adding test

javaagent-core/build.gradle.kts

@@ -53,4 +53,6 @@ dependencies {
     implementation("com.fasterxml.jackson.dataformat:jackson-dataformat-yaml:2.11.3")
 
     api("com.blogspot.mydailyjava:weak-lock-free:0.17")
+
+    runtimeOnly("io.grpc:grpc-netty-shaded:1.37.0")
 }

javaagent-core/src/main/java/org/hypertrace/agent/core/config/HypertraceConfig.java

@@ -48,7 +48,10 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-/** {@link HypertraceConfig} loads a yaml config from file. */
+/**
+ * {@link HypertraceConfig} loads a yaml config from file and gets dynamic config if dynamic config
+ * service url is set in env vars or system properties.
+ */
 public class HypertraceConfig {
 
   private HypertraceConfig() {}
@@ -76,7 +79,14 @@ public static AgentConfig get() {
       DynamicConfigFetcher dynamicConfigFetcher = null;
       if (dynamicConfigServiceUrl != null) {
         dynamicConfigFetcher = new DynamicConfigFetcher(dynamicConfigServiceUrl);
-        Executors.newScheduledThreadPool(1)
+        Executors.newScheduledThreadPool(
+                1,
+                runnable -> {
+                  Thread thread = new Thread(runnable, "dynamic_agent_config_fetcher");
+                  thread.setDaemon(true);
+                  //                  thread.setContextClassLoader(null);
+                  return thread;
+                })
             .scheduleAtFixedRate(dynamicConfigFetcher, 60, 30, TimeUnit.SECONDS);
       }
       synchronized (HypertraceConfig.class) {
@@ -145,7 +155,8 @@ public static void reset() {
     }
   }
 
-  private static AgentConfig load(DynamicConfigFetcher dynamicConfigFetcher) throws IOException {
+  @VisibleForTesting
+  static AgentConfig load(DynamicConfigFetcher dynamicConfigFetcher) throws IOException {
     String configFile = EnvironmentConfig.getProperty(EnvironmentConfig.CONFIG_FILE_PROPERTY);
     if (configFile == null) {
       AgentConfig.Builder configBuilder = AgentConfig.newBuilder();
@@ -263,22 +274,23 @@ public static class DynamicConfigFetcher implements Runnable {
 
     private final ConfigurationServiceGrpc.ConfigurationServiceBlockingStub blockingStub;
 
-    private static Int64Value configTimestamp;
+    private static Int64Value configUpdatedTimestamp;
 
     private DynamicConfigFetcher(String dynamicConfigServiceUrl) {
-      Channel channel = ManagedChannelBuilder.forTarget(dynamicConfigServiceUrl).build();
+      Channel channel =
+          ManagedChannelBuilder.forTarget(dynamicConfigServiceUrl).usePlaintext().build();
       blockingStub = ConfigurationServiceGrpc.newBlockingStub(channel);
-      configTimestamp = Int64Value.newBuilder().setValue(System.currentTimeMillis()).build();
+      configUpdatedTimestamp = Int64Value.newBuilder().setValue(System.currentTimeMillis()).build();
     }
 
     @Override
     public void run() {
       Service.UpdateConfigurationResponse response =
           blockingStub.updateConfiguration(
               Service.UpdateConfigurationRequest.newBuilder()
-                  .setTimestamp(configTimestamp)
+                  .setTimestamp(configUpdatedTimestamp)
                   .build());
-      configTimestamp = response.getTimestamp();
+      configUpdatedTimestamp = response.getTimestamp();
       AgentConfig.Builder configBuilder = HypertraceConfig.get().toBuilder();
       configBuilder.setEnabled(response.getEnabled());
       configBuilder.setDataCapture(response.getDataCapture());
@@ -290,7 +302,7 @@ private AgentConfig initializeConfig() {
       Service.InitialConfigurationResponse response =
           blockingStub.initialConfiguration(
               Service.InitialConfigurationRequest.newBuilder().build());
-      configTimestamp = response.getTimestamp();
+      configUpdatedTimestamp = response.getTimestamp();
       return response.getAgentConfig();
     }
   }

javaagent-core/src/test/java/org/hypertrace/agent/core/config/DynamicConfigServer.java

@@ -0,0 +1,116 @@
+/*
+ * Copyright The Hypertrace Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.hypertrace.agent.core.config;
+
+import io.grpc.Server;
+import io.grpc.ServerBuilder;
+import java.io.IOException;
+import java.util.concurrent.TimeUnit;
+import org.hypertrace.agent.config.ConfigurationServiceGrpc;
+import org.hypertrace.agent.config.Service;
+
+public class DynamicConfigServer {
+
+  private final Server server;
+  private Service.InitialConfigurationResponse initialConfigurationResponse;
+  private Service.UpdateConfigurationResponse updateConfigurationResponse;
+
+  public DynamicConfigServer(int port) {
+    server = ServerBuilder.forPort(port).addService(new DynamicConfigService()).build();
+  }
+
+  /** Start serving requests. */
+  public void start() throws IOException {
+    server.start();
+    Runtime.getRuntime()
+        .addShutdownHook(
+            new Thread() {
+              @Override
+              public void run() {
+                // Use stderr here since the logger may have been reset by its JVM shutdown hook.
+                System.err.println("*** shutting down gRPC server since JVM is shutting down");
+                try {
+                  DynamicConfigServer.this.stop();
+                } catch (InterruptedException e) {
+                  e.printStackTrace(System.err);
+                }
+                System.err.println("*** server shut down");
+              }
+            });
+  }
+
+  /** Stop serving requests and shutdown resources. */
+  public void stop() throws InterruptedException {
+    if (server != null) {
+      server.shutdown().awaitTermination(30, TimeUnit.SECONDS);
+    }
+  }
+
+  /** Await termination on the main thread since the grpc library uses daemon threads. */
+  public void blockUntilShutdown() throws InterruptedException {
+    if (server != null) {
+      server.awaitTermination();
+    }
+  }
+
+  public Service.InitialConfigurationResponse getInitialConfigurationResponse() {
+    return initialConfigurationResponse;
+  }
+
+  public void setInitialConfigurationResponse(
+      Service.InitialConfigurationResponse initialConfigurationResponse) {
+    this.initialConfigurationResponse = initialConfigurationResponse;
+  }
+
+  public Service.UpdateConfigurationResponse getUpdateConfigurationResponse() {
+    return updateConfigurationResponse;
+  }
+
+  public void setUpdateConfigurationResponse(
+      Service.UpdateConfigurationResponse updateConfigurationResponse) {
+    this.updateConfigurationResponse = updateConfigurationResponse;
+  }
+
+  /** Main method. This comment makes the linter happy. */
+  public static void main(String[] args) throws Exception {
+    DynamicConfigServer server = new DynamicConfigServer(8980);
+    server.start();
+    server.blockUntilShutdown();
+  }
+
+  private class DynamicConfigService extends ConfigurationServiceGrpc.ConfigurationServiceImplBase {
+    @Override
+    public void initialConfiguration(
+        org.hypertrace.agent.config.Service.InitialConfigurationRequest request,
+        io.grpc.stub.StreamObserver<
+                org.hypertrace.agent.config.Service.InitialConfigurationResponse>
+            responseObserver) {
+
+      responseObserver.onNext(initialConfigurationResponse);
+      responseObserver.onCompleted();
+    }
+
+    @Override
+    public void updateConfiguration(
+        org.hypertrace.agent.config.Service.UpdateConfigurationRequest request,
+        io.grpc.stub.StreamObserver<org.hypertrace.agent.config.Service.UpdateConfigurationResponse>
+            responseObserver) {
+      responseObserver.onNext(updateConfigurationResponse);
+      responseObserver.onCompleted();
+    }
+  }
+}

javaagent-core/src/test/java/org/hypertrace/agent/core/config/HypertraceConfigTest.java

@@ -16,27 +16,61 @@
 
 package org.hypertrace.agent.core.config;
 
+import com.google.protobuf.BoolValue;
+import com.google.protobuf.Int32Value;
+import com.google.protobuf.Int64Value;
 import com.google.protobuf.StringValue;
 import com.google.protobuf.util.JsonFormat;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.net.URL;
 import java.util.Arrays;
+import org.hypertrace.agent.config.Config;
 import org.hypertrace.agent.config.Config.AgentConfig;
 import org.hypertrace.agent.config.Config.PropagationFormat;
 import org.hypertrace.agent.config.Config.TraceReporterType;
+import org.hypertrace.agent.config.Service;
+import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
 import org.junitpioneer.jupiter.ClearSystemProperty;
 
 public class HypertraceConfigTest {
 
+  private static DynamicConfigServer server;
+
+  @BeforeAll
+  public static void setup() throws Exception {
+    server = new DynamicConfigServer(1234);
+    Thread thread =
+        new Thread(
+            () -> {
+              try {
+                server.start();
+              } catch (IOException e) {
+                e.printStackTrace();
+              }
+              try {
+                server.blockUntilShutdown();
+              } catch (InterruptedException e) {
+                e.printStackTrace();
+              }
+            });
+    thread.start();
+  }
+
+  @AfterAll
+  public static void cleanup() throws InterruptedException {
+    server.stop();
+  }
+
   @Test
   public void defaultValues() throws IOException {
     URL resource = getClass().getClassLoader().getResource("emptyconfig.yaml");
-    AgentConfig agentConfig = HypertraceConfig.load(resource.getPath());
+    AgentConfig agentConfig = HypertraceConfig.load(resource.getPath(), null);
     Assertions.assertTrue(agentConfig.getEnabled().getValue());
     Assertions.assertEquals("unknown", agentConfig.getServiceName().getValue());
     Assertions.assertEquals(
@@ -79,22 +113,42 @@ public void defaultValues() throws IOException {
   @Test
   public void config() throws IOException {
     URL resource = getClass().getClassLoader().getResource("config.yaml");
-    AgentConfig agentConfig = HypertraceConfig.load(resource.getPath());
+    AgentConfig agentConfig = HypertraceConfig.load(resource.getPath(), null);
     assertConfig(agentConfig);
   }
 
   @Test
   public void jsonConfig(@TempDir File tempFolder) throws IOException {
     URL resource = getClass().getClassLoader().getResource("config.yaml");
-    AgentConfig agentConfig = HypertraceConfig.load(resource.getPath());
+    AgentConfig agentConfig = HypertraceConfig.load(resource.getPath(), null);
 
     String jsonConfig = JsonFormat.printer().print(agentConfig);
     Assertions.assertTrue(!jsonConfig.contains("value"));
     File jsonFile = new File(tempFolder, "config.jSon");
     FileOutputStream fileOutputStream = new FileOutputStream(jsonFile);
     fileOutputStream.write(jsonConfig.getBytes());
 
-    agentConfig = HypertraceConfig.load(jsonFile.getAbsolutePath());
+    agentConfig = HypertraceConfig.load(jsonFile.getAbsolutePath(), null);
+    assertConfig(agentConfig);
+  }
+
+  @Test
+  @ClearSystemProperty(key = EnvironmentConfig.DYNAMIC_CONFIG_SERVICE_URL)
+  @ClearSystemProperty(key = EnvironmentConfig.CONFIG_FILE_PROPERTY)
+  public void dynamicInitialConfig() throws IOException {
+    URL resource = getClass().getClassLoader().getResource("config.yaml");
+    AgentConfig agentConfig = HypertraceConfig.load(resource.getPath(), null);
+    Service.InitialConfigurationResponse initialConfigurationResponse =
+        Service.InitialConfigurationResponse.newBuilder()
+            .setTimestamp(Int64Value.newBuilder().setValue(System.currentTimeMillis()).build())
+            .setAgentConfig(agentConfig)
+            .build();
+
+    server.setInitialConfigurationResponse(initialConfigurationResponse);
+    server.setUpdateConfigurationResponse(getUpdateConfigurationResponse());
+
+    System.setProperty(EnvironmentConfig.DYNAMIC_CONFIG_SERVICE_URL, "localhost:1234");
+    agentConfig = HypertraceConfig.get();
     assertConfig(agentConfig);
   }
 
@@ -136,9 +190,29 @@ public void configWithSystemProps() throws IOException {
     System.setProperty(EnvironmentConfig.REPORTING_ENDPOINT, "http://nowhere.here");
 
     URL resource = getClass().getClassLoader().getResource("config.yaml");
-    AgentConfig agentConfig = HypertraceConfig.load(resource.getPath());
+    AgentConfig agentConfig = HypertraceConfig.load(resource.getPath(), null);
     Assertions.assertEquals(
         "http://nowhere.here", agentConfig.getReporting().getEndpoint().getValue());
     Assertions.assertEquals("service", agentConfig.getServiceName().getValue());
   }
+
+  private Service.UpdateConfigurationResponse getUpdateConfigurationResponse() {
+    Config.DataCapture dataCapture =
+        Config.DataCapture.newBuilder()
+            .setBodyMaxSizeBytes(Int32Value.newBuilder().setValue(12).build())
+            .setHttpHeaders(
+                Config.Message.newBuilder()
+                    .setResponse(BoolValue.newBuilder().setValue(false).build())
+                    .build())
+            .build();
+    return Service.UpdateConfigurationResponse.newBuilder()
+        .setDataCapture(dataCapture)
+        .setEnabled(BoolValue.newBuilder().setValue(false).build())
+        .setTimestamp(Int64Value.newBuilder().setValue(System.currentTimeMillis()).build())
+        .setJavaAgent(
+            Config.JavaAgent.newBuilder()
+                .addFilterJarPaths(StringValue.newBuilder().setValue("random").build())
+                .build())
+        .build();
+  }
 }