Backport tail sooner enhancement

Author: rjeberhard

operator/src/main/resources/scripts/startServer.sh

@@ -64,6 +64,17 @@ function startWLS() {
 
   traceTiming "POD '${SERVICE_NAME}' MD5 END"
 
+  #
+  # We "tail" the future WL Server .out file to stdout in background _before_ starting
+  # the WLS Server because we use WLST 'nmStart()' to start the server and nmStart doesn't return
+  # control until WLS reaches the RUNNING state.
+  #
+
+  if [ "${SERVER_OUT_IN_POD_LOG}" == 'true' ] ; then
+    trace "Showing the server out file from ${SERVER_OUT_FILE}"
+    ${SCRIPTPATH}/tailLog.sh ${SERVER_OUT_FILE} ${SERVER_PID_FILE} &
+  fi
+
   #
   # Start WL Server
   #
@@ -76,6 +87,12 @@ function startWLS() {
   ${SCRIPTPATH}/wlst.sh $SCRIPTPATH/start-server.py
 
   traceTiming "POD '${SERVICE_NAME}' WLS STARTED"
+
+  FAIL_BOOT_ON_SITUATIONAL_CONFIG_ERROR=${FAIL_BOOT_ON_SITUATIONAL_CONFIG_ERROR:-true}
+  SERVER_OUT_MONITOR_INTERVAL=${SERVER_OUT_MONITOR_INTERVAL:-3}
+  if [ ${FAIL_BOOT_ON_SITUATIONAL_CONFIG_ERROR} == 'true' ] ; then
+    ${SCRIPTPATH}/monitorLog.sh ${SERVER_OUT_FILE} ${SERVER_OUT_MONITOR_INTERVAL} &
+  fi
 }
 
 function mockWLS() {
@@ -89,22 +106,6 @@ function mockWLS() {
   echo "RUNNING:Y:N" > $STATEFILE
 }
 
-function waitUntilShutdown() {
-  #
-  # Wait forever.   Kubernetes will monitor this pod via liveness and readyness probes.
-  #
-  if [ "${SERVER_OUT_IN_POD_LOG}" == 'true' ] ; then
-    trace "Showing the server out file from ${SERVER_OUT_FILE}"
-    ${SCRIPTPATH}/tailLog.sh ${SERVER_OUT_FILE} ${SERVER_PID_FILE} &
-  fi
-  FAIL_BOOT_ON_SITUATIONAL_CONFIG_ERROR=${FAIL_BOOT_ON_SITUATIONAL_CONFIG_ERROR:-true} 
-  SERVER_OUT_MONITOR_INTERVAL=${SERVER_OUT_MONITOR_INTERVAL:-3}
-  if [ ${FAIL_BOOT_ON_SITUATIONAL_CONFIG_ERROR} == 'true' ] ; then
-    ${SCRIPTPATH}/monitorLog.sh ${SERVER_OUT_FILE} ${SERVER_OUT_MONITOR_INTERVAL} &
-  fi
-  waitForShutdownMarker
-}
-
 # Define helper fn to copy sit cfg xml files from one dir to another
 #   $src_dir files are assumed to start with $fil_prefix and end with .xml
 #   Copied $tgt_dir files are stripped of their $fil_prefix
@@ -247,12 +248,18 @@ copySitCfg /weblogic-operator/introspector ${DOMAIN_HOME}/optconfig/jms
 copySitCfg /weblogic-operator/introspector ${DOMAIN_HOME}/optconfig/jdbc        'Sit-Cfg-JDBC--'
 copySitCfg /weblogic-operator/introspector ${DOMAIN_HOME}/optconfig/diagnostics 'Sit-Cfg-WLDF--'
 
-
+#
+# Start WLS
+#
 
 if [ "${MOCK_WLS}" == 'true' ]; then
   mockWLS
-  waitForShutdownMarker
 else
   startWLS
-  waitUntilShutdown
 fi
+
+#
+# Wait forever. Kubernetes will monitor this pod via liveness and readyness probes.
+#
+
+waitForShutdownMarker

operator/src/main/resources/scripts/tailLog.sh

@@ -10,4 +10,29 @@
 #
 
 echo $$ > $2
-tail -F -n +0 $1
+
+while true ; do
+  if [ -f $1 ]; then
+    tail -F -n +0 $1 || sleep 10
+  fi
+  sleep 0.1
+done
+
+#
+# Work around note:
+#
+#   The forever loop and '[ -f $1 ]' check above work around an
+#   unexpected  behavior  from  'tail -F'.  The  '-F'  expected
+#   behavior is meant to handle 'rolling' files by both:
+#
+#     A- Waiting  until the  file appears  instead of exiting
+#        with an error code.
+#
+#     B- Once the file is found, gracefully handling the file
+#        getting deleted or moved  (by pausing while the file
+#        is gone,  and starting up again once a new file with
+#        the same name appears in its place).
+#
+#   But 'A' is not working on WL pods and thus the work around.
+#   (Strangely and thankfully 'B' works fine.)
+#