refactor(o11y): merge SpanTracer and SpanManager (#4158)

Author: diegomarquezp

gax-java/gax/src/main/java/com/google/api/gax/tracing/OpenTelemetryTraceManager.java

@@ -32,52 +32,87 @@
 
 import com.google.api.core.BetaApi;
 import com.google.api.core.InternalApi;
+import io.opentelemetry.api.trace.Span;
+import io.opentelemetry.api.trace.SpanBuilder;
+import io.opentelemetry.api.trace.SpanKind;
+import io.opentelemetry.api.trace.Tracer;
 import java.util.HashMap;
 import java.util.Map;
 
-/**
- * An implementation of {@link ApiTracer} that uses a {@link TraceManager} to record traces. This
- * implementation is agnostic to the specific {@link TraceManager} in order to allow extensions that
- * interact with other backends.
- */
+/** An implementation of {@link ApiTracer} that uses OpenTelemetry to record traces. */
 @BetaApi
 @InternalApi
 public class SpanTracer implements ApiTracer {
   public static final String LANGUAGE_ATTRIBUTE = "gcp.client.language";
 
   public static final String DEFAULT_LANGUAGE = "Java";
 
-  private final TraceManager traceManager;
+  private final Tracer tracer;
   private final Map<String, Object> attemptAttributes;
   private final String attemptSpanName;
   private final ApiTracerContext apiTracerContext;
-  private TraceManager.Span attemptHandle;
+  private Span attemptSpan;
 
   /**
    * Creates a new instance of {@code SpanTracer}.
    *
-   * @param traceManager the {@link TraceManager} to use for recording spans
+   * @param tracer the {@link Tracer} to use for recording spans
+   * @param apiTracerContext the {@link ApiTracerContext} to use for recording spans
+   */
+  public SpanTracer(Tracer tracer, ApiTracerContext apiTracerContext) {
+    this.tracer = tracer;
+    this.apiTracerContext = apiTracerContext;
+    this.attemptSpanName = resolveAttemptSpanName(apiTracerContext);
+    this.attemptAttributes = new HashMap<>();
+    buildAttributes();
+  }
+
+  /**
+   * Creates a new instance of {@code SpanTracer} with an explicitly provided span name.
+   *
+   * @param tracer the {@link Tracer} to use for recording spans
+   * @param apiTracerContext the {@link ApiTracerContext} to use for recording spans
    * @param attemptSpanName the name of the individual attempt spans
    */
-  public SpanTracer(
-      TraceManager traceManager, ApiTracerContext apiTracerContext, String attemptSpanName) {
-    this.traceManager = traceManager;
+  @InternalApi
+  SpanTracer(Tracer tracer, ApiTracerContext apiTracerContext, String attemptSpanName) {
+    this.tracer = tracer;
     this.attemptSpanName = attemptSpanName;
     this.apiTracerContext = apiTracerContext;
     this.attemptAttributes = new HashMap<>();
     buildAttributes();
   }
 
+  private static String resolveAttemptSpanName(ApiTracerContext apiTracerContext) {
+    if (apiTracerContext.transport() == ApiTracerContext.Transport.GRPC) {
+      // gRPC Uses the full method name as span name.
+      return apiTracerContext.fullMethodName();
+    } else if (apiTracerContext.httpMethod() == null
+        || apiTracerContext.httpPathTemplate() == null) {
+      // HTTP method name without necessary components defaults to the full method name
+      return apiTracerContext.fullMethodName();
+    } else {
+      // We construct the span name with HTTP method and path template.
+      return String.format(
+          "%s %s", apiTracerContext.httpMethod(), apiTracerContext.httpPathTemplate());
+    }
+  }
+
   private void buildAttributes() {
     this.attemptAttributes.put(LANGUAGE_ATTRIBUTE, DEFAULT_LANGUAGE);
     this.attemptAttributes.putAll(this.apiTracerContext.getAttemptAttributes());
   }
 
   @Override
   public void attemptStarted(Object request, int attemptNumber) {
-    Map<String, Object> attemptAttributes = new HashMap<>(this.attemptAttributes);
-    // Start the specific attempt span with the operation span as parent
-    this.attemptHandle = traceManager.createSpan(attemptSpanName, attemptAttributes);
+    SpanBuilder spanBuilder = tracer.spanBuilder(attemptSpanName);
+
+    // Attempt spans are of the CLIENT kind
+    spanBuilder.setSpanKind(SpanKind.CLIENT);
+
+    spanBuilder.setAllAttributes(ObservabilityUtils.toOtelAttributes(this.attemptAttributes));
+
+    this.attemptSpan = spanBuilder.startSpan();
   }
 
   @Override
@@ -86,9 +121,9 @@ public void attemptSucceeded() {
   }
 
   private void endAttempt() {
-    if (attemptHandle != null) {
-      attemptHandle.end();
-      attemptHandle = null;
+    if (attemptSpan != null) {
+      attemptSpan.end();
+      attemptSpan = null;
     }
   }
 }

gax-java/gax/src/main/java/com/google/api/gax/tracing/SpanTracer.java

@@ -33,25 +33,27 @@
 import com.google.api.core.BetaApi;
 import com.google.api.core.InternalApi;
 import com.google.common.annotations.VisibleForTesting;
+import io.opentelemetry.api.OpenTelemetry;
+import io.opentelemetry.api.trace.Tracer;
 
 /**
  * A {@link ApiTracerFactory} to build instances of {@link SpanTracer}.
  *
- * <p>This class wraps the {@link TraceManager} and pass it to {@link SpanTracer}. It will be used
- * to record traces in {@link SpanTracer}.
+ * <p>This class wraps the {@link Tracer} and pass it to {@link SpanTracer}. It will be used to
+ * record traces in {@link SpanTracer}.
  *
  * <p>This class is expected to be initialized once during client initialization.
  */
 @BetaApi
 @InternalApi
 public class SpanTracerFactory implements ApiTracerFactory {
-  private final TraceManager traceManager;
+  private final Tracer tracer;
 
   private final ApiTracerContext apiTracerContext;
 
   /** Creates a SpanTracerFactory */
-  public SpanTracerFactory(TraceManager traceManager) {
-    this(traceManager, ApiTracerContext.empty());
+  public SpanTracerFactory(OpenTelemetry openTelemetry) {
+    this(openTelemetry.getTracer("gax-java"), ApiTracerContext.empty());
   }
 
   /**
@@ -60,8 +62,8 @@ public SpanTracerFactory(TraceManager traceManager) {
    * internally.
    */
   @VisibleForTesting
-  SpanTracerFactory(TraceManager traceManager, ApiTracerContext apiTracerContext) {
-    this.traceManager = traceManager;
+  SpanTracerFactory(Tracer tracer, ApiTracerContext apiTracerContext) {
+    this.tracer = tracer;
     this.apiTracerContext = apiTracerContext;
   }
 
@@ -71,28 +73,13 @@ public ApiTracer newTracer(ApiTracer parent, SpanName spanName, OperationType op
     // feature is developed.
     String attemptSpanName = spanName.getClientName() + "/" + spanName.getMethodName() + "/attempt";
 
-    SpanTracer spanTracer = new SpanTracer(traceManager, this.apiTracerContext, attemptSpanName);
-    return spanTracer;
+    return new SpanTracer(tracer, this.apiTracerContext, attemptSpanName);
   }
 
   @Override
   public ApiTracer newTracer(ApiTracer parent, ApiTracerContext apiTracerContext) {
     ApiTracerContext mergedContext = this.apiTracerContext.merge(apiTracerContext);
-
-    String attemptSpanName;
-    if (mergedContext.transport() == ApiTracerContext.Transport.GRPC) {
-      // gRPC Uses the full method name as span name.
-      attemptSpanName = mergedContext.fullMethodName();
-    } else if (mergedContext.httpMethod() == null || mergedContext.httpPathTemplate() == null) {
-      // HTTP method name without necessary components defaults to the full method name
-      attemptSpanName = mergedContext.fullMethodName();
-    } else {
-      // We construct the span name with HTTP method and path template.
-      attemptSpanName =
-          String.format("%s %s", mergedContext.httpMethod(), mergedContext.httpPathTemplate());
-    }
-
-    return new SpanTracer(traceManager, mergedContext, attemptSpanName);
+    return new SpanTracer(tracer, mergedContext);
   }
 
   @Override
@@ -102,6 +89,6 @@ public ApiTracerContext getApiTracerContext() {
 
   @Override
   public ApiTracerFactory withContext(ApiTracerContext context) {
-    return new SpanTracerFactory(traceManager, apiTracerContext.merge(context));
+    return new SpanTracerFactory(tracer, apiTracerContext.merge(context));
   }
 }