feat(lambda): adopt mini agent for Lambda Lite environments

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

@@ -21,7 +21,7 @@ const {
   getIsAzureFunction,
   enableGCPPubSubPushSubscription,
 } = require('../serverless')
-const { ORIGIN_KEY } = require('../constants')
+const { ORIGIN_KEY, DATADOG_MINI_AGENT_PATH } = require('../constants')
 const { appendRules } = require('../payload-tagging/config')
 const { getGitMetadataFromGitProperties, removeUserSensitiveInfo, getRemoteOriginURL, resolveGitHeadSHA } =
   require('./git_properties')
@@ -620,7 +620,7 @@ class Config {
     unprocessedTarget['experimental.aiguard.timeout'] = DD_AI_GUARD_TIMEOUT
     setBoolean(target, 'experimental.enableGetRumData', DD_TRACE_EXPERIMENTAL_GET_RUM_DATA_ENABLED)
     setString(target, 'experimental.exporter', DD_TRACE_EXPERIMENTAL_EXPORTER)
-    if (AWS_LAMBDA_FUNCTION_NAME) {
+    if (AWS_LAMBDA_FUNCTION_NAME && !fs.existsSync(DATADOG_MINI_AGENT_PATH)) {
       target.flushInterval = 0
     } else if (DD_TRACE_FLUSH_INTERVAL) {
       target.flushInterval = maybeInt(DD_TRACE_FLUSH_INTERVAL)

packages/dd-trace/src/constants.js

@@ -22,6 +22,7 @@ module.exports = {
   SPAN_SAMPLING_RULE_RATE: '_dd.span_sampling.rule_rate',
   SPAN_SAMPLING_MAX_PER_SECOND: '_dd.span_sampling.max_per_second',
   DATADOG_LAMBDA_EXTENSION_PATH: '/opt/extensions/datadog-agent',
+  DATADOG_MINI_AGENT_PATH: '/tmp/datadog/mini_agent_ready',
   DECISION_MAKER_KEY: '_dd.p.dm',
   SAMPLING_KNUTH_RATE: '_dd.p.ksr',
   PROCESS_ID: 'process_id',

packages/dd-trace/src/exporter.js

@@ -25,8 +25,11 @@ module.exports = function getExporter (name) {
       return require('./ci-visibility/exporters/test-worker')
     default: {
       const inAWSLambda = getEnvironmentVariable('AWS_LAMBDA_FUNCTION_NAME') !== undefined
-      const usingLambdaExtension = inAWSLambda && fs.existsSync(constants.DATADOG_LAMBDA_EXTENSION_PATH)
-      return require(inAWSLambda && !usingLambdaExtension ? './exporters/log' : './exporters/agent')
+      const usingAgent = inAWSLambda && (
+        fs.existsSync(constants.DATADOG_LAMBDA_EXTENSION_PATH) ||
+        fs.existsSync(constants.DATADOG_MINI_AGENT_PATH)
+      )
+      return require(inAWSLambda && !usingAgent ? './exporters/log' : './exporters/agent')
     }
   }
 }

packages/dd-trace/test/config/index.spec.js

@@ -2330,6 +2330,29 @@ describe('Config', () => {
     assert.strictEqual(config.remoteConfig.enabled, false)
   })
 
+  describe('flushInterval in Lambda', () => {
+    afterEach(() => {
+      existsSyncReturn = undefined
+    })
+
+    it('should set flushInterval to 0 in standard Lambda environment', () => {
+      process.env.AWS_LAMBDA_FUNCTION_NAME = 'my-great-lambda-function'
+
+      const config = getConfig()
+
+      assert.strictEqual(config.flushInterval, 0)
+    })
+
+    it('should not set flushInterval to 0 in Lambda environment with mini agent', () => {
+      process.env.AWS_LAMBDA_FUNCTION_NAME = 'my-great-lambda-function'
+      existsSyncReturn = true
+
+      const config = getConfig()
+
+      assert.strictEqual(config.flushInterval, 2000)
+    })
+  })
+
   it('should not set DD_REMOTE_CONFIGURATION_ENABLED if FUNCTION_NAME and GCP_PROJECT are present', () => {
     process.env.FUNCTION_NAME = 'function_name'
     process.env.GCP_PROJECT = 'project_name'

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

@@ -9,6 +9,7 @@ const sinon = require('sinon')
 require('./setup/core')
 const AgentExporter = require('../src/exporters/agent')
 const LogExporter = require('../src/exporters/log')
+const { DATADOG_MINI_AGENT_PATH } = require('../src/constants')
 
 describe('exporter', () => {
   let env
@@ -47,6 +48,17 @@ describe('exporter', () => {
     stub.restore()
   })
 
+  it('should create an AgentExporter when in Lambda environment with mini agent', () => {
+    process.env.AWS_LAMBDA_FUNCTION_NAME = 'my-func'
+    const stub = sinon.stub(fs, 'existsSync')
+    stub.withArgs(DATADOG_MINI_AGENT_PATH).returns(true)
+
+    const Exporter = require('../src/exporter')()
+
+    assert.strictEqual(Exporter, AgentExporter)
+    stub.restore()
+  })
+
   it('should allow configuring the exporter', () => {
     const Exporter = require('../src/exporter')('log')