Implement custom tags provider for HTTP metrics

- Allows to implement a CustomTagsProvider interface to provide tags out
of HttpRequest objects.
- Add tests

Fixes vert-x3#89

src/main/java/io/vertx/micrometer/MicrometerMetricsOptions.java

@@ -22,6 +22,8 @@
 import io.vertx.core.json.JsonObject;
 import io.vertx.core.metrics.MetricsOptions;
 import io.vertx.core.spi.VertxMetricsFactory;
+import io.vertx.core.spi.observability.HttpRequest;
+import io.vertx.micrometer.impl.CustomTagsProvider;
 
 import java.util.*;
 
@@ -66,6 +68,7 @@ public class MicrometerMetricsOptions extends MetricsOptions {
   private VertxJmxMetricsOptions jmxMetricsOptions;
   private boolean jvmMetricsEnabled;
   private MetricsNaming metricsNaming;
+  private CustomTagsProvider<HttpRequest> requestsTagsProvider;
 
   /**
    * Creates default options for Micrometer metrics.
@@ -77,6 +80,7 @@ public MicrometerMetricsOptions() {
     labelMatches = new ArrayList<>();
     jvmMetricsEnabled = DEFAULT_JVM_METRICS_ENABLED;
     metricsNaming = DEFAULT_METRICS_NAMING;
+    requestsTagsProvider = null;
   }
 
   /**
@@ -100,6 +104,7 @@ public MicrometerMetricsOptions(MicrometerMetricsOptions other) {
     }
     jvmMetricsEnabled = other.jvmMetricsEnabled;
     metricsNaming = other.metricsNaming;
+    requestsTagsProvider = other.requestsTagsProvider;
   }
 
   /**
@@ -415,4 +420,22 @@ public MicrometerMetricsOptions setMetricsNaming(MetricsNaming metricsNaming) {
     this.metricsNaming = metricsNaming;
     return this;
   }
+
+  /**
+   * @return an optional custom tags provider for HTTP requests
+   */
+  public CustomTagsProvider<HttpRequest> getRequestsTagsProvider() {
+    return requestsTagsProvider;
+  }
+
+  /**
+   * Sets a custom tags provider for HTTP requests. Allows to generate custom tags for every {@code HttpRequest} object processed through the metrics SPI.
+   *
+   * @param requestsTagsProvider an object implementing the {@code CustomTagsProvider} interface for {@code HttpRequest}.
+   * @return a reference to this, so that the API can be used fluently
+   */
+  public MicrometerMetricsOptions setRequestsTagsProvider(CustomTagsProvider<HttpRequest> requestsTagsProvider) {
+    this.requestsTagsProvider = requestsTagsProvider;
+    return this;
+  }
 }

src/main/java/io/vertx/micrometer/impl/CustomTagsProvider.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2021 Red Hat, Inc. and/or its affiliates
+ * and other contributors as indicated by the @author tags.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.vertx.micrometer.impl;
+
+import io.micrometer.core.instrument.Tag;
+
+/**
+ * @author Joel Takvorian
+ */
+public interface CustomTagsProvider<T> {
+  Iterable<Tag> extractTags(T object);
+}

src/main/java/io/vertx/micrometer/impl/VertxHttpServerMetrics.java

@@ -16,6 +16,7 @@
 package io.vertx.micrometer.impl;
 
 import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.Tag;
 import io.vertx.core.http.HttpMethod;
 import io.vertx.core.http.ServerWebSocket;
 import io.vertx.core.net.SocketAddress;
@@ -46,9 +47,11 @@ class VertxHttpServerMetrics extends VertxNetServerMetrics {
   private final Timers processingTime;
   private final Summaries responseBytes;
   private final Gauges<LongAdder> wsConnections;
+  private final CustomTagsProvider<HttpRequest> customTagsProvider;
 
-  VertxHttpServerMetrics(MeterRegistry registry, MetricsNaming names) {
+  VertxHttpServerMetrics(MeterRegistry registry, MetricsNaming names, CustomTagsProvider<HttpRequest> customTagsProvider) {
     super(registry, MetricsDomain.HTTP_SERVER, names);
+    this.customTagsProvider = customTagsProvider;
     requests = longGauges(names.getHttpActiveRequests(), "Number of requests being processed", Label.LOCAL, Label.REMOTE, Label.HTTP_PATH, Label.HTTP_METHOD);
     requestCount = counters(names.getHttpRequestsCount(), "Number of processed requests", Label.LOCAL, Label.REMOTE, Label.HTTP_ROUTE, Label.HTTP_PATH, Label.HTTP_METHOD, Label.HTTP_CODE);
     requestResetCount = counters(names.getHttpRequestResetsCount(), "Number of request resets", Label.LOCAL, Label.REMOTE, Label.HTTP_PATH, Label.HTTP_METHOD);
@@ -71,26 +74,29 @@ class Instance extends VertxNetServerMetrics.Instance implements HttpServerMetri
     @Override
     public Handler requestBegin(String remote, HttpRequest request) {
       Handler handler = new Handler(remote, request.uri(), request.method().name());
-      requests.get(local, remote, handler.path, handler.method).increment();
+      if (customTagsProvider != null) {
+        handler.customTags = customTagsProvider.extractTags(request);
+      }
+      requests.get(handler.customTags, local, remote, handler.path, handler.method).increment();
       handler.timer = processingTime.start();
       return handler;
     }
 
     @Override
     public void requestReset(Handler handler) {
-      requestResetCount.get(local, handler.address, handler.path, handler.method).increment();
-      requests.get(local, handler.address, handler.path, handler.method).decrement();
+      requestResetCount.get(handler.customTags, local, handler.address, handler.path, handler.method).increment();
+      requests.get(handler.customTags, local, handler.address, handler.path, handler.method).decrement();
     }
 
     @Override
     public void requestEnd(Handler handler, HttpRequest request, long bytesRead) {
-      requestBytes.get(local, handler.address, handler.path, handler.method).record(bytesRead);
+      requestBytes.get(handler.customTags, local, handler.address, handler.path, handler.method).record(bytesRead);
     }
 
     @Override
     public Handler responsePushed(String remote, HttpMethod method, String uri, HttpResponse response) {
       Handler handler = new Handler(remote, uri, method.name());
-      requests.get(local, remote, handler.path, handler.method).increment();
+      requests.get(handler.customTags, local, remote, handler.path, handler.method).increment();
       return handler;
     }
 
@@ -102,10 +108,10 @@ public void responseBegin(Handler handler, HttpResponse response) {
     public void responseEnd(Handler handler, HttpResponse response, long bytesWritten) {
       String code = String.valueOf(response.statusCode());
       String handlerRoute = handler.getRoute();
-      handler.timer.end(local, handler.address, handlerRoute, handler.path, handler.method, code);
-      requestCount.get(local, handler.address, handlerRoute, handler.path, handler.method, code).increment();
-      requests.get(local, handler.address, handler.path, handler.method).decrement();
-      responseBytes.get(local, handler.address, handlerRoute, handler.path, handler.method, code).record(bytesWritten);
+      handler.timer.end(handler.customTags, local, handler.address, handlerRoute, handler.path, handler.method, code);
+      requestCount.get(handler.customTags, local, handler.address, handlerRoute, handler.path, handler.method, code).increment();
+      requests.get(handler.customTags, local, handler.address, handler.path, handler.method).decrement();
+      responseBytes.get(handler.customTags, local, handler.address, handlerRoute, handler.path, handler.method, code).record(bytesWritten);
     }
 
     @Override
@@ -138,6 +144,7 @@ public static class Handler {
     // tracks length of resulting routes string
     private int routesLength;
     private Timers.EventTiming timer;
+    private Iterable<Tag> customTags;
 
     Handler(String address, String path, String method) {
       this.address = address;

src/main/java/io/vertx/micrometer/impl/VertxMetricsImpl.java

@@ -93,7 +93,7 @@ public VertxMetricsImpl(MicrometerMetricsOptions options, BackendRegistry backen
     httpClientMetrics = options.isMetricsCategoryDisabled(HTTP_CLIENT) ? null
       : new VertxHttpClientMetrics(registry, names);
     httpServerMetrics = options.isMetricsCategoryDisabled(HTTP_SERVER) ? null
-      : new VertxHttpServerMetrics(registry, names);
+      : new VertxHttpServerMetrics(registry, names, options.getRequestsTagsProvider());
     poolMetrics = options.isMetricsCategoryDisabled(NAMED_POOLS) ? null
       : new VertxPoolMetrics(registry, names);
   }

src/main/java/io/vertx/micrometer/impl/meters/Counters.java

@@ -18,9 +18,15 @@
 
 import io.micrometer.core.instrument.Counter;
 import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.Tag;
 import io.vertx.micrometer.Label;
 import io.vertx.micrometer.impl.Labels;
 
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
 /**
  * @author Joel Takvorian
  */
@@ -41,10 +47,17 @@ public Counters(String name,
   }
 
   public Counter get(String... values) {
+    return get(null, values);
+  }
+
+  public Counter get(Iterable<Tag> customTags, String... values) {
+    List<Tag> tags = customTags != null
+      ? Stream.concat(Labels.toTags(keys, values).stream(), StreamSupport.stream(customTags.spliterator(), false)).collect(Collectors.toList())
+      : Labels.toTags(keys, values);
     // Get or create the Counter
     return Counter.builder(name)
       .description(description)
-      .tags(Labels.toTags(keys, values))
+      .tags(tags)
       .register(registry);
   }
 }

src/main/java/io/vertx/micrometer/impl/meters/Gauges.java

@@ -19,13 +19,18 @@
 import io.micrometer.core.instrument.Gauge;
 import io.micrometer.core.instrument.Meter;
 import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.Tag;
 import io.vertx.micrometer.Label;
 import io.vertx.micrometer.impl.Labels;
 
+import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.Supplier;
 import java.util.function.ToDoubleFunction;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
 
 /**
  * @author Joel Takvorian
@@ -53,7 +58,14 @@ public Gauges(String name,
     this.keys = keys;
   }
 
-  public synchronized T get(String... values) {
+  public T get(String... values) {
+    return get(null, values);
+  }
+
+  public synchronized T get(Iterable<Tag> customTags, String... values) {
+    List<Tag> tags = customTags != null
+      ? Stream.concat(Labels.toTags(keys, values).stream(), StreamSupport.stream(customTags.spliterator(), false)).collect(Collectors.toList())
+      : Labels.toTags(keys, values);
     // This method is synchronized to make sure the "T" built via supplier will match the one passed to Gauge
     //  since it is stored as WeakReference in Micrometer DefaultGauge, it must not be lost.
     T t = tSupplier.get();
@@ -63,7 +75,7 @@ public synchronized T get(String... values) {
     //  Micrometer will not register the gauge twice if it was already created.
     Gauge g = Gauge.builder(name, t, dGetter)
       .description(description)
-      .tags(Labels.toTags(keys, values))
+      .tags(tags)
       .register(registry);
     return gauges.computeIfAbsent(g.getId(), v -> t);
   }

src/main/java/io/vertx/micrometer/impl/meters/Summaries.java

@@ -18,9 +18,15 @@
 
 import io.micrometer.core.instrument.DistributionSummary;
 import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.Tag;
 import io.vertx.micrometer.Label;
 import io.vertx.micrometer.impl.Labels;
 
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
 /**
  * @author Joel Takvorian
  */
@@ -41,10 +47,17 @@ public Summaries(String name,
   }
 
   public DistributionSummary get(String... values) {
+    return get(null, values);
+  }
+
+  public DistributionSummary get(Iterable<Tag> customTags, String... values) {
+    List<Tag> tags = customTags != null
+      ? Stream.concat(Labels.toTags(keys, values).stream(), StreamSupport.stream(customTags.spliterator(), false)).collect(Collectors.toList())
+      : Labels.toTags(keys, values);
     // Get or create the Summary
     return DistributionSummary.builder(name)
       .description(description)
-      .tags(Labels.toTags(keys, values))
+      .tags(tags)
       .register(registry);
   }
 }

src/main/java/io/vertx/micrometer/impl/meters/Timers.java

@@ -17,11 +17,16 @@
 package io.vertx.micrometer.impl.meters;
 
 import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.Tag;
 import io.micrometer.core.instrument.Timer;
 import io.vertx.micrometer.Label;
 import io.vertx.micrometer.impl.Labels;
 
+import java.util.List;
 import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
 
 /**
  * @author Joel Takvorian
@@ -43,10 +48,17 @@ public Timers(String name,
   }
 
   public Timer get(String... values) {
+    return get(null, values);
+  }
+
+  public Timer get(Iterable<Tag> customTags, String... values) {
+    List<Tag> tags = customTags != null
+      ? Stream.concat(Labels.toTags(keys, values).stream(), StreamSupport.stream(customTags.spliterator(), false)).collect(Collectors.toList())
+      : Labels.toTags(keys, values);
     // Get or create the Timer
     return Timer.builder(name)
       .description(description)
-      .tags(Labels.toTags(keys, values))
+      .tags(tags)
       .register(registry);
   }
 
@@ -64,7 +76,11 @@ private EventTiming(Timers ref) {
     }
 
     public void end(String... values) {
-      Timer t = ref.get(values);
+      end(null, values);
+    }
+
+    public void end(Iterable<Tag> customTags, String... values) {
+      Timer t = ref.get(customTags, values);
       t.record(System.nanoTime() - nanoStart, TimeUnit.NANOSECONDS);
     }
   }