JAVA¶

Link Guance to JAVA applications:

• Collect custom Metrics data from the application;
• Collect APM data from the application;
• Manage all LOGs of the application.

Configuration¶

Metric Collection¶

You can refer to the JVM documentation

APM Data Collection¶

Enable the corresponding collector in the application, then use the JAVA agent tool to obtain trace information and send it to Guance.

Log Correlation¶

opentelemetry-java (hereinafter referred to as "Agent") is injected into the application via the javaagent method. After the application generates trace information, by setting MDC, traceId and spanId can be passed as parameters to log, so that the log will carry traceId and spanId when outputting.

It contains thread-local context information and copies it into each log event captured by the logging library.

The OTEL JAVA Agent injects several pieces of information about the current span into the MDC copy of each log record event:

• trace_id The current trace id (the same as Span.current().getSpanContext().getTraceId());
• span_id The current span id (the same as Span.current().getSpanContext().getSpanId());
• trace_flags Current trace flags, formatted according to the W3C Trace Flags format (the same as Span.current().getSpanContext().getTraceFlags().asHex()).

These three pieces of information can be included in log statements generated by the logging library by specifying them in the pattern/format.

Tip: For SpringBoot configurations using logback, you can add MDC to log lines by simply overriding the following content for logging.pattern.level:

logging.pattern.level = trace_id=%mdc{trace_id} span_id=%mdc{span_id} trace_flags=%mdc{trace_flags} %5p

This way, any service or tool parsing application logs can associate traces/spans with log statements.

Log Configuration¶

Log pattern configurations differ for various APM tools. Here's an example using logback.xml:

<property name="log.pattern" value="%d{HH:mm:ss} [%thread] %-5level %logger{10} [traceId=%X{trace_id} spanId=%X{span_id} userId=%X{user-id}] %msg%n" />

<!-- %m outputs information, %p log level, %t thread name, %d date, %c full class name,,,, -->
<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
    <encoder>
        <pattern>${log.pattern}</pattern>
        <charset>UTF-8</charset>
    </encoder>
</appender>

<property name="log.pattern" value="%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger - [%method,%line] %X{dd.service} %X{dd.trace_id} %X{dd.span_id} - %msg%n" />

<!-- %m outputs information, %p log level, %t thread name, %d date, %c full class name,,,, -->
<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
    <encoder>
        <pattern>${log.pattern}</pattern>
        <charset>UTF-8</charset>
    </encoder>
</appender>-

Reference Documentation¶

DDTrace Log

springboot-ddtrace-server

springboot-opentelemetry-otlp-server