synapse/docker/prefix-log

#!/bin/bash
#
# Prefixes all lines on stdout and stderr with the process name (as determined by
# the SUPERVISOR_PROCESS_NAME env var, which is automatically set by Supervisor).
#
# Usage:
#   prefix-log command [args...]
#

# '-W interactive' is a `mawk` extension which disables buffering on stdout and sets line-buffered reads on
# stdin. The effect is that the output is flushed after each line, rather than being batched, which helps reduce
# confusion due to to interleaving of the different processes.
exec 1> >(awk -W interactive '{print "'"${SUPERVISOR_PROCESS_NAME}"' | "$0 }' >&1)
exec 2> >(awk -W interactive '{print "'"${SUPERVISOR_PROCESS_NAME}"' | "$0 }' >&2)
exec "$@"