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From build...@apache.org
Subject svn commit: r1008292 - in /websites/production/cxf/content: cache/docs.pageCache docs/using-apache-htrace.html
Date Tue, 14 Mar 2017 02:47:38 GMT
Author: buildbot
Date: Tue Mar 14 02:47:38 2017
New Revision: 1008292

Log:
Production update by buildbot for cxf

Modified:
    websites/production/cxf/content/cache/docs.pageCache
    websites/production/cxf/content/docs/using-apache-htrace.html

Modified: websites/production/cxf/content/cache/docs.pageCache
==============================================================================
Binary files - no diff available.

Modified: websites/production/cxf/content/docs/using-apache-htrace.html
==============================================================================
--- websites/production/cxf/content/docs/using-apache-htrace.html (original)
+++ websites/production/cxf/content/docs/using-apache-htrace.html Tue Mar 14 02:47:38 2017
@@ -33,6 +33,8 @@
 
 <script src='/resources/highlighter/scripts/shCore.js'></script>
 <script src='/resources/highlighter/scripts/shBrushJava.js'></script>
+<script src='/resources/highlighter/scripts/shBrushXml.js'></script>
+<script src='/resources/highlighter/scripts/shBrushBash.js'></script>
 <script>
   SyntaxHighlighter.defaults['toolbar'] = false;
   SyntaxHighlighter.all();
@@ -117,18 +119,18 @@ Apache CXF -- Using Apache HTrace
            <!-- Content -->
            <div class="wiki-content">
 <div id="ConfluenceContent"><p><style type="text/css">/*<![CDATA[*/
-div.rbtoc1485917207094 {padding: 0px;}
-div.rbtoc1485917207094 ul {list-style: disc;margin-left: 0px;}
-div.rbtoc1485917207094 li {margin-left: 0px;padding-left: 0px;}
+div.rbtoc1489459622897 {padding: 0px;}
+div.rbtoc1489459622897 ul {list-style: disc;margin-left: 0px;}
+div.rbtoc1489459622897 li {margin-left: 0px;padding-left: 0px;}
 
-/*]]>*/</style></p><div class="toc-macro rbtoc1485917207094">
+/*]]>*/</style></p><div class="toc-macro rbtoc1489459622897">
 <ul class="toc-indentation"><li><a shape="rect" href="#UsingApacheHTrace-Overview">Overview</a></li><li><a
shape="rect" href="#UsingApacheHTrace-DistributedTracinginNutshell">Distributed Tracing
in Nutshell</a></li><li><a shape="rect" href="#UsingApacheHTrace-DistributedTracinginApacheCXFusingApacheHTrace">Distributed
Tracing in Apache CXF using Apache HTrace</a></li><li><a shape="rect"
href="#UsingApacheHTrace-ConfiguringClientconfigure.client">Configuring Client</a>
 <ul class="toc-indentation"><li><a shape="rect" href="#UsingApacheHTrace-Configuringtracingheadernames">Configuring
tracing header names</a></li></ul>
 </li><li><a shape="rect" href="#UsingApacheHTrace-ConfiguringServerconfigure.server">Configuring
Server</a>
 <ul class="toc-indentation"><li><a shape="rect" href="#UsingApacheHTrace-Configuringtracingheadernames.1">Configuring
tracing header names</a></li></ul>
 </li><li><a shape="rect" href="#UsingApacheHTrace-DistributedTracingInAction:UsageScenarios">Distributed
Tracing In Action: Usage Scenarios</a>
 <ul class="toc-indentation"><li><a shape="rect" href="#UsingApacheHTrace-Example#1:ClientandServerwithdefaultdistributedtracingconfigured">Example
#1: Client and Server with default distributed tracing configured</a></li><li><a
shape="rect" href="#UsingApacheHTrace-Example#2:ClientandServerwithnestedtrace">Example
#2: Client and Server with nested trace</a></li><li><a shape="rect" href="#UsingApacheHTrace-Example#3:ClientandServertracewithtimeline">Example
#3: Client and Server trace with timeline</a></li><li><a shape="rect"
href="#UsingApacheHTrace-Example#4:ClientandServerwithannotatedtrace(key/value)">Example
#4: Client and Server with annotated trace (key/value)</a></li><li><a
shape="rect" href="#UsingApacheHTrace-Example#5:ClientandServerwithparalleltrace(involvingthreadpools)">Example
#5: Client and Server with parallel trace (involving thread pools)</a></li><li><a
shape="rect" href="#UsingApacheHTrace-Example#6:ClientandServerwithasynchronousJAX-RSservice(server-side)">Exampl
 e #6: Client and Server with asynchronous JAX-RS service (server-side)</a></li><li><a
shape="rect" href="#UsingApacheHTrace-Example#7:ClientandServerwithasynchronousinvocation(client-side)">Example
#7: Client and Server with asynchronous invocation (client-side)</a></li></ul>
-</li><li><a shape="rect" href="#UsingApacheHTrace-DistributedTracingApacheHTraceandJAX-WSsupport">Distributed
Tracing Apache HTrace and JAX-WS support</a></li><li><a shape="rect"
href="#UsingApacheHTrace-FutureWork">Future Work</a></li></ul>
+</li><li><a shape="rect" href="#UsingApacheHTrace-DistributedTracingApacheHTraceandJAX-WSsupport">Distributed
Tracing Apache HTrace and JAX-WS support</a></li><li><a shape="rect"
href="#UsingApacheHTrace-PropagatingTraceDetailsToLogs">Propagating Trace Details To Logs</a></li><li><a
shape="rect" href="#UsingApacheHTrace-FutureWork">Future Work</a></li></ul>
 </div><h1 id="UsingApacheHTrace-Overview">Overview</h1><p><a shape="rect"
class="external-link" href="http://htrace.incubator.apache.org/index.html">Apache HTrace</a>
is a tracing framework intended for use with distributed systems written in java. Since version
<strong>3.1.3</strong>, Apache CXF fully supports integration with <a shape="rect"
class="external-link" href="http://htrace.incubator.apache.org/index.html">Apache HTrace</a>,
both on client side and server side. This section gives a complete overview on how distributed
tracing support is supported in JAX-RS applications built on top of Apache CXF.</p><h1
id="UsingApacheHTrace-DistributedTracinginNutshell">Distributed Tracing in Nutshell</h1><p>Distributed
tracing, first described by Google in <a shape="rect" class="external-link" href="http://research.google.com/pubs/pub36356.html"
rel="nofollow">Dapper, a Large-Scale Distributed Systems Tracing Infrastructure</a>
paper became increasingly important topic these days. With 
 microservices (aka SOA) gaining more and more adoption, the typical applications are built
using dozens or even hundreds of small, distributed pieces. The end-to-end traceability of
the requests (or any kind of work performed on user's behalf) is hard task to accomplish,
particularly taking into account asyncronous or/and concurrent invocations. <a shape="rect"
class="external-link" href="http://htrace.incubator.apache.org/index.html">Apache HTrace</a>
is inspired by <a shape="rect" class="external-link" href="http://research.google.com/pubs/pub36356.html"
rel="nofollow">Dapper, a Large-Scale Distributed Systems Tracing Infrastructure</a>
paper and essentially is a full-fledged distributed tracing framework.</p><p>Distributed
tracing is additional instrumentation layer on top of new or existing applications. In terms
of distributed tracing, <strong>span</strong> represents a basic unit of work.
For example, executing database query is a <strong>span</strong>. <strong>Spans</strong>

 are identified by a unique 128-bit ID. <strong>Spans</strong> also have other
data, such as <strong>descriptions</strong>, <strong>timelines</strong>,<strong>
key-value annotations</strong>, the <strong>ID</strong> of the <strong>span</strong>
that caused them (parent), and <strong>process/tracer</strong> ID&#8217;s
(normally IP address and process name). Spans are started and stopped, and they keep track
of their timing information. Once <strong>span</strong> is created, it should
be stopped at some point in the future. In turn, <strong>trace</strong> is a set
of spans forming a tree-like structure. For example, if you are running a JAX-RS service,
a trace might be formed by a <strong>PUT</strong> request and downstream work.</p><p>From
implementation perspective, and in context of Java applications, <strong>spans</strong>
are attached to their threads (in general, thread which created the <strong>span</strong>
should close it). However it is possible to transfer <strong>spans</str
 ong> from thread to thread in order to model a complex execution flows. It is also possible
to have many <strong>spans</strong> in the same thread, as long as they are properly
created and closed. In the next sections we are going to see the examples of that.</p><p>Another
two important concepts in context of distributed tracing are <strong>span receivers</strong>
and <strong>samplers</strong>. Essentially, all spans (including start/stop time,
key/value annotations, timelines, ..) should be persisted (or collected) somewhere. <strong>Span
receiver</strong> is a collector within a process that is the destination of <strong>spans</strong>
when a trace is running (it could be a console, local file, data store, ...). <a shape="rect"
class="external-link" href="http://htrace.incubator.apache.org/index.html">Apache HTrace</a>
provides span receivers for <a shape="rect" class="external-link" href="http://hbase.apache.org">Apache
HBase</a>, <a shape="rect" class="external-link" href="https
 ://flume.apache.org/">Apache Flume</a> and <a shape="rect" class="external-link"
href="http://zipkin.io/" rel="nofollow">Twitter Zipkin</a>. From other side, <strong>samplers</strong>
allow to control the frequency of the tracing (all the time, never, probability driven, ...).
Using the <strong>sampler</strong> is the way to minimize tracing overhead (or
just amount of traces) by limiting them to particular conditions.</p><h1 id="UsingApacheHTrace-DistributedTracinginApacheCXFusingApacheHTrace">Distributed
Tracing in Apache CXF using Apache HTrace</h1><p><a shape="rect" href="http://cxf.apache.org/">Apache
CXF</a> is a very popular framework for building services and web APIs. No doubts, it
is going to play even more important role in context of microservices architecture letting
developers to quickly build and deploy individual JAX-RS/JAX-WS services. As it was just mentioned
before, distributed tracing is an essential technique to monitor the application as whole,
breaking the req
 uest to individual service traces as it goes through and crosses the boundaries of threads,
processes and machines.</p><p>The current integration of distributed tracing in
<a shape="rect" href="http://cxf.apache.org/">Apache CXF</a> supports <a shape="rect"
class="external-link" href="http://htrace.incubator.apache.org/index.html">Apache HTrace</a>
(<strong>4.x+</strong> release branch) only in JAX-RS 2.x applications. From high-level
prospective, it consists of three main parts:</p><ul style="list-style-type: square;"><li><strong>TracerContext</strong>
(injectable through <strong>@Context</strong> annotation)</li><li><strong>HTraceProvider</strong>
(server-side JAX-RS provider) and <strong>HTraceClientProvider</strong> (client-side
JAX-RS provider)</li><li><strong>HTraceFeature</strong> (server-side
<a shape="rect" href="http://cxf.apache.org/">Apache CXF</a> feature to simplify
<a shape="rect" class="external-link" href="http://htrace.incubator.apache.org/index.html">Apache
HTrace
 </a> configuration and integration)</li></ul><p><a shape="rect"
href="http://cxf.apache.org/">Apache CXF</a> uses HTTP headers to hand off tracing
context from the client to the service and from the service to service. Those headers are
used internally by <strong>HTraceProvider</strong> and <strong>HTraceClientProvider</strong>,
but are configurable. The default header names are declared in the TracerHeaders class:</p><ul
style="list-style-type: square;"><li><strong>X-Span-Id</strong>: contains
a current span ID</li></ul><p>By default, <strong>HTraceProvider</strong>
will try to pass the currently active <strong>span</strong> through HTTP headers
on each service invocation. If there is no active spans, the new span will be created and
passed through HTTP headers on per-invocation basis. Essentially, just registering the <strong>HTraceClientProvider</strong>
on the client and&#160;<strong>HTraceProvider</strong> on the server is enough
to have tracing context to be properly passed ev
 erywhere. The only configuration part which is necessary are <strong>span receiver(s)</strong>
and <strong>sampler</strong>(s).</p><p>It is also worth to mention
the way <a shape="rect" href="http://cxf.apache.org/">Apache CXF</a> attaches
the description to <strong>spans</strong>. With regards to the client integration,
the description becomes a full URL being invoked prefixed by HTTP method, for example: <strong>GET
</strong><a shape="rect" class="external-link" href="http://localhost:8282/books"
rel="nofollow"><strong>http://localhost:8282</strong>/books</a>. On the
server side integration, the description becomes a relative JAX-RS resource path prefixed
by HTTP method, f.e.: <strong>GET books, POST book/123</strong></p><h1
id="UsingApacheHTrace-ConfiguringClientconfigure.client">Configuring Client <span class="confluence-anchor-link"
id="UsingApacheHTrace-configure.client"></span></h1><p>There are a couple
of ways the JAX-RS client could be configured, depending on the client im
 plementation. <a shape="rect" href="http://cxf.apache.org/">Apache CXF</a> provides
its own <strong>WebClient</strong> which could be configured just like that (in
future versions, there would be a simpler ways to do that using client specific features):</p><div
class="code panel pdl" style="border-width: 1px;"><div class="codeContent panelContent
pdl">
 <pre class="brush: java; gutter: false; theme: Default" style="font-size:12px;">final
Map&lt;String, String&gt; properties = new HashMap&lt;String, String&gt;();
 properties.put(Tracer.SPAN_RECEIVER_CLASSES_KEY, ...);
@@ -356,7 +358,24 @@ factory.getOutInterceptors().add(new HTr
 factory.getInInterceptors().add(new HTraceClientStopInterceptor());
 ...
 factory.create();</pre>
-</div></div><h1 id="UsingApacheHTrace-FutureWork">Future Work</h1><p>The
<a shape="rect" href="http://cxf.apache.org/">Apache CXF</a> is very proud to
offer <a shape="rect" class="external-link" href="http://htrace.incubator.apache.org/index.html">Apache
HTrace</a> integration. At the current stage, it was a conscious decision to keep the
minimal API and provide the set of necessary features only. However, there is a strong commitment
to evolve not only <a shape="rect" class="external-link" href="http://htrace.incubator.apache.org/index.html">Apache
HTrace</a> integration, but the distributed tracing support in general.</p></div>
+</div></div><h1 id="UsingApacheHTrace-PropagatingTraceDetailsToLogs">Propagating
Trace Details To Logs</h1><p>In order to have better correlation between ongoing
traces and logs, <a shape="rect" href="http://cxf.apache.org/">Apache CXF</a>
since <strong>3.1.11</strong> / <strong>3.2.0</strong> releases distributes
a helpful extension for <a shape="rect" class="external-link" href="https://logback.qos.ch/"
rel="nofollow">Logback</a> users, <strong>LogbackSpanConverter</strong>.
This converter can be used to complement log records with current trace details, such as tracer
id and span id. For example, here is a simple <strong>logback.xml</strong> configuration
file.</p><div class="code panel pdl" style="border-width: 1px;"><div class="codeContent
panelContent pdl">
+<pre class="brush: xml; gutter: false; theme: Default" style="font-size:12px;">&lt;?xml
version="1.0" encoding="UTF-8"?&gt;
+&lt;configuration scan="true" scanPeriod="5 seconds"&gt;
+    &lt;conversionRule conversionWord="trace" converterClass="org.apache.cxf.tracing.htrace.ext.LogbackSpanConverter"
/&gt;
+    &lt;appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender"&gt;
+        &lt;encoder&gt;
+            &lt;pattern&gt;[%level] [%trace] %d{yyyy-MM-dd HH:mm:ss.SSS} %logger{36}
%msg%n&lt;/pattern&gt;
+        &lt;/encoder&gt;
+    &lt;/appender&gt;
+    &lt;root level="INFO"&gt;
+        &lt;appender-ref ref="STDOUT" /&gt;
+    &lt;/root&gt;
+&lt;/configuration&gt;</pre>
+</div></div><p>In this case the tracing details will be propagated to each
log record in following format: <strong>&lt;tracer_id&gt;, span: &lt;span
id&gt;</strong>. For example:</p><div class="code panel pdl" style="border-width:
1px;"><div class="codeContent panelContent pdl">
+<pre class="brush: bash; gutter: false; theme: Default" style="font-size:12px;">[INFO]
[-, -] 2017-03-11 14:40:13.603 org.eclipse.jetty.server.Server Started @2731ms
+[INFO] [tracer-server/192.168.0.101, span: 6d3e0d975d4c883cce12aee1fd8f3e7e] 2017-03-11 14:40:24.013
com.example.rs.PeopleRestService Getting all employees
+[INFO] [tracer-server/192.168.0.101, span: 6d3e0d975d4c883c7592f4c2317dec22] 2017-03-11 14:40:28.017
com.example.rs.PeopleRestService Looking up manager in the DB database</pre>
+</div></div><p>The special <strong>[-, -]</strong> placeholder
indicates that no trace details are being available at the moment of logging the record.</p><h1
id="UsingApacheHTrace-FutureWork">Future Work</h1><p>The <a shape="rect"
href="http://cxf.apache.org/">Apache CXF</a> is very proud to offer <a shape="rect"
class="external-link" href="http://htrace.incubator.apache.org/index.html">Apache HTrace</a>
integration. At the current stage, it was a conscious decision to keep the minimal API and
provide the set of necessary features only. However, there is a strong commitment to evolve
not only <a shape="rect" class="external-link" href="http://htrace.incubator.apache.org/index.html">Apache
HTrace</a> integration, but the distributed tracing support in general.</p></div>
            </div>
            <!-- Content -->
          </td>



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