Building in git version information into a Go language program

This demonstration Golang program demonstrates various techniques related to application versioning within the Go language environment. The references at the end also provide useful information for versioning and its use in Go programs.

The following build commands are for building this program on Linux or Windows. It should be straight forward to make something like this work your favorite Go program or module. NB: the variables main.Ver, main.Dat and main.Githash correspond to package scope variables in the main package. If version information was needed in an imported package, with this kind of version data being linked in the package would need to define these variables and use them in package code accordingly.

	HEAD=`git rev-parse HEAD` go build -ldflags "-X main.Ver=`git describe
		--tags $HEAD` -X main.Dat=`date -u '+%Y-%m-%d_%I:%M:%S%p'`
		-X main.Githash=`git rev-parse HEAD`" bldver.go

	git rev-parse HEAD > temp.txt
	set /p GITHASH=<temp.txt
	git describe --tags %GITHASH% > temp.txt
	set /p VER=<temp.txt
	go build -ldflags "-X main.Ver=%VER% -X appversion.Dat=%DATE%_%TIME%
		-X main.Githash=%GITHASH%" bldver.go

Displaying the git hash for the HEAD

git rev-parse HEAD

Listing all the tags

git tag --list

List the last tag. This method requires two commands, which does not work well when passed to the linler by go build.

git tag --sort=taggerdate | tail -1

List the githash for the HEAD

$ HEAD=`git rev-list --tags --max-count=1` && echo $HEAD
3d1cc50d8f96d5a4a08e6c679a30ea16cb0f878d

Listing the githash for the HEAD and using it to display the associated tag.

$ HEAD=`git rev-list --tags --max-count=1` && git describe --tags $HEAD
v0.0.1

Add a tag to the HEAD

git tag v0.0.10

Pushing tags

git push <tag-name>
git push --tags

Deleting tags

git tag -d v1.0.0
git push --delete <tag-name>

• How to display modules version from inside of code https://stackoverflow.com/questions/62009264/golang-how-to-display-modules-version-from-inside-of-code
• Go Runtime - Returning the build information embedded in the running binary. https://pkg.go.dev/runtime/debug#ReadBuildInfo
• Golang Auto Build Versioning https://www.atatus.com/blog/golang-auto-build-versioning/
• Module version numbering https://go.dev/doc/modules/version-numbers#pseudo-version-number
• Semantic Versioning https://semver.org/
• Git Tags https://initialcommit.com/blog/git-tag