Issue ReactiveX#126: Feature ratpack events

* check

* adding streaming

* checkpoint on ratelimiter events

* added ratelimiter event endpoint tests

* added retry events

* configurable

Author: Dan Maas

resilience4j-documentation/src/docs/asciidoc/addon_guides/ratpack.adoc

@@ -340,16 +340,199 @@ public class MyModule extends AbstractModule {
 }
 ----
 
+==== Event Monitoring
 
+===== CircuitBreaker
+
+The emitted CircuitBreaker events are stored in a separate circular event consumer buffers. The size of a event consumer buffer can be configured per CircuitBreaker in the application.yml file (eventConsumerBufferSize).
+The demo adds a custom Ratpack actuator endpoint which can be used to monitor the emitted events of your CircuitBreakers.
+The endpoint `/circuitbreaker` lists the names of all CircuitBreaker instances.
+For example:
+
+----
+{
+    "circuitBreakers": [
+      "backendA",
+      "backendB"
+    ]
+}
+----
 
-==== Monitoring
-TODO
-Ratpack provides the concept of a health check. See https://ratpack.io/manual/current/api/ratpack/health/HealthCheckHandler.html for details.
-CircuitBreaker, RateLimiter, and Retry health checks have not been implemented yet.
-When implemented they should function similarly to the spring boot health checks.
+The endpoint `/circuitbreaker/events` lists the latest 100 emitted events of all CircuitBreaker instances.
+The endpoint `/circuitbreaker/stream/events` streams emitted events of all CircuitBreaker instances using Server-Sent Events.
 
-==== CircuitBreaker Event Monitoring
-TODO
-Handlers for displaying the last X CircuitBreaker, Ratelimiter, or Retry events are not yet implemented.
-When implemented they should function similarly to the spring boot management endpoints.
+----
+{
+"circuitBreakerEvents":[
+  {
+    "circuitBreakerName": "backendA",
+    "type": "ERROR",
+    "creationTime": "2017-01-10T15:39:17.117+01:00[Europe/Berlin]",
+    "errorMessage": "org.springframework.web.client.HttpServerErrorException: 500 This is a remote exception",
+    "durationInMs": 0
+  },
+  {
+    "circuitBreakerName": "backendA",
+    "type": "SUCCESS",
+    "creationTime": "2017-01-10T15:39:20.518+01:00[Europe/Berlin]",
+    "durationInMs": 0
+  },
+  {
+    "circuitBreakerName": "backendB",
+    "type": "ERROR",
+    "creationTime": "2017-01-10T15:41:31.159+01:00[Europe/Berlin]",
+    "errorMessage": "org.springframework.web.client.HttpServerErrorException: 500 This is a remote exception",
+    "durationInMs": 0
+  },
+  {
+    "circuitBreakerName": "backendB",
+    "type": "SUCCESS",
+    "creationTime": "2017-01-10T15:41:33.526+01:00[Europe/Berlin]",
+    "durationInMs": 0
+  }
+]
+}
+----
 
+The endpoint `/circuitbreaker/events/{circuitBreakerName}` lists the latest emitted events of a specific CircuitBreaker.
+The endpoint `/circuitbreaker/stream/events/{circuitBreakerName}` streams emitted events using Server-Sent Events.
+For example `/circuitbreaker/events/backendA`:
+
+----
+{
+"circuitBreakerEvents":[
+  {
+    "circuitBreakerName": "backendA",
+    "type": "ERROR",
+    "creationTime": "2017-01-10T15:39:17.117+01:00[Europe/Berlin]",
+    "errorMessage": "org.springframework.web.client.HttpServerErrorException: 500 This is a remote exception",
+    "durationInMs": 0
+  },
+  {
+    "circuitBreakerName": "backendA",
+    "type": "SUCCESS",
+    "creationTime": "2017-01-10T15:39:20.518+01:00[Europe/Berlin]",
+    "durationInMs": 0
+  },
+  {
+    "circuitBreakerName": "backendA",
+    "type": "STATE_TRANSITION",
+    "creationTime": "2017-01-10T15:39:22.341+01:00[Europe/Berlin]",
+    "stateTransition": "CLOSED_TO_OPEN"
+  },
+  {
+    "circuitBreakerName": "backendA",
+    "type": "NOT_PERMITTED",
+    "creationTime": "2017-01-10T15:39:22.780+01:00[Europe/Berlin]"
+  }
+]
+}
+----
+
+You can even filter the list of  events.
+The endpoint `/circuitbreaker/events/{circuitBreakerName}/{eventType}` lists the filtered events.
+The endpoint `/circuitbreaker/stream/events/{circuitBreakerName}/{eventType}` streams emitted events using Server-Sent Events.
+Event types can be:
+
+* ERROR: A CircuitBreakerEvent which informs that an error has been recorded.
+* IGNORED_ERROR: A CircuitBreakerEvent which informs that an error has been ignored.
+* SUCCESS: A CircuitBreakerEvent which informs that a success has been recorded.
+* NOT_PERMITTED: A CircuitBreakerEvent which informs that a call was not permitted because the CircuitBreaker state is OPEN.
+* STATE_TRANSITION: A CircuitBreakerEvent which informs the state of the CircuitBreaker has been changed.
+
+For example /circuitbreaker/events/backendA/ERROR`:
+----
+{
+"circuitBreakerEvents":[
+  {
+    "circuitBreakerName": "backendA",
+    "type": "ERROR",
+    "creationTime": "2017-01-10T15:42:59.324+01:00[Europe/Berlin]",
+    "errorMessage": "org.springframework.web.client.HttpServerErrorException: 500 This is a remote exception",
+    "durationInMs": 0
+  },
+  {
+    "circuitBreakerName": "backendA",
+    "type": "ERROR",
+    "creationTime": "2017-01-10T15:43:22.802+01:00[Europe/Berlin]",
+    "errorMessage": "org.springframework.web.client.HttpServerErrorException: 500 This is a remote exception",
+    "durationInMs": 0
+  }
+]
+}
+----
+
+===== RateLimiter
+These are the same endpoints as implemented for CircuitBreaker,
+so for detailed documentation please refer to previous section.
+
+List of available endpoints:
+
+* `/ratelimiter/events`
+* `/ratelimiter/stream/events`
+* `/ratelimiter/events/{retryName}`
+* `/ratelimiter/stream/events/{retryName}`
+* `/ratelimiter/events/{retryName}/{eventType}`
+* `/ratelimiter/stream/events/{retryName}/{eventType}`
+
+Example of response:
+----
+{
+  "rateLimiterEvents": [
+    {
+      "rateLimiterName": "backendA",
+      "rateLimiterEventType": "SUCCESSFUL_ACQUIRE",
+      "rateLimiterCreationTime": "2017-05-05T21:29:40.463+03:00[Europe/Uzhgorod]"
+    },
+    {
+      "rateLimiterName": "backendA",
+      "rateLimiterEventType": "SUCCESSFUL_ACQUIRE",
+      "rateLimiterCreationTime": "2017-05-05T21:29:40.469+03:00[Europe/Uzhgorod]"
+    },
+    {
+      "rateLimiterName": "backendA",
+      "rateLimiterEventType": "FAILED_ACQUIRE",
+      "rateLimiterCreationTime": "2017-05-05T21:29:41.268+03:00[Europe/Uzhgorod]"
+    }
+  ]
+}
+----
+
+===== Retry
+These are the same endpoints as implemented for CircuitBreaker,
+so for detailed documentation please refer to previous sections.
+
+List of available endpoints:
+
+* `/retry/events`
+* `/retry/stream/events`
+* `/retry/events/{retryName}`
+* `/retry/stream/events/{retryName}`
+* `/retry/events/{retryName}/{eventType}`
+* `/retry/stream/events/{retryName}/{eventType}`
+
+Example of response:
+----
+{
+  "retryEvents": [
+    {
+      "retryName": "backendA",
+      "retryEventType": "ERROR",
+      "numberOfRetryAttempts":3,
+      "retryCreationTime": "2017-05-05T21:29:40.463+03:00[Europe/Uzhgorod]"
+    },
+    {
+      "retryName": "backendA",
+      "retryEventType": "ERROR",
+      "numberOfRetryAttempts":3,
+      "retryCreationTime": "2017-05-05T21:29:40.469+03:00[Europe/Uzhgorod]"
+    },
+    {
+      "retryName": "backendA",
+      "retryEventType": "ERROR",
+      "numberOfRetryAttempts":3,
+      "retryCreationTime": "2017-05-05T21:29:41.268+03:00[Europe/Uzhgorod]"
+    }
+  ]
+}
+----

resilience4j-ratpack/build.gradle

@@ -5,6 +5,7 @@ dependencies {
     compile project(':resilience4j-circuitbreaker')
     compile project(':resilience4j-ratelimiter')
     compile project(':resilience4j-retry')
+    compile project(':resilience4j-consumer')
     compileOnly ( libraries.ratpack_metrics )
     compileOnly project(':resilience4j-prometheus')
     compileOnly project(':resilience4j-metrics')
@@ -16,5 +17,5 @@ dependencies {
 }
 
 test {
-    maxParallelForks = 8
+    maxParallelForks = 1
 }

resilience4j-ratpack/src/main/java/io/github/resilience4j/ratpack/EndpointsConfig.java

@@ -0,0 +1,107 @@
+/*
+ * Copyright 2017 Dan Maas
+ *
+ * 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.ratpack;
+
+import ratpack.func.Function;
+
+import static ratpack.util.Exceptions.uncheck;
+
+public class EndpointsConfig {
+
+    private EndpointConfig circuitBreakers = new EndpointConfig("circuitbreaker");
+    private EndpointConfig rateLimiters = new EndpointConfig("ratelimiter");
+    private EndpointConfig retries = new EndpointConfig("retry");
+
+    public EndpointConfig getCircuitBreakers() {
+        return circuitBreakers;
+    }
+
+    public EndpointsConfig circuitBreakers(Function<? super EndpointConfig, ? extends EndpointConfig> configure) {
+        try {
+            circuitBreakers = configure.apply(new EndpointConfig("circuitbreaker"));
+            return this;
+        } catch (Exception e) {
+            throw uncheck(e);
+        }
+    }
+
+    public EndpointConfig getRateLimiters() {
+        return rateLimiters;
+    }
+
+    public EndpointsConfig rateLimiters(Function<? super EndpointConfig, ? extends EndpointConfig> configure) {
+        try {
+            rateLimiters = configure.apply(new EndpointConfig("ratelimiter"));
+            return this;
+        } catch (Exception e) {
+            throw uncheck(e);
+        }
+    }
+
+    public EndpointConfig getRetries() {
+        return retries;
+    }
+
+    public EndpointsConfig retries(Function<? super EndpointConfig, ? extends EndpointConfig> configure) {
+        try {
+            retries = configure.apply(new EndpointConfig("retry"));
+            return this;
+        } catch (Exception e) {
+            throw uncheck(e);
+        }
+    }
+
+    public static class EndpointConfig {
+        private boolean enabled = true;
+        private String path;
+        private int eventConsumerBufferSize = 100;
+
+        public EndpointConfig() {
+        }
+
+        public EndpointConfig(String path) {
+            this.path = path;
+        }
+
+        public boolean isEnabled() {
+            return enabled;
+        }
+
+        public EndpointConfig enabled(boolean enabled) {
+            this.enabled = enabled;
+            return this;
+        }
+
+        public String getPath() {
+            return path;
+        }
+
+        public EndpointConfig path(String path) {
+            this.path = path;
+            return this;
+        }
+
+        public int getEventConsumerBufferSize() {
+            return eventConsumerBufferSize;
+        }
+
+        public EndpointConfig eventConsumerBufferSize(int eventConsumerBufferSize) {
+            this.eventConsumerBufferSize = eventConsumerBufferSize;
+            return this;
+        }
+    }
+}

resilience4j-ratpack/src/main/java/io/github/resilience4j/ratpack/Resilience4jConfig.java

@@ -32,6 +32,7 @@ public class Resilience4jConfig {
     private Map<String, RetryConfig> retries = new HashMap<>();
     private boolean metrics = false;
     private boolean prometheus = false;
+    private EndpointsConfig endpoints = new EndpointsConfig();
 
     public Resilience4jConfig circuitBreaker(String name, Function<? super CircuitBreakerConfig, ? extends CircuitBreakerConfig> configure) {
         try {
@@ -73,6 +74,15 @@ public Resilience4jConfig prometheus(boolean prometheus) {
         return this;
     }
 
+    public Resilience4jConfig endpoints(Function<? super EndpointsConfig, ? extends EndpointsConfig> configure) {
+        try {
+            endpoints = configure.apply(new EndpointsConfig());
+            return this;
+        } catch (Exception e) {
+            throw uncheck(e);
+        }
+    }
+
     public Map<String, CircuitBreakerConfig> getCircuitBreakers() {
         return circuitBreakers;
     }
@@ -92,4 +102,8 @@ public boolean isMetrics() {
     public boolean isPrometheus() {
         return prometheus;
     }
+
+    public EndpointsConfig getEndpoints() {
+        return endpoints;
+    }
 }