openstack/devstack
Code Issues Proposed changes

Add run_process() to start services without screen

Browse Source 
* USE_SCREEN defaults to True, set it to False to exec the services
  directly via bash.  SCREEN_DEV is still supported until the CI
  scripts get updated.
* The extra logging file descriptors are properly closed in the child process
  and stdout/stderr are redirected to the log files.
* The screen_rc() call is still present; this means that stack-screenrc will
  have a complete record of what was started and rejoin-stack.sh may be able
  to re-create the setup under screen.
* The python interpreter was unwilling to write to the log files without
  unbufering stdout by using PYTHONUNBUFFERED.  This feels hackish and should
  be investigated further.

Change-Id: I012ed049f2c8b185a2e6929d73edc29e167bc21f
This commit is contained in:
Dean Troyer
2013-02-27 19:00:39 -06:00
parent 43eb8f823f
commit 681f3fddec
3 changed files with 69 additions and 19 deletions

62
functions

@ -735,26 +735,69 @@ function restart_service() {
}
# _run_process() is designed to be backgrounded by run_process() to simulate a
# fork. It includes the dirty work of closing extra filehandles and preparing log
# files to produce the same logs as screen_it(). The log filename is derived
# from the service name and global-and-now-misnamed SCREEN_LOGDIR
# _run_process service "command-line"
function _run_process() {
local service=$1
local command="$2"
# Undo logging redirections and close the extra descriptors
exec 1>&3
exec 2>&3
exec 3>&-
exec 6>&-
if [[ -n ${SCREEN_LOGDIR} ]]; then
exec 1>&${SCREEN_LOGDIR}/screen-${1}.${CURRENT_LOG_TIME}.log 2>&1
ln -sf ${SCREEN_LOGDIR}/screen-${1}.${CURRENT_LOG_TIME}.log ${SCREEN_LOGDIR}/screen-${1}.log
# TODO(dtroyer): Hack to get stdout from the Python interpreter for the logs.
export PYTHONUNBUFFERED=1
fi
exec /bin/bash -c "$command"
die "$service exec failure: $command"
}
# run_process() launches a child process that closes all file descriptors and
# then exec's the passed in command. This is meant to duplicate the semantics
# of screen_it() without screen. PIDs are written to
# $SERVICE_DIR/$SCREEN_NAME/$service.pid
# run_process service "command-line"
function run_process() {
local service=$1
local command="$2"
# Spawn the child process
_run_process "$service" "$command" &
echo $!
}
# Helper to launch a service in a named screen
# screen_it service "command-line"
function screen_it {
SCREEN_NAME=${SCREEN_NAME:-stack}
SERVICE_DIR=${SERVICE_DIR:-${DEST}/status}
SCREEN_DEV=`trueorfalse True $SCREEN_DEV`
USE_SCREEN=$(trueorfalse True $USE_SCREEN)
if is_service_enabled $1; then
# Append the service to the screen rc file
screen_rc "$1" "$2"
screen -S $SCREEN_NAME -X screen -t $1
if [[ "$USE_SCREEN" = "True" ]]; then
screen -S $SCREEN_NAME -X screen -t $1
if [[ -n ${SCREEN_LOGDIR} ]]; then
screen -S $SCREEN_NAME -p $1 -X logfile ${SCREEN_LOGDIR}/screen-${1}.${CURRENT_LOG_TIME}.log
screen -S $SCREEN_NAME -p $1 -X log on
ln -sf ${SCREEN_LOGDIR}/screen-${1}.${CURRENT_LOG_TIME}.log ${SCREEN_LOGDIR}/screen-${1}.log
fi
if [[ -n ${SCREEN_LOGDIR} ]]; then
screen -S $SCREEN_NAME -p $1 -X logfile ${SCREEN_LOGDIR}/screen-${1}.${CURRENT_LOG_TIME}.log
screen -S $SCREEN_NAME -p $1 -X log on
ln -sf ${SCREEN_LOGDIR}/screen-${1}.${CURRENT_LOG_TIME}.log ${SCREEN_LOGDIR}/screen-${1}.log
fi
if [[ "$SCREEN_DEV" = "True" ]]; then
# sleep to allow bash to be ready to be send the command - we are
# creating a new window in screen and then sends characters, so if
# bash isn't running by the time we send the command, nothing happens
@ -763,7 +806,8 @@ function screen_it {
NL=`echo -ne '\015'`
screen -S $SCREEN_NAME -p $1 -X stuff "$2 || touch \"$SERVICE_DIR/$SCREEN_NAME/$1.failure\"$NL"
else
screen -S $SCREEN_NAME -p $1 -X exec /bin/bash -c "$2 || touch \"$SERVICE_DIR/$SCREEN_NAME/$1.failure\""
# Spawn directly without screen
run_process "$1" "$2" >$SERVICE_DIR/$SCREEN_NAME/$service.pid
fi
fi
}