SpanReporter for Java
SpanReporter forward to backend Tracer and reports trace into Reporter.
public interface Reporter {
void start(long timestampMicroseconds, SpanR span);
void finish(long timestampMicroseconds, SpanR span);
void log(long timestampMicroseconds, SpanR span, Map<String, ?> event);
}Use Case
- As zero server tracer.
- To use OpenTracing API, before selection and deployment of your Server Tracer.
- To log with spanId, context, without using MDC.
- To add log support to some server tracer that doesn't support
.log(...) - To report some metrics (eg. histogram of span)
Slf4jReporter
- Message is reported as structured message (json)
- Message at start and at finish is logged with level TRACE
19:48:36.828 [main] TRACE tracer - {"ts":1490982516828,"elapsed":0,"spanId":"d4f6df3d-8dc0-4287-b1a0-1b2bc52978c6","action":"start","operation":"span-0","tags":{"description":"top level initial span in the original process"},"baggage":{},"references":{}}
19:48:36.828 [main] TRACE tracer - {"ts":1490982516828,"elapsed":0,"spanId":"da7d843a-4564-4480-a6cb-19550c24a344","action":"start","operation":"span-1","tags":{"description":"the first inner span in the original process"},"baggage":{},"references":{"child_of":"d4f6df3d-8dc0-4287-b1a0-1b2bc52978c6"}}
19:48:36.828 [main] TRACE tracer - {"ts":1490982516828,"elapsed":0,"spanId":"c4bf987f-2d0c-49f1-87bd-a23930570b96","action":"start","operation":"span-2","tags":{"description":"the second inner span in the original process"},"baggage":{},"references":{"child_of":"da7d843a-4564-4480-a6cb-19550c24a344"}}
19:48:36.841 [main] TRACE tracer - {"ts":1490982516841,"elapsed":13,"spanId":"c4bf987f-2d0c-49f1-87bd-a23930570b96","action":"finish","operation":"span-2","tags":{"description":"the second inner span in the original process"},"baggage":{},"references":{"child_of":"da7d843a-4564-4480-a6cb-19550c24a344"}}
19:48:36.841 [main] TRACE tracer - {"ts":1490982516841,"elapsed":13,"spanId":"da7d843a-4564-4480-a6cb-19550c24a344","action":"finish","operation":"span-1","tags":{"description":"the first inner span in the original process"},"baggage":{},"references":{"child_of":"d4f6df3d-8dc0-4287-b1a0-1b2bc52978c6"}}
19:48:36.841 [main] TRACE tracer - {"ts":1490982516841,"elapsed":13,"spanId":"d4f6df3d-8dc0-4287-b1a0-1b2bc52978c6","action":"finish","operation":"span-0","tags":{"description":"top level initial span in the original process","http.url":"/orders"},"baggage":{},"references":{}}
- Message for Span.log report with level INFO by default, the level could be set explicitly by setting the key "loglevel"
span.log("blablabala");
span.log(MapMaker.fields(LogLevel.FIELD_NAME, LogLevel.DEBUG, "k0", "v0", "k1", 42));
span.log(MapMaker.fields(LogLevel.FIELD_NAME, LogLevel.WARN, "k0", "v0", "ex", new Exception("boom !")));22:16:23.911 [main] INFO tracer - {"ts":1490991383911,"elapsed":1,"spanId":"dbebbda2-501e-4461-b9c6-32020df8008f","action":"log","operation":"span-2","tags":{"description":"the second inner span in the original process"},"fields":{"event":"blablabala"}}
22:16:23.911 [main] DEBUG tracer - {"ts":1490991383911,"elapsed":1,"spanId":"dbebbda2-501e-4461-b9c6-32020df8008f","action":"log","operation":"span-2","tags":{"description":"the second inner span in the original process"},"fields":{"k0":"v0","k1":42.0}}
22:16:23.911 [main] WARN tracer - {"ts":1490991383911,"elapsed":1,"spanId":"dbebbda2-501e-4461-b9c6-32020df8008f","action":"log","operation":"span-2","tags":{"description":"the second inner span in the original process"},"fields":{"ex":"java.lang.Exception: boom !\n\tat examples.Sample01.run0(Sample01.java:92)\n\tat examples.Sample01.main(Sample01.java:45)\n","k0":"v0"}}
Usage
Application intialization
- Add dependency (format depends of your build tool)
"io.opentracing.contrib" % "java-span-reporter" % "${span-reporter.version}"
- Instantiate the TracerR (For using DI, you can take inspiration from Guice samples ):
tracer = ... // if not backend tracer use NoopTracerFactory.create()
tracer = new TracerR(tracer, new Slf4jReporter(LoggerFactory.getLogger("tracer")));- Setup your logger (example below use logback, but any slf4j compatible logger should work)
- add dependencies
"ch.qos.logback" % "logback-classic" % "1.1.3"- configure le logger (simplest)
<logger name="tracer" level="TRACE"/>
Custom Reporter(s)
Developer can provide its own Reporter:
- to report log in an other log system
- to report log in an other format
- to report metrics about span/operation (histogram, nb calls, duration, ...)
To report to several Reporters at once, you can use the CompositeReporter:
Tracer tracer = ...
tracer = new TracerR(tracer, new CompositeReporter(
new Slf4jReporter(LoggerFactory.getLogger("tracer")),
new DropwizardMetricsReporter(...)
));Build
- build localy
./gradlew assemble - publish to local maven repository
./gradlew publishToMavenLocal - release
git tag -a "${version}" -m "release" git push --tags