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| <title>Session Clustering with MongoDB</title><link rel="stylesheet" type="text/css" href="css/docbook.css"><meta name="generator" content="DocBook XSL Stylesheets V1.79.1"><meta name="keywords" content="jetty, servlet, servlet-api, cometd, http, websocket, eclipse, maven, java, server, software"><link rel="home" href="index.html" title="Jetty"><link rel="up" href="session-management.html" title="Chapter 10. Session Management"><link rel="prev" href="session-clustering-jdbc.html" title="Session Clustering with a Database"><link rel="next" href="session-clustering-infinispan.html" title="Session Clustering with Infinispan"><link xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times" rel="shortcut icon" href="images/favicon.ico"><link rel="stylesheet" href="css/highlighter/foundation.css"><script src="js/highlight.pack.js"></script><script> |
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| Version: 9.3.28.v20191105</span></td><td style="width: 50%"></td></tr></table><div xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Session Clustering with MongoDB</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="session-clustering-jdbc.html"><i class="fa fa-chevron-left" aria-hidden="true"></i> Previous</a> </td><th width="60%" align="center">Chapter 10. Session Management<br><a accesskey="p" href="index.html"><i class="fa fa-home" aria-hidden="true"></i> Home</a></th><td width="20%" align="right"> <a accesskey="n" href="session-clustering-infinispan.html">Next <i class="fa fa-chevron-right" aria-hidden="true"></i></a></td></tr></table><hr></div><div xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times" class="jetty-callout"><h5 class="callout"><a href="http://www.webtide.com/">Contact the core Jetty developers at |
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| </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="session-clustering-mongodb"></a>Session Clustering with MongoDB</h2></div></div></div><div class="toc"><dl class="toc"><dt><span class="section"><a href="session-clustering-mongodb.html#_configuration_2">Configuration</a></span></dt><dt><span class="section"><a href="session-clustering-mongodb.html#_the_nosql_module">The nosql Module</a></span></dt></dl></div><p>Jetty can support session clustering by persisting sessions into <a class="link" href="http://www.mogodb.org" target="_top">MongoDB</a>. |
| Each Jetty instance locally caches sessions for which it has received requests, writing any changes to the session through to the cluster as the request exits the server. |
| Sessions must obey the Serialization contract, and servlets must call the <code class="literal">Session.setAttribute()</code> method to ensure that changes are persisted.</p><p>The session persistence mechanism works in conjunction with a load balancer that supports stickiness. |
| Stickiness can be based on various data items, such as source IP address or characteristics of the session ID or a load-balancer specific mechanism. |
| For those load balancers that examine the session ID, the Jetty persistent session mechanism appends a node ID to the session ID, which can be used for routing.</p><p>In this type of solution, the traffic on the network needs to be carefully watched and tends to be the bottleneck. |
| You are probably investigating this solution in order to scale to large amount of users and sessions, so careful attention should be paid to your usage scenario. |
| Applications with a heavy write profile to their sessions will consume more network bandwidth than profiles that are predominately read oriented. |
| We recommend using this session manager with largely read based session scenarios.</p><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="_configuration_2"></a>Configuration</h3></div></div></div><p>There are two components to session management in Jetty: a session ID manager and a session manager.</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">The session ID manager ensures that session IDs are unique across all webapps hosted on a Jetty instance, and thus there can only be one session ID manager per Jetty instance.</li><li class="listitem">The session manager handles the session lifecycle (create/update/invalidate/expire) on behalf of a web application, so there is one session manager per web application instance.</li></ul></div><p>These managers also cooperate and collaborate with the <code class="literal">org.eclipse.jetty.server.session.SessionHandler</code> to enable cross-context dispatch.</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="_the_nosql_module"></a>The nosql Module</h3></div></div></div><p>When using the jetty distribution, to enable the MongoDB session persistence mechanism, you will first need to enable the nosql <a class="link" href="startup-modules.html" title="Managing Startup Modules">module</a> for your <a class="link" href="quickstart-running-jetty.html#creating-jetty-base" title="Creating a new Jetty Base">base</a> using the <code class="literal">--add-to-start</code> or <code class="literal">--add-to-startd</code> argument to the <a class="link" href="startup.html#startup-overview" title="Startup Overview">start.jar</a>. |
| This module will automatically download the <code class="literal">mongodb-java-driver</code> and install it to your base’s <code class="literal">lib/nosql</code> directory.</p><p>As part of the module installation, the necessary mongo java driver jars will be dynamically downloaded and installed to your <code class="literal">${jetty.base}/lib/nosql</code> directory. |
| If you need to up or downgrade the version of these jars, then you can delete the jars that were automatically installed and replace them. |
| Once you’ve done that, you will need to prevent Jetty’s startup checks from detecting the missing jars. |
| To do that, you can use <code class="literal">--skip-file-validation=nosql</code> argument to start.jar on the command line, or place that line inside <code class="literal">${jetty.base}/start.ini</code> to ensure it is used for every start.</p><p>You will also find the following properties, either in your base’s <code class="literal">start.d/nosql.ini</code> file or appended to your <code class="literal">start.ini</code>, depending on how you enabled the module:</p><pre xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times"><code>## Unique identifier for this node in the cluster |
| jetty.nosqlSession.workerName=node1 |
| |
| |
| ## Interval in seconds between scavenging expired sessions |
| jetty.nosqlSession.scavenge=1800</code></pre><p>The <code class="literal">jetty.nosqlSession.workerName</code> is the unique name for this Jetty Server instance. |
| It will be used by the sticky load balancer to uniquely identify the node. |
| You should change this value on <span class="strong"><strong>each</strong></span> node to which you install MongoDB session management.</p><p>The <code class="literal">jetty.nosqlSession.scavenge</code> property defines the time in seconds between runs of the scavenger: the scavenger is a task which runs periodically to clean out sessions that have expired but become stranded in the database for whatever reason.</p><p>These properties are substituted into the configuration of the <code class="literal">MongoDBSessionIdManager</code> and <code class="literal">MongoSessionManager</code>.</p><div class="section"><div class="titlepage"><div><div><h4 class="title"><a name="_configuring_the_mongosessionidmanager"></a>Configuring the MongoSessionIdManager</h4></div></div></div><p>The nosql module will have installed file called <code class="literal">$\{jetty.home}/etc/jetty-nosql.xml</code>. |
| This file configures an instance of the <code class="literal">MongoSessionIdManager</code> that will be shared across all webapps deployed on that server. |
| It looks like this:</p><pre xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times"><code><?xml version="1.0"?> |
| <!DOCTYPE Configure PUBLIC "-//Jetty//Configure//EN" "http://www.eclipse.org/jetty/configure_9_3.dtd"> |
| |
| <Configure id="Server" class="org.eclipse.jetty.server.Server"> |
| |
| <!-- ===================================================================== --> |
| <!-- Configure a MongoSessionIdManager --> |
| <!-- ===================================================================== --> |
| <Set name="sessionIdManager"> |
| <New id="sessionIdMgr" class="org.eclipse.jetty.nosql.mongodb.MongoSessionIdManager"> |
| <Arg> |
| <Ref refid="Server"/> |
| </Arg> |
| <Set name="workerName"><Property name="jetty.nosqlSession.workerName" default="node1"/></Set> |
| <Set name="scavengePeriod"><Property name="jetty.nosqlSession.scavenge" default="1800"/></Set> |
| </New> |
| </Set> |
| |
| </Configure></code></pre><p>The <code class="literal">MongoSessionIdManager</code> needs access to a MongoDB cluster, and the <code class="literal">jetty-nosql.xml</code> file assumes the defaults of localhost and default MongoDB port. |
| If you need to configure something else, you will need to edit this file. |
| Here’s an example of a more complex setup to use a remote MongoDB instance:</p><pre xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times"><code> <New id="mongodb" class="com.mongodb.Mongo"> |
| <Arg> |
| <New class="java.util.ArrayList"> |
| <Call name="add"> |
| <Arg> |
| <New class="com.mongodb.ServerAddress"> |
| <Arg type="java.lang.String">foo.example.com</Arg> |
| <Arg type="int">27017</Arg> |
| </New> |
| </Arg> |
| </Call> |
| <!-- Add more Call statements here as desired --> </New> |
| </Arg> |
| |
| <Call name="getDB"> |
| <Arg>HttpSessions</Arg> |
| <Call id="sessionDocument" name="getCollection"> |
| <Arg>sessions</Arg> |
| </Call> |
| </Call> |
| <!-- If you want to configure Jetty to be able to read through the slaves, call the following: --> |
| <Call name="slaveOk"/> |
| </New> |
| |
| <Set name="sessionIdManager"> |
| <New id="mongoIdMgr" class="org.eclipse.jetty.nosql.mongodb.MongoSessionIdManager"> |
| <Arg> |
| <Ref id="Server"/> |
| </Arg> |
| <Arg> |
| <Ref id="sessionDocument"/> |
| </Arg> |
| <Set name="workerName"><Property name="jetty.nosqlSession.workerName" default="node1"/></Set> |
| <Set name="scavengePeriod"><Property name="jetty.nosqlSession.scavenge" default="1800"/></Set> |
| </New> |
| </Set></code></pre><p>As Jetty configuration files are direct mappings of XML to Java, it is straight forward to do this in code:</p><pre xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times"><code> Server server = new Server(); |
| ... |
| MongoSessionIdManager idMgr = newMongoSessionIdManager(server); |
| idMgr.setWorkerName("node1"); |
| idMgr.setScavengePeriod(1800); |
| server.setSessionIdManager(idMgr);</code></pre><p>The MongoSessionIdManager has slightly different options than some of our more traditional session options. |
| The <code class="literal">MongoDBSessionIdManager</code> has the same scavenge timers which govern the setting of a valid session to invalid after a certain period of inactivity. |
| New to this session id manager is the extra purge setting which governs removal from the MongoDB cluster. |
| This can be configured through the <span class="emphasis"><em>purge</em></span> option. Purge is by default set to true and by default runs daily for each node on the cluster. |
| Also able to be configured is the age in which an invalid session will be retained which is set to 1 day by default. |
| This means that invalid sessions will be removed after lingering in the MongoDB instance for a day. |
| There is also an option for purging valid sessions that have not been used recently. |
| The default time for this is 1 week. You can disable these behaviors by setting purge to false.</p><div class="variablelist"><dl class="variablelist"><dt><span class="term">scavengeDelay</span></dt><dd>How long to delay before periodically looking for sessions to scavenge?</dd><dt><span class="term">scavengePeriod</span></dt><dd>How much time after a scavenge has completed should you wait before doing it again?</dd><dt><span class="term">scavengeBlockSize</span></dt><dd>Number of session ids to which to limit each scavenge query. |
| If you have a very large number of sessions in memory then setting this to a non 0 value may help speed up scavenging by breaking the scavenge into multiple, queries. |
| The default is 0, which means that all session ids are considered in a single query.</dd><dt><span class="term">purge (Boolean)</span></dt><dd>Do you want to purge (delete) sessions that are invalid from the session store completely?</dd><dt><span class="term">purgeDelay</span></dt><dd>How often do you want to perform this purge operation?</dd><dt><span class="term">purgeInvalidAge</span></dt><dd>How old should an invalid session be before it is eligible to be purged?</dd><dt><span class="term">purgeValidAge</span></dt><dd>How old should a valid session be before it is eligible to be marked invalid and purged? |
| Should this occur at all?</dd><dt><span class="term">purgeLimit</span></dt><dd>Integer value that represents how many items to return from a purge query. |
| The default is 0, which is unlimited. |
| If you have a lot of old expired orphaned sessions then setting this value may speed up the purge process.</dd><dt><span class="term">preserveOnStop</span></dt><dd>Whether or not to retain all sessions when the session manager stops. |
| Default is <code class="literal">true</code>.</dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a name="_configuring_a_mongosessionmanager"></a>Configuring a MongoSessionManager</h4></div></div></div><p>As mentioned elsewhere, there should be one <code class="literal">MongoSessionManager</code> per context (e.g. webapp). |
| It will need to reference the single <code class="literal">MongoSessionIdManager</code> configured previously for the Server.</p><p>The way you configure a <a class="link" href="http://www.eclipse.org/jetty/javadoc/9.3.28.v20191105/org/eclipse/jetty/nosql/MongoSessionManager.html" target="_top">org.eclipse.jetty.nosql.mongodb.MongoSessionManager</a> depends on whether you’re configuring from a <a class="link" href="configuring-specific-webapp-deployment.html#deployable-descriptor-file" title="Jetty Deployable Descriptor XML File">context xml</a> file or a <a class="link" href="jetty-web-xml-config.html" title="jetty-web.xml">jetty-web.xml</a> file or code. |
| The basic difference is how you get a reference to the Jetty <code class="literal">org.eclipse.jetty.server.Server</code> instance.</p><p>From a context xml file, you reference the Server instance as a Ref:</p><pre xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times"><code><Ref name="Server" id="Server"> |
| <Call id="mongoIdMgr" name="getSessionIdManager"/> |
| </Ref> |
| |
| <Set name="sessionHandler"> |
| <New class="org.eclipse.jetty.server.session.SessionHandler"> |
| <Arg> |
| <New id="mongoMgr" class="org.eclipse.jetty.nosql.mongodb.MongoSessionManager"> |
| <Set name="sessionIdManager"> |
| <Ref id="mongoIdMgr"/> |
| </Set> |
| </New> |
| </Arg> |
| </New> |
| </Set></code></pre><p>From a <code class="literal">WEB-INF/jetty-web.xml</code> file, you can reference the Server instance directly:</p><pre xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times"><code><Get name="server"> |
| <Get id="mongoIdMgr" name="sessionIdManager"/> |
| </Get> |
| <Set name="sessionHandler"> |
| <New class="org.eclipse.jetty.server.session.SessionHandler"> |
| <Arg> |
| <New class="org.eclipse.jetty.nosql.mongodb.MongoSessionManager"> |
| <Set name="sessionIdManager"> |
| <Ref id="mongoIdMgr"/> |
| </Set> |
| </New> |
| </Arg> |
| </New> |
| </Set></code></pre><p>If you’re embedding this in code:</p><pre xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times"><code>//assuming you have already set up the MongoSessionIdManager as shown earlier |
| //and have a reference to the Server instance: |
| |
| WebAppContext wac = new WebAppContext(); |
| ... //configure your webapp context |
| MongoSessionManager mongoMgr = new MongoSessionManager(); |
| mongoMgr.setSessionIdManager(server.getSessionIdManager()); |
| wac.setSessionHandler(new SessionHandler(mongoMgr));</code></pre></div></div></div><script type="text/javascript"> |
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