Added observability utility for Tracer and Meter usage

core/src/main/java/tech/ydb/core/grpc/YdbHeaders.java

@@ -41,7 +41,6 @@ private YdbHeaders() { }
     public static ClientInterceptor createMetadataInterceptor(GrpcTransportBuilder builder) {
         Metadata extraHeaders = new Metadata();
         extraHeaders.put(YdbHeaders.DATABASE, builder.getDatabase());
-        extraHeaders.put(YdbHeaders.BUILD_INFO, builder.getBuildInfo());
         String appName = builder.getApplicationName();
         if (appName != null) {
             extraHeaders.put(YdbHeaders.APPLICATION_NAME, appName);

core/src/main/java/tech/ydb/core/impl/BaseGrpcTransport.java

@@ -56,13 +56,15 @@ public abstract class BaseGrpcTransport implements GrpcTransport {
     private final AtomicBoolean isClosed = new AtomicBoolean(false);
 
     protected final EndpointRecord serverEndpoint;
+    private final String buildInfo;
 
     protected BaseGrpcTransport(GrpcTransportBuilder builder) {
-        this.serverEndpoint = getDiscoveryEndpoint(builder);
+        this(getDiscoveryEndpoint(builder), builder.getBuildInfo());
     }
 
-    protected BaseGrpcTransport(EndpointRecord serverEndpoint) {
+    protected BaseGrpcTransport(EndpointRecord serverEndpoint, String buildInfo) {
         this.serverEndpoint = serverEndpoint;
+        this.buildInfo = buildInfo;
     }
 
     protected abstract AuthCallOptions getAuthCallOptions();
@@ -244,6 +246,7 @@ private static Status deadlineExpiredStatus(MethodDescriptor<?, ?> method, GrpcR
 
     private Metadata makeMetadataFromSettings(GrpcRequestSettings settings, EndpointRecord endpoint) {
         Metadata metadata = new Metadata();
+        metadata.put(YdbHeaders.BUILD_INFO, buildInfo);
         String token = getAuthCallOptions().getToken();
         if (token != null) {
             metadata.put(YdbHeaders.AUTH_TICKET, token);

core/src/main/java/tech/ydb/core/impl/FixedCallOptionsTransport.java

@@ -2,9 +2,6 @@
 
 import java.util.concurrent.ScheduledExecutorService;
 
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
 import tech.ydb.core.grpc.GrpcRequestSettings;
 import tech.ydb.core.impl.auth.AuthCallOptions;
 import tech.ydb.core.impl.pool.EndpointRecord;
@@ -16,8 +13,6 @@
  * @author Aleksandr Gorshenin
  */
 public class FixedCallOptionsTransport extends BaseGrpcTransport {
-    private static final Logger logger = LoggerFactory.getLogger(FixedCallOptionsTransport.class);
-
     private final ScheduledExecutorService scheduler;
     private final AuthCallOptions callOptions;
     private final String database;
@@ -27,9 +22,10 @@ public FixedCallOptionsTransport(
             ScheduledExecutorService scheduler,
             AuthCallOptions callOptions,
             String database,
+            String buildInfo,
             EndpointRecord endpoint,
             ManagedChannelFactory channelFactory) {
-        super(endpoint);
+        super(endpoint, buildInfo);
         this.scheduler = scheduler;
         this.callOptions = callOptions;
         this.database = database;

core/src/main/java/tech/ydb/core/impl/Observability.java

@@ -0,0 +1,44 @@
+package tech.ydb.core.impl;
+
+import com.google.common.annotations.VisibleForTesting;
+
+import tech.ydb.core.metrics.Meter;
+import tech.ydb.core.tracing.NoopTracer;
+import tech.ydb.core.tracing.Tracer;
+
+/**
+ *
+ * @author Aleksandr Gorshenin {@literal <alexandr268@ydb.tech>}
+ */
+public final class Observability {
+    public static final String TRACING_CHAIN = ";ydb-sdk-tracing/0.1.0";
+    public static final String METRICS_CHAIN = ";ydb-sdk-metrics/0.1.0";
+
+    private static volatile boolean isTracingEnabled = false;
+    private static volatile boolean isMetricsEnabled = false;
+
+    private Observability() {
+    }
+
+    public static void reportTracingUsage(Tracer tracer) {
+        if (tracer != NoopTracer.getInstance()) {
+            isTracingEnabled = true;
+        }
+    }
+
+    public static void reportMetricsUsage(Meter meter) {
+        if (meter != Meter.NOOP) {
+            isMetricsEnabled = true;
+        }
+    }
+
+    static String getDiscoveryBuildInfo(String base) {
+        return base + (isTracingEnabled ? TRACING_CHAIN : "") + (isMetricsEnabled ? METRICS_CHAIN : "");
+    }
+
+    @VisibleForTesting
+    static void reset() {
+        isTracingEnabled = false;
+        isMetricsEnabled = false;
+    }
+}

core/src/main/java/tech/ydb/core/impl/YdbTransportImpl.java

@@ -45,6 +45,7 @@ public YdbTransportImpl(GrpcTransportBuilder builder) {
 
         this.database = Strings.nullToEmpty(builder.getDatabase());
         this.tracer = builder.getTracer();
+        Observability.reportTracingUsage(this.tracer);
 
         logger.info("Create YDB transport with endpoint {} and {}", serverEndpoint, balancingSettings);
 
@@ -54,7 +55,8 @@ public YdbTransportImpl(GrpcTransportBuilder builder) {
                 channelFactory, builder);
         this.channelPool = new GrpcChannelPool(channelFactory, scheduler);
         this.endpointPool = new EndpointPool(balancingSettings);
-        this.discovery = new YdbDiscovery(new DiscoveryHandler(), scheduler, database, discoveryTimeout);
+        DiscoveryHandler handler = new DiscoveryHandler(builder.getBuildInfo());
+        this.discovery = new YdbDiscovery(handler, scheduler, database, discoveryTimeout);
     }
 
     public void start(GrpcTransportBuilder.InitMode mode) {
@@ -149,6 +151,12 @@ protected void pessimizeEndpoint(EndpointRecord endpoint, String reason) {
     }
 
     private class DiscoveryHandler implements YdbDiscovery.Handler {
+        private final String baseBuildInfo;
+
+        DiscoveryHandler(String buildInfo) {
+            this.baseBuildInfo = buildInfo;
+        }
+
         @Override
         public Instant instant() {
             return Instant.now();
@@ -167,7 +175,10 @@ public CompletableFuture<Boolean> handleEndpoints(List<EndpointRecord> endpoints
 
         @Override
         public GrpcTransport createDiscoveryTransport() {
-            return new FixedCallOptionsTransport(scheduler, callOptions, database, serverEndpoint, channelFactory);
+            String buildInfo = Observability.getDiscoveryBuildInfo(baseBuildInfo);
+            return new FixedCallOptionsTransport(
+                    scheduler, callOptions, database, buildInfo, serverEndpoint, channelFactory
+            );
         }
     }
 }

core/src/main/java/tech/ydb/core/impl/auth/AuthCallOptions.java

@@ -38,7 +38,9 @@ public AuthCallOptions(
 
         AuthRpcProvider<? super GrpcAuthRpc> authProvider = builder.getAuthProvider();
         if (authProvider != null) {
-            GrpcAuthRpc rpc = new GrpcAuthRpc(endpoints, scheduler, builder.getDatabase(), channelFactory);
+            String database = builder.getDatabase();
+            String buildInfo = builder.getBuildInfo();
+            GrpcAuthRpc rpc = new GrpcAuthRpc(endpoints, scheduler, database, buildInfo, channelFactory);
             authIdentity = builder.getAuthProvider().createAuthIdentity(rpc);
         } else {
             authIdentity = null;

core/src/main/java/tech/ydb/core/impl/auth/GrpcAuthRpc.java

@@ -18,20 +18,23 @@ public class GrpcAuthRpc {
     private final List<EndpointRecord> endpoints;
     private final ScheduledExecutorService scheduler;
     private final String database;
+    private final String buildInfo;
     private final ManagedChannelFactory channelFactory;
     private final AtomicInteger endpointIdx = new AtomicInteger();
 
     public GrpcAuthRpc(
             List<EndpointRecord> endpoints,
             ScheduledExecutorService scheduler,
             String database,
+            String buildInfo,
             ManagedChannelFactory channelFactory) {
         if (endpoints == null || endpoints.isEmpty()) {
             throw new IllegalStateException("Empty endpoints list for auth rpc");
         }
         this.endpoints = endpoints;
         this.scheduler = scheduler;
         this.database = database;
+        this.buildInfo = buildInfo;
         this.channelFactory = channelFactory;
     }
 
@@ -60,6 +63,7 @@ public GrpcTransport createTransport() {
                 scheduler,
                 new AuthCallOptions(),
                 database,
+                buildInfo,
                 endpoints.get(endpointIdx.get()),
                 channelFactory
         );

core/src/test/java/tech/ydb/core/impl/MockedCall.java

@@ -15,15 +15,21 @@
 
 public abstract class MockedCall<ResT, RespT> extends ClientCall<ResT, RespT> {
     private final Executor executor;
+    private volatile Metadata lastMetadata = null;
 
     protected MockedCall(Executor executor) {
         this.executor = executor;
     }
 
     protected abstract void complete(Listener<RespT> listener);
 
+    public Metadata getLastCallMetadata() {
+        return lastMetadata;
+    }
+
     @Override
     public void start(Listener<RespT> listener, Metadata headers) {
+        lastMetadata = headers;
         executor.execute(() -> complete(listener));
     }
 

core/src/test/java/tech/ydb/core/impl/ObservabilityTest.java

@@ -0,0 +1,49 @@
+package tech.ydb.core.impl;
+
+import org.junit.After;
+import org.junit.Assert;
+import org.junit.Test;
+
+import tech.ydb.core.metrics.Meter;
+import tech.ydb.core.tracing.NoopTracer;
+import tech.ydb.core.tracing.Span;
+import tech.ydb.core.tracing.SpanKind;
+
+/**
+ *
+ * @author Aleksandr Gorshenin {@literal <alexandr268@ydb.tech>}
+ */
+public class ObservabilityTest {
+    private static final String BASE = "ydb-java-sdk/1.2.3";
+
+    @After
+    public void reset() {
+        Observability.reset();
+    }
+
+    @Test
+    public void baseTest() {
+        Assert.assertEquals(BASE, Observability.getDiscoveryBuildInfo(BASE));
+
+        // noop implementations ignored
+        Observability.reportMetricsUsage(Meter.NOOP);
+        Observability.reportTracingUsage(NoopTracer.getInstance());
+        Assert.assertEquals(BASE, Observability.getDiscoveryBuildInfo(BASE));
+
+        Observability.reportMetricsUsage(new Meter() { });
+        Assert.assertEquals(BASE + ";ydb-sdk-metrics/0.1.0", Observability.getDiscoveryBuildInfo(BASE));
+
+        Observability.reportTracingUsage((String spanName, SpanKind spanKind) -> Span.NOOP);
+        Assert.assertEquals(
+                BASE + ";ydb-sdk-tracing/0.1.0;ydb-sdk-metrics/0.1.0",
+                Observability.getDiscoveryBuildInfo(BASE)
+        );
+
+        Observability.reportMetricsUsage(Meter.NOOP);
+        Observability.reportTracingUsage(NoopTracer.getInstance());
+        Assert.assertEquals(
+                BASE + ";ydb-sdk-tracing/0.1.0;ydb-sdk-metrics/0.1.0",
+                Observability.getDiscoveryBuildInfo(BASE)
+        );
+    }
+}

core/src/test/java/tech/ydb/core/impl/YdbDiscoveryTest.java

@@ -255,7 +255,8 @@ public Instant instant() {
         @Override
         public GrpcTransport createDiscoveryTransport() {
             EndpointRecord discovery = new EndpointRecord("unknown", 1234);
-            return new FixedCallOptionsTransport(scheduler, new AuthCallOptions(), "/test", discovery, channelFactory);
+            AuthCallOptions options = new AuthCallOptions();
+            return new FixedCallOptionsTransport(scheduler, options, "/test", "test_sdk", discovery, channelFactory);
         }
 
         @Override