This action installs and runs the CLI for Nerdbank.GitVersioning. It does the equivalent of:

dotnet tool install -g nbgv
nbgv cloud --all-vars --common-vars

This sets many environment variables to the various forms of the version for your repo or project.

Optional The path to the directory for which the version should be determined. This should be at or below the directory containing the version.json file. Default is repo root directory.

Optional Defines a few common version variables as cloud build variables, with a "Git" prefix (e.g. GitBuildVersion, GitBuildVersionSimple, GitAssemblyInformationalVersion).

Adds the --common-vars switch to the nbgv cloud command.

Default value is true.

Optional Defines ALL version variables as cloud build variables, with a "NBGV_" prefix.

Adds the --all-vars switch to the nbgv cloud command.

Default value is true.

Optional The version of the nbgv dotnet CLI tool to install and use. If not specified, the default is the latest stable version.

- uses: aarnott/nbgv@master
  with:
    path: src # optional path to directory to compute version for
- run: echo "NBGV_SemVer2 $NBGV_SemVer2"

The action runs in about 13 seconds.

Git history based versioning tools rely on history being included in the clone. actions/checkout@v1 does this by default. But if you're using actions/checkout@v2 you'll need to add a step before running this action:

- name: Deep clone
  run: git fetch --prune --unshallow origin HEAD