Inject git metadata in datadog esbuild plugin (#6388)

Automatically retrieve and inject Git tags (`GIT_REPOSITORY_URL` and
`GIT_COMMIT_SHA`) in apps bundled with the Datadog esbuild plugin.

Co-authored-by: Thomas Watson <thomas.watson@datadoghq.com>

Author: olivwalsh

integration-tests/esbuild/build-and-test-git-tags.js

@@ -0,0 +1,57 @@
+#!/usr/bin/env node
+'use strict'
+
+/* eslint-disable no-console */
+const fs = require('fs')
+const { spawnSync } = require('child_process')
+const assert = require('assert')
+
+const ddPlugin = require('../../esbuild')
+const esbuild = require('esbuild')
+
+const SCRIPT = './git-tags-out.js'
+
+esbuild.build({
+  entryPoints: ['basic-test.js'],
+  bundle: true,
+  outfile: SCRIPT,
+  plugins: [ddPlugin],
+  platform: 'node',
+  target: ['node18'],
+  external: [
+    // dead code paths introduced by knex
+    'pg',
+    'mysql2',
+    'better-sqlite3',
+    'sqlite3',
+    'mysql',
+    'oracledb',
+    'pg-query-stream',
+    'tedious'
+  ]
+}).then(() => {
+  const { status, stdout, stderr } = spawnSync('node', [SCRIPT], {
+    env: { ...process.env, DD_TRACE_DEBUG: 'true' },
+    encoding: 'utf8'
+  })
+  if (stderr.length) {
+    console.error(stderr)
+  }
+  if (status) {
+    throw new Error(`Generated script exited with unexpected exit code: ${status}`)
+  }
+  if (stdout.length === 0) {
+    throw new Error('No debug output received. Git metadata may not be injected properly')
+  }
+  const repositoryURL = stdout.match(/"_dd\.git\.repository_url":"([^"]+)"/)?.[1]
+  const commitSha = stdout.match(/"_dd\.git\.commit\.sha":"([^"]+)"/)?.[1]
+  assert.ok(repositoryURL, '_dd.git.repository_url should be present')
+  assert.ok(commitSha, '_dd.git.commit.sha should be present')
+  assert.equal(commitSha.length, 40, 'Git commit sha tag should be valid')
+  console.log('ok')
+}).catch((err) => {
+  console.error(err)
+  process.exit(1)
+}).finally(() => {
+  fs.rmSync(SCRIPT, { force: true })
+})

integration-tests/esbuild/index.spec.js

@@ -87,6 +87,14 @@ esbuildVersions.forEach((version) => {
       })
     })
 
+    it('injects Git metadata into bundled applications', () => {
+      const command = 'node ./build-and-test-git-tags.js'
+      console.log(command)
+      chproc.execSync(command, {
+        timeout: 1000 * 30
+      })
+    })
+
     describe('ESM', () => {
       afterEach(() => {
         fs.rmSync('./out.mjs', { force: true })

packages/datadog-esbuild/index.js

@@ -33,6 +33,7 @@ const RAW_BUILTINS = require('module').builtinModules
 const CHANNEL = 'dd-trace:bundler:load'
 const path = require('path')
 const fs = require('fs')
+const { execSync } = require('child_process')
 
 const builtins = new Set()
 
@@ -61,6 +62,39 @@ function isESMBuild (build) {
   return format === 'esm' || outputFile?.endsWith('.mjs') || outExtension === '.mjs'
 }
 
+function getGitMetadata () {
+  const gitMetadata = {
+    repositoryURL: null,
+    commitSHA: null
+  }
+
+  try {
+    gitMetadata.repositoryURL = execSync('git config --get remote.origin.url', {
+      encoding: 'utf8',
+      stdio: ['pipe', 'pipe', 'ignore'],
+      cwd: process.cwd()
+    }).trim()
+  } catch (e) {
+    if (DEBUG) {
+      console.warn('Warning: failed to get git repository URL:', e.message)
+    }
+  }
+
+  try {
+    gitMetadata.commitSHA = execSync('git rev-parse HEAD', {
+      encoding: 'utf8',
+      stdio: ['pipe', 'pipe', 'ignore'],
+      cwd: process.cwd()
+    }).trim()
+  } catch (e) {
+    if (DEBUG) {
+      console.warn('Warning: failed to get git commit SHA:', e.message)
+    }
+  }
+
+  return gitMetadata
+}
+
 module.exports.setup = function (build) {
   const externalModules = new Set(build.initialOptions.external || [])
   if (isESMBuild(build)) {
@@ -77,6 +111,28 @@ ${build.initialOptions.banner.js}`
     }
   }
 
+  // Get git metadata at build time and add it to the banner for both ESM and CommonJS builds
+  const gitMetadata = getGitMetadata()
+  if (gitMetadata.repositoryURL || gitMetadata.commitSHA) {
+    build.initialOptions.banner ??= {}
+    build.initialOptions.banner.js ??= ''
+
+    build.initialOptions.banner.js = `if (typeof process === 'object' && process !== null &&
+    process.env !== null && typeof process.env === 'object') {
+  ${gitMetadata.repositoryURL ? `process.env.DD_GIT_REPOSITORY_URL = '${gitMetadata.repositoryURL}';` : ''}
+  ${gitMetadata.commitSHA ? `process.env.DD_GIT_COMMIT_SHA = '${gitMetadata.commitSHA}';` : ''}
+}
+${build.initialOptions.banner.js}`
+
+    if (DEBUG) {
+      console.log('Info: automatically injected git metadata:')
+      console.log(`DD_GIT_REPOSITORY_URL: ${gitMetadata.repositoryURL || 'not available'}`)
+      console.log(`DD_GIT_COMMIT_SHA: ${gitMetadata.commitSHA || 'not available'}`)
+    }
+  } else if (DEBUG) {
+    console.warn('Warning: No git metadata available - skipping injection')
+  }
+
   build.onResolve({ filter: /.*/ }, args => {
     if (externalModules.has(args.path)) {
       // Internal Node.js packages will still be instrumented via require()