[KARAF-6990] Add loki appender
diff --git a/appender/loki/NOTICE b/appender/loki/NOTICE
new file mode 100644
index 0000000..4e4af9e
--- /dev/null
+++ b/appender/loki/NOTICE
@@ -0,0 +1,57 @@
+Apache Karaf Decanter
+Copyright 2015-2019 The Apache Software Foundation
+
+I. Included Software
+
+This product includes software developed at
+The Apache Software Foundation (http://www.apache.org/).
+Licensed under the Apache License 2.0.
+
+This product includes software developed at
+Elastic (https://www.elastic.co/).
+Licensed under the Apache License 2.0.
+
+This product includes software developed at
+OrientDB (http://orientdb.com).
+Licensed under the Apache License 2.0.
+
+II. Used Software
+
+This product uses software developed at
+The OSGi Alliance (http://www.osgi.org/).
+Copyright (c) OSGi Alliance (2000, 2010).
+Licensed under the Apache License 2.0.
+
+This product uses software developed at
+OPS4J (http://www.ops4j.org/).
+Licensed under the Apache License 2.0.
+
+This product uses software developed at
+SLF4J (http://www.slf4j.org/).
+Licensed under the MIT License.
+
+This product uses software developed at
+JUnit (http://www.junit.org/).
+Licensed under the Eclipse Public License 1.0.
+
+This product uses software developed at
+Redis (http://www.redis.io).
+Licensed under the BSD license.
+
+This product uses software developed at
+Dropwizard (http://www.dropwizard.io).
+Licensed under the Apache License 2.0.
+
+This product uses software developed at
+searchbox.io (https://github.com/searchbox-io)
+Licensed under the Apache License 2.0.
+
+This product uses software developed at
+MongoDB (https://www.mongodb.com/)
+Licensed under the Apache License 2.0.
+
+III. License Summary
+- Apache License 2.0
+- MIT License
+- Eclipse Public License 1.0
+- BSD License
diff --git a/appender/loki/pom.xml b/appender/loki/pom.xml
new file mode 100644
index 0000000..d603dc8
--- /dev/null
+++ b/appender/loki/pom.xml
@@ -0,0 +1,91 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<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/xsd/maven-4.0.0.xsd">
+
+ <!--
+
+ Licensed to the Apache Software Foundation (ASF) under one or more
+ contributor license agreements. See the NOTICE file distributed with
+ this work for additional information regarding copyright ownership.
+ The ASF licenses this file to You 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.
+ -->
+
+ <modelVersion>4.0.0</modelVersion>
+
+ <parent>
+ <groupId>org.apache.karaf.decanter</groupId>
+ <artifactId>appender</artifactId>
+ <version>2.7.0-SNAPSHOT</version>
+ <relativePath>../pom.xml</relativePath>
+ </parent>
+
+ <groupId>org.apache.karaf.decanter.appender</groupId>
+ <artifactId>org.apache.karaf.decanter.appender.loki</artifactId>
+ <packaging>bundle</packaging>
+ <name>Apache Karaf :: Decanter :: Appender :: Loki</name>
+
+ <dependencies>
+ <dependency>
+ <groupId>org.apache.karaf.decanter</groupId>
+ <artifactId>org.apache.karaf.decanter.api</artifactId>
+ </dependency>
+ <dependency>
+ <groupId>org.apache.karaf.decanter.appender</groupId>
+ <artifactId>org.apache.karaf.decanter.appender.utils</artifactId>
+ </dependency>
+ </dependencies>
+
+ <build>
+ <plugins>
+ <plugin>
+ <groupId>org.apache.felix</groupId>
+ <artifactId>maven-bundle-plugin</artifactId>
+ <inherited>true</inherited>
+ <extensions>true</extensions>
+ <configuration>
+ <obrRepository>NONE</obrRepository>
+ <instructions>
+ <Bundle-SymbolicName>${project.artifactId}</Bundle-SymbolicName>
+ <Export-Package>!*</Export-Package>
+ <Import-Package>*</Import-Package>
+ <Private-Package>
+ org.apache.karaf.decanter.appender.loki,
+ org.apache.karaf.decanter.appender.utils
+ </Private-Package>
+ <_dsannotations>*</_dsannotations>
+ </instructions>
+ </configuration>
+ </plugin>
+ <plugin>
+ <groupId>org.codehaus.mojo</groupId>
+ <artifactId>build-helper-maven-plugin</artifactId>
+ <executions>
+ <execution>
+ <phase>package</phase>
+ <goals>
+ <goal>attach-artifact</goal>
+ </goals>
+ <configuration>
+ <artifacts>
+ <artifact>
+ <file>src/main/cfg/org.apache.karaf.decanter.appender.loki.cfg</file>
+ <type>cfg</type>
+ </artifact>
+ </artifacts>
+ </configuration>
+ </execution>
+ </executions>
+ </plugin>
+ </plugins>
+ </build>
+
+</project>
\ No newline at end of file
diff --git a/appender/loki/src/main/cfg/org.apache.karaf.decanter.appender.loki.cfg b/appender/loki/src/main/cfg/org.apache.karaf.decanter.appender.loki.cfg
new file mode 100644
index 0000000..1e21de7
--- /dev/null
+++ b/appender/loki/src/main/cfg/org.apache.karaf.decanter.appender.loki.cfg
@@ -0,0 +1,35 @@
+################################################################################
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements. See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You 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.
+#
+################################################################################
+
+######################################
+# Decanter Loki Appender Configuration
+######################################
+
+# Loki push API location
+#loki.url=http://localhost:3100/loki/api/v1/push
+
+# Loki tenant
+#loki.tenant=my-tenant
+
+# Loki basic authentication
+#loki.username=
+#loki.password=
+
+# Marshaller
+#marshaller.target=(dataFormat=raw)
\ No newline at end of file
diff --git a/appender/loki/src/main/java/org/apache/karaf/decanter/appender/loki/LokiAppender.java b/appender/loki/src/main/java/org/apache/karaf/decanter/appender/loki/LokiAppender.java
new file mode 100644
index 0000000..58c1bba
--- /dev/null
+++ b/appender/loki/src/main/java/org/apache/karaf/decanter/appender/loki/LokiAppender.java
@@ -0,0 +1,116 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.karaf.decanter.appender.loki;
+
+import org.apache.karaf.decanter.api.marshaller.Marshaller;
+import org.apache.karaf.decanter.appender.utils.EventFilter;
+import org.osgi.service.component.ComponentContext;
+import org.osgi.service.component.annotations.Activate;
+import org.osgi.service.component.annotations.Component;
+import org.osgi.service.component.annotations.Reference;
+import org.osgi.service.component.annotations.ReferenceCardinality;
+import org.osgi.service.event.Event;
+import org.osgi.service.event.EventConstants;
+import org.osgi.service.event.EventHandler;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.BufferedWriter;
+import java.io.OutputStreamWriter;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.nio.charset.StandardCharsets;
+import java.util.Base64;
+import java.util.Dictionary;
+
+@Component(
+ name = "org.apache.karaf.decanter.appender.loki",
+ immediate = true,
+ property = EventConstants.EVENT_TOPIC + "=decanter/collect/*"
+)
+public class LokiAppender implements EventHandler {
+
+ private final static Logger LOGGER = LoggerFactory.getLogger(LokiAppender.class);
+
+ @Reference(cardinality = ReferenceCardinality.OPTIONAL)
+ public Marshaller marshaller;
+
+ private String url;
+ private String tenant = null;
+ private String username = null;
+ private String password = null;
+ private Dictionary<String, Object> config;
+
+ @Activate
+ public void activate(ComponentContext componentContext) {
+ activate(componentContext.getProperties());
+ }
+
+ public void activate(Dictionary<String, Object> config) {
+ this.config = config;
+ url = (config.get("loki.url") != null) ? (String) config.get("loki.url") : "http://localhost:3100/loki/api/v1/push";
+ tenant = (config.get("loki.tenant") != null) ? (String) config.get("loki.tenant") : null;
+ username = (config.get("loki.username") != null) ? (String) config.get("loki.username") : null;
+ password = (config.get("loki.password") != null) ? (String) config.get("loki.password") : null;
+ }
+
+ @Override
+ public void handleEvent(Event event) {
+ if (EventFilter.match(event, config)) {
+ String log;
+ if (marshaller != null) {
+ log = marshaller.marshal(event);
+ } else {
+ StringBuilder builder = new StringBuilder();
+ for (String innerKey : event.getPropertyNames()) {
+ builder.append(innerKey).append(":").append(toString(event.getProperty(innerKey))).append(" | ");
+ }
+ log = builder.toString();
+ }
+ try {
+ HttpURLConnection connection = (HttpURLConnection) new URL(url).openConnection();
+ connection.setDoOutput(true);
+ connection.setRequestMethod("POST");
+ connection.setRequestProperty("Content-Type", "application/json");
+ if (tenant != null) {
+ connection.setRequestProperty("X-Scope-OrgId", tenant);
+ }
+ if (username != null) {
+ String authentication = username + ":" + password;
+ byte[] encodedAuthentication = Base64.getEncoder().encode(authentication.getBytes(StandardCharsets.UTF_8));
+ String authenticationHeader = "Basic " + new String(encodedAuthentication);
+ connection.setRequestProperty("Authorization", authenticationHeader);
+ }
+ String jsonPush = "{\"streams\": [{ \"stream\": { \"job\": \"decanter\" }, \"values\": [ [ \"" + System.currentTimeMillis() * 1000L * 1000L + "\", \"" + log + "\" ] ] }]}";
+ try (BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(connection.getOutputStream()))) {
+ writer.write(jsonPush);
+ writer.flush();
+ }
+ if (connection.getResponseCode() != 204) {
+ LOGGER.warn("Can't push to Loki ({}): {}", connection.getResponseCode(), connection.getResponseMessage());
+ }
+ } catch (Exception e) {
+ LOGGER.warn("Error occurred while pushing to Loki", e);
+ }
+ }
+ }
+
+ private Object toString(Object value) {
+ return value == null ? null : value.toString();
+ }
+
+}
diff --git a/appender/pom.xml b/appender/pom.xml
index 1d43b67..8e7b5bc 100644
--- a/appender/pom.xml
+++ b/appender/pom.xml
@@ -45,6 +45,7 @@
<module>jms</module>
<module>kafka</module>
<module>log</module>
+ <module>loki</module>
<module>orientdb</module>
<module>mongodb</module>
<module>mqtt</module>
diff --git a/assembly/src/main/feature/feature.xml b/assembly/src/main/feature/feature.xml
index 8302043..3ed6305 100644
--- a/assembly/src/main/feature/feature.xml
+++ b/assembly/src/main/feature/feature.xml
@@ -468,13 +468,19 @@
<bundle>mvn:org.apache.karaf.decanter.appender/org.apache.karaf.decanter.appender.websocket-servlet/${project.version}</bundle>
</feature>
- <feature name="decanter-appender-prometheus" version="${project.Version}" description="Karaf Decanter Prometheus Servlet Appender">
+ <feature name="decanter-appender-prometheus" version="${project.version}" description="Karaf Decanter Prometheus Servlet Appender">
<feature>decanter-common</feature>
<feature>http</feature>
<configfile finalname="/etc/org.apache.karaf.decanter.appender.prometheus.cfg">mvn:org.apache.karaf.decanter.appender/org.apache.karaf.decanter.appender.prometheus/${project.version}/cfg</configfile>
<bundle>mvn:org.apache.karaf.decanter.appender/org.apache.karaf.decanter.appender.prometheus/${project.version}</bundle>
</feature>
+ <feature name="decanter-appender-loki" version="${project.version}" description="Karaf Decanter Loki appender">
+ <feature>decanter-common</feature>
+ <configfile finalname="/etc/org.apache.karaf.decanter.appender.loki.cfg">mvn:org.apache.karaf.decanter.appender/org.apache.karaf.decanter.appender.loki/${project.version}/cfg</configfile>
+ <bundle>mvn:org.apache.karaf.decanter.appender/org.apache.karaf.decanter.appender.loki/${project.version}</bundle>
+ </feature>
+
<feature name="decanter-processor-passthrough" version="${project.version}" description="Karaf Decanter Pass Through Processor">
<feature>decanter-common</feature>
<bundle>mvn:org.apache.karaf.decanter.processor/org.apache.karaf.decanter.processor.passthrough/${project.version}</bundle>
diff --git a/manual/src/main/asciidoc/user-guide/appenders.adoc b/manual/src/main/asciidoc/user-guide/appenders.adoc
index 739962b..97e3832 100644
--- a/manual/src/main/asciidoc/user-guide/appenders.adoc
+++ b/manual/src/main/asciidoc/user-guide/appenders.adoc
@@ -321,6 +321,44 @@
It's also possible to enable SSL security (with Kafka 0.9.x) using the SSL properties.
+==== Loki
+
+Loki (https://grafana.com/oss/loki/) is a log aggregation system. The Decanter Loki appender is able to push collected data
+to Loki via the Push API.
+
+The Decanter Loki appender converts any kind of collected data (coming from the dispatcher) as a log string that can be stored in Loki.
+
+The `decanter-appender-loki` feature installs the Loki appender:
+
+----
+karaf@root()> feature:install decanter-appender-loki
+----
+
+This feature also adds `etc/org.apache.karaf.decanter.appender.loki.cfg` configuration file:
+
+----
+######################################
+# Decanter Loki Appender Configuration
+######################################
+
+# Loki push API location
+#loki.url=http://localhost:3100/loki/api/v1/push
+
+# Loki tenant
+#loki.tenant=my-tenant
+
+# Loki basic authentication
+#loki.username=
+#loki.password=
+
+# Marshaller
+#marshaller.target=(dataFormat=raw)
+----
+
+* `loki.url` is the location of the Loki push API
+* `loki.tenant` is optional and define the tenant used to push data
+* `loki.username` and `loki.password` are used for basic authentication
+
==== Redis
The Decanter Redis appender sends the data (collected by the collectors) to a Redis broker.
