[#206] Support grpc built-in retry header

lib/client/grpc-data-sender.js

@@ -15,20 +15,13 @@ const GrpcClientSideStream = require('./grpc-client-side-stream')
 const Scheduler = require('../utils/scheduler')
 const makeAgentInformationMetadataInterceptor = require('./grpc/make-agent-information-metadata-interceptor')
 const socketIdInterceptor = require('./grpc/socketid-interceptor')
+const grpcBuiltInRetryHeaderInterceptor = require('./grpc/grpc-built-in-retry-header-interceptor')
 const CallArgumentsBuilder = require('./call-arguments-builder')
 const OptionsBuilder = require('./grpc/options-builder')
 
 // AgentInfoSender.java
 // refresh daily
 const DEFAULT_AGENT_INFO_REFRESH_INTERVAL_MS = 24 * 60 * 60 * 1000
-// retry every 3 seconds
-const DEFAULT_AGENT_INFO_SEND_INTERVAL_MS = 3 * 1000
-// retry 3 times per attempt
-const DEFAULT_MAX_TRY_COUNT_PER_ATTEMPT = 3
-
-// in GrpcTransportConfig.java
-const DEFAULT_METADATA_RETRY_MAX_COUNT = 3
-const DEFAULT_METADATA_RETRY_DELAY_MILLIS = 1000
 
 class GrpcDataSender {
   constructor(collectorIp, collectorTcpPort, collectorStatPort, collectorSpanPort, agentInfo, config) {
@@ -70,6 +63,7 @@ class GrpcDataSender {
     const agentBuilder = new OptionsBuilder()
       .addInterceptor(makeAgentInformationMetadataInterceptor(this.agentInfo))  
       .addInterceptor(socketIdInterceptor)
+      .addInterceptor(grpcBuiltInRetryHeaderInterceptor)
 
     if (config && config.grpcServiceConfig && typeof config.grpcServiceConfig.getAgentServiceConfig === 'function') {
       agentBuilder.setGrpcServiceConfig(config.grpcServiceConfig.getAgentServiceConfig())
@@ -80,6 +74,7 @@ class GrpcDataSender {
   initializeMetadataClients(collectorIp, collectorTcpPort, config) {
     const metadataBuilder = new OptionsBuilder()
       .addInterceptor(makeAgentInformationMetadataInterceptor(this.agentInfo))
+      .addInterceptor(grpcBuiltInRetryHeaderInterceptor)
 
     if (config && config.grpcServiceConfig && typeof config.grpcServiceConfig.getMetadataServiceConfig === 'function') {
       metadataBuilder.setGrpcServiceConfig(config.grpcServiceConfig.getMetadataServiceConfig())

lib/client/grpc/grpc-built-in-retry-header-interceptor.js

@@ -0,0 +1,21 @@
+/**
+ * Pinpoint Node.js Agent
+ * Copyright 2020-present NAVER Corp.
+ * Apache License v2.0
+ */
+
+'use strict'
+
+const grpc = require('@grpc/grpc-js')
+const InterceptingCall = grpc.InterceptingCall
+
+const grpcBuiltInRetryHeaderInterceptor = function (options, nextCall) {
+    return new InterceptingCall(nextCall(options), {
+        start: function (metadata, listener, next) {
+            metadata.add('grpc.built-in.retry', 'true')
+            next(metadata, listener, next)
+        },
+    })
+}
+
+module.exports = grpcBuiltInRetryHeaderInterceptor

test/client/grpc-unary-rpc.test.js

@@ -24,6 +24,7 @@ const SqlUidMetaData = require('../../lib/client/sql-uid-meta-data')
 let callCount = 0
 let afterCount = 0
 let callRequests = []
+let callMetadata = []
 // https://github.com/agreatfool/grpc_tools_node_protoc_ts/blob/v5.0.0/examples/src/grpcjs/client.ts
 const service = (call, callback) => {
     const succeedOnRetryAttempt = call.metadata.get('succeed-on-retry-attempt')
@@ -35,6 +36,7 @@ const service = (call, callback) => {
         result.setSuccess(true)
         result.setMessage(`succeed-on-retry-attempt: ${succeedOnRetryAttempt[0]}, grpc-previous-rpc-attempts: ${previousAttempts[0]}`)
         callRequests.push(call.request)
+        callMetadata.push(call.metadata)
         callback(null, result)
     } else {
         const statusCode = call.metadata.get('respond-with-status')
@@ -58,6 +60,7 @@ function beforeSpecificOne(port, one, serviceConfig) {
     afterCount = 0
     config.clear()
     callRequests = []
+    callMetadata = []
     const actualConfig = config.getConfig({ 'grpc.service_config': serviceConfig })
     actualConfig.collectorIp = 'localhost'
     actualConfig.collectorTcpPort = port
@@ -241,6 +244,9 @@ test('sendApiMetaInfo retry', (t) => {
                 t.fail(error)
             }
             t.true(response.getSuccess(), '1st PResult.success is true')
+
+            const metadata = callMetadata[0]
+            t.deepEqual(metadata.get('grpc.built-in.retry'), ['true'], '1st metadata.get("grpc.built-in.retry") is "true"')
             afterOne(t)
         }).build()
         dataSender.sendApiMetaInfo(actual, callArguments)