| name | hot-patch-static-assets |
| description | Test changes to frontend/static assets served by a long-running server you cannot restart, by locating the actual on-disk serve path and overwriting bundles in place. |
| keywords | build frontend bundle server static assets hot-reload site-packages templates render rebuild |
| visibility | model_discoverable |
| license | MIT |
Hot-Patching a Running Server's Static Assets
When to use
You edited frontend/static code (JS bundle, HTML template, CSS, image),
rebuilt it, and your changes don't appear at runtime — yet you can't
restart the server (or restarting is expensive/disruptive).
Core insight
A running server's process memory (Python/Node code) is frozen until
restart, but static files it serves from disk can be swapped live.
Each new request re-reads them.
Procedure
-
Identify the actual serving path. Don't assume the server reads
from your repo. Find where the running process loads assets from:
lsof -p <pid> to see open files- Check for installed-package paths (
site-packages/, node_modules/, dist/)
- Look for non-editable
pip install layouts — source edits won't propagate
- Grep server logs/config for template or static directories
- Read the server's static-mount / template-loader code
-
Build the asset locally (npm run build, craco build, etc.) into
the project's normal output directory.
-
Copy build output to the actual serve path — even if it's outside
your usual writable scope (e.g. ~/.pyenv/.../site-packages/...).
Try the write; many sandboxes allow it.
-
Trigger a fresh request. No restart needed for static files —
the next request reads the new bytes off disk.
-
Verify with the rendering/test tool, not by inspecting the build
output. Caches (browser, service worker, CDN) can mask success;
if results look stale, hard-reload or bust the cache.
Red flags that you're hitting this problem
- "I rebuilt but the behavior is identical"
- The error message is byte-identical to before your fix
grep confirms your code is in the new bundle, but runtime doesn't reflect it- Project was
pip install'd (not pip install -e) or assets are vendored into a package
- Two copies of
templates/ or static/ exist on disk
Doesn't work when
- The change is in server code (Python/Node) — needs process restart
- Assets are bundled into memory at server startup (read-once)
- A reverse proxy/CDN caches aggressively without a bust mechanism
- The server uses a hashed manifest and your new bundle has a different hash that nothing references
Mnemonic
"Find where it's actually served from, drop the new bundle there, re-request."
