Add Socketfile support for systemd-style socket activation#816
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Ericson2314 wants to merge 2 commits into
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Add Socketfile support for systemd-style socket activation#816Ericson2314 wants to merge 2 commits into
Socketfile support for systemd-style socket activation#816Ericson2314 wants to merge 2 commits into
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Foreman can now pre-bind sockets and pass them to child processes using
the `LISTEN_FDS` / `LISTEN_FDNAMES` protocol (the same protocol systemd
uses for socket activation). This lets processes survive restarts without
rebinding their listen addresses.
A `Socketfile` declares which process gets which sockets:
web: http=:3000
api: grpc=:50051
Foreman binds these before spawning children, then maps them to fd 3, 4, ...
via `Process.spawn` and sets the corresponding environment variables.
Ericson2314
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Add a `Socketfile` that declares sockets for `hydra-server` and `hydra-queue-runner`, so foreman can pass sockets to them just like systemd socket activation would. This means that development with foreman is once again exercising the same code paths that production will use. The foreman start scripts are updated accordingly: - `hydra-server` switches from `hydra-dev-server --port` to `hydra-server -f` (Starman with fork mode), picking up the socket via the `Net::Server::Systemd::PreFork` personality. - `hydra-queue-runner` gets `--rest-bind - --grpc-bind -` to use socket activation for both its REST and gRPC servers. - All services now `wait_for_hydra_db` before starting, since with socket activation the listen port is open before the server is ready, so `wait_for_hydra_server` alone is no longer sufficient. - `queue_runner_endpoint` is added to the generated `hydra.conf` so the web UI can fetch machine status. The foreman fork (Ericson2314/foreman@socketfile, PR ddollar/foreman#816) adds the `Socketfile` feature. Foreman is packaged from source in `packaging/foreman/` because it was not clear how to override the Nixpkgs version which gets its source from rubygems. I would not use forked projects when I am far from sure that upstream would accept the change in production, but foreman is just a developer convenience in the dev shell. That to me makes this OK --- it's just for developer convenience.
Ericson2314
added a commit
to obsidiansystems/hydra
that referenced
this pull request
May 6, 2026
Add a `Socketfile` that declares sockets for `hydra-server` and `hydra-queue-runner`, so foreman can pass sockets to them just like systemd socket activation would. This means that development with foreman is once again exercising the same code paths that production will use. The foreman start scripts are updated accordingly: - `hydra-server` switches from `hydra-dev-server --port` to `hydra-server -f` (Starman with fork mode), picking up the socket via the `Net::Server::Systemd::PreFork` personality. - `hydra-queue-runner` gets `--rest-bind - --grpc-bind -` to use socket activation for both its REST and gRPC servers. - All services now `wait_for_hydra_db` before starting, since with socket activation the listen port is open before the server is ready, so `wait_for_hydra_server` alone is no longer sufficient. - `queue_runner_endpoint` is added to the generated `hydra.conf` so the web UI can fetch machine status. The foreman fork (Ericson2314/foreman@socketfile, PR ddollar/foreman#816) adds the `Socketfile` feature. Foreman is packaged from source in `packaging/foreman/` because it was not clear how to override the Nixpkgs version which gets its source from rubygems. I would not use forked projects when I am far from sure that upstream would accept the change in production, but foreman is just a developer convenience in the dev shell. That to me makes this OK --- it's just for developer convenience.
Ericson2314
added a commit
to obsidiansystems/hydra
that referenced
this pull request
May 6, 2026
Add a `Socketfile` that declares sockets for `hydra-server` and `hydra-queue-runner`, so foreman can pass sockets to them just like systemd socket activation would. This means that development with foreman is once again exercising the same code paths that production will use. The foreman start scripts are updated accordingly: - `hydra-server` switches from `hydra-dev-server --port` to `hydra-server -f` (Starman with fork mode), picking up the socket via the `Net::Server::Systemd::PreFork` personality. - `hydra-queue-runner` gets `--rest-bind - --grpc-bind -` to use socket activation for both its REST and gRPC servers. - All services now `wait_for_hydra_db` before starting, since with socket activation the listen port is open before the server is ready, so `wait_for_hydra_server` alone is no longer sufficient. The foreman fork (Ericson2314/foreman@socketfile, PR ddollar/foreman#816) adds the `Socketfile` feature. Foreman is packaged from source in `packaging/foreman/` because it was not clear how to override the Nixpkgs version which gets its source from rubygems. I would not use forked projects when I am far from sure that upstream would accept the change in production, but foreman is just a developer convenience in the dev shell. That to me makes this OK --- it's just for developer convenience.
Require explicit `tcp://` or `unix://` scheme prefixes:
hydra-server: http=tcp://:3000
hydra-drv-daemon: daemon=unix:///tmp/drv-daemon.sock
Unix sockets are cleaned up on shutdown.
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Note
I don't know if this project would accept a such a blatantly new feature extending the Procfile defacto spec, but it was useful for me, so I am making this PR. Look at https://github.com/mitsuhiko/systemfd for some prior art.
Foreman can now pre-bind sockets and pass them to child processes using the
LISTEN_FDS/LISTEN_FDNAMESprotocol (the same protocol systemd uses for socket activation). This lets processes survive restarts without rebinding their listen addresses.A
Socketfiledeclares which process gets which sockets:Foreman binds these before spawning children, then maps them to fd 3, 4, ... via
Process.spawnand sets the corresponding environment variables.