Add tracing support to send information to the WebJobs extension

CHANGELOG.md

@@ -1,3 +1,7 @@
+## v1.5.2
+* Add distributed tracing support for Azure Functions client scenarios ([#211](https://github.com/microsoft/durabletask-java/pull/211))
+
+
 ## v1.5.1
 * Improve logging for unexpected connection failures in DurableTaskGrpcWorker ([#216](https://github.com/microsoft/durabletask-java/pull/216/files))
 * Add User-Agent Header to gRPC Metadata ([#213](https://github.com/microsoft/durabletask-java/pull/213))

client/build.gradle

@@ -15,6 +15,7 @@ archivesBaseName = 'durabletask-client'
 def grpcVersion = '1.59.0'
 def protocVersion = '3.12.0'
 def jacksonVersion = '2.15.3'
+def openTelemetryVersion = '1.25.0'
 // When build on local, you need to set this value to your local jdk11 directory.
 // Java11 is used to compile and run all the tests.
 // Example for Windows:  C:/Program Files/Java/openjdk-11.0.12_7/
@@ -34,6 +35,9 @@ dependencies {
     implementation "com.fasterxml.jackson.core:jackson-databind:${jacksonVersion}"
     implementation "com.fasterxml.jackson.core:jackson-annotations:${jacksonVersion}"
     implementation "com.fasterxml.jackson.datatype:jackson-datatype-jsr310:${jacksonVersion}"
+
+    implementation "io.opentelemetry:opentelemetry-api:${openTelemetryVersion}"
+    implementation "io.opentelemetry:opentelemetry-context:${openTelemetryVersion}"
 
     testImplementation(platform('org.junit:junit-bom:5.7.2'))
     testImplementation('org.junit.jupiter:junit-jupiter')

client/src/main/java/com/microsoft/durabletask/DurableTaskGrpcClient.java

@@ -17,6 +17,10 @@
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
 import java.util.logging.Logger;
+import java.util.stream.Collectors;
+
+import io.opentelemetry.api.trace.Span;
+import io.opentelemetry.api.trace.SpanContext;
 
 /**
  * Durable Task client implementation that uses gRPC to connect to a remote "sidecar" process.
@@ -110,6 +114,37 @@ public String scheduleNewOrchestrationInstance(
             builder.setScheduledStartTimestamp(ts);
         }
 
+        Span currentSpan = Span.current();
+        String traceParent = null;
+        String traceState = null;
+
+        if (currentSpan != null && currentSpan.getSpanContext().isValid()) {
+            SpanContext spanContext = currentSpan.getSpanContext();
+
+            // Construct the traceparent according to the W3C Trace Context specification
+            // https://www.w3.org/TR/trace-context/#traceparent-header
+            traceParent = String.format("00-%s-%s-%02x",
+                spanContext.getTraceId(), // 32-character trace ID
+                spanContext.getSpanId(),  // 16-character span ID
+                spanContext.getTraceFlags().asByte() // Trace flags (i.e. sampled or not)
+            );
+
+            // Get the tracestate
+            traceState = spanContext.getTraceState().asMap()
+                .entrySet()
+                .stream()
+                .map(entry -> entry.getKey() + "=" + entry.getValue())
+                .collect(Collectors.joining(","));
+        }
+
+        if (traceParent != null) {
+            TraceContext traceContext = TraceContext.newBuilder()
+                .setTraceParent(traceParent)
+                .setTraceState(traceState != null ? StringValue.of(traceState) : StringValue.getDefaultInstance())
+                .build();
+            builder.setParentTraceContext(traceContext); // Set the TraceContext in the CreateInstanceRequest
+        }
+
         CreateInstanceRequest request = builder.build();
         CreateInstanceResponse response = this.sidecarClient.startInstance(request);
         return response.getInstanceId();