Added Logback with Logstash JSON logging pattern

README.adoc

@@ -143,6 +143,101 @@ filter {
        }
 }
 
+===== JSON Logback with Logstash
+
+Often you do not want to store your logs in a text file but in a JSON file that Logstash can immediately pick. To do that you have to do the following (for readability
+we're passing the dependencies in the `groupId:artifactId:version` notation.
+
+*Dependencies setup*
+
+- Ensure that Logback is on the classpath (`ch.qos.logback:logback-core`)
+- Add Logstash Logback encode - example for version `4.6` : `net.logstash.logback:logstash-logback-encoder:4.6`
+
+*Logback setup*
+
+Below you can find an example of a Logback configuration (file named `https://github.com/spring-cloud-samples/sleuth-documentation-apps/blob/master/service1/src/main/resources/logback-spring.xml[logback-spring.xml]`) that:
+
+- logs information from the application in a JSON format to a `build/${spring.application.name}.json` file
+- has commented out two additional appenders - console and standard log file
+- has the same logging pattern as the one presented in the previous section
+
+[source,xml]
+-----
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+	<include resource="org/springframework/boot/logging/logback/defaults.xml"/>
+	​
+	<springProperty scope="context" name="springAppName" source="spring.application.name"/>
+	<!-- Example for logging into the build folder of your project -->
+	<property name="LOG_FILE" value="${BUILD_FOLDER:-build}/${springAppName}"/>​
+
+	<property name="CONSOLE_LOG_PATTERN"
+			  value="%clr(%d{yyyy-MM-dd HH:mm:ss.SSS}){faint} %clr(${LOG_LEVEL_PATTERN:-%5p}) %clr([${springAppName:-},%X{X-B3-TraceId:-},%X{X-B3-SpanId:-},%X{X-Span-Export:-}]){yellow} %clr(${PID:- }){magenta} %clr(---){faint} %clr([%15.15t]){faint} %clr(%-40.40logger{39}){cyan} %clr(:){faint} %m%n${LOG_EXCEPTION_CONVERSION_WORD:-%wEx}"/>
+
+	<!-- Appender to log to console -->
+	<appender name="console" class="ch.qos.logback.core.ConsoleAppender">
+		<filter class="ch.qos.logback.classic.filter.ThresholdFilter">
+			<!-- Minimum logging level to be presented in the console logs-->
+			<level>INFO</level>
+		</filter>
+		<encoder>
+			<pattern>${CONSOLE_LOG_PATTERN}</pattern>
+			<charset>utf8</charset>
+		</encoder>
+	</appender>
+
+	<!-- Appender to log to file -->​
+	<appender name="flatfile" class="ch.qos.logback.core.rolling.RollingFileAppender">
+		<file>${LOG_FILE}</file>
+		<rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
+			<fileNamePattern>${LOG_FILE}.%d{yyyy-MM-dd}.gz</fileNamePattern>
+			<maxHistory>7</maxHistory>
+		</rollingPolicy>
+		<encoder>
+			<pattern>${CONSOLE_LOG_PATTERN}</pattern>
+			<charset>utf8</charset>
+		</encoder>
+	</appender>
+	​
+	<!-- Appender to log to file in a JSON format -->
+	<appender name="logstash" class="ch.qos.logback.core.rolling.RollingFileAppender">
+		<file>${LOG_FILE}.json</file>
+		<rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
+			<fileNamePattern>${LOG_FILE}.json.%d{yyyy-MM-dd}.gz</fileNamePattern>
+			<maxHistory>7</maxHistory>
+		</rollingPolicy>
+		<encoder class="net.logstash.logback.encoder.LoggingEventCompositeJsonEncoder">
+			<providers>
+				<timestamp>
+					<timeZone>UTC</timeZone>
+				</timestamp>
+				<pattern>
+					<pattern>
+						{
+						"severity": "%level",
+						"service": "${springAppName:-}",
+						"trace": "%X{X-B3-TraceId:-}",
+						"span": "%X{X-B3-SpanId:-}",
+						"exportable": "%X{X-Span-Export:-}",
+						"pid": "${PID:-}",
+						"thread": "%thread",
+						"class": "%logger{40}",
+						"rest": "%message"
+						}
+					</pattern>
+				</pattern>
+			</providers>
+		</encoder>
+	</appender>
+	​
+	<root level="INFO">
+		<!--<appender-ref ref="console"/>-->
+		<appender-ref ref="logstash"/>
+		<!--<appender-ref ref="flatfile"/>-->
+	</root>
+</configuration>
+-----
+
 === Adding to the project
 
 ==== Only Sleuth (log correlation)

docs/src/main/asciidoc/intro.adoc

@@ -135,6 +135,29 @@ filter {
        }
 }
 
+===== JSON Logback with Logstash
+
+Often you do not want to store your logs in a text file but in a JSON file that Logstash can immediately pick. To do that you have to do the following (for readability
+we're passing the dependencies in the `groupId:artifactId:version` notation.
+
+*Dependencies setup*
+
+- Ensure that Logback is on the classpath (`ch.qos.logback:logback-core`)
+- Add Logstash Logback encode - example for version `4.6` : `net.logstash.logback:logstash-logback-encoder:4.6`
+
+*Logback setup*
+
+Below you can find an example of a Logback configuration (file named `https://github.com/spring-cloud-samples/sleuth-documentation-apps/blob/master/service1/src/main/resources/logback-spring.xml[logback-spring.xml]`) that:
+
+- logs information from the application in a JSON format to a `build/${spring.application.name}.json` file
+- has commented out two additional appenders - console and standard log file
+- has the same logging pattern as the one presented in the previous section
+
+[source,xml]
+-----
+include::https://raw.githubusercontent.com/spring-cloud-samples/sleuth-documentation-apps/master/service1/src/main/resources/logback-spring.xml[]
+-----
+
 === Adding to the project
 
 ==== Only Sleuth (log correlation)