Parallelise scale

Signed-off-by: Mazz Mosley <mazz@houseofmnowster.com>

compose/utils.py

@@ -12,6 +12,51 @@ from threading import Thread
 log = logging.getLogger(__name__)
 
 
+def parallel_create_execute(create_function, container_numbers, msgs={}, **options):
+    """
+    Parallel container creation by calling the create_function for each new container
+    number passed in.
+    """
+    stream = codecs.getwriter('utf-8')(sys.stdout)
+    lines = []
+    errors = {}
+
+    for number in container_numbers:
+        write_out_msg(stream, lines, number, msgs['doing'])
+
+    q = Queue()
+
+    def inner_call_function(create_function, number):
+        try:
+            container = create_function(number)
+        except APIError as e:
+            errors[number] = e.explanation
+        q.put(container)
+
+    for number in container_numbers:
+        t = Thread(
+            target=inner_call_function,
+            args=(create_function, number),
+            kwargs=options,
+        )
+        t.daemon = True
+        t.start()
+
+    done = 0
+    total_to_create = len(container_numbers)
+    while done < total_to_create:
+        try:
+            container = q.get(timeout=1)
+            write_out_msg(stream, lines, container.name, msgs['done'])
+            done += 1
+        except Empty:
+            pass
+
+    if errors:
+        for number in errors:
+            stream.write("ERROR: for {}  {} \n".format(number, errors[number]))
+
+
 def parallel_execute(command, containers, doing_msg, done_msg, **options):
     """
     Execute a given command upon a list of containers in parallel.