
});

Answer 3

You could create a Docker container from the distinct OS you need for your executable, and map a volume to your src directory. Run the container and make the executable from within the container. You end up with a binary that you can run on the distinct OS.