socket-event (7) - Linux Man Pages
socket-event: event signalling that a socket connection has been made
socket - event signalling that a socket connection has been made
SYNOPSISsocket PROTO=PROTO PORT=PORT ADDR=ADDR
The socket event is generated by the upstart-socket-bridge(8) daemon when a socket connection is made whose details match the socket event condition and environment specified in a jobs start on or stop on stanza.
When an incoming connection is detected, the file descriptor representing the socket is passed to the job in question to allow it to accept(2) the connection. Additionally, the environment variable UPSTART_EVENTS will contain the name of the event ("socket") and the environment variable UPSTART_FDS will contain the number of the file descriptor corresponding to the listening socket.
Internet (IPv4) socketStart web server when first client connects from localhost:
start on socket PROTO=inet PORT=80 ADDR=127.0.0.1
Internet (IPv6) socketStart job when a client connects from localhost:
start on socket PROTO=inet6 PORT=80 ADDR=::1
start on socket PROTO=unix SOCKET_PATH=/var/run/.s.pgsql.1234
start on socket PROTO=unix SOCKET_PATH=@/at/upstart/example