Force disable proxy when communicating with Lambda runtime API. - #2578
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GarrettBeatty
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Sep 17, 2026
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🟢 Approval recommended
The implementation is correctly scoped and covered by an appropriate unit test.
Pull request overview
Disables proxy usage for the Runtime API HTTP client so customer proxy environment variables cannot interfere with Lambda runtime communication.
Changes:
- Sets
SocketsHttpHandler.UseProxy = false. - Adds a unit test verifying proxy bypass behavior.
- Adds a patch changelog entry.
File summaries
| File | Description |
|---|---|
LambdaBootstrap.cs |
Disables proxy use for Runtime API requests. |
LambdaBootstrapTests.cs |
Verifies the handler bypasses proxies. |
.autover/changes/...json |
Documents the patch release change. |
Review details
- Files reviewed: 3/3 changed files
- Comments generated: 0
- Review effort level: Lite
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dscpinheiro
approved these changes
Sep 17, 2026
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Description of changes:
The
HttpClientthatAmazon.Lambda.RuntimeSupportuses to communicate with the Lambda Runtime API (RAPID) now forces proxy usage off. Its underlyingSocketsHttpHandleris created withUseProxy = false.Problem:
SocketsHttpHandlerhonorsHttpClient.DefaultProxy, which is populated from theHTTP_PROXY/HTTPS_PROXYenvironment variables. When a customer configures a proxy, internal Runtime API calls were being routed through it. That fails because the RAPID endpoint is not necessarily on a loopback address (onlylocalhostis implicitly exempt in most proxy implementations), so the runtime could not talk to the Runtime API.Fix: Disable the proxy on the Runtime API handler only. This is scoped to the
HttpClientused for Runtime API communication and has no impact on HTTP calls made from customer handler code.This mirrors the equivalent fix made in the Java Lambda runtime client.
Testing:
RuntimeApiHttpClientBypassesProxyunit test asserting the Runtime API handler hasUseProxy == false.By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.