[feature] Properly handle run events in order

This patch implements a small finite state machine on the cmd side to be
able to run a command, wait for all of its output, and then exit.

As the daemon can send those message in any order, we need to wait them
properly, in particular the closing of stdout/stderr before exiting.

This patch also fixes the read_until_close callback creation to ensure
that the stream EOF is handled as a distinct message.

bin/cmd

@@ -67,17 +67,43 @@ class CommandLineInterface(object):
                    'args': argv.args,
                    'uuid': containerid,
                    }
-
+        # command fsm
+        state = 'init'
+        outeof = False
+        erreof = False
+        exitmsg = None
+        self.upstream_pub_socket.send_json(command)
         while(True):
-            self.upstream_pub_socket.send_json(command)
             msg = self.upstream_sub_socket.recv_json()
-            logger.info("new message: %r", msg)
-            # ignore other messages
             if isinstance(msg, dict) and msg.get('type') == 'container':
                 if msg['uuid'] == containerid:
-                    logger.info("container msg: %r", msg)
-                    if msg['event'] == 'exit':
-                        break
+                    if msg['event'] == 'start':
+                        if state == 'init':
+                            state = 'started'
+                            logger.info("container started: %r", msg)
+                        else:
+                            logger.info("unexpected start message: %r", state)
+                            exit(1)
+                    elif msg['event'] == 'stdout':
+                        logger.info("container msg: %r", msg)
+                        if msg['payload'] == 'eof':
+                            outeof = True
+                    elif msg['event'] == 'stderr':
+                        logger.info("container msg: %r", msg)
+                        if msg['payload'] == 'eof':
+                            erreof = True
+                    elif msg['event'] == 'exit':
+                        if state == 'started':
+                            state = 'exiting'
+                            exitmsg = msg
+                        else:
+                            logger.info("unexpected exit message: %r", msg)
+            if state == 'init':
+                self.upstream_pub_socket.send_json(command)
+            if outeof and erreof and state == 'exiting':
+                state = 'exit'
+                logger.info("container ended: %r", exitmsg)
+                break
 
     def do_list(self, argv):
         """Connect to the NRM and ask to list the containers present on the

nrm/daemon.py

@@ -137,8 +137,8 @@ class Daemon(object):
                 # setup io callbacks
                 outcb = partial(self.do_children_io, container_uuid, 'stdout')
                 errcb = partial(self.do_children_io, container_uuid, 'stderr')
-                container.process.stdout.read_until_close(outcb)
-                container.process.stderr.read_until_close(errcb)
+                container.process.stdout.read_until_close(outcb, outcb)
+                container.process.stderr.read_until_close(errcb, outcb)
             elif command == 'kill':
                 logger.info("asked to kill container: %r", msg)
                 response = self.container_manager.kill(msg['uuid'])