Do not use Google's HTTP client to get the default project ID

As described in [this issue](quarkusio/quarkus#35500), Quarkus w/ the Google clooud services and OpenCensus shim does not startup due to a static initialization issue.

`com.google.cloud.ServiceOptions` is used by the extension to get the Google cloud default-project-ID, which uses Google's HTTP client, which uses OpenCensus, which triggers an initialization of OpenTelemetry, which conflicts with the OTel init from Quarkus.

This change updates `GcpDefaultsConfigSourceFactory` to use Java's HTTP client.

See also #487, the alternatives mentioned in [this comment](#487 (comment)) to implement a `ConfigSource` and in [this comment](#487 (comment)) to set `otel.java.global-autoconfigure.enabled=false)` end in the same OpenCensus/OpenTracing init race.

Fixes quarkusio/quarkus#35500

common/runtime/pom.xml

@@ -64,6 +64,28 @@
             <groupId>org.graalvm.sdk</groupId>
             <artifactId>graal-sdk</artifactId>
         </dependency>
+
+        <!-- Tests -->
+        <dependency>
+            <groupId>io.quarkus</groupId>
+            <artifactId>quarkus-junit5</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>io.opentelemetry</groupId>
+            <artifactId>opentelemetry-opencensus-shim</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>

common/runtime/src/main/java/io/quarkiverse/googlecloudservices/common/GcpDefaultsConfigSourceFactory.java

@@ -3,11 +3,23 @@
 import static java.util.Collections.emptyList;
 import static java.util.Collections.singletonList;
 
+import java.io.IOException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.time.Duration;
 import java.util.Map;
+import java.util.Set;
+import java.util.function.Supplier;
 
 import org.eclipse.microprofile.config.spi.ConfigSource;
 
+import com.google.cloud.PlatformInformation;
+import com.google.cloud.ServiceDefaults;
 import com.google.cloud.ServiceOptions;
+import com.google.common.annotations.VisibleForTesting;
 
 import io.smallrye.config.ConfigSourceContext;
 import io.smallrye.config.ConfigSourceFactory;
@@ -17,40 +29,138 @@
 
 public class GcpDefaultsConfigSourceFactory implements ConfigSourceFactory {
 
-    private static final String OPENTELEMETRY_CONTEXT_CONTEXT_STORAGE_PROVIDER_SYS_PROP = "io.opentelemetry.context.contextStorageProvider";
+    private final Supplier<String> defaultProjectIdSupplier;
+
+    public GcpDefaultsConfigSourceFactory() {
+        this(ServiceOptionsHelper::getDefaultProjectId);
+    }
+
+    @VisibleForTesting
+    GcpDefaultsConfigSourceFactory(Supplier<String> defaultProjectIdSupplier) {
+        this.defaultProjectIdSupplier = defaultProjectIdSupplier;
+    }
 
     @Override
     public Iterable<ConfigSource> getConfigSources(final ConfigSourceContext context) {
         ConfigValue enableMetadataServer = context.getValue("quarkus.google.cloud.enable-metadata-server");
         if (enableMetadataServer.getValue() != null) {
             if (Converters.getImplicitConverter(Boolean.class).convert(enableMetadataServer.getValue())) {
-                String previousContextStorageSysProp = null;
-                try {
-                    // Google HTTP Client under the hood which attempts to record traces via OpenCensus which is wired
-                    // to delegate to OpenTelemetry.
-                    // This can lead to problems with the Quarkus OpenTelemetry extension which expects Vert.x to be running,
-                    // something that is not the case at build time, see https://github.com/quarkusio/quarkus/issues/35500
-                    previousContextStorageSysProp = System.setProperty(OPENTELEMETRY_CONTEXT_CONTEXT_STORAGE_PROVIDER_SYS_PROP,
-                            "default");
-
-                    String defaultProjectId = ServiceOptions.getDefaultProjectId();
-                    if (defaultProjectId != null) {
-                        return singletonList(
-                                new PropertiesConfigSource(Map.of("quarkus.google.cloud.project-id", defaultProjectId),
-                                        "GcpDefaultsConfigSource",
-                                        -Integer.MAX_VALUE));
-                    }
-                } finally {
-                    if (previousContextStorageSysProp == null) {
-                        System.clearProperty(OPENTELEMETRY_CONTEXT_CONTEXT_STORAGE_PROVIDER_SYS_PROP);
-                    } else {
-                        System.setProperty(OPENTELEMETRY_CONTEXT_CONTEXT_STORAGE_PROVIDER_SYS_PROP,
-                                previousContextStorageSysProp);
+                String defaultProjectId = defaultProjectIdSupplier.get();
+                if (defaultProjectId != null) {
+                    return singletonList(
+                            new PropertiesConfigSource(Map.of("quarkus.google.cloud.project-id", defaultProjectId),
+                                    "GcpDefaultsConfigSource",
+                                    -Integer.MAX_VALUE));
+                }
+            }
+        }
+        return emptyList();
+    }
+
+    /**
+     * This is a partial copy of {@link ServiceOptions} to prevent the use of Google's HTTP client, which causes
+     * static initialization trouble via OpenCensus-shim with OpenTelemetry.
+     *
+     * <p>
+     * This helper class is only intended to not use the Google HTTP client but not change any other aspects of
+     * how the default project ID is retrieved.
+     *
+     * <p>
+     * (The {@link ServiceOptions} class is licensed using ASL2.)
+     */
+    @SuppressWarnings("rawtypes")
+    static class ServiceOptionsHelper extends ServiceOptions {
+        @SuppressWarnings("unchecked")
+        protected ServiceOptionsHelper(Class serviceFactoryClass, Class rpcFactoryClass, Builder builder,
+                ServiceDefaults serviceDefaults) {
+            super(serviceFactoryClass, rpcFactoryClass, builder, serviceDefaults);
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        protected Set<String> getScopes() {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public Builder toBuilder() {
+            throw new UnsupportedOperationException();
+        }
+
+        public static String getDefaultProjectId() {
+            // As in the original `ServiceOptions` class
+            String projectId = System.getProperty("GOOGLE_CLOUD_PROJECT", System.getenv("GOOGLE_CLOUD_PROJECT"));
+            if (projectId == null) {
+                projectId = System.getProperty("GCLOUD_PROJECT", System.getenv("GCLOUD_PROJECT"));
+            }
+
+            if (projectId == null) {
+                projectId = getAppEngineProjectId();
+            }
+
+            if (projectId == null) {
+                projectId = getServiceAccountProjectId();
+            }
+
+            return projectId != null ? projectId : getGoogleCloudProjectId();
+        }
+
+        protected static String getAppEngineProjectId() {
+            // As in the original `ServiceOptions` class
+            String projectId;
+            if (PlatformInformation.isOnGAEStandard7()) {
+                projectId = getAppEngineProjectIdFromAppId();
+            } else {
+                projectId = System.getenv("GOOGLE_CLOUD_PROJECT");
+                if (projectId == null) {
+                    projectId = System.getenv("GCLOUD_PROJECT");
+                }
+
+                if (projectId == null) {
+                    projectId = getAppEngineProjectIdFromAppId();
+                }
+
+                if (projectId == null) {
+                    try {
+                        projectId = getAppEngineProjectIdFromMetadataServer();
+                    } catch (IOException var2) {
+                        // projectId = null;
                     }
                 }
+            }
+
+            return projectId;
+        }
 
+        /**
+         * This function has been changed to use the (new) Java HTTP client.
+         */
+        private static String getAppEngineProjectIdFromMetadataServer() throws IOException {
+            String metadata = "http://metadata.google.internal";
+            String projectIdURL = "/computeMetadata/v1/project/project-id";
+
+            try {
+                URI uri = new URI(metadata + projectIdURL);
+                HttpClient client = HttpClient.newBuilder().connectTimeout(Duration.ofMillis(500)).build();
+                HttpRequest request = HttpRequest.newBuilder().timeout(Duration.ofMillis(500)).GET().uri(uri)
+                        .header("Metadata-Flavor", "Google").build();
+                HttpResponse.BodyHandler<String> bodyHandler = HttpResponse.BodyHandlers.ofString();
+                HttpResponse<String> response = client.send(request, bodyHandler);
+                return headerContainsMetadataFlavor(response) ? response.body() : null;
+            } catch (URISyntaxException e) {
+                throw new RuntimeException(e);
+            } catch (InterruptedException e) {
+                Thread.currentThread().interrupt();
+                throw new IOException(e);
             }
         }
-        return emptyList();
+
+        /**
+         * This function has been adopted for the Java HTTP client.
+         */
+        private static boolean headerContainsMetadataFlavor(HttpResponse<?> response) {
+            String metadataFlavorValue = response.headers().firstValue("Metadata-Flavor").orElse("");
+            return "Google".equals(metadataFlavorValue);
+        }
     }
 }

common/runtime/src/test/java/io/quarkiverse/googlecloudservices/common/GcpDefaultsConfigSourceFactoryTest.java

@@ -0,0 +1,63 @@
+package io.quarkiverse.googlecloudservices.common;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.eclipse.microprofile.config.spi.ConfigSource;
+import org.junit.jupiter.api.Test;
+import org.mockito.Mockito;
+
+import io.opentelemetry.api.GlobalOpenTelemetry;
+import io.opentelemetry.api.OpenTelemetry;
+import io.smallrye.config.ConfigSourceContext;
+import io.smallrye.config.ConfigValue;
+
+class GcpDefaultsConfigSourceFactoryTest {
+    @Test
+    void configSourceWorks() {
+        ConfigSourceContext context = Mockito.mock(ConfigSourceContext.class);
+        Mockito.when(context.getValue("quarkus.google.cloud.enable-metadata-server"))
+                .thenReturn(ConfigValue.builder().withValue("true").build());
+
+        Iterable<ConfigSource> configSources = new GcpDefaultsConfigSourceFactory(() -> "test-project-id")
+                .getConfigSources(context);
+        assertThat(configSources).asList().hasSize(1);
+
+        ConfigSource configSource = configSources.iterator().next();
+        assertThat(configSource.getProperties()).containsEntry("quarkus.google.cloud.project-id", "test-project-id");
+    }
+
+    @Test
+    void metadataServerDisabled() {
+        ConfigSourceContext context = Mockito.mock(ConfigSourceContext.class);
+        Mockito.when(context.getValue("quarkus.google.cloud.enable-metadata-server"))
+                .thenReturn(ConfigValue.builder().withValue("false").build());
+
+        Iterable<ConfigSource> configSources = new GcpDefaultsConfigSourceFactory(() -> "test-project-id")
+                .getConfigSources(context);
+        assertThat(configSources).isEmpty();
+    }
+
+    /**
+     * Tests that OpenCensus does not get implicitly initialized and in turn does not "collide" with
+     * OpenTelemetry, as used in Quarkus.
+     */
+    @Test
+    void staticOpenCensusOpenTelemetryInit() {
+        try {
+            GlobalOpenTelemetry.resetForTest();
+
+            ConfigSourceContext context = Mockito.mock(ConfigSourceContext.class);
+            Mockito.when(context.getValue("quarkus.google.cloud.enable-metadata-server"))
+                    .thenReturn(ConfigValue.builder().withValue("true").build());
+
+            // Uses the "real" implementation that tries to fetch the default-project-id
+            Iterable<ConfigSource> configSources = new GcpDefaultsConfigSourceFactory().getConfigSources(context);
+            assertThat(configSources).asList().hasSizeLessThanOrEqualTo(1);
+
+            // This is a pretty ugly way, because it changes static state
+            GlobalOpenTelemetry.set(OpenTelemetry.noop());
+        } finally {
+            GlobalOpenTelemetry.resetForTest();
+        }
+    }
+}

pom.xml

@@ -21,6 +21,7 @@
     <compiler-plugin.version>3.8.1</compiler-plugin.version>
     <enforcer-plugin.version>3.4.1</enforcer-plugin.version>
     <assertj.version>3.24.2</assertj.version>
+    <opentelemetry-alpha.version>1.28.0-alpha</opentelemetry-alpha.version>
   </properties>
   <scm>
     <connection>scm:git:[email protected]:quarkiverse/quarkus-google-cloud-services.git</connection>
@@ -63,6 +64,11 @@
         <artifactId>assertj-core</artifactId>
         <version>${assertj.version}</version>
       </dependency>
+      <dependency>
+        <groupId>io.opentelemetry</groupId>
+        <artifactId>opentelemetry-opencensus-shim</artifactId>
+        <version>${opentelemetry-alpha.version}</version>
+      </dependency>
     </dependencies>
   </dependencyManagement>
   <build>