gcloud-logging json log appender for sl4j + logback

This library provides a simple json based layout that can be used to send structured logs to gcloud logging.

This appender is particularly useful in Google Container Engine where logs should be emitted to stdout.

Stackdriver fluentd plugin implementation

https://github.com/GoogleCloudPlatform/fluent-plugin-google-cloud/blob/master/lib/fluent/plugin/out_google_cloud.rb

Is this production ready?

Yes.

Usage

Add dependency to build.gradle:

dependencies {
    // refer to badge for latest version
    compile 'com.github.ankurcha:google-cloud-logging-logback-slf4j:LATEST'
}

or to maven pom.xml:

<dependency>
    <groupId>com.github.ankurcha</groupId>
    <artifactId>google-cloud-logging-logback-slf4j</artifactId>
    <version>LATEST</version>
</dependency>

Add entry to logback.xml

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <appender name="KUBE_CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
        <encoder class="ch.qos.logback.core.encoder.LayoutWrappingEncoder">
            <layout class="com.google.cloud.logging.GoogleCloudLoggingV2Layout">
                <appendLineSeparator>true</appendLineSeparator>
                <serviceName>@service-name@</serviceName>
                <serviceVersion>@git.sha@</serviceVersion>
                <jsonFormatter class="com.google.cloud.logging.GSONJsonFormatter"/>
            </layout>
        </encoder>
    </appender>

    <root level="info">
        <appender-ref ref="KUBE_CONSOLE"/>
    </root>

</configuration>

Example log line (prettified here):

{
   "severity":"INFO",
   "logging.googleapis.com/trace": "projects/<project-id>/traces/<trace_id>",
   "logging.googleapis.com/spanId": "<span_id>",
   "context":{
      "reportLocation":{
         "functionName":"org.springframework.web.servlet.FrameworkServlet.initServletBean",
         "filePath":"org/springframework/web/servlet/FrameworkServlet.class",
         "logger":"org.springframework.web.servlet.DispatcherServlet",
         "thread":"http-nio-8080-exec-1",
         "lineNumber":508
      }
   },
   "serviceContext":{
      "version":"dc23b8d342e95b48a80219a2af67388b1c1a52d0",
      "service":"ferric"
   },
   "message":"FrameworkServlet \u0027dispatcherServlet\u0027: initialization completed in 27 ms",
   "timestamp":{
      "seconds":1478201184,
      "nanos":753000000
   }
}

Adding trace context (since 1.1.7)

Add an argument to the log statement of type com.google.cloud.logging.TraceContext with trace and spanId if available. Trace id should be of the format: projects/<project-id>/traces/<trace_id> where project-id is the gcp project id and trace_id is the 16-character hexadecimal encoding of the trace id. Similarly for the <span-id>.

Adding http request context (since 1.1.8)

Add an argument to the log statement of type com.google.cloud.logging.HttpRequestContext to provide the httpRequest fields. This field will be emitted as the httpRequest field in the output.

Source location (since 1.1.9)

The source location is now populated as the logging.googleapis.com/sourceLocation field when available.

TODO

• Update in readme
• Add some tests for the formatter