Cap live SSE stream lifetime and fix response-time telemetry - #1805
Merged
David Pine (IEvangelist) merged 2 commits intoOct 1, 2026
Merged
David Pine (IEvangelist) merged 2 commits into
David Pine (IEvangelist) merged 2 commits into
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- End each /api/live/stream after a jittered Live:StreamMaxLifetimeSeconds (default 600s) - Close the stream in tabs hidden for 60s; reconnect when visible - Add jitter to the client reconnect backoff - Exclude /api/live/stream from ASP.NET Core request traces - Honor Front Door's X-Azure-ClientIP as the client IP - Update Live README and appsettings Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
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Copilot review overview
🟡 Changes recommended
Blocked response writes can exceed the lifetime cap, and the randomized lifetime test is nondeterministically flaky.
Review effort: Balanced
Findings: 2
Open (2)
What changed in this PR
Caps SSE lifetimes, improves reconnect behavior, filters stream telemetry, and restores Front Door client IPs.
Changes:
- Adds server-side SSE lifetime limits and telemetry filtering.
- Closes hidden-tab streams and jitters reconnect delays.
- Adds configuration, documentation, and tests.
| File | Description |
|---|---|
tests/StaticHost.Tests/Live/LiveStreamTests.cs |
Tests stream lifetime limits. |
src/statichost/StaticHost/Program.cs |
Enables forwarded client IP handling. |
src/statichost/StaticHost/Live/README.md |
Documents stream lifecycle behavior. |
src/statichost/StaticHost/Live/LiveStatusOptions.cs |
Defines maximum stream lifetime. |
src/statichost/StaticHost/Live/LiveEndpoints.cs |
Applies jittered stream cancellation. |
src/statichost/StaticHost/Extensions.cs |
Configures forwarding and telemetry filtering. |
src/statichost/StaticHost/appsettings.json |
Sets the default lifetime. |
src/frontend/tests/unit/live-status.vitest.test.ts |
Tests reconnect and visibility behavior. |
src/frontend/src/components/live-status.ts |
Adds reconnect jitter and hidden-tab cleanup. |
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Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
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Frontend HTML artifact readyThe latest frontend build uploaded the This comment updates automatically when a new frontend build artifact is uploaded. |
Eric Erhardt (eerhardt)
approved these changes
Oct 1, 2026
David Pine (IEvangelist)
deleted the
ievangelist-statichost-429-response-time-analysis
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October 1, 2026 19:36
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Summary
After the release/13.6 deploy, App Service response time showed a sawtooth: the maximum grew about one second per second until restart (around 369,000 s) and the mean was about 79 s. The likely cause is
/api/live/stream. The SSE stream had no lifetime cap, a 15 s heartbeat kept it open indefinitely, and hidden tabs never closed it. Each stream was recorded as a single request lasting hours or days, so the chart probably reflects stream lifetimes, not slow page serving.Changes:
Live:StreamMaxLifetimeSeconds(default 600 s), and the client reconnects./api/live/streamis excluded from ASP.NET Core request traces.X-Azure-ClientIP(ForwardLimit = 1) as the client IP. Before this,RemoteIpAddresswas always the Front Door edge address, so any future per-IP rate limit would put every user in one bucket. Callers that bypass Front Door can spoof this header, so use the value for telemetry only.appsettings.jsonupdated.HTTP 429 posture: the app has no rate limiter, and this repo's infrastructure code defines no Front Door WAF policy, so 429s can't originate here. Twitch/YouTube upstream calls are leader-leased through Redis, which keeps quota risk low.
Third-party links and affiliations
None
Validation
dotnet test tests\StaticHost.Tests --filter "FullyQualifiedName!~Integration": passed (307). Includes the newStreamSse_EndsWithinJitteredMaxLifetimetest.pnpm exec vitest run tests/unit/live-status.vitest.test.ts: passed (12). New tests cover jitter, hidden-tab close, and reconnect on visible.Not yet confirmed: whether the original chart is the App Insights or the App Service metric. After deploy, check with: