kafka-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From guozh...@apache.org
Subject [kafka] branch trunk updated: KAFKA-6938: Add documentation for accessing Headers on Kafka Streams Processor API (#5128)
Date Mon, 04 Jun 2018 22:40:07 GMT
This is an automated email from the ASF dual-hosted git repository.

guozhang pushed a commit to branch trunk
in repository https://gitbox.apache.org/repos/asf/kafka.git


The following commit(s) were added to refs/heads/trunk by this push:
     new e8ddb76  KAFKA-6938: Add documentation for accessing Headers on Kafka Streams Processor
API (#5128)
e8ddb76 is described below

commit e8ddb76573d0aba659dd97d42ac02f5ec24516d2
Author: Jorge Quilcate Otoya <quilcate.jorge@gmail.com>
AuthorDate: Tue Jun 5 00:39:20 2018 +0200

    KAFKA-6938: Add documentation for accessing Headers on Kafka Streams Processor API (#5128)
    
    Reviewers: Guozhang Wang <wangguoz@gmail.com>
---
 docs/streams/developer-guide/processor-api.html | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/docs/streams/developer-guide/processor-api.html b/docs/streams/developer-guide/processor-api.html
index 8236ded..e07efb1 100644
--- a/docs/streams/developer-guide/processor-api.html
+++ b/docs/streams/developer-guide/processor-api.html
@@ -53,6 +53,7 @@
                     </ul>
                 </li>
                 <li><a class="reference internal" href="#connecting-processors-and-state-stores"
id="id8">Connecting Processors and State Stores</a></li>
+                <li><a class="reference internal" href="#accessing-processor-context"
id="id10">Accessing Processor Context</a></li>
             </ul>
         </div>
         <div class="section" id="overview">
@@ -351,6 +352,22 @@
                     your store.</p>
             </div>
         </div>
+        <div class="section" id="accessing-processor-context">
+            <h2><a class="toc-backref" href="#id10">Accessing Processor Context</a><a
class="headerlink" href="#accessing-processor-context" title="Permalink to this headline"></a></h2>
+            <p>As we have mentioned in <href=#defining-a-stream-processor>Defining
a Stream Processor<\href>, a <code>ProcessorContext</code> control the processing
workflow, such as scheduling a punctuation function, and committing the current processed
state.</p>
+            <p>This object can also be used to access the metadata related with the
application like 
+            <code class="docutils literal"><span class="pre">applicationId</span></code>,
<code class="docutils literal"><span class="pre">taskId</span></code>,

+                and <code class="docutils literal"><span class="pre">stateDir</span></code>,
and also record related metadata as <code class="docutils literal"><span class="pre">topic</span></code>,

+                <code class="docutils literal"><span class="pre">partition</span></code>,
<code class="docutils literal"><span class="pre">offset</span></code>,
<code class="docutils literal"><span class="pre">timestamp</span></code>
and 
+                <code class="docutils literal"><span class="pre">headers</span></code>.</p>
+            <p>Here is an example implementation of how to add a new header to the
record:</p>
+            <div class="highlight-java"><div class="highlight"><pre><span></span><span
class="n">public void process(String key, String value) {</span>
+            
+            <span class="c1">// add a heaeder to the elements</span>
+            <span class="n">context()</span><span class="o">.</span><span
class="na">headers</span><span class="o">()</span><span class="o">.</span><span
class="na">add</span><span class="o">.</span><span class="o">(</span><span
class="s">&quot;key&quot;</span><span class="o">,</span> <span
class="s">&quot;key&quot;</span>
+            <span class="o">}</span>
+            </pre></div>
+        </div>
         <div class="section" id="connecting-processors-and-state-stores">
             <h2><a class="toc-backref" href="#id8">Connecting Processors and
State Stores</a><a class="headerlink" href="#connecting-processors-and-state-stores"
title="Permalink to this headline"></a></h2>
             <p>Now that a <a class="reference internal" href="#streams-developer-guide-stream-processor"><span
class="std std-ref">processor</span></a> (WordCountProcessor) and the
@@ -399,8 +416,8 @@
                 runtime, indicating the state store is not accessible from this processor.</p>
             <p>Now that you have fully defined your processor topology in your application,
you can proceed to
                 <a class="reference internal" href="running-app.html#streams-developer-guide-execution"><span
class="std std-ref">running the Kafka Streams application</span></a>.</p>
-</div>
-</div>
+        </div>
+        </div>
 
 
                </div>

-- 
To stop receiving notification emails like this one, please contact
guozhang@apache.org.

Mime
View raw message