kenshaw / git-buildnumber

git-buildnumber provides a way to generate standardized build numbers from a git repository.

About git-buildnumber

git-buildnumber produces versions strings for Git repositories in a W.X.Y.Z format, such that:

W - Number of years since the start of the repo
X - Month of year of a git commit
Y - Day of the month of a git commit
Z - Order (the number) of the git commit that day

By default, git-buildnumber calculates W as the number of calendar years since the repo's initial commit, but can be changed via a command-line option (see below).

Use-case

git-buildnumber produces standardized version strings in a human-readable form for use with rolling release cycles, or when a lexicographically-ordered build number is desirable. Version strings generated by git-buildnumber are not meant as a replacement for standard short/long Git commit hashes.

Installing

Install in the usual Go way:

$ go get -u github.com/brankas/git-buildnumber

Using

The following examples are for the HEAD of a Git repo created in 2014, and where the latest commit (ie, the 0th) was made on March 3rd, 2015:

# general (from within the git worktree)
$ cd /path/to/repo
$ git-buildnumber
v1.2.3.0

# specify path to repo
$ git-buildnumber /path/to/repo
v1.2.3.0

# short form (trims last ".0")
$ git-buildnumber -short
v1.2.3

# use 2000 as year offset
$ git-buildnumber -year 2000
v15.2.3.0

# use 2015 as year offset
$ git-buildnumber -year 2015
v0.2.3.0

# short form and 2000 as year offset
$ git-buildnumber -short -year 2000
v15.2.3

# short form and 0 as year offset
$ git-buildnumber -short -year 0
v2015.2.3

# inverse
$ git-buildnumber -inverse v1.2.3.0
a3efd74543d3402b62184081ed93bfdf2c65421d

Command-line parameters

Usage of git-buildnumber:
  -inverse string
    	string to inverse
  -prefix string
    	prefix (default "v")
  -rev string
    	git revision (default "HEAD")
  -sep string
    	field separator (default ".")
  -short
    	trim last "<sep>0" from version
  -year string
    	start year offset

Note: when -year is not specified, then an attempt is made to use the year of the first commit in the repository. If the year cannot be determined, then no offset calculation will be performed.

git-buildnumber's Issues

outputs v0.0.0.0 if git isn't available

It should error. Or even better, not depend on git being installed at all, by using go-git.

Performance

I've just given git-buildnumber a try.
It's a great concept, but the performance leaves a little to be desired:

$ git count
total 8888

$ time git buildnumber 
v20.4.11.0

real  15m1.018s
user  19m13.620s
sys    0m28.517s

Quarter of an hour :-)