falcon
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socketry
Graceful shutdown on kubernetes
After reading #71, testing and reading the code, my understanding is that falcon expects a SIGINT to trigger a graceful shutdown. However, in kubernetes, SIGTERM is sent to trigger shutdown. When this happens, falcon immediately shuts down children, exits with code 1 and logs several errors. I'm not totally sure what the impact is on code running in the children.
Is it possible to enable a clean shutdown with SIGTERM?
SIGINT behaviour:
❯ bundle exec falcon host
0.0s info: Falcon::Command::Host [oid=0x9d0] [ec=0x9d8] [pid=92915] [2025-12-01 10:08:45 -0800]
| Falcon Host v0.52.4 taking flight!
| - Configuration: falcon.rb
| - To terminate: Ctrl-C or kill 92915
| - To reload: kill -HUP 92915
0.01s info: Async::Container::Notify::Console [oid=0x9e0] [ec=0x9d8] [pid=92915] [2025-12-01 10:08:45 -0800]
| {status: "Initializing controller..."}
0.01s info: Falcon::Service::Server [oid=0x9f0] [ec=0x9d8] [pid=92915] [2025-12-01 10:08:45 -0800]
| Preloading preload.rb...
1.6s info: Falcon::Service::Server [oid=0x9f0] [ec=0x9d8] [pid=92915] [2025-12-01 10:08:47 -0800]
| Starting my-app on #<Async::HTTP::Endpoint http://0.0.0.0:3000/ {protocol: Async::HTTP::Protocol::HTTP11}>
1.6s info: Async::Service::Controller [oid=0x2df0] [ec=0x9d8] [pid=92915] [2025-12-01 10:08:47 -0800]
| Controller starting...
1.6s info: Async::Service::Controller [oid=0x2df0] [ec=0x9d8] [pid=92915] [2025-12-01 10:08:47 -0800]
| Starting container...
1.64s info: Async::Service::Controller [oid=0x2df0] [ec=0x9d8] [pid=92915] [2025-12-01 10:08:47 -0800]
| Waiting for startup...
1.65s info: Async::Service::Controller [oid=0x2df0] [ec=0x9d8] [pid=92915] [2025-12-01 10:08:47 -0800]
| Finished startup.
1.65s info: Async::Container::Notify::Console [oid=0x9e0] [ec=0x9d8] [pid=92915] [2025-12-01 10:08:47 -0800]
| {ready: true, size: 11}
1.65s info: Async::Service::Controller [oid=0x2df0] [ec=0x9d8] [pid=92915] [2025-12-01 10:08:47 -0800]
| Controller started...
34.39s info: Async::Container::Forked [oid=0x2ea8] [ec=0x9d8] [pid=92915] [2025-12-01 10:09:20 -0800]
| Stopping container...
| {
| "timeout": true,
| "caller": [...]
| }
34.39s info: Async::Container::Group [oid=0x2eb0] [ec=0x9d8] [pid=92915] [2025-12-01 10:09:20 -0800]
| Sending interrupt to 11 running processes...
34.53s info: Async::Container::Forked [oid=0x2ea8] [ec=0x9d8] [pid=92915] [2025-12-01 10:09:20 -0800]
| Group has stopped.
SIGTERM behaviour:
❯ bundle exec falcon host
0.0s info: Falcon::Command::Host [oid=0x9d0] [ec=0x9d8] [pid=99553] [2025-12-01 10:44:22 -0800]
| Falcon Host v0.52.4 taking flight!
| - Configuration: falcon.rb
| - To terminate: Ctrl-C or kill 99553
| - To reload: kill -HUP 99553
0.01s info: Async::Container::Notify::Console [oid=0x9e0] [ec=0x9d8] [pid=99553] [2025-12-01 10:44:22 -0800]
| {status: "Initializing controller..."}
0.01s info: Falcon::Service::Server [oid=0x9f0] [ec=0x9d8] [pid=99553] [2025-12-01 10:44:22 -0800]
| Preloading preload.rb...
2.08s info: Falcon::Service::Server [oid=0x9f0] [ec=0x9d8] [pid=99553] [2025-12-01 10:44:24 -0800]
| Starting my-app on #<Async::HTTP::Endpoint http://0.0.0.0:3000/ {protocol: Async::HTTP::Protocol::HTTP11}>
2.08s info: Async::Service::Controller [oid=0x2df0] [ec=0x9d8] [pid=99553] [2025-12-01 10:44:24 -0800]
| Controller starting...
2.08s info: Async::Service::Controller [oid=0x2df0] [ec=0x9d8] [pid=99553] [2025-12-01 10:44:24 -0800]
| Starting container...
2.09s info: Async::Service::Controller [oid=0x2df0] [ec=0x9d8] [pid=99553] [2025-12-01 10:44:24 -0800]
| Waiting for startup...
2.09s info: Async::Service::Controller [oid=0x2df0] [ec=0x9d8] [pid=99553] [2025-12-01 10:44:24 -0800]
| Finished startup.
2.09s info: Async::Container::Notify::Console [oid=0x9e0] [ec=0x9d8] [pid=99553] [2025-12-01 10:44:24 -0800]
| {ready: true, size: 2}
2.09s info: Async::Service::Controller [oid=0x2df0] [ec=0x9d8] [pid=99553] [2025-12-01 10:44:24 -0800]
| Controller started...
10.37s info: Async::Container::Forked [oid=0x2e18] [ec=0x9d8] [pid=99553] [2025-12-01 10:44:33 -0800]
| Stopping container...
| {
| "timeout": false,
| "caller": [...]
| }
10.37s info: Async::Container::Group [oid=0x2e20] [ec=0x9d8] [pid=99553] [2025-12-01 10:44:33 -0800]
| Sending terminate to 2 running processes...
10.37s error: Async::Container::Forked::Child [ec=0x2df8] [pid=99556] [2025-12-01 10:44:33 -0800]
| SIGTERM
| Async::Container::Terminate: SIGTERM
| → /Users/matt.books/.local/share/mise/installs/ruby/3.4.2/lib/ruby/gems/3.4.0/gems/async-2.34.0/lib/async/scheduler.rb:525 in 'Thread.handle_interrupt' [...]
10.37s error: Async::Container::Forked::Child [ec=0x2e08] [pid=99557] [2025-12-01 10:44:33 -0800]
| SIGTERM
| Async::Container::Terminate: SIGTERM
| → /Users/matt.books/.local/share/mise/installs/ruby/3.4.2/lib/ruby/gems/3.4.0/gems/async-2.34.0/lib/async/scheduler.rb:525 in 'Thread.handle_interrupt' [...]
10.38s error: Async::Container::Forked [oid=0x2e18] [ec=0x2e28] [pid=99553] [2025-12-01 10:44:33 -0800]
| Child exited with error!
| {
| "status": "pid 99557 exit 1",
| "running": false
| }
10.38s error: Async::Container::Forked [oid=0x2e18] [ec=0x2e30] [pid=99553] [2025-12-01 10:44:33 -0800]
| Child exited with error!
| {
| "status": "pid 99556 exit 1",
| "running": false
| }
10.38s info: Async::Container::Forked [oid=0x2e18] [ec=0x9d8] [pid=99553] [2025-12-01 10:44:33 -0800]
| Group has stopped.
