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From build...@apache.org
Subject svn commit: r965607 - in /websites/production/cxf/content: cache/docs.pageCache docs/using-apache-htrace.data/image2015-9-15-21:26:5.png docs/using-apache-htrace.html
Date Wed, 16 Sep 2015 01:47:18 GMT
Author: buildbot
Date: Wed Sep 16 01:47:18 2015
New Revision: 965607

Log:
Production update by buildbot for cxf

Added:
    websites/production/cxf/content/docs/using-apache-htrace.data/image2015-9-15-21:26:5.png
  (with props)
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
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Added: websites/production/cxf/content/docs/using-apache-htrace.data/image2015-9-15-21:26:5.png
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Propchange: websites/production/cxf/content/docs/using-apache-htrace.data/image2015-9-15-21:26:5.png
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    svn:mime-type = image/png

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 Wed Sep 16 01:47:18 2015
@@ -117,14 +117,14 @@ Apache CXF -- Using Apache HTrace
            <!-- Content -->
            <div class="wiki-content">
 <div id="ConfluenceContent"><p><style type="text/css">/*<![CDATA[*/
-div.rbtoc1442364417969 {padding: 0px;}
-div.rbtoc1442364417969 ul {list-style: disc;margin-left: 0px;}
-div.rbtoc1442364417969 li {margin-left: 0px;padding-left: 0px;}
+div.rbtoc1442368005830 {padding: 0px;}
+div.rbtoc1442368005830 ul {list-style: disc;margin-left: 0px;}
+div.rbtoc1442368005830 li {margin-left: 0px;padding-left: 0px;}
 
-/*]]>*/</style></p><div class="toc-macro rbtoc1442364417969">
+/*]]>*/</style></p><div class="toc-macro rbtoc1442368005830">
 <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-DistributedTracinginApacheCXF">Distributed
Tracing in Apache CXF</a></li><li><a shape="rect" href="#UsingApacheHTrace-ConfiguringClientconfigure.client">Configuring
Client</a></li><li><a shape="rect" href="#UsingApacheHTrace-ConfiguringServerconfigure.server">Configuring
Server</a></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></ul>
-</li></ul>
+<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-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 64-bit ID for the <strong>span</strong> and another
64-bit ID for the <strong>trace</strong> the span is a <strong>part</strong>
of. <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</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.</p><p>From implementation prospective,
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</strong>
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 of 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" h
 ref="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-DistributedTracinginApacheCXF">Distributed
Tracing in Apache CXF</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 tec
 hnique to monitor the application as whole, breaking the request 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> 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/inde
 x.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-Trace-Id</strong>: contains
a current trace ID</li><li><strong>X-Span-Id</strong>: contains a
current span ID</li></ul><p>By default, <strong>HTraceProvider</strong>
will try pass the currently active <strong>span</strong> through HTTP headers
on each service invocation. If there is no active span, the new span will be created and passed
through HTTP headers on per-invocation basis. Essentially, just registering the <strong>HTraceProvider</strong>
on the client and <strong>HTraceClientProvider</str
 ong> on the server is enough to have tracing context to be properly passed everywhere.
The only configuration part which is necessary are <strong>span receiver(s)</strong>
and <strong>sampler</strong>.</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 relation 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 way the JAX-RS client could be configured, depending on the client implementation. <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;();
 final HTraceConfiguration conf = HTraceConfiguration.fromMap(properties);
@@ -253,7 +253,32 @@ public Collection&lt;Book&gt; getBooks(@
        
     return Arrays.asList(book1.get(), book2.get());
 }</pre>
-</div></div><p>The actual invocation of the request by the client (with
process name <strong><span class="label label-default service-filter-label service-tag-filtered">jaxrsclient/192.168.0.100</span></strong>)
and consequent invocation of the service on the server side (process name<strong> <span
class="label label-default service-filter-label">jaxrsserver/192.168.0.100</span></strong>)
is going to generate the following sample traces:</p><p><span class="confluence-embedded-file-wrapper
confluence-embedded-manual-size"><img class="confluence-embedded-image" height="250"
src="using-apache-htrace.data/image2015-9-15%2020:44:20.png"></span></p><h2
id="UsingApacheHTrace-Example#6:ClientandServerwithasynchronousJAX-RSservice(server-side)">Example
#6: Client and Server with asynchronous JAX-RS service (server-side)</h2><p>TODO</p></div>
+</div></div><p>The actual invocation of the request by the client (with
process name <strong><span class="label label-default service-filter-label service-tag-filtered">jaxrsclient/192.168.0.100</span></strong>)
and consequent invocation of the service on the server side (process name<strong> <span
class="label label-default service-filter-label">jaxrsserver/192.168.0.100</span></strong>)
is going to generate the following sample traces:</p><p><span class="confluence-embedded-file-wrapper
confluence-embedded-manual-size"><img class="confluence-embedded-image" height="250"
src="using-apache-htrace.data/image2015-9-15%2020:44:20.png"></span></p><h2
id="UsingApacheHTrace-Example#6:ClientandServerwithasynchronousJAX-RSservice(server-side)">Example
#6: Client and Server with asynchronous JAX-RS service (server-side)</h2><p>In
this example server-side implementation of the JAX-RS service is going to be executed asynchronously.
It poses a challenge from the tracing prospective as request a
 nd response are processed in different threads (in general). At the moment, <a shape="rect"
href="http://cxf.apache.org/">Apache CXF</a> does not support the transparent tracing
spans management (except for default use case) but provides the simple ways to do that (by
letting to transfer spans from thread to thread). The client-side code stays unchanged.</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;">@Produces(
{ MediaType.APPLICATION_JSON } )
+@GET
+public void getBooks(@Suspended final AsyncResponse response, @Context final TracerContext
tracer) throws Exception {
+    tracer.continueSpan(new Traceable&lt;Future&lt;Void&gt;&gt;() {
+        public Future&lt;Void&gt; call(final TracerContext context) throws Exception
{
+            return executor.submit(
+                tracer.wrap("Getting Book", new Traceable&lt;Void&gt;() {
+                    public Void call(final TracerContext context) throws Exception {
+                        // Simulating a processing delay of 50ms
+                        Thread.sleep(50);
+                            
+                        response.resume(
+                            Arrays.asList(
+                                new Book("Apache CXF Web Service Development", "Naveen Balani,
Rajeev Hathi")
+                            )
+                        );
+                            
+                        return null;
+                    }
+                })
+            );
+        }
+    });
+}</pre>
+</div></div><p>The actual invocation of the request by the client (with
process name <strong><span class="label label-default service-filter-label service-tag-filtered">jaxrsclient/192.168.0.100</span></strong>)
and consequent invocation of the service on the server side (process name<strong> <span
class="label label-default service-filter-label">jaxrsserver/192.168.0.100</span></strong>)
is going to generate the following sample traces:</p><p><span class="confluence-embedded-file-wrapper
confluence-embedded-manual-size"><img class="confluence-embedded-image" height="250"
src="using-apache-htrace.data/image2015-9-15%2021:26:5.png"></span></p><h2
id="UsingApacheHTrace-Example#7:ClientandServerwithasynchronousinvocation(client-side)">Example
#7: Client and Server with asynchronous invocation (client-side)</h2><p>TODO</p><h1
id="UsingApacheHTrace-FutureWork">Future Work</h1><p>TODO</p></div>
            </div>
            <!-- Content -->
          </td>



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