Ensure that the REST Client registers Vert.x HTTP Client metrics

docs/src/main/asciidoc/rest-client.adoc

@@ -1883,6 +1883,30 @@ When setting up the client programmatically using the `QuarkusRestClientBuilder`
 For declarative clients using `@RegisterRestClient`, simply providing a CDI bean that implements `ClientLogger` is enough for that logger to be used by said clients.
 ====
 
+== Metrics
+
+All declarative REST Client instances produce metrics using the `http.clients` prefix. Furthermore, the metrics contain a tag named `clientName` which corresponds to the config key of the client (as specified by the `configKey` property of the `@RegisterRestClient` annotation).
+
+To enable metrics for programmatically created REST Clients, the following snippet can be used:
+
+[source,java]
+----
+var builder = QuarkusRestClientBuilder.newBuilder();
+
+// use the builder to configure the client
+
+// now configure a customizer that sets the metrics name
+builder.httpClientOptionsCustomizer(new Consumer<>() {
+    @Override
+    public void accept(HttpClientOptions httpClientOptions) {
+        String metricsName = httpClientOptions.getMetricsName();
+        if (metricsName == null || metricsName.isEmpty()) {
+            httpClientOptions.setMetricsName("rest-client|" + "someName"); // the 'rest-client|' prefix is absolutely necessary here
+        }
+    }
+});
+----
+
 == Mocking the client for tests
 If you use a client injected with the `@RestClient` annotation, you can easily mock it for tests.
 You can do it with Mockito's `@InjectMock` or with `QuarkusMock`.

extensions/resteasy-reactive/rest-client/runtime/src/main/java/io/quarkus/rest/client/reactive/QuarkusRestClientBuilder.java

@@ -6,6 +6,7 @@
 import java.time.Duration;
 import java.util.ServiceLoader;
 import java.util.concurrent.TimeUnit;
+import java.util.function.Consumer;
 
 import javax.net.ssl.HostnameVerifier;
 import javax.net.ssl.SSLContext;
@@ -284,6 +285,12 @@ static QuarkusRestClientBuilder newBuilder() {
      */
     QuarkusRestClientBuilder httpClientOptions(HttpClientOptions httpClientOptions);
 
+    /**
+     * Specifies a callback which will be invoked after Quarkus has populated {@link HttpClientOptions} but before Vert.x uses
+     * it to create {@link io.vertx.core.http.HttpClient}
+     */
+    QuarkusRestClientBuilder httpClientOptionsCustomizer(Consumer<HttpClientOptions> httpClientOptionsCustomizer);
+
     /**
      * Specifies the client logger to use.
      *

extensions/resteasy-reactive/rest-client/runtime/src/main/java/io/quarkus/rest/client/reactive/runtime/QuarkusRestClientBuilderImpl.java

@@ -6,6 +6,7 @@
 import java.time.Duration;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
+import java.util.function.Consumer;
 
 import javax.net.ssl.HostnameVerifier;
 import javax.net.ssl.SSLContext;
@@ -246,6 +247,13 @@ public QuarkusRestClientBuilder httpClientOptions(HttpClientOptions httpClientOp
         return this;
     }
 
+    @Override
+    public QuarkusRestClientBuilder httpClientOptionsCustomizer(
+            Consumer<HttpClientOptions> httpClientOptionsCustomizer) {
+        delegate.clientOptionsCustomizer(httpClientOptionsCustomizer);
+        return this;
+    }
+
     @Override
     public QuarkusRestClientBuilder clientLogger(ClientLogger clientLogger) {
         delegate.clientLogger(clientLogger);

extensions/resteasy-reactive/rest-client/runtime/src/main/java/io/quarkus/rest/client/reactive/runtime/RestClientBuilderImpl.java

@@ -17,6 +17,7 @@
 import java.util.Optional;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.TimeUnit;
+import java.util.function.Consumer;
 
 import javax.net.ssl.HostnameVerifier;
 import javax.net.ssl.SSLContext;
@@ -54,6 +55,7 @@
 import io.quarkus.restclient.config.RestClientsConfig;
 import io.quarkus.tls.TlsConfiguration;
 import io.smallrye.config.SmallRyeConfig;
+import io.vertx.core.http.HttpClientOptions;
 import io.vertx.core.net.KeyCertOptions;
 import io.vertx.core.net.ProxyType;
 import io.vertx.core.net.SSLOptions;
@@ -96,6 +98,7 @@ public class RestClientBuilderImpl implements RestClientBuilder {
     private String userAgent;
     private Boolean disableDefaultMapper;
     private Boolean enableCompression;
+    private Consumer<HttpClientOptions> clientOptionsCustomizer;
 
     @Override
     public RestClientBuilderImpl baseUrl(URL url) {
@@ -301,6 +304,11 @@ public RestClientBuilderImpl enableCompression(boolean enableCompression) {
         return this;
     }
 
+    public RestClientBuilderImpl clientOptionsCustomizer(Consumer<HttpClientOptions> clientOptionsCustomizer) {
+        clientBuilder.clientOptionsCustomizer(clientOptionsCustomizer);
+        return this;
+    }
+
     @Override
     public RestClientBuilderImpl executorService(ExecutorService executor) {
         throw new IllegalArgumentException("Specifying executor service is not supported. " +

extensions/resteasy-reactive/rest-client/runtime/src/main/java/io/quarkus/rest/client/reactive/runtime/RestClientCDIDelegateBuilder.java

@@ -19,6 +19,7 @@
 import java.util.Optional;
 import java.util.OptionalInt;
 import java.util.concurrent.TimeUnit;
+import java.util.function.Consumer;
 import java.util.function.Function;
 
 import javax.net.ssl.HostnameVerifier;
@@ -39,6 +40,7 @@
 import io.quarkus.tls.TlsConfiguration;
 import io.quarkus.tls.TlsConfigurationRegistry;
 import io.smallrye.config.SmallRyeConfig;
+import io.vertx.core.http.HttpClientOptions;
 
 public class RestClientCDIDelegateBuilder<T> {
 
@@ -87,6 +89,7 @@ void configureBuilder(QuarkusRestClientBuilder builder) {
         configureShared(builder);
         configureLogging(builder);
         configureCustomProperties(builder);
+        configureClientOptionsCustomizer(builder);
     }
 
     private void configureLogging(QuarkusRestClientBuilder builder) {
@@ -447,6 +450,18 @@ private void configureBaseUrl(QuarkusRestClientBuilder builder) {
         }
     }
 
+    private void configureClientOptionsCustomizer(QuarkusRestClientBuilder builder) {
+        builder.httpClientOptionsCustomizer(new Consumer<>() {
+            @Override
+            public void accept(HttpClientOptions httpClientOptions) {
+                String metricsName = httpClientOptions.getMetricsName();
+                if (metricsName == null || metricsName.isEmpty()) {
+                    httpClientOptions.setMetricsName("rest-client|" + configKey);
+                }
+            }
+        });
+    }
+
     @SafeVarargs
     private static <T> Optional<T> oneOf(Optional<T>... optionals) {
         for (Optional<T> o : optionals) {

independent-projects/resteasy-reactive/client/runtime/src/main/java/org/jboss/resteasy/reactive/client/impl/ClientBuilderImpl.java

@@ -10,12 +10,14 @@
 import java.security.NoSuchAlgorithmException;
 import java.security.cert.CertificateException;
 import java.time.Duration;
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
+import java.util.function.Consumer;
 import java.util.regex.Pattern;
 
 import javax.net.ssl.HostnameVerifier;
@@ -87,6 +89,7 @@ public class ClientBuilderImpl extends ClientBuilder {
 
     private Boolean enableCompression;
     private Integer http2UpgradeMaxContentLength;
+    private List<Consumer<HttpClientOptions>> clientOptionsCustomizers = new ArrayList<>();
 
     public ClientBuilderImpl() {
         configuration = new ConfigurationImpl(RuntimeType.CLIENT);
@@ -221,6 +224,11 @@ public ClientBuilder maxChunkSize(int maxChunkSize) {
         return this;
     }
 
+    public ClientBuilder clientOptionsCustomizer(Consumer<HttpClientOptions> clientOptionsCustomizer) {
+        this.clientOptionsCustomizers.add(clientOptionsCustomizer);
+        return this;
+    }
+
     public TlsConfig getTlsConfig() {
         return tlsConfig;
     }
@@ -308,6 +316,11 @@ public ClientImpl build() {
         clientLogger.setBodySize(loggingBodySize);
 
         options.setMaxChunkSize(maxChunkSize);
+
+        for (Consumer<HttpClientOptions> clientOptionsCustomizer : clientOptionsCustomizers) {
+            clientOptionsCustomizer.accept(options);
+        }
+
         return new ClientImpl(options,
                 new ConfigurationImpl(configuration),
                 CLIENT_CONTEXT_RESOLVER.resolve(Thread.currentThread().getContextClassLoader()),

integration-tests/micrometer-prometheus/src/main/java/io/quarkus/ExporterResource.java

@@ -40,4 +40,16 @@ public Integer countServerRequests(@QueryParam("method") String method,
         }
         return search.timers().size();
     }
+
+    @Path("/client/count")
+    @Produces(MediaType.APPLICATION_JSON)
+    @GET
+    public Integer countClientRequests(@QueryParam("clientName") String clientName) {
+        final Search search = registry
+                .find("http.client.requests");
+        if (clientName != null) {
+            search.tag("clientName", clientName);
+        }
+        return search.timers().size();
+    }
 }

integration-tests/micrometer-prometheus/src/test/java/io/quarkus/it/micrometer/prometheus/ClientRequestTest.java

@@ -113,5 +113,12 @@ void testClientRequests() {
                         .when().get("/server-requests/count")
                         .body().as(Integer.class),
                 "Expected: http.server.requests, method=GET, status=500, uri=/client/status/{statusCode}");
+
+        assertEquals(5,
+                given()
+                        .queryParam("clientName", "pingpong")
+                        .when().get("/server-requests/client/count")
+                        .body().as(Integer.class),
+                "Expected: http.client.requests, clientName=pingpong");
     }
 }