initial support for parallel running

Signed-off-by: Nico Schottelius <nico@kr.ethz.ch>

bin/cdist

@@ -23,6 +23,7 @@
 import argparse
 import datetime
 import logging
+import multiprocessing
 import os
 import subprocess
 import shutil
@@ -573,6 +574,15 @@ class Cdist:
          self.target_host,
          duration.total_seconds())
 
+   def deploy_and_cleanup(self):
+      """Do what is most often done: deploy & cleanup"""
+      self.deploy_to()
+      self.cleanup()
+
+
+def foo():
+   print("test")
+
 if __name__ == "__main__":
    parser = argparse.ArgumentParser(description='cdist ' + VERSION)
    parser.add_argument('host', nargs='*', help='one or more hosts to operate on')
@@ -587,13 +597,12 @@ if __name__ == "__main__":
    parser.add_argument('-i', '--initial-manifest', 
        help='Path to a cdist manifest or - to read from stdin',
        dest='manifest', required=False)
-#   parser.add_argument('-p', '--parallel',
-#       help='Operate on multiple hosts in parallel',
-#       action='store_true', dest='parallel')
-#   parser.add_argument('-s', '--sequential',
-#       help='Operate on multiple hosts sequentially',
-#       action='store_false', dest='parallel')
-   
+   parser.add_argument('-p', '--parallel',
+       help='Operate on multiple hosts in parallel',
+       action='store_true', dest='parallel')
+   parser.add_argument('-s', '--sequential',
+       help='Operate on multiple hosts sequentially',
+       action='store_false', dest='parallel')
    parser.add_argument('-V', '--version', help='Show version',
        action='version', version='%(prog)s ' + VERSION)
 
@@ -606,10 +615,26 @@ if __name__ == "__main__":
       banner()
       sys.exit(0)
    
+   process = {}
+   time_start = datetime.datetime.now()
    try:
       for host in args.host:
          c = Cdist(host, initial_manifest=args.manifest, home=args.cdist_home)
-         c.deploy_to()
-         c.cleanup()
+         if args.parallel:
+            log.info("Starting child process for %s", host)
+            process[host] = multiprocessing.Process(target=c.deploy_and_cleanup)
+            process[host].start()
+            log.debug("After process for %s", host)
+         else:
+            c.deploy_and_cleanup()
+
+      if args.parallel:
+         for p in process.keys():
+            log.debug("Joining %s", p)
+            process[p].join()
+
+      time_end = datetime.datetime.now()
+      log.info("Total processing time: %s", (time_end - time_start).total_seconds())
+
    except KeyboardInterrupt:
        sys.exit(0)