feat(serverless): tag Vercel runtime spans (#9660)

* feat(serverless): tag Vercel runtime spans

* refactor(serverless): collect platform span tags

Author: wconti27

packages/dd-trace/src/config/index.js

@@ -15,6 +15,7 @@ const { isTrue } = require('../util')
 const telemetry = require('../telemetry')
 const telemetryMetrics = require('../telemetry/metrics')
 const {
+  getPlatformTags,
   IS_SERVERLESS,
   getIsGCPFunction,
   getIsAzureFunction,
@@ -597,6 +598,9 @@ class Config extends ConfigBase {
       this.tags.version = this.version
     }
     this.tags['runtime-id'] = RUNTIME_ID
+    for (const [name, value] of Object.entries(getPlatformTags())) {
+      this.tags[name] ??= value
+    }
 
     if (IS_SERVERLESS) {
       setAndTrack(this, 'telemetry.DD_INSTRUMENTATION_TELEMETRY_ENABLED', false)

packages/dd-trace/src/serverless.js

@@ -42,7 +42,36 @@ function isInServerlessEnvironment () {
   return inAWSLambda || isGCPFunction || isAzureFunction
 }
 
+/**
+ * Gets tags describing the platform where the tracer is running.
+ *
+ * @returns {Record<string, string>}
+ */
+function getPlatformTags () {
+  return getVercelTags()
+}
+
+/**
+ * @returns {Record<string, string>}
+ */
+function getVercelTags () {
+  if (getEnvironmentVariable('VERCEL') !== '1') return {}
+
+  const tags = {
+    'vercel.project_id': getEnvironmentVariable('VERCEL_PROJECT_ID'),
+    'vercel.environment': getEnvironmentVariable('VERCEL_ENV'),
+    'vercel.region': getEnvironmentVariable('VERCEL_REGION'),
+  }
+
+  for (const [name, value] of Object.entries(tags)) {
+    if (!value) delete tags[name]
+  }
+
+  return tags
+}
+
 module.exports = {
+  getPlatformTags,
   getIsGCPFunction,
   getIsAzureFunction,
   enableGCPPubSubPushSubscription,

packages/dd-trace/test/plugins/agent.js

@@ -61,6 +61,10 @@ const TRACKED_NON_PREFIX_ENV_NAMES = new Set([
   'FUNCTIONS_WORKER_RUNTIME',
   'GCP_PROJECT',
   'K_SERVICE',
+  'VERCEL',
+  'VERCEL_ENV',
+  'VERCEL_PROJECT_ID',
+  'VERCEL_REGION',
   'WEBSITE_SKU',
   // lambda RITM target path (computed once at module load)
   'LAMBDA_TASK_ROOT',

packages/dd-trace/test/serverless.spec.js

@@ -6,7 +6,8 @@ const { describe, it, afterEach } = require('mocha')
 
 require('./setup/core')
 
-const { enableGCPPubSubPushSubscription } = require('../src/serverless')
+const { getPlatformTags, enableGCPPubSubPushSubscription } = require('../src/serverless')
+const agent = require('./plugins/agent')
 
 describe('enableGCPPubSubPushSubscription', () => {
   const originalKService = process.env.K_SERVICE
@@ -36,3 +37,76 @@ describe('enableGCPPubSubPushSubscription', () => {
     assert.strictEqual(enableGCPPubSubPushSubscription(), false)
   })
 })
+
+describe('Vercel span metadata', () => {
+  const environment = process.env
+
+  afterEach(async () => {
+    process.env = environment
+    await agent.close()
+  })
+
+  it('does not add tags outside Vercel', async () => {
+    process.env = {
+      ...environment,
+      VERCEL_DEPLOYMENT_ID: 'dpl_123',
+      VERCEL_ENV: 'preview',
+      VERCEL_PROJECT_ID: 'prj_123',
+      VERCEL_REGION: 'iad1',
+      VERCEL_TARGET_ENV: 'staging',
+    }
+    delete process.env.VERCEL
+
+    const tracer = await agent.load([], [], { service: 'vercel-metadata-test' })
+    tracer.startSpan('non-vercel-span').finish()
+
+    await agent.assertSomeTraces(traces => {
+      const { meta } = traces[0][0]
+      assert.strictEqual(meta['vercel.project_id'], undefined)
+      assert.strictEqual(meta['vercel.environment'], undefined)
+      assert.strictEqual(meta['vercel.region'], undefined)
+    })
+  })
+
+  it('adds present Vercel metadata to encoded spans', async () => {
+    process.env = {
+      ...environment,
+      VERCEL: '1',
+      VERCEL_DEPLOYMENT_ID: 'dpl_123',
+      VERCEL_ENV: 'preview',
+      VERCEL_PROJECT_ID: 'prj_123',
+      VERCEL_REGION: 'iad1',
+      VERCEL_TARGET_ENV: 'staging',
+    }
+
+    const tracer = await agent.load([], [], {
+      service: 'vercel-metadata-test',
+      tags: { 'vercel.region': 'custom-region' },
+    })
+    tracer.startSpan('vercel-span').finish()
+
+    await agent.assertSomeTraces(traces => {
+      assert.deepStrictEqual(Object.fromEntries(
+        Object.entries(traces[0][0].meta).filter(([name]) => name.startsWith('vercel.'))
+      ), {
+        'vercel.project_id': 'prj_123',
+        'vercel.environment': 'preview',
+        'vercel.region': 'custom-region',
+      })
+    })
+  })
+
+  it('discovers only present Vercel metadata as platform tags', () => {
+    process.env = {
+      ...environment,
+      VERCEL: '1',
+      VERCEL_ENV: 'preview',
+      VERCEL_PROJECT_ID: 'prj_123',
+    }
+
+    assert.deepStrictEqual(getPlatformTags(), {
+      'vercel.project_id': 'prj_123',
+      'vercel.environment': 'preview',
+    })
+  })
+})