Snapstart Minimal API Performance Improvements #2010

ppittle · 2025-03-12T18:17:24Z

Issue #, if available:
It is not feasible for users to warm up the asp.net and lambda pipelines via SnapshotRestore.RegisterBeforeSnapshot when using .NET MinimalAPI Lambda.

Description of changes:
Creates a new extension method, AddAWSLambdaBeforeSnapshotRequest that allows users to add a function meant to initialize the asp.net and lambda pipelines during SnapshotRestore.RegisterBeforeSnapshot, improving the performance gains offered by SnapStart.

Example:

var builder = WebApplication.CreateSlimBuilder(args);

builder.Services.AddAWSLambdaHosting(LambdaEventSource.HttpApi);

// Initialize asp.net pipeline before Snapshot
builder.Services.AddAWSLambdaBeforeSnapshotRequest(async httpClient =>
{
     await httpClient.GetAsync($"/test");
});

var app = builder.Build();
 
app.MapGet($"/test", () => "Success");
 
app.Run();

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

Libraries/src/Amazon.Lambda.RuntimeSupport/Client/RuntimeApiHeaders.cs

...mbda.AspNetCoreServer.Hosting/Internal/LambdaSnapstartExecuteRequestsBeforeSnapshotHelper.cs

Libraries/src/Amazon.Lambda.AspNetCoreServer.Hosting/Internal/LambdaRuntimeSupportServer.cs

…et/lambda pipelines automatically during BeforeSnapshot callback.

philasmar · 2025-03-13T13:15:02Z

Libraries/src/Amazon.Lambda.RuntimeSupport/Amazon.Lambda.RuntimeSupport.csproj

@normj I don't know if there's an implication of Strong Name signing the RuntimeSupport library. Not sure if there are any ramifications for Lambda and our customers.

philasmar · 2025-03-13T13:18:15Z

Ran the AWS CI PR check manually https://github.com/aws/aws-lambda-dotnet/actions/runs/13835574482/job/38709627134

Libraries/Libraries.sln.DotSettings

...ies/src/Amazon.Lambda.AspNetCoreServer.Hosting/Amazon.Lambda.AspNetCoreServer.Hosting.csproj

Libraries/src/Amazon.Lambda.AspNetCoreServer.Hosting/Internal/LambdaRuntimeSupportServer.cs

...mbda.AspNetCoreServer.Hosting/Internal/LambdaSnapstartExecuteRequestsBeforeSnapshotHelper.cs

Libraries/src/Amazon.Lambda.RuntimeSupport/Amazon.Lambda.RuntimeSupport.csproj

...mbda.AspNetCoreServer.Hosting/Internal/LambdaSnapstartExecuteRequestsBeforeSnapshotHelper.cs

…d unit tests

…ng json serialization, adjust #if blocks and fix simple warnings

…sibileTo Amazon.Lambda.AspNetCorServer.Hosting

…ing calls to HttpClient

normj · 2025-04-12T00:04:11Z

Libraries/src/Amazon.Lambda.RuntimeSupport/Amazon.Lambda.RuntimeSupport.csproj

@@ -16,6 +16,13 @@
 	<LangVersion>9.0</LangVersion>
  </PropertyGroup>

+  <PropertyGroup>


This should be removable now that you got rid of the internal visible to and the strong naming is already being controlled via the <repo-root>/buildtools/common.props.

normj

My reading is there are 2 different solutions being implemented here. One for AspNetCoreServer.Hosting and one for just using AspNetCoreServer. I would rather we not have different solutions and it seems like the subclasses in AspNetCoreServer.Hosting could override the virtual method for getting the list or requests to run and the service collection extension method could provide a way to get the request into that collection returned in the override.

Plus if you do it that way you can remove any changes you did to RuntimeSupport.

normj · 2025-04-12T00:26:42Z

Libraries/src/Amazon.Lambda.AspNetCoreServer/Amazon.Lambda.AspNetCoreServer.csproj

@@ -31,6 +31,7 @@

  <ItemGroup>
    <FrameworkReference Include="Microsoft.AspNetCore.App" />
+    <ProjectReference Include="..\Amazon.Lambda.RuntimeSupport\Amazon.Lambda.RuntimeSupport.csproj" />


From what I can tell this is only need for SnapStartEmptyLambdaContext to get the name environment variables. This is a big dependency being added that users using only this library and not hosting don't need. This could cause a performance regression for non snapstart use cases. We should not add this here and copy the constants used in runtime support for looking up the environment variables in SnapStartEmptyLambdaContext.

normj · 2025-04-12T00:28:03Z

Libraries/src/Amazon.Lambda.AspNetCoreServer/Internal/HttpRequestMessageSerializer.cs

+            return await r.Content.ReadAsStringAsync();
+        }
+
+        [JsonSourceGenerationOptions(WriteIndented = true)]


Why indented? That seems unnecessary bloat when in production.

normj · 2025-04-12T00:43:37Z

Libraries/src/Amazon.Lambda.AspNetCoreServer/Internal/HttpRequestMessageSerializer.cs

+        [JsonSerializable(typeof(ApplicationLoadBalancerRequest))]
+        [JsonSerializable(typeof(APIGatewayHttpApiV2ProxyRequest))]
+        [JsonSerializable(typeof(APIGatewayProxyRequest))]
+        [JsonSerializable(typeof(APIGatewayProxyRequest.ClientCertValidity))]


Why do we need these inner types. Shouldn't having APIGatewayProxyRequest cover all of these cases?

normj · 2025-04-12T00:43:59Z

Libraries/src/Amazon.Lambda.AspNetCoreServer/Internal/HttpRequestMessageSerializer.cs

+        [JsonSerializable(typeof(APIGatewayProxyRequest.ProxyRequestContext))]
+        [JsonSerializable(typeof(APIGatewayProxyRequest.RequestIdentity))]
+
+        internal partial class LambdaRequestTypeClasses : JsonSerializerContext


This doesn't compile for me because the parent class also has to be marked as partial.

normj · 2025-04-12T00:48:44Z

Libraries/src/Amazon.Lambda.AspNetCoreServer/Internal/HttpRequestMessageSerializer.cs

+            // make request absolut (relative to localhost) otherwise parsing the query will not work
+            request.RequestUri = new Uri(_baseUri, request.RequestUri);
+
+            var duckRequest = new


Using anonymous types is likely going to be a problem for Native AOT. Sadly a lot of Native AOT warnings don't surface till you actually publish with Native AOT turned on.

normj · 2025-04-12T00:58:48Z

Libraries/src/Amazon.Lambda.AspNetCoreServer/AbstractAspNetCoreFunction.cs

+        /// ]]>
+        /// </code>
+        /// </summary>
+        protected virtual IEnumerable<HttpRequestMessage> RegisterBeforeSnapshotRequest() =>


The name RegisterBeforeSnapshotRequest throws me off since invoking it doesn't register it. Instead it returns back a list of request to run. I would think something like GetBeforeSnapshotRequests.

normj · 2025-04-12T01:02:12Z

Libraries/src/Amazon.Lambda.AspNetCoreServer/AbstractAspNetCoreFunction.cs

+
+                    var context = CreateContext(features);
+
+                    var lambdaContext = new SnapStartEmptyLambdaContext();


Create a new one per iteration. The context has the time remaining which should be reset during each invocation.

normj · 2025-04-12T01:02:37Z

Libraries/src/Amazon.Lambda.AspNetCoreServer/Internal/SnapStartEmptyLambdaContext.cs

+    public ILambdaLogger Logger => null;
+    public string LogGroupName => _lambdaEnvironment.LogGroupName;
+    public string LogStreamName => _lambdaEnvironment.LogStreamName;
+    public int MemoryLimitInMB => 128;


Grab the write value from the AWS_LAMBDA_FUNCTION_MEMORY_SIZE environment variable.

normj · 2025-04-12T01:03:28Z

Libraries/src/Amazon.Lambda.AspNetCoreServer/Internal/SnapStartEmptyLambdaContext.cs

+
+internal class SnapStartEmptyLambdaContext : ILambdaContext, ICognitoIdentity, IClientContext
+{
+    private LambdaEnvironment _lambdaEnvironment = new();


As commented else where we should not add a dependency for RuntimeSupport on this library. So you should remove LambdaEnvironment from here and copy the environment variable constants from RuntimeSupport.

ppittle changed the base branch from master to dev March 12, 2025 18:25

ppittle changed the title ~~Snapstart Minimal API Performance Improvements~~ [DRAFT] Snapstart Minimal API Performance Improvements Mar 12, 2025

ppittle marked this pull request as draft March 12, 2025 18:25

ppittle commented Mar 12, 2025

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Libraries/src/Amazon.Lambda.RuntimeSupport/Client/RuntimeApiHeaders.cs Outdated Show resolved Hide resolved

ppittle commented Mar 12, 2025

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...mbda.AspNetCoreServer.Hosting/Internal/LambdaSnapstartExecuteRequestsBeforeSnapshotHelper.cs Outdated Show resolved Hide resolved

ppittle commented Mar 12, 2025

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Libraries/src/Amazon.Lambda.AspNetCoreServer.Hosting/Internal/LambdaRuntimeSupportServer.cs Outdated Show resolved Hide resolved

ppittle added 3 commits March 12, 2025 15:52

Add AddAWSLambdaBeforeSnapshotRequest to support warming up the asp.n…

220b292

…et/lambda pipelines automatically during BeforeSnapshot callback.

inline SnapstartHelperLambdaRequest

dee7589

add auto version change

784e195

ppittle force-pushed the snapstart-minapi-perf-improvements branch from 520905f to 784e195 Compare March 12, 2025 22:52

add support for additional LambdaEventSource

856574d

ppittle marked this pull request as ready for review March 13, 2025 05:48

philasmar requested a review from normj March 13, 2025 13:12

philasmar reviewed Mar 13, 2025

View reviewed changes

update documentation

bac5afb

ppittle changed the title ~~[DRAFT] Snapstart Minimal API Performance Improvements~~ Snapstart Minimal API Performance Improvements Mar 14, 2025

ppittle requested a review from philasmar March 19, 2025 19:06

normj requested changes Mar 21, 2025

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normj reviewed Mar 21, 2025

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...mbda.AspNetCoreServer.Hosting/Internal/LambdaSnapstartExecuteRequestsBeforeSnapshotHelper.cs Show resolved Hide resolved

ppittle force-pushed the snapstart-minapi-perf-improvements branch 2 times, most recently from 3df5501 to fa3658e Compare March 25, 2025 23:40

ppittle added 2 commits March 26, 2025 15:12

Fix bugs in LambdaSnapstartExecuteRequestsBeforeSnapshotHelper and ad…

3a2a866

…d unit tests

removed duplicate reference to snk

c182df3

ppittle force-pushed the snapstart-minapi-perf-improvements branch from fa3658e to fc98552 Compare March 26, 2025 22:13

ppittle added 3 commits April 9, 2025 08:42

update AddAWSLambdaBeforeSnapshotRequest() to support AOT by optimizi…

62367b7

…ng json serialization, adjust #if blocks and fix simple warnings

remove requirement that Amazon.Lambda.RuntimeSupport make InternalsVi…

fe3635e

…sibileTo Amazon.Lambda.AspNetCorServer.Hosting

migrate extension method to use HttpRequestMethods instead of collect…

bfa3ca9

…ing calls to HttpClient

ppittle force-pushed the snapstart-minapi-perf-improvements branch from e3a87f5 to c7d6057 Compare April 9, 2025 15:46

Add Snapstart helper to AbstractAspNetCoreFunction

b476fcd

ppittle force-pushed the snapstart-minapi-perf-improvements branch from c7d6057 to b476fcd Compare April 9, 2025 19:39

ppittle requested a review from normj April 9, 2025 19:39

normj reviewed Apr 12, 2025

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normj requested changes Apr 12, 2025

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Snapstart Minimal API Performance Improvements #2010

Snapstart Minimal API Performance Improvements #2010

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		var context = CreateContext(features);

		var lambdaContext = new SnapStartEmptyLambdaContext();

Snapstart Minimal API Performance Improvements #2010

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ppittle commented Mar 12, 2025 •

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