Add option to make screen starting more robust.

vishvananda · vishvananda · commit 58e21349644f · 2013-02-12T09:12:45.000-08:00
We have seen a number of failures in ci where a host is overloaded
and the 1.5 second sleep before stuffing data into screen is not
long enough. This means the service doesn't start and tests fail.

This change adds a config option to allow us to turn off the developer
friendly option to stuff text into the screen. When SCREEN_DEV is
set to False it will use a simple exec in screen instead of stuff.
This should be far more reliable because we don't have to wait
for bash to start.

Change-Id: I7f1b5dbf5329b23507cb767d54a2795be0d73e01
diff --git a/functions b/functions
@@ -738,26 +738,31 @@ function restart_service() {
 # Helper to launch a service in a named screen
 # screen_it service "command-line"
 function screen_it {
-    NL=`echo -ne '\015'`
     SCREEN_NAME=${SCREEN_NAME:-stack}
     SERVICE_DIR=${SERVICE_DIR:-${DEST}/status}
+    SCREEN_DEV=`trueorfalse True $SCREEN_DEV`
 
     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
-        # 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
-        sleep 1.5
-
-        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
+        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
+            sleep 1.5
+
+            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
+            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\""
         fi
-        screen -S $SCREEN_NAME -p $1 -X stuff "$2 || touch \"$SERVICE_DIR/$SCREEN_NAME/$1.failure\"$NL"
     fi
 }
 
diff --git a/stackrc b/stackrc
@@ -29,6 +29,13 @@ ENABLED_SERVICES=g-api,g-reg,key,n-api,n-crt,n-obj,n-cpu,n-net,n-cond,cinder,c-s
 # Set the default Nova APIs to enable
 NOVA_ENABLED_APIS=ec2,osapi_compute,metadata
 
+# Whether to use 'dev mode' for screen windows. Dev mode works by
+# stuffing text into the screen windows so that a developer can use
+# ctrl-c, up-arrow, enter to restart the service. Starting services
+# this way is slightly unreliable, and a bit slower, so this can
+# be disabled for automated testing by setting this value to false.
+SCREEN_DEV=True
+
 # Repositories
 # ------------
 
