feat: Implement OpenTelemetry metrics, tracing, and context propagation

demo-applications/cymbal-transit/pom.xml

@@ -69,7 +69,7 @@
     <dependency>
         <groupId>com.google.cloud.mcp</groupId>
         <artifactId>mcp-toolbox-sdk-java</artifactId>
-        <version>0.2.0</version>
+        <version>0.2.1-SNAPSHOT</version>
     </dependency>
 
     <!-- Java Annotations -->

demo-applications/cymbal-transit/src/main/java/cloudcode/cymbal/CymbalTransitApplication.java

@@ -40,6 +40,8 @@ public static void main(final String[] args) throws Exception {
     // Start the Spring Boot application.
     app.run(args);
     logger.info(
-        "Hello from Cloud Run! The container started successfully and is listening for HTTP requests on " + port);
+        "Hello from Cloud Run! The container started successfully and is listening for HTTP"
+            + " requests on "
+            + port);
   }
 }

example/pom.xml

@@ -33,7 +33,7 @@
     <dependency>
         <groupId>com.google.cloud.mcp</groupId>
         <artifactId>mcp-toolbox-sdk-java</artifactId>
-        <version>0.2.0</version><!-- {x-version-update:mcp-toolbox-sdk-java:released} -->
+        <version>0.2.1-SNAPSHOT</version>
     </dependency>
 
     <dependency>

example/src/main/java/cloudcode/helloworld/ExampleUsage.java

@@ -16,145 +16,166 @@
 
 package cloudcode.helloworld;
 
-import java.util.Map;
-import java.util.Collections;
-import java.util.concurrent.CompletableFuture;
-import java.io.FileInputStream;
-import com.google.cloud.mcp.McpToolboxClient;
-import com.google.cloud.mcp.AuthTokenGetter;
 import com.google.auth.oauth2.GoogleCredentials;
 import com.google.auth.oauth2.IdTokenProvider;
+import com.google.cloud.mcp.McpToolboxClient;
+import com.google.cloud.mcp.auth.AuthTokenGetter;
+import java.io.FileInputStream;
+import java.util.Collections;
+import java.util.Map;
+import java.util.concurrent.CompletableFuture;
 
 /**
- * Sample Application to demostrate the usage of the MCP Toolbox Java SDK.
- * Covers: Global Auth, Parameterized Auth, Discovery, Simple Tool, Authenticated Tool, Parameter Binding.
+ * Sample Application to demostrate the usage of the MCP Toolbox Java SDK. Covers: Global Auth,
+ * Parameterized Auth, Discovery, Simple Tool, Authenticated Tool, Parameter Binding.
  */
 public class ExampleUsage {
-    public static void main(String[] args) {
-        // CONFIGURATION
-        String targetUrl = "YOUR_TOOLBOX_SERVICE_ENDPOINT";
-
-        // Match the Service URL if using Cloud Run OIDC
-        String tokenAudience = targetUrl;
-
-        // --------------------------------------------------------------------------------
-        // AUTHENTICATION SETUP
-        // --------------------------------------------------------------------------------
-        // FOR LOCAL DEVELOPMENT: Use a Service Account Key JSON file.
-        // FOR PRODUCTION (Cloud Run): Comment out the 'keyPath' logic and use ADC directly.
-        // --------------------------------------------------------------------------------
-
-        String keyPath = "YOUR_CREDENTIALS_JSON_FILE_PATH.json";
-
-        System.out.println("--- Starting MCP Toolbox Integration Test ---");
-        System.out.println("Target Server: " + targetUrl);
-
-try {
-            System.out.println("    [Init] Fetching ID Token...");
-
-            GoogleCredentials credentials;
-
-            // --- OPTION A: LOCAL DEV (Explicit Key File) ---
-            if (keyPath != null && !keyPath.isEmpty()) {
-                 System.out.println("    [Auth] Using Service Account Key File: " + keyPath);
-                 credentials = GoogleCredentials.fromStream(new FileInputStream(keyPath));
-            }
-            // --- OPTION B: PRODUCTION (ADC) ---
-            else {
-                 System.out.println("    [Auth] Using Application Default Credentials (ADC)");
-                 credentials = GoogleCredentials.getApplicationDefault();
-            }
-
-            if (!(credentials instanceof IdTokenProvider)) {
-                throw new RuntimeException("Loaded credentials do not support ID Tokens.");
-            }
-
-            // Generate Token for the specified Audience
-            String idToken = ((IdTokenProvider) credentials).idTokenWithAudience(tokenAudience, Collections.emptyList()).getTokenValue();
-            System.out.println("    [Debug] Token Generated.");
-
-            // Initialize Client with Global Auth (Applies to ALL calls - Gate 1)
-            McpToolboxClient client = McpToolboxClient.builder()
-                .baseUrl(targetUrl)
-                .apiKey(idToken)
-                .build();
-
-            // STEP 1: TEST DISCOVERY METHODS
-            client.listTools()
-                .thenCompose(tools -> {
-                    System.out.println("\n[1] listTools(): Success. Found " + tools.size() + " tools.");
-                    return client.loadToolset();
-                })
-                .thenCompose(tools -> {
-                    System.out.println("[2] loadToolset() (Alias): Success.");
-                    return client.loadToolset("retail")
-                        .handle((res, ex) -> {
-                            if (ex == null) System.out.println("[3] loadToolset('retail'): Found " + res.size() + " tools.");
-                            else System.out.println("[3] loadToolset('retail'): Skipped (Not configured on server).");
-                            return null;
+  public static void main(String[] args) {
+    // CONFIGURATION
+    String targetUrl = "YOUR_TOOLBOX_SERVICE_ENDPOINT";
+
+    // Match the Service URL if using Cloud Run OIDC
+    String tokenAudience = targetUrl;
+
+    // --------------------------------------------------------------------------------
+    // AUTHENTICATION SETUP
+    // --------------------------------------------------------------------------------
+    // FOR LOCAL DEVELOPMENT: Use a Service Account Key JSON file.
+    // FOR PRODUCTION (Cloud Run): Comment out the 'keyPath' logic and use ADC directly.
+    // --------------------------------------------------------------------------------
+
+    String keyPath = "YOUR_CREDENTIALS_JSON_FILE_PATH.json";
+
+    System.out.println("--- Starting MCP Toolbox Integration Test ---");
+    System.out.println("Target Server: " + targetUrl);
+
+    try {
+      System.out.println("    [Init] Fetching ID Token...");
+
+      GoogleCredentials credentials;
+
+      // --- OPTION A: LOCAL DEV (Explicit Key File) ---
+      if (keyPath != null && !keyPath.isEmpty()) {
+        System.out.println("    [Auth] Using Service Account Key File: " + keyPath);
+        credentials = GoogleCredentials.fromStream(new FileInputStream(keyPath));
+      }
+      // --- OPTION B: PRODUCTION (ADC) ---
+      else {
+        System.out.println("    [Auth] Using Application Default Credentials (ADC)");
+        credentials = GoogleCredentials.getApplicationDefault();
+      }
+
+      if (!(credentials instanceof IdTokenProvider)) {
+        throw new RuntimeException("Loaded credentials do not support ID Tokens.");
+      }
+
+      // Generate Token for the specified Audience
+      String idToken =
+          ((IdTokenProvider) credentials)
+              .idTokenWithAudience(tokenAudience, Collections.emptyList())
+              .getTokenValue();
+      System.out.println("    [Debug] Token Generated.");
+
+      // Initialize Client with Global Auth (Applies to ALL calls - Gate 1)
+      McpToolboxClient client =
+          McpToolboxClient.builder().baseUrl(targetUrl).apiKey(idToken).build();
+
+      // STEP 1: TEST DISCOVERY METHODS
+      client
+          .listTools()
+          .thenCompose(
+              tools -> {
+                System.out.println("\n[1] listTools(): Success. Found " + tools.size() + " tools.");
+                return client.loadToolset();
+              })
+          .thenCompose(
+              tools -> {
+                System.out.println("[2] loadToolset() (Alias): Success.");
+                return client
+                    .loadToolset("retail")
+                    .handle(
+                        (res, ex) -> {
+                          if (ex == null)
+                            System.out.println(
+                                "[3] loadToolset('retail'): Found " + res.size() + " tools.");
+                          else
+                            System.out.println(
+                                "[3] loadToolset('retail'): Skipped (Not configured on server).");
+                          return null;
                         });
-                })
-                .thenCompose(ignore -> {
-
-                    // STEP 2: INVOKE TOOL WITHOUT EXTRA AUTH
-                    System.out.println("\n[4] Testing Simple Tool: 'get-retail-facet-filters'...");
-                    return client.invokeTool("get-retail-facet-filters", Map.of());
-                })
-                .thenCompose(result -> {
-                        System.out.println("    -> Result: " + (result.content() != null ? "Received Data" : "Empty"));
-
-                    // STEP 3: INVOKE TOOL WITH AUTHENTICATED PARAMETERS
-                    System.out.println("\n[5] Testing Authenticated Tool: 'get-toy-price'...");
-
-                    // Define the getter for the 'google_auth' service
-                    AuthTokenGetter toolAuthGetter = () -> CompletableFuture.completedFuture(idToken);
-
-                    // Load using the sophisticated overload
-                    return client.loadTool("get-toy-price", Map.of("google_auth", toolAuthGetter));
-                })
-                .thenCompose(tool -> {
-                    System.out.println("    -> Loaded Tool: " + tool.definition().description());
-
-                    // STEP 4: TEST BINDING PARAMETERS SEQUENTIALLY
-                    System.out.println("\n[A] Executing UNBOUND (Runtime arg: 'barbie')...");
-
-                    return tool.execute(Map.of("description", "barbie"))
-                        .thenCompose(result1 -> {
-                            if (result1.content() != null && !result1.content().isEmpty()) {
-                                        System.out
-                                                .println("    -> Result (Unbound): " + result1.content().get(0).text());
-                            }
-
-                            // NOW bind the parameter
-                            System.out.println("\n[B] Binding 'description' to 'soft toy'...");
-                            tool.bindParam("description", "soft toy");
-
-                            System.out.println("    -> Executing BOUND (Runtime arg: 'barbie' - should be IGNORED)...");
-                            // We pass 'barbie', but expecting 'soft toy' price because of binding override
-                            return tool.execute(Map.of("description", "barbie"));
+              })
+          .thenCompose(
+              ignore -> {
+
+                // STEP 2: INVOKE TOOL WITHOUT EXTRA AUTH
+                System.out.println("\n[4] Testing Simple Tool: 'get-retail-facet-filters'...");
+                return client.invokeTool("get-retail-facet-filters", Map.of());
+              })
+          .thenCompose(
+              result -> {
+                System.out.println(
+                    "    -> Result: " + (result.content() != null ? "Received Data" : "Empty"));
+
+                // STEP 3: INVOKE TOOL WITH AUTHENTICATED PARAMETERS
+                System.out.println("\n[5] Testing Authenticated Tool: 'get-toy-price'...");
+
+                // Define the getter for the 'google_auth' service
+                AuthTokenGetter toolAuthGetter = () -> CompletableFuture.completedFuture(idToken);
+
+                // Load using the sophisticated overload
+                return client.loadTool("get-toy-price", Map.of("google_auth", toolAuthGetter));
+              })
+          .thenCompose(
+              tool -> {
+                System.out.println("    -> Loaded Tool: " + tool.definition().description());
+
+                // STEP 4: TEST BINDING PARAMETERS SEQUENTIALLY
+                System.out.println("\n[A] Executing UNBOUND (Runtime arg: 'barbie')...");
+
+                return tool.execute(Map.of("description", "barbie"))
+                    .thenCompose(
+                        result1 -> {
+                          if (result1.content() != null && !result1.content().isEmpty()) {
+                            System.out.println(
+                                "    -> Result (Unbound): " + result1.content().get(0).text());
+                          }
+
+                          // NOW bind the parameter
+                          System.out.println("\n[B] Binding 'description' to 'soft toy'...");
+                          tool.bindParam("description", "soft toy");
+
+                          System.out.println(
+                              "    -> Executing BOUND (Runtime arg: 'barbie' - should be"
+                                  + " IGNORED)...");
+                          // We pass 'barbie', but expecting 'soft toy' price because of binding
+                          // override
+                          return tool.execute(Map.of("description", "barbie"));
                         });
-                })
-                .thenAccept(result -> {
-                    System.out.println("\n[6] Final Result (Bound):");
-                    if (result.isError()) {
-                            System.err.println("Tool execution failed: " + result.content().get(0).text());
-                    } else if (result.content() != null && !result.content().isEmpty()) {
-                            String output = result.content().get(0).text();
-                        System.out.println("    " + output.substring(0, Math.min(output.length(), 200)) + "...");
-                    } else {
-                        System.out.println("    Empty Response");
-                    }
-                })
-                .exceptionally(ex -> {
-                    System.err.println("\n!!! TEST FAILED !!!");
-                    ex.printStackTrace();
-                    return null;
-                })
-                .join();
-
-        } catch (Exception e) {
-            e.printStackTrace();
-        }
-        System.out.println("\n--- Test Suite Complete ---");
+              })
+          .thenAccept(
+              result -> {
+                System.out.println("\n[6] Final Result (Bound):");
+                if (result.isError()) {
+                  System.err.println("Tool execution failed: " + result.content().get(0).text());
+                } else if (result.content() != null && !result.content().isEmpty()) {
+                  String output = result.content().get(0).text();
+                  System.out.println(
+                      "    " + output.substring(0, Math.min(output.length(), 200)) + "...");
+                } else {
+                  System.out.println("    Empty Response");
+                }
+              })
+          .exceptionally(
+              ex -> {
+                System.err.println("\n!!! TEST FAILED !!!");
+                ex.printStackTrace();
+                return null;
+              })
+          .join();
+
+    } catch (Exception e) {
+      e.printStackTrace();
     }
+    System.out.println("\n--- Test Suite Complete ---");
+  }
 }