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<ol class="chapter"><li class="chapter-item expanded "><a href="index.html" class="active"><strong aria-hidden="true">1.</strong> Introduction</a></li><li class="chapter-item expanded "><a href="installation_features.html"><strong aria-hidden="true">2.</strong> Installation and Features</a></li><li class="chapter-item expanded "><a href="connecting.html"><strong aria-hidden="true">3.</strong> Connecting to the Database</a></li><li class="chapter-item expanded "><a href="reading.html"><strong aria-hidden="true">4.</strong> Reading From the Database</a></li><li class="chapter-item expanded "><div><strong aria-hidden="true">5.</strong> Writing To the Database</div></li><li class="chapter-item expanded "><a href="performance.html"><strong aria-hidden="true">6.</strong> Performance</a></li><li class="chapter-item expanded "><div><strong aria-hidden="true">7.</strong> Serde Integration</div></li><li class="chapter-item expanded "><div><strong aria-hidden="true">8.</strong> Sessions and Transactions</div></li><li class="chapter-item expanded "><div><strong aria-hidden="true">9.</strong> Change Streams</div></li><li class="chapter-item expanded "><div><strong aria-hidden="true">10.</strong> Monitoring</div></li><li class="chapter-item expanded "><a href="tracing.html"><strong aria-hidden="true">11.</strong> Tracing and Logging</a></li><li class="chapter-item expanded "><a href="web_framework_examples.html"><strong aria-hidden="true">12.</strong> Web Framework Examples</a></li><li class="chapter-item expanded "><a href="encryption.html"><strong aria-hidden="true">13.</strong> Encryption</a></li><li class="chapter-item expanded affix "><li class="part-title">Development</li><li class="chapter-item expanded "><div><strong aria-hidden="true">14.</strong> Writing Tests</div></li></ol>
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<h1 class="menu-title">MongoDB Rust Driver</h1>
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<h1 id="introduction"><a class="header" href="#introduction">Introduction</a></h1>
<p><a href="https://crates.io/crates/mongodb"><img src="https://img.shields.io/crates/v/mongodb.svg" alt="Crates.io" /></a> <a href="https://docs.rs/mongodb"><img src="https://docs.rs/mongodb/badge.svg" alt="docs.rs" /></a> <a href="LICENSE"><img src="https://img.shields.io/badge/license-Apache%202.0-blue.svg" alt="License" /></a></p>
<p>This is the manual for the officially supported MongoDB Rust driver, a client side library that can be used to interact with MongoDB deployments in Rust applications. It uses the <a href="https://docs.rs/bson/latest"><code>bson</code></a> crate for BSON support. The driver contains a fully async API that supports either <a href="https://crates.io/crates/tokio"><code>tokio</code></a> (default) or <a href="https://crates.io/crates/async-std"><code>async-std</code></a>, depending on the feature flags set. The driver also has a sync API that may be enabled via feature flag.</p>
<h2 id="warning-about-timeouts--cancellation"><a class="header" href="#warning-about-timeouts--cancellation">Warning about timeouts / cancellation</a></h2>
<p>In async Rust, it is common to implement cancellation and timeouts by dropping a future after a certain period of time instead of polling it to completion. This is how <a href="https://docs.rs/tokio/latest/tokio/time/fn.timeout.html"><code>tokio::time::timeout</code></a> works, for example. However, doing this with futures returned by the driver can leave the driver's internals in an inconsistent state, which may lead to unpredictable or incorrect behavior (see <a href="https://jira.mongodb.org/browse/RUST-937">RUST-937</a> for more details). As such, it is <strong><em>highly</em></strong> recommended to poll all futures returned from the driver to completion. In order to still use timeout mechanisms like <code>tokio::time::timeout</code> with the driver, one option is to spawn tasks and time out on their <a href="https://docs.rs/tokio/latest/tokio/task/struct.JoinHandle.html"><code>JoinHandle</code></a> futures instead of on the driver's futures directly. This will ensure the driver's futures will always be completely polled while also allowing the application to continue in the event of a timeout.</p>
<p>e.g.</p>
<pre><pre class="playground"><code class="language-rust no_run edition2021"><span class="boring">#![allow(unused)]
</span><span class="boring">fn main() {
</span><span class="boring">extern crate mongodb;
</span><span class="boring">extern crate tokio;
</span><span class="boring">use std::time::Duration;
</span><span class="boring">use mongodb::{
</span><span class="boring"> Client,
</span><span class="boring"> bson::doc,
</span><span class="boring">};
</span><span class="boring">
</span><span class="boring">async fn foo() -> std::result::Result<(), Box<dyn std::error::Error>> {
</span><span class="boring">
</span><span class="boring">let client = Client::with_uri_str("mongodb://example.com").await?;
</span>let collection = client.database("foo").collection("bar");
let handle = tokio::task::spawn(async move {
collection.insert_one(doc! { "x": 1 }, None).await
});
tokio::time::timeout(Duration::from_secs(5), handle).await???;
<span class="boring">Ok(())
</span><span class="boring">}
</span><span class="boring">}</span></code></pre></pre>
<h2 id="minimum-supported-rust-version-msrv"><a class="header" href="#minimum-supported-rust-version-msrv">Minimum supported Rust version (MSRV)</a></h2>
<p>The MSRV for this crate is currently 1.61.0. This will rarely be increased, and if it ever is,
it will only happen in a minor or major version release.</p>
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