Initial revision of prometheus exporter.
Metrics are available through the ${GERRIT_URL}/plugins/metrics-reporter-prometheus/metrics
url.
diff --git a/pom.xml b/pom.xml
new file mode 100644
index 0000000..17da0a2
--- /dev/null
+++ b/pom.xml
@@ -0,0 +1,125 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+Copyright (C) 2018 The Android Open Source Project
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+ xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+ xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+ <modelVersion>4.0.0</modelVersion>
+
+ <groupId>com.parrot.gerrit.plugins</groupId>
+ <artifactId>metrics-reporter-prometheus</artifactId>
+ <name>metrics-reporter-prometheus</name>
+ <packaging>jar</packaging>
+ <version>2.14</version>
+ <properties>
+ <Gerrit-ApiType>plugin</Gerrit-ApiType>
+ <Gerrit-ApiVersion>${project.version}</Gerrit-ApiVersion>
+ <Promethus-ApiVersion>0.2.0</Promethus-ApiVersion>
+ </properties>
+
+ <build>
+ <plugins>
+ <plugin>
+ <groupId>org.apache.maven.plugins</groupId>
+ <artifactId>maven-jar-plugin</artifactId>
+ <version>2.4</version>
+ <configuration>
+ <archive>
+ <manifestEntries>
+ <Gerrit-PluginName>metrics-reporter-prometheus</Gerrit-PluginName>
+ <Implementation-Vendor>Gerrit Code Review</Implementation-Vendor>
+ <Implementation-URL>https://gerrit-review.googlesource.com/#/admin/projects/plugins/metrics-reporter-prometheus</Implementation-URL>
+ <Implementation-Title>Prometheus metrics plugin</Implementation-Title>
+ <Implementation-Version>${project.version}</Implementation-Version>
+ <Gerrit-ApiType>${Gerrit-ApiType}</Gerrit-ApiType>
+ <Gerrit-ApiVersion>${Gerrit-ApiVersion}</Gerrit-ApiVersion>
+ </manifestEntries>
+ </archive>
+ </configuration>
+ </plugin>
+
+ <plugin>
+ <groupId>org.apache.maven.plugins</groupId>
+ <artifactId>maven-compiler-plugin</artifactId>
+ <version>2.3.2</version>
+ <configuration>
+ <source>1.8</source>
+ <target>1.8</target>
+ <encoding>UTF-8</encoding>
+ </configuration>
+ </plugin>
+
+ <plugin>
+ <groupId>org.apache.maven.plugins</groupId>
+ <artifactId>maven-shade-plugin</artifactId>
+ <version>3.1.0</version>
+ <configuration>
+ <artifactSet>
+ <includes>
+ <include>io.prometheus:*</include>
+ </includes>
+ </artifactSet>
+ </configuration>
+ <executions>
+ <execution>
+ <phase>package</phase>
+ <goals>
+ <goal>shade</goal>
+ </goals>
+ </execution>
+ </executions>
+ </plugin>
+ </plugins>
+
+ </build>
+
+ <dependencies>
+ <dependency>
+ <groupId>com.google.gerrit</groupId>
+ <artifactId>gerrit-${Gerrit-ApiType}-api</artifactId>
+ <version>${Gerrit-ApiVersion}</version>
+ <scope>provided</scope>
+ </dependency>
+ <dependency>
+ <groupId>io.prometheus</groupId>
+ <artifactId>simpleclient</artifactId>
+ <version>${Promethus-ApiVersion}</version>
+ </dependency>
+ <dependency>
+ <groupId>io.prometheus</groupId>
+ <artifactId>simpleclient_servlet</artifactId>
+ <version>${Promethus-ApiVersion}</version>
+ </dependency>
+ <dependency>
+ <groupId>io.prometheus</groupId>
+ <artifactId>simpleclient_dropwizard</artifactId>
+ <version>${Promethus-ApiVersion}</version>
+ </dependency>
+ <dependency>
+ <groupId>io.dropwizard.metrics</groupId>
+ <artifactId>metrics-core</artifactId>
+ <version>3.1.0</version>
+ <scope>provided</scope>
+ </dependency>
+ </dependencies>
+
+ <repositories>
+ <repository>
+ <id>gerrit-api-repository</id>
+ <url>https://gerrit-api.commondatastorage.googleapis.com/release/</url>
+ </repository>
+ </repositories>
+</project>
diff --git a/src/main/java/com/googlesource/gerrit/plugins/metricsreporters/GerritPrometheusExporter.java b/src/main/java/com/googlesource/gerrit/plugins/metricsreporters/GerritPrometheusExporter.java
new file mode 100644
index 0000000..b561c5e
--- /dev/null
+++ b/src/main/java/com/googlesource/gerrit/plugins/metricsreporters/GerritPrometheusExporter.java
@@ -0,0 +1,33 @@
+// Copyright (C) 2018 The Android Open Source Project
+//
+// 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.googlesource.gerrit.plugins.metricsreporters;
+
+import com.codahale.metrics.MetricRegistry;
+import com.google.gerrit.extensions.annotations.Export;
+import com.google.inject.Inject;
+import com.google.inject.Singleton;
+import io.prometheus.client.CollectorRegistry;
+import io.prometheus.client.dropwizard.DropwizardExports;
+import io.prometheus.client.exporter.MetricsServlet;
+
+@Export("/metrics")
+@Singleton
+public class GerritPrometheusExporter extends MetricsServlet {
+ @Inject
+ public GerritPrometheusExporter(MetricRegistry registry) {
+ // Hook the Dropwizard registry into the Prometheus registry
+ // via the DropwizardExports collector.
+ CollectorRegistry.defaultRegistry.register(new DropwizardExports(registry));
+ }
+};
