deploy: show a warming page while a cold-started app wakes - #392
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Deployed apps on sleeping microVMs hung for the full 20s dial timeout and then showed raw gateway JSON — they looked broken while merely waking. The deployment proxy now tracks when each upstream last answered; a document GET/HEAD to an upstream not seen healthy recently gets a short first-byte window, and on a dial timeout or connection failure the browser receives an auto-refreshing warming page instead of an error blob. Applies to every proxy path (path-prefix, subdomain, and admin routes) since they share the layer.
ReganBell
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Deployed apps on sleeping microVMs hung for the full 20s dial timeout and then showed raw gateway JSON — they looked broken while merely waking. The deployment proxy now tracks when each upstream last answered; a document GET/HEAD to an upstream not seen healthy recently gets a short first-byte window, and on a dial timeout or connection failure the browser receives an auto-refreshing warming page instead of an error blob. Applies to every proxy path (path-prefix, subdomain, and admin routes) since they share the layer. **Deployment notes** Behavior flip at the proxy: browser GET/HEAD to an upstream not seen healthy in 60s now gets a 4sfirstbytewindowthenanHTML503warmingpage(autoretry2mingiveup)insteadof 4s first-byte window then an HTML 503 warming page (auto-retry, 2min give-up) instead of hanging the full dial timeout and landing on raw gateway JSON — anything programmatically fetching app pages with document Accept headers and expecting JSON errors sees HTML now; non-document requests keep the JSON 502/504 contract No config, no DB; recently-healthy upstreams keep the full timeout so slow pages aren't misclassified <!-- codesmith:footer --> --- <a href="https://app.blacksmith.sh/yc-software/codesmith/qm/pr/392"><picture><source media="(prefers-color-scheme: dark)" srcset="https://pr-comments-assets.blacksmith.sh/codesmith/view-with-codesmith-dark-v2.svg"><source media="(prefers-color-scheme: light)" srcset="https://pr-comments-assets.blacksmith.sh/codesmith/view-with-codesmith-light-v2.svg"><img alt="View with [code]smith" src="https://pr-comments-assets.blacksmith.sh/codesmith/view-with-codesmith-dark-v2.svg"></picture></a> <a href="https://backend.blacksmith.sh/track/enable-autofix?expires=1789237848&installation_model_id=19911&pr_number=392&repository=yc-software%2Fqm&return_to=https%3A%2F%2Fgithub.com%2Fyc-software%2Fqm%2Fpull%2F392&signature=854169d0df2b3fb067e0b3f7a4cdcbf454d271d06dc19308e3dadfd4a5e23694"><picture><source media="(prefers-color-scheme: dark)" srcset="https://pr-comments-assets.blacksmith.sh/codesmith/autofix-with-codesmith-dark.svg"><source media="(prefers-color-scheme: light)" srcset="https://pr-comments-assets.blacksmith.sh/codesmith/autofix-with-codesmith-light.svg"><img alt="Autofix with [code]smith" src="https://pr-comments-assets.blacksmith.sh/codesmith/autofix-with-codesmith-dark.svg"></picture></a> <sup>Need help on this PR? Tag <code>@codesmith-bot</code> with what you need. Autofix is disabled.</sup> <!-- codesmith:autofix:disabled --> <!-- /codesmith:footer -->
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Deployed apps on sleeping microVMs hung for the full 20s dial timeout and then showed raw gateway JSON — they looked broken while merely waking. The deployment proxy now tracks when each upstream last answered; a document GET/HEAD to an upstream not seen healthy recently gets a short first-byte window, and on a dial timeout or connection failure the browser receives an auto-refreshing warming page instead of an error blob. Applies to every proxy path (path-prefix, subdomain, and admin routes) since they share the layer.
Deployment notes
Behavior flip at the proxy: browser GET/HEAD to an upstream not seen healthy in 60s now gets a
4sfirstbytewindowthenanHTML503warmingpage(autoretry2mingiveup)insteadof
4s first-byte window then an HTML 503 warming page (auto-retry, 2min give-up) instead of
hanging the full dial timeout and landing on raw gateway JSON — anything programmatically
fetching app pages with document Accept headers and expecting JSON errors sees HTML now;
non-document requests keep the JSON 502/504 contract
No config, no DB; recently-healthy upstreams keep the full timeout so slow pages aren't
misclassified
Need help on this PR? Tag
@codesmith-botwith what you need. Autofix is disabled.