Issue ReactiveX#71: Implementation of Prometheus exporters for Circui…

…tBreaker and RateLimiter (ReactiveX#81)

libraries.gradle

@@ -15,6 +15,7 @@ ext {
     vertxVersion = '3.4.1'
     springBootVersion = '1.4.3.RELEASE'
     retrofitVersion = '2.1.0'
+    prometheusSimpleClientVersion = '0.0.21'
 
     libraries = [
             // compile
@@ -52,6 +53,9 @@ ext {
             metrics: "io.dropwizard.metrics:metrics-core:${metricsVersion}",
 
             // CircuitBreaker documentation
-            metrics_healthcheck: "io.dropwizard.metrics:metrics-healthchecks:${metricsVersion}"
+            metrics_healthcheck: "io.dropwizard.metrics:metrics-healthchecks:${metricsVersion}",
+
+            // Prometheus addon
+            prometheus_simpleclient: "io.prometheus:simpleclient_common:${prometheusSimpleClientVersion}"
     ]
 }

resilience4j-prometheus/README.adoc

@@ -0,0 +1,70 @@
+= resilience4j-prometheus
+
+Direct integration of circuit breaker and rate limiter metrics with
+https://github.com/prometheus/client_java[Prometheus simple client]
+
+For the circuit breaker library exports 2 metrics:
+
+1. By state with default metric name `circuit_breaker_states` and label `state`:
+
+    - `closed`
+    - `open`
+    - `half_open`
+
+2. By call result with default metric name `circuit_breaker_calls` and label `call_result`:
+
+    - `successful`
+    - `failed`
+    - `not_permitted`
+    - `buffered`
+    - `buffered_max`
+
+For the rate limiter following metric with default name `rate_limiter` and label `param` exported:
+
+- `available_permissions`
+- `waiting_threads`
+
+The names of the rate limiters and circuit breakers are exposed using label `name`.
+
+== Usage
+
+=== CircuitBreaker
+
+[source,java]
+--
+final CircuitBreakerRegistry circuitBreakerRegistry = new InMemoryCircuitBreakerRegistry();
+
+final CircuitBreaker foo = circuitBreakerRegistry.circuitBreaker("foo");
+final CircuitBreaker boo = circuitBreakerRegistry.circuitBreaker("boo");
+
+// Registering metrics in default prometeus CollectorRegistry
+new CircuitBreakerExports(circuitBreakerRegistry).register();
+--
+
+=== RateLimiter
+
+[source,java]
+--
+final RateLimiterRegistry rateLimiterRegistry = new InMemoryRateLimiterRegistry();
+
+final RateLimiter foo = rateLimiterRegistry.rateLimiter("foo");
+final RateLimiter boo = rateLimiterRegistry.rateLimiter("boo");
+
+// Registering metrics in default prometeus CollectorRegistry
+new RateLimiterExports(rateLimiterRegistry).register();
+--
+
+For both it is possible to use just a collection of breakers and limiters instead of registry.
+
+== License
+
+Copyright 2017 Oleksandr Goldobin
+
+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.

resilience4j-prometheus/build.gradle

@@ -0,0 +1,5 @@
+dependencies {
+    compile (libraries.prometheus_simpleclient)
+    compile project(':resilience4j-circuitbreaker')
+    compile project(':resilience4j-ratelimiter')
+}

resilience4j-prometheus/src/main/java/io/github/resilience4j/prometheus/CircuitBreakerExports.java

@@ -0,0 +1,170 @@
+/*
+ *
+ *  Copyright 2017 Oleksandr Goldobin
+ *
+ *  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.github.resilience4j.prometheus;
+
+import io.github.resilience4j.circuitbreaker.CircuitBreaker;
+import io.github.resilience4j.circuitbreaker.CircuitBreakerRegistry;
+import io.prometheus.client.Collector;
+import io.prometheus.client.GaugeMetricFamily;
+import javaslang.Tuple;
+import javaslang.Tuple2;
+import javaslang.collection.Array;
+
+import java.util.List;
+import java.util.function.Supplier;
+
+import static java.util.Arrays.asList;
+import static java.util.Objects.requireNonNull;
+
+/**
+ * An adapter from builtin {@link CircuitBreaker.Metrics} to prometheus
+ * {@link io.prometheus.client.CollectorRegistry}.
+ *
+ * Also exports {@link CircuitBreaker} state as a labeled metric
+ */
+public class CircuitBreakerExports extends Collector {
+
+    private static final String DEFAULT_NAME = "circuit_breaker";
+    private static Array<Tuple2<CircuitBreaker.State, String>> STATE_NAME_MAP =
+            Array.ofAll(asList(CircuitBreaker.State.values()))
+                .map(state -> Tuple.of(state, state.name().toLowerCase()));
+
+    private final String prefix;
+    private final Supplier<Iterable<CircuitBreaker>> circuitBreakersSupplier;
+
+    /**
+     * Creates a new instance of {@link CircuitBreakerExports} with default metrics names prefix and
+     * {@link CircuitBreakerRegistry} as a source of circuit breakers.
+
+     * @param circuitBreakerRegistry the registry of circuit breakers
+     */
+    public CircuitBreakerExports(CircuitBreakerRegistry circuitBreakerRegistry) {
+        this(circuitBreakerRegistry::getAllCircuitBreakers);
+    }
+
+    /**
+     * Creates a new instance of {@link CircuitBreakerExports} with default metrics names prefix and
+     * {@link Iterable} of circuit breakers.
+     *
+     * @param circuitBreakers the circuit breakers
+     */
+    public CircuitBreakerExports(Iterable<CircuitBreaker> circuitBreakers) {
+        this(() -> circuitBreakers);
+    }
+
+
+    /**
+     * Creates a new instance of {@link CircuitBreakerExports} with default metrics names prefix and
+     * {@link Supplier} of circuit breakers
+     *
+     * @param circuitBreakersSupplier the supplier of circuit breakers
+     */
+    public CircuitBreakerExports(Supplier<Iterable<CircuitBreaker>> circuitBreakersSupplier) {
+        this(DEFAULT_NAME, circuitBreakersSupplier);
+    }
+
+    /**
+     * Creates a new instance of {@link CircuitBreakerExports} with specified metrics names prefix and
+     * {@link CircuitBreakerRegistry} as a source of circuit breakers.
+     *
+     * @param prefix the prefix of metrics names
+     * @param circuitBreakerRegistry the registry of circuit breakers
+     */
+    public CircuitBreakerExports(String prefix, CircuitBreakerRegistry circuitBreakerRegistry) {
+        this(prefix, circuitBreakerRegistry::getAllCircuitBreakers);
+    }
+
+    /**
+     * Creates a new instance of {@link CircuitBreakerExports} with specified metrics names prefix and
+     * {@link Iterable} of circuit breakers.
+     *
+     * @param prefix the prefix of metrics names
+     * @param circuitBreakers the circuit breakers
+     */
+    public CircuitBreakerExports(String prefix, Iterable<CircuitBreaker> circuitBreakers) {
+        this(prefix, () -> circuitBreakers);
+    }
+
+    /**
+     * Creates a new instance of {@link CircuitBreakerExports} with specified metrics names prefix and
+     * {@link Supplier} of circuit breakers
+     *
+     * @param prefix the prefix of metrics names
+     * @param circuitBreakersSupplier the supplier of circuit breakers
+     */
+    public CircuitBreakerExports(String prefix, Supplier<Iterable<CircuitBreaker>> circuitBreakersSupplier) {
+        requireNonNull(prefix);
+        requireNonNull(circuitBreakersSupplier);
+
+        this.prefix = prefix;
+        this.circuitBreakersSupplier = circuitBreakersSupplier;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public List<MetricFamilySamples> collect() {
+
+        final GaugeMetricFamily states = new GaugeMetricFamily(
+                prefix + "_states",
+                "Circuit Breaker States",
+                asList("name","state"));
+
+        final GaugeMetricFamily calls = new GaugeMetricFamily(
+                prefix + "_calls",
+                "Circuit Breaker Call Stats",
+                asList("name", "call_result"));
+
+        for (CircuitBreaker circuitBreaker : circuitBreakersSupplier.get()) {
+
+            STATE_NAME_MAP.forEach(e -> {
+                final CircuitBreaker.State state = e._1;
+                final String name = e._2;
+                final double value = state == circuitBreaker.getState() ? 1.0 : 0.0;
+
+                states.addMetric(asList(circuitBreaker.getName(), name), value);
+            });
+
+            final CircuitBreaker.Metrics metrics = circuitBreaker.getMetrics();
+
+            calls.addMetric(
+                    asList(circuitBreaker.getName(), "successful"),
+                    metrics.getNumberOfSuccessfulCalls());
+
+            calls.addMetric(
+                    asList(circuitBreaker.getName(), "failed"),
+                    metrics.getNumberOfFailedCalls());
+
+            calls.addMetric(
+                    asList(circuitBreaker.getName(), "not_permitted"),
+                    metrics.getNumberOfNotPermittedCalls());
+
+            calls.addMetric(
+                    asList(circuitBreaker.getName(), "buffered"),
+                    metrics.getNumberOfBufferedCalls());
+
+            calls.addMetric(
+                    asList(circuitBreaker.getName(), "buffered_max"),
+                    metrics.getMaxNumberOfBufferedCalls());
+        }
+
+        return asList(calls, states);
+    }
+}