Merge pull request #81 from jisqyv/buildserversupport

Add the tools used to run a buildserver to the source tree along with

appinventor/misc/buildserver/README

+The files in this directory are for supporting an App Inventor
+buildserver on a Ubuntu Linux server.[*] What you do:
+
+ * Create an account named "buildserver":
+
+   prompt% sudo adduser buildserver --system
+
+ * copy launch-buildserver and buildmonitor.py to
+   /home/buildserver/
+
+ * Create /home/buildserver/lib
+
+ * Copy file files from
+   ${ROOT}/appinventor/buildserver/build/run/lib/*
+   to /home/buildserver/lib/
+
+   (${ROOT} is the source root directory)
+
+ * Copy buildserver.conf to /etc/init/buildserver.conf
+
+You can now start the buildserver via:
+
+   prompt% sudo start buildserver
+
+Note: The buildserver will now automatically start when the server
+boots. The buildmonitor.py script arranges to restart the buildserver
+if it exits. So you cannot just kill the buildserver java
+program. Instead you "sudo stop buildserver" which instructs "upstart"
+(the Ubuntu daemon management program) to shut it down.
+
+[*] Valid at least as of Ubuntu 12.04LTS

appinventor/misc/buildserver/buildmonitor.py

+from subprocess import Popen,PIPE
+import time
+import signal
+import os
+import pwd
+from logging.handlers import SysLogHandler
+import logging
+
+server = None
+stopping = False
+
+def main():
+    '''Start the buildserver and keep track of it, i.e., restart if it fails'''
+    global server, log
+    signal.signal(signal.SIGTERM, sighandler)
+    signal.signal(signal.SIGQUIT, sighandler)
+    signal.signal(signal.SIGINT, sighandler)
+    count = 0
+    buildpwd = pwd.getpwnam('buildserver')
+    os.setgid(buildpwd.pw_gid)
+    os.setuid(buildpwd.pw_uid)
+    os.chdir('/home/buildserver')
+    log = logging.getLogger()
+    log.addHandler(SysLogHandler('/dev/log'))
+    log.handlers[0].setFormatter(logging.Formatter('BUILDSERVER: %(levelname)s: %(message)s'))
+    log.info('Buildserver Monitor Starting')
+    while True:
+        ts = time.time()
+        server = Popen(['./launch-buildserver',], close_fds=True)
+        while not server.poll():     # While we are still running
+            time.sleep(10)      # Sleep for ten seconds
+        nts = time.time()
+        code = server.wait()
+        server = None
+        log.warn('Build Server Terminated with code = %d' % code)
+        if (nts - ts) < 60:     # It was running less then a minute?
+            log.error('Build Server Terminated within 1 minute of start!')
+            count += 1          # Bump count
+            if count > 4:
+                log.critical('Count of looping buildserver > 4, just hanging...')
+                while True:
+                    signal.pause()
+                    
+def sighandler(*args):
+    if server:
+        server.terminate()
+    log.warn('Build Server Shutdown')
+    logging.shutdown()
+    raise SystemExit            # bye bye
+
+if __name__ == '__main__':
+    main()
+
+                

appinventor/misc/buildserver/buildserver.conf

+# buildserver - App Inventor Build Server Process Manager
+
+description	"App Inventor Build Server Process Manager"
+
+start on runlevel [2345]
+stop on runlevel [!2345]
+
+expect fork
+respawn
+
+exec /usr/bin/python /home/buildserver/buildmonitor.py