Adding database update lock support to the test setup/teardown files

- Legacy-Id: 334

test/shell-utils

@@ -10,6 +10,7 @@ function err() {
 	echo "$program: Error: $*" 1>&2; 
 	exit 2
 }
+alias die='err'
 
 function warn() { 
 	echo "$program: Warning: $*" 1>&2; 

test/test-setup

@@ -47,9 +47,32 @@ say "Setting up the Django settings for the test suite"
 cd $build
 
 settings_local=$(py_module_file "settings_local")
-[ "$settings_local" ] || err
+[ "$settings_local" ] || die "No setting_local file available"
 
 cat $settings_local test/settings_local_test.py > ietf/settings_local.py
 
+# Acquire lock, to prevent running test and database update at the same time
+
+LOCKDIR=$build/test/update-db.lock
+PIDFILE=$build/test/update-db.lock/pid
+
+while true; do
+    if mkdir $build/test/update-db.lock; then
+	echo "$$" > $PIDFILE
+	break
+    else
+	pid=$(< $PIDFILE ) || die "Couldn't read pidfile '$PIDFILE'"
+	if kill -0 $pid; then
+	    echo "Pidfile for process $pid exists, and process is running. Sleeping."
+	    sleep 10
+	else
+	    echo "Pidfile for process $pid exists, but process isn't running."
+	    echo "Removing lock and old pid file $pidfile."
+	    rm -rf $LOCKDIR
+	    break 
+	fi
+    fi
+done
+
 
 exit $warnings

test/test-teardown

@@ -19,4 +19,9 @@ if echo "show databases;" | python ietf/manage.py dbshell | grep test_ietf; then
     echo "test database removed."
 fi
 
+# Release database update lock
+
+LOCKDIR=$build/test/update-db.lock
+rm -rf $LOCKDIR
+
 exit $warnings