<!DOCTYPE html><html lang="en"><head><meta charSet="utf-8"/><meta http-equiv="X-UA-Compatible" content="IE=edge"/><title>Metrics for Pulsar Functions · Apache Pulsar</title><meta name="viewport" content="width=device-width, initial-scale=1.0"/><meta name="generator" content="Docusaurus"/><meta name="description" content="Pulsar Functions can publish arbitrary metrics to the metrics interface which can then be queried. This doc contains instructions for publishing metrics using the [Java](#java-sdk) and [Python](#python-sdk) Pulsar Functions SDKs."/><meta name="docsearch:version" content="2.4.1"/><meta name="docsearch:language" content="en"/><meta property="og:title" content="Metrics for Pulsar Functions · Apache Pulsar"/><meta property="og:type" content="website"/><meta property="og:url" content="https://pulsar.apache.org/"/><meta property="og:description" content="Pulsar Functions can publish arbitrary metrics to the metrics interface which can then be queried. This doc contains instructions for publishing metrics using the [Java](#java-sdk) and [Python](#python-sdk) Pulsar Functions SDKs."/><meta name="twitter:card" content="summary"/><meta name="twitter:image" content="https://pulsar.apache.org/img/pulsar.svg"/><link rel="shortcut icon" href="/img/pulsar.ico"/><link rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/highlight.js/9.12.0/styles/atom-one-dark.min.css"/><link rel="alternate" type="application/atom+xml" href="https://pulsar.apache.org/blog/atom.xml" title="Apache Pulsar Blog ATOM Feed"/><link rel="alternate" type="application/rss+xml" href="https://pulsar.apache.org/blog/feed.xml" title="Apache Pulsar Blog RSS Feed"/><link rel="stylesheet" href="/css/code-blocks-buttons.css"/><script type="text/javascript" src="https://buttons.github.io/buttons.js"></script><script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/clipboard.js/2.0.0/clipboard.min.js"></script><script type="text/javascript" src="/js/custom.js"></script><script src="/js/scrollSpy.js"></script><link rel="stylesheet" href="/css/main.css"/><script src="/js/codetabs.js"></script></head><body class="sideNavVisible separateOnPageNav"><div class="fixedHeaderContainer"><div class="headerWrapper wrapper"><header><a href="/en"><img class="logo" src="/img/pulsar.svg" alt="Apache Pulsar"/></a><a href="/en/versions"><h3>2.4.1</h3></a><div class="navigationWrapper navigationSlider"><nav class="slidingNav"><ul class="nav-site nav-site-internal"><li class=""><a href="/docs/en/2.4.1/getting-started-standalone" target="_self">Docs</a></li><li class=""><a href="/en/download" target="_self">Download</a></li><li class=""><a href="/docs/en/2.4.1/client-libraries" target="_self">Clients</a></li><li class=""><a href="#restapis" target="_self">REST APIs</a></li><li class=""><a href="#cli" target="_self">Cli</a></li><li class=""><a href="/blog/" target="_self">Blog</a></li><li class=""><a href="#community" target="_self">Community</a></li><li class=""><a href="#apache" target="_self">Apache</a></li><li class=""><a href="https://pulsar-next.staged.apache.org/" target="_self">New Website (Beta)</a></li><span><li><a id="languages-menu" href="#"><img class="languages-icon" src="/img/language.svg" alt="Languages icon"/>English</a><div id="languages-dropdown" class="hide"><ul id="languages-dropdown-items"><li><a href="/docs/ja/2.4.1/functions-metrics">日本語</a></li><li><a href="/docs/fr/2.4.1/functions-metrics">Français</a></li><li><a href="/docs/ko/2.4.1/functions-metrics">한국어</a></li><li><a href="/docs/zh-CN/2.4.1/functions-metrics">中文</a></li><li><a href="/docs/zh-TW/2.4.1/functions-metrics">繁體中文</a></li><li><a href="https://crowdin.com/project/apache-pulsar" target="_blank" rel="noreferrer noopener">Help Translate</a></li></ul></div></li><script>
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<blockquote>
<h4><a class="anchor" aria-hidden="true" id="metrics-and-stats-not-available-through-language-native-interfaces"></a><a href="#metrics-and-stats-not-available-through-language-native-interfaces" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Metrics and stats not available through language-native interfaces</h4>
<p>If a Pulsar Function uses the language-native interface for <a href="/docs/en/2.4.1/functions-api#java-native-functions">Java</a> or <a href="#python-native-functions">Python</a>, that function will not be able to publish metrics and stats to Pulsar.</p>
</blockquote>
<h2><a class="anchor" aria-hidden="true" id="accessing-metrics"></a><a href="#accessing-metrics" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Accessing metrics</h2>
<p>For a guide to accessing metrics created by Pulsar Functions, see the guide to <a href="/docs/en/2.4.1/deploy-monitoring">Monitoring</a> in Pulsar.</p>
<h2><a class="anchor" aria-hidden="true" id="java-sdk"></a><a href="#java-sdk" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Java SDK</h2>
<p>If you're creating a Pulsar Function using the <a href="/docs/en/2.4.1/functions-api#java-sdk-functions">Java SDK</a>, the <a href="https://pulsar.apache.org/api/pulsar-functions/2.4.1/org/apache/pulsar/functions/api/Context">Context</a>
 object has a <code>recordMetric</code> method that you can use to register both a name for the metric and a value. Here's the signature for that method:</p>
<pre><code class="hljs css language-java"><span class="hljs-function"><span class="hljs-keyword">void</span> <span class="hljs-title">recordMetric</span><span class="hljs-params">(String metricName, <span class="hljs-keyword">double</span> value)</span></span>;
</code></pre>
<p>Here's an example function:</p>
<pre><code class="hljs css language-java"><span class="hljs-keyword">import</span> org.apache.pulsar.functions.api.Context;
<span class="hljs-keyword">import</span> org.apache.pulsar.functions.api.Function;

<span class="hljs-keyword">public</span> <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">MetricRecordingFunction</span> <span class="hljs-keyword">implements</span> <span class="hljs-title">Function</span>&lt;<span class="hljs-title">String</span>, <span class="hljs-title">Void</span>&gt; </span>{
    <span class="hljs-meta">@Override</span>
    <span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">apply</span><span class="hljs-params">(String input, Context context)</span> </span>{
        context.recordMetric(<span class="hljs-string">"number-of-characters"</span>, input.length());
        <span class="hljs-keyword">return</span> <span class="hljs-keyword">null</span>;
    }
}
</code></pre>
<p>This function counts the length of each incoming message (of type <code>String</code>) and then registers that under the <code>number-of-characters</code> metric.</p>
<h2><a class="anchor" aria-hidden="true" id="python-sdk"></a><a href="#python-sdk" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Python SDK</h2>
<p>Documentation for the <a href="/docs/en/2.4.1/functions-api#python-sdk-functions">Python SDK</a> is coming soon.</p>
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