feat(bench): make gunicorn keep-alive and worker-tmp-dir configurable

[mrrobot47]

Problem

frappe_manager/site_manager/modules/bench_supervisor.py builds the gunicorn command line for the generated web-server wrapper in _write_gunicorn_wrapper. Two useful gunicorn runtime flags are not supported there:

• --keep-alive — how long gunicorn keeps an idle client connection open between requests.
• --worker-tmp-dir — where gunicorn places its per-worker heartbeat files (commonly pointed at a tmpfs such as /dev/shm).

Because the wrapper is regenerated on setup / restart / migrate, an operator who edits the generated script by hand to add either flag loses that customization on the very next FM operation. There is currently no supported way to set these values persistently.

Solution

Expose both flags via common_site_config.json, consistent with the existing gunicorn_workers / gunicorn_max_requests / gunicorn_threads keys:

Key	Gunicorn flag	Default
gunicorn_keep_alive	--keep-alive	unset (flag omitted)
gunicorn_worker_tmp_dir	--worker-tmp-dir	unset (flag omitted)

generate_supervisor_config reads the two keys and adds them to the render context; _write_gunicorn_wrapper conditionally appends the flags only when they are configured.

Backward compatibility

Defaults preserve current behavior exactly. When neither key is set, the generated command is byte-identical to today's output — no --keep-alive, no --worker-tmp-dir.

Default (both keys unset):

-b 0.0.0.0:80 -w 5 --worker-class=gthread --threads 2 --max-requests 1000 --max-requests-jitter 100 -t 120 --graceful-timeout 30 frappe.app:application --preload

With gunicorn_keep_alive=5 and gunicorn_worker_tmp_dir=/dev/shm:

-b 0.0.0.0:80 -w 5 --worker-class=gthread --threads 2 --max-requests 1000 --max-requests-jitter 100 -t 120 --graceful-timeout 30 --keep-alive 5 --worker-tmp-dir /dev/shm frappe.app:application --preload

Emission rules:

• gunicorn_keep_alive uses an is not None check, so an explicit 0 still emits --keep-alive 0 (a valid gunicorn value); leaving the key unset omits the flag.
• gunicorn_worker_tmp_dir is emitted only when set to a non-empty path.

Usage

fm shell mybench -c "bench set-config -g gunicorn_keep_alive 5"
fm shell mybench -c "bench set-config -g gunicorn_worker_tmp_dir /dev/shm"
fm restart mybench

Scope notes

• --graceful-timeout is intentionally not touched here — it is left hardcoded at 30, exactly as on develop, because making it configurable is already handled by fix(gunicorn): align --graceful-timeout with --timeout and expose as config #418. This PR is scoped to the two flags that no open PR covers.
• Gunicorn's --keep-alive (idle client-connection lifetime on the gunicorn side) complements the nginx-to-gunicorn upstream keepalive added in perf(nginx): enable HTTP/1.1 keepalive between nginx and gunicorn upstream #417; the two operate at different layers and are independent.

Docs: adds an "Optional Gunicorn Flags" subsection to docs/reference/workers.md documenting the two new keys.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 12.50000% with 7 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (develop@6c477d8). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
...e_manager/site_manager/modules/bench_supervisor.py	12.50%	7 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
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[Copilot]

Pull request overview

This PR adds persistent configuration support for two additional Gunicorn runtime flags (--keep-alive and --worker-tmp-dir) by sourcing new keys from common_site_config.json and emitting them into the generated fm-web-server.sh wrapper when set, with documentation updates to match.

Changes:

• Read gunicorn_keep_alive / gunicorn_worker_tmp_dir from common_site_config.json and pass them through the supervisor render context.
• Conditionally append --keep-alive and --worker-tmp-dir to the generated Gunicorn command line.
• Document the new optional keys in docs/reference/workers.md.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
frappe_manager/site_manager/modules/bench_supervisor.py	Adds two new config-derived Gunicorn flags to the generated wrapper command line.
docs/reference/workers.md	Documents the new optional Gunicorn flags and how to configure them.

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