README.md

Stamp

Stamp exposes information about the build (user, host, time) and code version (description, commit, branch) at runtime.

Configuration

To include the library, add the following to your WORKSPACE:

load("@bazel_gazelle//:deps.bzl", "go_repository")
go_repository(
    name = "com_github_gebn_go_stamp_v2",
    tag = "v2.2.1",
    importpath = "github.com/gebn/go-stamp/v2",
)

Stamp uses a combination of workspace_status_command and x_defs to substitute values of Go vars at link time. Unfortunately, there does not currently appear to be a way to add to the workspace status from Starlark, so this must be manually configured.

First, create an executable script with the following contents somewhere in your workspace, e.g. bin/workspace_status (if you already have a workspace status script, you just need to add the three echo lines to it). N.B. due to this issue, having Bazel execute a script in the workspace root is awkward.

#!/bin/bash

set -o errexit
set -o nounset
set -o pipefail

echo "STABLE_STAMP_COMMIT $(git rev-parse HEAD)"
echo "STABLE_STAMP_BRANCH $(git rev-parse --abbrev-ref HEAD)"  # will be HEAD in detached HEAD state
echo "STABLE_STAMP_VERSION $(git describe --always --tags --dirty)"

Then add the following line to .bazelrc to execute the script during the build:

build --workspace_status_command=bin/workspace_status --stamp

You can test everything is working by calling Summary() in your project, which summarises all information gathered by this library:

package main

import (
    "fmt"

    "github.com/gebn/go-stamp/v2"
)

func main() {
    fmt.Println(stamp.Summary())
}

This should print something similar to:

v1.0.0 (709d67c5f0563c685838312cb33a2a92ab1788f5, master), built with go1.18.1 by george@dev on 2022-04-23T18:29:58+01:00

See examples for more detail. vanilla demos using this library without Bazel.