DropWizard metrics (#76)

* Setup DropWizard metrics

* Add Prometheus port configuration to README

* Unit tests for metrics

* Add metrics, rewrite MetricTest based on the objects that handle the metrics

* Clear changed properties in MetricTest

* Change the name of sendLatency metric

* Move test classes to the correct packages

* Decorate NettyHttpServer with MetricHttpServer

* Close server in finally block in MetricHttpServer

* Change closing order in MetricHttpServer

* Refactor Metrics into Report and split the logic into decorators

README.adoc

@@ -37,6 +37,7 @@ lookups.hostname.file,etc/hostname.json,Path to username-to-hostname lookup tabl
 lookups.appname.file,etc/appname.json,Path to username-to-appname lookup table
 payload.splitRegex, \n (newline), A regex based on which incoming requests will be split into multiple outgoing messages
 payload.splitEnabled, false, Sets whether splitting incoming messages by splitRegex is enabled
+prometheus.port, 1234, Port used by the server that provides DropWizard metrics
 |===
 
 === Lookup tables

etc/config.properties

@@ -22,3 +22,5 @@ lookups.appname.file=etc/appname.json
 
 payload.splitRegex=\n
 payload.splitEnabled=false
+
+prometheus.port=1234

pom.xml

@@ -15,8 +15,10 @@
     <log4j.version>2.23.1</log4j.version>
     <maven.compiler.source>${java.version}</maven.compiler.source>
     <maven.compiler.target>${java.version}</maven.compiler.target>
+    <metrics.version>4.2.8</metrics.version>
     <netty.version>4.1.108.Final</netty.version>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <prometheus-simpleclient.version>0.16.0</prometheus-simpleclient.version>
     <revision>0.0.1</revision>
     <rlo_14.version>1.0.1</rlo_14.version>
     <rlp_01.version>4.0.1</rlp_01.version>
@@ -90,6 +92,43 @@
       <artifactId>netty-handler</artifactId>
       <version>${netty.version}</version>
     </dependency>
+    <!-- metrics -->
+    <dependency>
+      <groupId>io.dropwizard.metrics</groupId>
+      <artifactId>metrics-core</artifactId>
+      <version>${metrics.version}</version>
+    </dependency>
+    <dependency>
+      <groupId>io.dropwizard.metrics</groupId>
+      <artifactId>metrics-jmx</artifactId>
+      <version>${metrics.version}</version>
+    </dependency>
+    <dependency>
+      <groupId>io.prometheus</groupId>
+      <artifactId>simpleclient</artifactId>
+      <version>${prometheus-simpleclient.version}</version>
+    </dependency>
+    <dependency>
+      <groupId>io.prometheus</groupId>
+      <artifactId>simpleclient_dropwizard</artifactId>
+      <version>${prometheus-simpleclient.version}</version>
+    </dependency>
+    <dependency>
+      <groupId>io.prometheus</groupId>
+      <artifactId>simpleclient_servlet</artifactId>
+      <version>${prometheus-simpleclient.version}</version>
+    </dependency>
+    <dependency>
+      <groupId>io.prometheus</groupId>
+      <artifactId>simpleclient_hotspot</artifactId>
+      <version>${prometheus-simpleclient.version}</version>
+    </dependency>
+    <!-- for exporting prometheus -->
+    <dependency>
+      <groupId>org.eclipse.jetty</groupId>
+      <artifactId>jetty-servlet</artifactId>
+      <version>10.0.15</version>
+    </dependency>
     <!-- log4j -->
     <dependency>
       <groupId>org.apache.logging.log4j</groupId>

src/main/java/com/teragrep/lsh_01/HttpServer.java

@@ -0,0 +1,25 @@
+/*
+  logstash-http-input to syslog bridge
+  Copyright 2024 Suomen Kanuuna Oy
+
+  Derivative Work of Elasticsearch
+  Copyright 2012-2015 Elasticsearch
+
+  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 com.teragrep.lsh_01;
+
+import java.io.Closeable;
+
+public interface HttpServer extends Runnable, Closeable {
+}

src/main/java/com/teragrep/lsh_01/Main.java

@@ -19,13 +19,20 @@
 */
 package com.teragrep.lsh_01;
 
+import com.codahale.metrics.MetricRegistry;
 import com.teragrep.lsh_01.authentication.BasicAuthentication;
 import com.teragrep.lsh_01.authentication.BasicAuthenticationFactory;
 import com.teragrep.lsh_01.config.*;
+import com.teragrep.lsh_01.metrics.HttpReport;
+import com.teragrep.lsh_01.metrics.JmxReport;
+import com.teragrep.lsh_01.metrics.Report;
+import com.teragrep.lsh_01.metrics.Slf4jReport;
 import com.teragrep.lsh_01.pool.*;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
+import java.io.IOException;
+
 public class Main {
 
     private final static Logger LOGGER = LogManager.getLogger(Main.class);
@@ -38,13 +45,15 @@ public static void main(String[] args) {
         InternalEndpointUrlConfig internalEndpointUrlConfig = new InternalEndpointUrlConfig();
         LookupConfig lookupConfig = new LookupConfig();
         PayloadConfig payloadConfig = new PayloadConfig();
+        MetricsConfig metricsConfig = new MetricsConfig();
         try {
             nettyConfig.validate();
             relpConfig.validate();
             securityConfig.validate();
             internalEndpointUrlConfig.validate();
             lookupConfig.validate();
             payloadConfig.validate();
+            metricsConfig.validate();
         }
         catch (IllegalArgumentException e) {
             LOGGER.error("Can't parse config properly: {}", e.getMessage());
@@ -57,28 +66,32 @@ public static void main(String[] args) {
         LOGGER.info("Got payload config: <[{}]>", payloadConfig);
         LOGGER.info("Authentication required: <[{}]>", securityConfig.authRequired);
 
-        RelpConnectionFactory relpConnectionFactory = new RelpConnectionFactory(relpConfig);
+        // metrics
+        MetricRegistry metricRegistry = new MetricRegistry();
+        Report report = new Slf4jReport(
+                new JmxReport(new HttpReport(metricRegistry, metricsConfig.prometheusPort), metricRegistry),
+                metricRegistry
+        );
+
+        RelpConnectionFactory relpConnectionFactory = new RelpConnectionFactory(relpConfig, metricRegistry);
         Pool<IManagedRelpConnection> pool = new Pool<>(relpConnectionFactory, new ManagedRelpConnectionStub());
 
-        RelpConversion relpConversion = new RelpConversion(
-                pool,
-                securityConfig,
-                basicAuthentication,
-                lookupConfig,
-                payloadConfig
+        IMessageHandler relpConversion = new MetricRelpConversion(
+                new RelpConversion(pool, securityConfig, basicAuthentication, lookupConfig, payloadConfig),
+                metricRegistry
         );
 
         try (
-                NettyHttpServer server = new NettyHttpServer(
-                        nettyConfig,
-                        relpConversion,
-                        null,
-                        200,
-                        internalEndpointUrlConfig
+                HttpServer server = new MetricHttpServer(
+                        new NettyHttpServer(nettyConfig, relpConversion, null, 200, internalEndpointUrlConfig),
+                        report
                 )
         ) {
             server.run();
         }
+        catch (IOException e) {
+            throw new IllegalArgumentException("Failed to close the server: " + e.getMessage());
+        }
         finally {
             pool.close();
         }

src/main/java/com/teragrep/lsh_01/MetricHttpServer.java

@@ -0,0 +1,54 @@
+/*
+  logstash-http-input to syslog bridge
+  Copyright 2024 Suomen Kanuuna Oy
+
+  Derivative Work of Elasticsearch
+  Copyright 2012-2015 Elasticsearch
+
+  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 com.teragrep.lsh_01;
+
+import com.teragrep.lsh_01.metrics.Report;
+
+import java.io.IOException;
+
+/**
+ * Decorator for a HttpServer that applies metrics.
+ */
+public class MetricHttpServer implements HttpServer {
+
+    private final HttpServer server;
+    private final Report report;
+
+    public MetricHttpServer(HttpServer server, Report report) {
+        this.server = server;
+        this.report = report;
+    }
+
+    @Override
+    public void run() {
+        report.start();
+        server.run();
+    }
+
+    @Override
+    public void close() throws IOException {
+        try {
+            server.close();
+        }
+        finally {
+            report.close();
+        }
+    }
+}

src/main/java/com/teragrep/lsh_01/MetricRelpConversion.java

@@ -0,0 +1,75 @@
+/*
+  logstash-http-input to syslog bridge
+  Copyright 2024 Suomen Kanuuna Oy
+
+  Derivative Work of Elasticsearch
+  Copyright 2012-2015 Elasticsearch
+
+  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 com.teragrep.lsh_01;
+
+import com.codahale.metrics.MetricRegistry;
+import com.codahale.metrics.SlidingWindowReservoir;
+import com.codahale.metrics.Timer;
+import com.teragrep.lsh_01.authentication.Subject;
+
+import java.util.Map;
+
+import static com.codahale.metrics.MetricRegistry.name;
+
+/**
+ * Decorator for IMessageHandler. Responsible for reporting metrics.
+ */
+public class MetricRelpConversion implements IMessageHandler {
+
+    private final IMessageHandler relpConversion;
+    private final MetricRegistry metricRegistry;
+    private final Timer sendLatency;
+
+    public MetricRelpConversion(IMessageHandler relpConversion, MetricRegistry metricRegistry) {
+        this.relpConversion = relpConversion;
+        this.metricRegistry = metricRegistry;
+        this.sendLatency = metricRegistry
+                .timer(name(MetricRelpConversion.class, "sendLatency"), () -> new Timer(new SlidingWindowReservoir(10000)));
+    }
+
+    @Override
+    public boolean onNewMessage(Subject subject, Map<String, String> headers, String body) {
+        boolean sent;
+        try (Timer.Context ctx = sendLatency.time()) {
+            sent = relpConversion.onNewMessage(subject, headers, body);
+        }
+        return sent;
+    }
+
+    @Override
+    public IMessageHandler copy() {
+        return new MetricRelpConversion(relpConversion.copy(), metricRegistry);
+    }
+
+    @Override
+    public Subject asSubject(String token) {
+        return relpConversion.asSubject(token);
+    }
+
+    @Override
+    public boolean requiresToken() {
+        return relpConversion.requiresToken();
+    }
+
+    @Override
+    public Map<String, String> responseHeaders() {
+        return relpConversion.responseHeaders();
+    }
+}

src/main/java/com/teragrep/lsh_01/NettyHttpServer.java

@@ -31,7 +31,6 @@
 import com.teragrep.lsh_01.util.CustomRejectedExecutionHandler;
 import com.teragrep.lsh_01.util.SslHandlerProvider;
 
-import java.io.Closeable;
 import java.util.concurrent.ArrayBlockingQueue;
 import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
@@ -41,7 +40,7 @@
 /**
  * Created by joaoduarte on 11/10/2017.
  */
-public class NettyHttpServer implements Runnable, Closeable {
+public class NettyHttpServer implements HttpServer {
 
     private final ServerBootstrap serverBootstrap;
     private final String host;

src/main/java/com/teragrep/lsh_01/config/MetricsConfig.java

@@ -0,0 +1,44 @@
+/*
+  logstash-http-input to syslog bridge
+  Copyright 2024 Suomen Kanuuna Oy
+
+  Derivative Work of Elasticsearch
+  Copyright 2012-2015 Elasticsearch
+
+  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 com.teragrep.lsh_01.config;
+
+public class MetricsConfig implements Validateable {
+
+    public final int prometheusPort;
+
+    public MetricsConfig() {
+        PropertiesReaderUtilityClass propertiesReader = new PropertiesReaderUtilityClass(
+                System.getProperty("properties.file", "etc/config.properties")
+        );
+        prometheusPort = propertiesReader.getIntProperty("prometheus.port");
+    }
+
+    @Override
+    public void validate() {
+        if (prometheusPort < 1 || prometheusPort > 65535) {
+            throw new IllegalArgumentException("prometheus.port wasn't a valid port");
+        }
+    }
+
+    @Override
+    public String toString() {
+        return "RelpConfig{" + "prometheusPort=" + prometheusPort + "}";
+    }
+}