build-go
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build.go - Program for building Go binaries without a GOPATH
This repository contains a small and self-contained Go program called
build.go. It used to compile a binary (package main) from either a checkout
of the repository, or from an extracted release tar file. This enables
end-users to compile the program without having to setup a GOPATH.
For it to function correctly, all dependencies need to be vendored, e.g. with
dep or go mod vendor. Then, your build does not depend on any third-party
resources on the Internet. For Go >= 1.11, modules are used for building and
GOPROXY is set to off so that no Internet is needed when building.
The program has a build tag that is not set normally (ignore_build_go) so it
is not considered when compiling the other Go code in a repository.
Usage
In order to use it, copy build.go to the root level into your repository and
edit the configuration section at the top. You can see an example in the
restic repository.
Instruct your users to call go run build.go and it will produce a binary from
either a checkout of the repository or from an extracted release tar file. For
Go 1.11, it needs to be called as go run -mod=vendor build.go so that no
network access is needed.
For cross-compilation, the options --goos and --goarch can be used, e.g.
like this:
$ go run build.go --goos windows --goarch 386
The tests can be run by specifying --test. By default, cgo is explicitly
disabled by passing CGO_ENABLED=0 to go build, it can be re-enabled
manually by running go run build.go --enable-cgo.
The program will set the string variable version in package main to a
version string consisting of the contents of the file VERSION (if present)
and the output of git describe (if available).
The version string can then be used e.g. in a version command, like with
restic:
$ ./restic version
restic 0.8.1 (v0.8.1-154-g74665a22)
The version string consists of:
- The contents of the
VERSIONfile:0.8.1 - The nearest tag (
v0.8.1), the number of commits (154) and the Git commit hash (74665a22)
Background
The program build.go constructs a temporary GOPATH (for Go < 1.11, or when
no go.mod exists) in a temporary directory as configured at the beginning of
the program, then calls go build using the temporary GOPATH. This means
that end-users do not have to setup a GOPATH of their own.
Testing
The tests need to be run with the build tag ignore_build_go set:
$ go test -tags ignore_build_go
PASS
ok github.com/fd0/build-go 0.001s
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