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<title>3. Features</title><link rel="stylesheet" type="text/css" href="css/manual-multipage.css"><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"><link rel="home" href="multi_spring-cloud-sleuth.html" title="Spring Cloud Sleuth"><link rel="up" href="multi_spring-cloud-sleuth.html" title="Spring Cloud Sleuth"><link rel="prev" href="multi__additional_resources.html" title="2. Additional resources"><link rel="next" href="multi__sampling.html" title="4. Sampling"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">3. Features</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="multi__additional_resources.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="multi__sampling.html">Next</a></td></tr></table><hr></div><div class="chapter"><div class="titlepage"><div><div><h1 class="title"><a name="_features" href="#_features"></a>3. Features</h1></div></div></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p class="simpara">Adds trace and span ids to the Slf4J MDC, so you can extract all the logs from a given trace or span in a log aggregator. Example logs:</p><pre class="screen">2016-02-02 15:30:57.902 INFO [bar,6bfd228dc00d216b,6bfd228dc00d216b,false] 23030 --- [nio-8081-exec-3] ...
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2016-02-02 15:30:58.372 ERROR [bar,6bfd228dc00d216b,6bfd228dc00d216b,false] 23030 --- [nio-8081-exec-3] ...
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2016-02-02 15:31:01.936 INFO [bar,46ab0d418373cbc9,46ab0d418373cbc9,false] 23030 --- [nio-8081-exec-4] ...</pre><p class="simpara">notice the <code class="literal">[appname,traceId,spanId,exportable]</code> entries from the MDC:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: circle; "><li class="listitem"><span class="strong"><strong>spanId</strong></span> - the id of a specific operation that took place</li><li class="listitem"><span class="strong"><strong>appname</strong></span> - the name of the application that logged the span</li><li class="listitem"><span class="strong"><strong>traceId</strong></span> - the id of the latency graph that contains the span</li><li class="listitem"><span class="strong"><strong>exportable</strong></span> - whether the log should be exported to Zipkin or not. When would you like the span not to be
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exportable? In the case in which you want to wrap some operation in a Span and have it written to the logs
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only.</li></ul></div></li><li class="listitem">Provides an abstraction over common distributed tracing data models: traces, spans (forming a DAG), annotations,
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key-value annotations. Loosely based on HTrace, but Zipkin (Dapper) compatible.</li><li class="listitem"><p class="simpara">Sleuth records timing information to aid in latency analysis. Using sleuth, you can pinpoint causes of
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latency in your applications. Sleuth is written to not log too much, and to not cause your production application to crash.</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: circle; "><li class="listitem">propagates structural data about your call-graph in-band, and the rest out-of-band.</li><li class="listitem">includes opinionated instrumentation of layers such as HTTP</li><li class="listitem">includes sampling policy to manage volume</li><li class="listitem">can report to a Zipkin system for query and visualization</li></ul></div></li><li class="listitem">Instruments common ingress and egress points from Spring applications (servlet filter, async endpoints,
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rest template, scheduled actions, message channels, zuul filters, feign client).</li><li class="listitem">Sleuth includes default logic to join a trace across http or messaging boundaries. For example, http propagation
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works via Zipkin-compatible request headers. This propagation logic is defined and customized via
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<code class="literal">SpanInjector</code> and <code class="literal">SpanExtractor</code> implementations.</li><li class="listitem">Sleuth gives you the possibility to propagate context (also known as baggage) between processes. That means that if you set on a Span
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a baggage element then it will be sent downstream either via HTTP or messaging to other processes.</li><li class="listitem">Provides a way to create / continue spans and add tags and logs via annotations.</li><li class="listitem">Provides simple metrics of accepted / dropped spans.</li><li class="listitem"><p class="simpara">If <code class="literal">spring-cloud-sleuth-zipkin</code> is on the classpath then the app will generate and collect Zipkin-compatible traces.
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By default it sends them via HTTP to a Zipkin server on localhost (port 9411).
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Configure the location of the service using <code class="literal">spring.zipkin.baseUrl</code>.</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: circle; "><li class="listitem">If you depend on <code class="literal">spring-rabbit</code> or <code class="literal">spring-kafka</code> your app will send traces to a broker instead of http.</li><li class="listitem">Note: <code class="literal">spring-cloud-sleuth-stream</code> is deprecated and should no longer be used.</li></ul></div></li></ul></div><div class="important" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Important"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Important]" src="images/important.png"></td><th align="left">Important</th></tr><tr><td align="left" valign="top"><p>If using Zipkin, configure the percentage of spans exported using <code class="literal">spring.sleuth.sampler.percentage</code>
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(default 0.1, i.e. 10%). <span class="strong"><strong>Otherwise you might think that Sleuth is not working cause it’s omitting some spans.</strong></span></p></td></tr></table></div><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td align="left" valign="top"><p>the SLF4J MDC is always set and logback users will immediately see the trace and span ids in logs per the example
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above. Other logging systems have to configure their own formatter to get the same result. The default is
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<code class="literal">logging.pattern.level</code> set to <code class="literal">%5p [${spring.zipkin.service.name:${spring.application.name:-}},%X{X-B3-TraceId:-},%X{X-B3-SpanId:-},%X{X-Span-Export:-}]</code>
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(this is a Spring Boot feature for logback users).
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<span class="strong"><strong>This means that if you’re not using SLF4J this pattern WILL NOT be automatically applied</strong></span>.</p></td></tr></table></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="multi__additional_resources.html">Prev</a> </td><td width="20%" align="center"> </td><td width="40%" align="right"> <a accesskey="n" href="multi__sampling.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">2. Additional resources </td><td width="20%" align="center"><a accesskey="h" href="multi_spring-cloud-sleuth.html">Home</a></td><td width="40%" align="right" valign="top"> 4. Sampling</td></tr></table></div></body></html> |