Do not enable GCP resource detector by default

Author: psx95

javaagent-extensions/gcp-auth/README.md

@@ -59,10 +59,11 @@ application {
   // Configure the GCP Auth extension using system properties.
   // This can also be configured using environment variables.
   "-Dgoogle.cloud.project=${googleCloudProjectId}",
-  "-Dgoogle.cloud.region=${googleCloudRegion}",  
   // Configure auto instrumentation.
   "-Dotel.exporter.otlp.traces.endpoint=${googleOtlpEndpoint}",
   '-Dotel.java.global-autoconfigure.enabled=true',
+  // Optionally enable the built-in GCP resource detector
+  '-Dotel.resource.providers.gcp.enabled=true'
   '-Dotel.traces.exporter=otlp',
   '-Dotel.metrics.exporter=logging',
 }

javaagent-extensions/gcp-auth/src/main/java/com/google/cloud/opentelemetry/extension/auth/GcpAuthAutoConfigurationCustomizerProvider.java

@@ -74,7 +74,6 @@ public void customize(AutoConfigurationCustomizer autoConfiguration) {
       autoConfiguration
           .addSpanExporterCustomizer(
               (exporter, configProperties) -> addAuthorizationHeaders(exporter, credentials))
-          .addPropertiesSupplier(this::getRequiredProperties)
           .addResourceCustomizer(this::customizeResource);
     } catch (IOException e) {
       throw new GoogleAuthException(Reason.FAILED_ADC_RETRIEVAL, e);
@@ -116,13 +115,6 @@ private Map<String, String> getRequiredHeaderMap(GoogleCredentials credentials)
     return gcpHeaders;
   }
 
-  // Sets the required properties that are essential for exporting OTLP data to GCP.
-  private Map<String, String> getRequiredProperties() {
-    Map<String, String> properties = new HashMap<>();
-    properties.put("otel.resource.providers.gcp.enabled", "true");
-    return properties;
-  }
-
   // Updates the current resource with the attributes required for ingesting OTLP data on GCP.
   private Resource customizeResource(Resource resource, ConfigProperties configProperties) {
     Resource res =

javaagent-extensions/gcp-auth/src/test/java/com/google/cloud/opentelemetry/extension/auth/ExtensionIntegrationTest.java

@@ -56,6 +56,7 @@ public void smokeTest() throws IOException, InterruptedException {
                 "-Dotel.javaagent.logging=none",
                 "-Dotel.exporter.otlp.endpoint=http://localhost:" + backendServerPort,
                 "-Dotel.exporter.otlp.insecure=true",
+                "-Dotel.resource.providers.gcp.enabled=true",
                 "-Dotel.traces.exporter=otlp",
                 "-Dotel.metrics.exporter=none",
                 "-Dotel.logs.exporter=none",