Add JDK built-in support for UDS on Java 16+ (#8314)

* Use the JDK's built-in support for Unix Domain Sockets on Java 16+

* First draft of timeout test.

* Add server to test.

* Fix build.gradle file.

* Add debugging statements.

* Second draft of timeout test.

* Update getInputStream to use a selector.

* Clean code.

* Adjust dd-java-agent build.gradle.

* Revert dd-java-agent build.gradle change

* Revert another build.gradle change.

* Try specifying setSrcDirs.

* Try changing compatibility version.

* Revert previous two changes.

* Avoid implementation dependency for Java17.

* Make gradle dependency more specific and add testImplementation to socket-utils.

* Add synchronization to ensure that server starts before client connects.

* Try this...

* Add print statements.

* Add catch statement.

* Refactor getInputStream and getOutputStream.

* Address PR comments.

* Add test for when timeout is 0.

* Add config option.

---------

Co-authored-by: Stuart McCulloch <[email protected]>

Author: sarahchen6

dd-trace-api/src/main/java/datadog/trace/api/config/GeneralConfig.java

@@ -94,6 +94,7 @@ public final class GeneralConfig {
   public static final String AGENTLESS_LOG_SUBMISSION_LEVEL = "agentless.log.submission.level";
   public static final String AGENTLESS_LOG_SUBMISSION_URL = "agentless.log.submission.url";
   public static final String APM_TRACING_ENABLED = "apm.tracing.enabled";
+  public static final String JDK_SOCKET_ENABLED = "jdk.socket.enabled";
 
   private GeneralConfig() {}
 }

gradle/java_no_deps.gradle

@@ -59,9 +59,15 @@ if (project.hasProperty('minJavaVersionForTests') && project.getProperty('minJav
     targetCompatibility = version
   }
 
+  // "socket-utils" is only set to compileOnly because the implementation dependency incorrectly adds Java17 classes to all jar prefixes.
+  // This causes the AgentJarIndex to search for other non-Java17 classes in the wrong prefix location and fail to resolve class names.
   dependencies {
-    compileOnly files(project.sourceSets."main_$name".compileClasspath)
-    implementation files(project.sourceSets."main_$name".output)
+    if ("${project.projectDir}".endsWith("socket-utils")) {
+      compileOnly files(project.sourceSets."main_$name".output)
+    } else {
+      compileOnly files(project.sourceSets."main_$name".compileClasspath)
+      implementation files(project.sourceSets."main_$name".output)
+    }
   }
 
   jar {

internal-api/src/main/java/datadog/trace/api/Config.java

@@ -563,6 +563,8 @@ public static String getHostName() {
   private final boolean apmTracingEnabled;
   private final Set<String> experimentalFeaturesEnabled;
 
+  private final boolean jdkSocketEnabled;
+
   // Read order: System Properties -> Env Variables, [-> properties file], [-> default value]
   private Config() {
     this(ConfigProvider.createDefault());
@@ -1959,6 +1961,8 @@ PROFILING_DATADOG_PROFILER_ENABLED, isDatadogProfilerSafeInCurrentEnvironment())
 
     this.apmTracingEnabled = configProvider.getBoolean(GeneralConfig.APM_TRACING_ENABLED, true);
 
+    this.jdkSocketEnabled = configProvider.getBoolean(JDK_SOCKET_ENABLED, true);
+
     log.debug("New instance: {}", this);
   }
 
@@ -3537,6 +3541,10 @@ public boolean isApmTracingEnabled() {
     return apmTracingEnabled;
   }
 
+  public boolean isJdkSocketEnabled() {
+    return jdkSocketEnabled;
+  }
+
   /** @return A map of tags to be applied only to the local application root span. */
   public Map<String, Object> getLocalRootSpanTags() {
     final Map<String, String> runtimeTags = getRuntimeTags();
@@ -4784,6 +4792,8 @@ public String toString() {
         + dataJobsCommandPattern
         + ", apmTracingEnabled="
         + apmTracingEnabled
+        + ", jdkSocketEnabled="
+        + jdkSocketEnabled
         + ", cloudRequestPayloadTagging="
         + cloudRequestPayloadTagging
         + ", cloudResponsePayloadTagging="

internal-api/src/test/groovy/datadog/trace/api/ConfigTest.groovy

@@ -51,6 +51,7 @@ import static datadog.trace.api.config.GeneralConfig.GLOBAL_TAGS
 import static datadog.trace.api.config.GeneralConfig.HEALTH_METRICS_ENABLED
 import static datadog.trace.api.config.GeneralConfig.HEALTH_METRICS_STATSD_HOST
 import static datadog.trace.api.config.GeneralConfig.HEALTH_METRICS_STATSD_PORT
+import static datadog.trace.api.config.GeneralConfig.JDK_SOCKET_ENABLED
 import static datadog.trace.api.config.GeneralConfig.PERF_METRICS_ENABLED
 import static datadog.trace.api.config.GeneralConfig.SERVICE_NAME
 import static datadog.trace.api.config.GeneralConfig.SITE
@@ -261,6 +262,7 @@ class ConfigTest extends DDSpecification {
     prop.setProperty(DYNAMIC_INSTRUMENTATION_EXCLUDE_FILES, "exclude file")
     prop.setProperty(EXCEPTION_REPLAY_ENABLED, "true")
     prop.setProperty(TRACE_X_DATADOG_TAGS_MAX_LENGTH, "128")
+    prop.setProperty(JDK_SOCKET_ENABLED, "false")
 
     when:
     Config config = Config.get(prop)
@@ -354,6 +356,7 @@ class ConfigTest extends DDSpecification {
     config.dynamicInstrumentationInstrumentTheWorld == true
     config.dynamicInstrumentationExcludeFiles == "exclude file"
     config.debuggerExceptionEnabled == true
+    config.jdkSocketEnabled == false
 
     config.xDatadogTagsMaxLength == 128
   }

utils/socket-utils/build.gradle

@@ -1,8 +1,31 @@
+ext {
+  minJavaVersionForTests = JavaVersion.VERSION_17
+}
+
 apply from: "$rootDir/gradle/java.gradle"
+apply plugin: "idea"
+
+[compileMain_java17Java, compileTestJava].each {
+  it.configure {
+    setJavaVersion(it, 17)
+    sourceCompatibility = JavaVersion.VERSION_1_8
+    targetCompatibility = JavaVersion.VERSION_1_8
+  }
+}
 
 dependencies {
   implementation libs.slf4j
   implementation project(':internal-api')
+  implementation libs.jnr.unixsocket
+  testImplementation files(sourceSets.main_java17.output)
+}
+
+forbiddenApisMain_java17 {
+  failOnMissingClasses = false
+}
 
-  implementation group: 'com.github.jnr', name: 'jnr-unixsocket', version: libs.versions.jnr.unixsocket.get()
+idea {
+  module {
+    jdkName = '17'
+  }
 }

utils/socket-utils/src/main/java/datadog/common/socket/UnixDomainSocketFactory.java

@@ -3,6 +3,7 @@
 import static java.util.concurrent.TimeUnit.MINUTES;
 
 import datadog.trace.api.Config;
+import datadog.trace.api.Platform;
 import datadog.trace.relocate.api.RatelimitedLogger;
 import java.io.File;
 import java.io.IOException;
@@ -24,6 +25,8 @@
 public final class UnixDomainSocketFactory extends SocketFactory {
   private static final Logger log = LoggerFactory.getLogger(UnixDomainSocketFactory.class);
 
+  private static final boolean JDK_SUPPORTS_UDS = Platform.isJavaVersionAtLeast(16);
+
   private final RatelimitedLogger rlLog = new RatelimitedLogger(log, 5, MINUTES);
 
   private final File path;
@@ -35,8 +38,14 @@ public UnixDomainSocketFactory(final File path) {
   @Override
   public Socket createSocket() throws IOException {
     try {
-      final UnixSocketChannel channel = UnixSocketChannel.open();
-      return new TunnelingUnixSocket(path, channel);
+      if (JDK_SUPPORTS_UDS && Config.get().isJdkSocketEnabled()) {
+        try {
+          return new TunnelingJdkSocket(path.toPath());
+        } catch (Throwable ignore) {
+          // fall back to jnr-unixsocket library
+        }
+      }
+      return new TunnelingUnixSocket(path, UnixSocketChannel.open());
     } catch (Throwable e) {
       if (Config.get().isAgentConfiguredUsingDefault()) {
         // fall back to port if we previously auto-discovered this socket file