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File Descriptor Socket Passing

SWS provides the ability to accept a socket listener as a file descriptor for use in sandboxing and on-demand applications via systemd (Linux), launchd (Macos) or similar.


The Socket Activation model is an alternative to TCP port binding.

Socket activation is supported by the -f, --fd option or the equivalent SERVER_LISTEN_FD env.

If you are using inetd, its "wait" option should be used in conjunction with static-web-server's --fd 0 option.


If you're using systemd on Linux, there is a fully working example in the SWS Git repository under the ./systemd directory.


Alternatively, the lightweight systemfd utility may be useful, especially for testing purposes.

For example, using systemfd utility as follow:

systemfd --no-pid -s http::8091 -- path/to/static-web-server --fd 0

Last update: 2022-10-20