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<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Aggregate memory admission for gRPC services."><title>servers::grpc::memory_limit - Rust</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-6b053e98.ttf.woff2,FiraSans-Italic-81dc35de.woff2,FiraSans-Regular-0fe48ade.woff2,FiraSans-MediumItalic-ccf7e434.woff2,FiraSans-Medium-e1aa3f0a.woff2,SourceCodePro-Regular-8badfe75.ttf.woff2,SourceCodePro-Semibold-aa29a496.ttf.woff2".split(",").map(f=>`<link rel="preload" as="font" type="font/woff2"href="../../../static.files/${f}">`).join(""))</script><link rel="stylesheet" href="../../../static.files/normalize-9960930a.css"><link rel="stylesheet" href="../../../static.files/rustdoc-1ed95124.css"><meta name="rustdoc-vars" data-root-path="../../../" data-static-root-path="../../../static.files/" data-current-crate="servers" data-themes="" data-resource-suffix="" data-rustdoc-version="1.98.1 (48a229cea 2026-09-01)" data-channel="1.98.1" data-search-js="search-9944d736.js" data-stringdex-js="stringdex-2da4960a.js" data-settings-js="settings-170eb4bf.js" ><script src="../../../static.files/storage-41dd4d93.js"></script><script defer src="../sidebar-items.js"></script><script defer src="../../../static.files/main-417ebf0a.js"></script><noscript><link rel="stylesheet" href="../../../static.files/noscript-f7c3ffd8.css"></noscript><link rel="alternate icon" type="image/png" href="../../../static.files/favicon-32x32-eab170b8.png"><link rel="icon" type="image/svg+xml" href="../../../static.files/favicon-044be391.svg"></head><body class="rustdoc mod"><a class="skip-main-content" href="#main-content">Skip to main content</a><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><rustdoc-topbar><h2><a href="#">Module memory_limit</a></h2></rustdoc-topbar><nav class="sidebar"><div class="sidebar-crate"><h2><a href="../../../servers/index.html">servers</a><span class="version">1.4.0-alpha.0</span></h2></div><div class="sidebar-elems"><section id="rustdoc-toc"><h2 class="location"><a href="#">Module memory_<wbr>limit</a></h2><h3><a href="#structs">Module Items</a></h3><ul class="block"><li><a href="#structs" title="Structs">Structs</a></li><li><a href="#constants" title="Constants">Constants</a></li></ul></section><div id="rustdoc-modnav"><h2><a href="../index.html">In servers::<wbr>grpc</a></h2></div></div></nav><div class="sidebar-resizer" title="Drag to resize sidebar"></div><main><div class="width-limiter"><section id="main-content" class="content" tabindex="-1"><div class="main-heading"><div class="rustdoc-breadcrumbs"><a href="../../index.html">servers</a>::<wbr><a href="../index.html">grpc</a></div><h1>Module <span>memory_<wbr>limit</span>&nbsp;<button id="copy-path" title="Copy item path to clipboard">Copy item path</button></h1><rustdoc-toolbar></rustdoc-toolbar><span class="sub-heading"><a class="src" href="../../../src/servers/grpc/memory_limit.rs.html#15-292">Source</a> </span></div><details class="toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Aggregate memory admission for gRPC services.</p>
<p>Tonic decompresses and decodes a complete request message (up to
<code>max_recv_message_size</code>, 512 MiB by default) <em>before</em> the typed handler is
invoked, so a handler that charges the <a href="../../request_memory_limiter/struct.ServerMemoryLimiter.html" title="struct servers::request_memory_limiter::ServerMemoryLimiter"><code>ServerMemoryLimiter</code></a> only sees
the request after the memory is already allocated. For transport-compressed
messages (<code>grpc-encoding: gzip/zstd</code>) a few KiB on the wire can expand to
hundreds of MiB during that window, which would bypass any aggregate quota.</p>
<p><a href="struct.MemoryLimiterExtensionLayer.html" title="struct servers::grpc::memory_limit::MemoryLimiterExtensionLayer"><code>MemoryLimiterExtensionLayer</code></a> therefore reserves the configured maximum
decoded message size for every compressed request <em>before</em> the inner
(tonic) service runs, and holds the reservation for the whole request.
Handlers can detect the reservation via <a href="struct.PreDecodeMemoryReservation.html" title="struct servers::grpc::memory_limit::PreDecodeMemoryReservation"><code>PreDecodeMemoryReservation</code></a> in
the request extensions and skip their own post-decode charge to avoid
double accounting.</p>
<p>The reservation is intentionally conservative (it upper-bounds the decoded
size before it is known); with the default unlimited limiter it is a no-op.</p>
</div></details><h2 id="structs" class="section-header">Structs<a href="#structs" class="anchor">§</a></h2><dl class="item-table"><dt><a class="struct" href="struct.MemoryLimiterExtensionLayer.html" title="struct servers::grpc::memory_limit::MemoryLimiterExtensionLayer">Memory<wbr>Limiter<wbr>Extension<wbr>Layer</a></dt><dt><a class="struct" href="struct.MemoryLimiterExtensionService.html" title="struct servers::grpc::memory_limit::MemoryLimiterExtensionService">Memory<wbr>Limiter<wbr>Extension<wbr>Service</a></dt><dt><a class="struct" href="struct.PreDecodeMemoryReservation.html" title="struct servers::grpc::memory_limit::PreDecodeMemoryReservation">PreDecode<wbr>Memory<wbr>Reservation</a><span title="Restricted Visibility">&nbsp;🔒</span> </dt><dd>Present in the request extensions when memory for the (compressed)
request’s decoded message was reserved before tonic decompression.</dd></dl><h2 id="constants" class="section-header">Constants<a href="#constants" class="anchor">§</a></h2><dl class="item-table"><dt><a class="constant" href="constant.GRPC_ENCODING_HEADER.html" title="constant servers::grpc::memory_limit::GRPC_ENCODING_HEADER">GRPC_<wbr>ENCODING_<wbr>HEADER</a><span title="Restricted Visibility">&nbsp;🔒</span> </dt><dd>The gRPC request compression selector header.</dd><dt><a class="constant" href="constant.IDENTITY_ENCODING.html" title="constant servers::grpc::memory_limit::IDENTITY_ENCODING">IDENTITY_<wbr>ENCODING</a><span title="Restricted Visibility">&nbsp;🔒</span> </dt><dd>The “no compression” encoding value.</dd></dl></section></div></main></body></html>