speech-dispatcher: Autospawning
4.6 Autospawning
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It is suggested that client libraries offer an autospawn functionality
to automatically start the server process when connecting locally and if
it is not already running. E.g. if the client application starts and
Speech Dispatcher is not running already, the client will start Speech
Dispatcher.
The library API should provide a possibility to turn this
functionality off, but we suggest to set the default behavior to
autospawn.
Autospawn is performed by executing Speech Dispatcher with the -spawn
parameter under the same user and permissions as the client process:
speech-dispatcher --spawn
With the '--spawn' parameter, the process will start and return with
an exit code of 0 only if a) it is not already running (pidfile check)
b) the server doesn't have autospawn disabled in its configuration c) no
other error preventing the start occurs. Otherwise, Speech Dispatcher
is not started and the error code of 1 is returned.
The location of the 'speech-dispatcher' command should be obtained
from the 'SPEECHD_CMD' environment variable if defined, and otherwise
fallback to the 'SPD_SPAWN_CMD' compile-time constant, i.e.
'$bindir/speech-dispatcher'.
The client library should redirect its stdout and stderr outputs
either to nowhere or to its logging system. It should subsequently
completely detach from the newly spawned process.
Due to a bug in Speech Dispatcher, it is currently necessary to
include a wait statement after the autospawn for about 0.5 seconds
before attempting a connection.
Please see how autospawn is implemented in the C API and in the
Python API for an example.
Info Catalog
speech-dispatcher: Common Lisp API
speech-dispatcher: Client Programming