multiarchimport.py: add --sequential option

1 files changed, 17 insertions, 2 deletions

diff --git a/multiarchimport.py b/multiarchimport.py
index 2804612..84eab35 100755
--- a/multiarchimport.py
+++ b/multiarchimport.py
@@ -141,6 +141,19 @@ def consume_items(dct):
         except KeyError:
             break
 
+class SequentialPool:
+    """A multiprocessing.Pool replacement that isn't parallel at all."""
+    @staticmethod
+    def apply_async(function, args, callback=None, error_callback=None):
+        try:
+            result = function(*args)
+        except Exception as exception:
+            if error_callback is not None:
+                error_callback(exception)
+        else:
+            if callback is not None:
+                callback(result)
+
 def bounded_imap_unordered(bound, pool, function, iterable):
     iterable = iter(iterable)
     results = queue.Queue()
@@ -190,11 +203,13 @@ def main():
     parser.add_argument("-m", "--mirror", action="store",
                         default="http://deb.debian.org/debian",
                         help="Debian mirror to use")
+    parser.add_argument("--sequential", action="store_true", default=False,
+                        help="avoid using multiple processes or CPUs")
     args = parser.parse_args()
     architectures = release_architectures(args.mirror)
     architectures.add("all")
-    workers = multiprocessing.cpu_count()
-    pool = multiprocessing.Pool(workers)
+    workers = 1 if args.sequential else multiprocessing.cpu_count()
+    pool = multiprocessing.Pool(workers) if workers > 1 else SequentialPool()
     db = sqlite3.connect(args.database)
     cur = db.cursor()
     cur.execute("PRAGMA foreign_keys = ON;")