irc: Limit number of processes spawned

1 files changed, 23 insertions, 20 deletions

diff --git a/crocoite/irc.py b/crocoite/irc.py
index fea09b3..d2eda45 100644
--- a/crocoite/irc.py
+++ b/crocoite/irc.py
@@ -106,15 +106,17 @@ class Job:
                 prettyBytes (stats.get ('bytesRcv', 0)))
 
 class Bot(bottom.Client):
-    __slots__ = ('jobs', 'channels', 'nick', 'tempdir', 'destdir', 'parser')
+    __slots__ = ('jobs', 'channels', 'nick', 'tempdir', 'destdir', 'parser', 'processLimit')
 
-    def __init__ (self, host, port, ssl, nick, channels=[], tempdir=tempfile.gettempdir(), destdir='.'):
+    def __init__ (self, host, port, ssl, nick, channels=[],
+            tempdir=tempfile.gettempdir(), destdir='.', processLimit=1):
         super().__init__ (host=host, port=port, ssl=ssl)
         self.jobs = {}
         self.channels = channels
         self.nick = nick
         self.tempdir = tempdir
         self.destdir = destdir
+        self.processLimit = asyncio.Semaphore (processLimit)
 
         self.parser = NonExitingArgumentParser (prog=self.nick + ': ', add_help=False)
         subparsers = self.parser.add_subparsers(help='Sub-commands')
@@ -162,24 +164,25 @@ class Bot(bottom.Client):
         self.send ('PRIVMSG', target=target, message='{}: {} has been queued as {} with {}'.format (
                 nick, args.url, j.id, strargs))
 
-        j.process = await asyncio.create_subprocess_exec (*cmdline, stdout=asyncio.subprocess.PIPE,
-                stderr=asyncio.subprocess.DEVNULL, stdin=asyncio.subprocess.DEVNULL)
-        while True:
-            data = await j.process.stdout.readline ()
-            if not data:
-                break
-
-            # job is marked running after the first message is received from it
-            if j.status == Status.pending:
-                j.status = Status.running
-
-            data = json.loads (data)
-            msgid = data.get ('uuid')
-            if msgid == '24d92d16-770e-4088-b769-4020e127a7ff':
-                j.stats = data
-            elif msgid == '5b8498e4-868d-413c-a67e-004516b8452c':
-                j.rstats = data
-        code = await j.process.wait ()
+        async with self.processLimit:
+            j.process = await asyncio.create_subprocess_exec (*cmdline, stdout=asyncio.subprocess.PIPE,
+                    stderr=asyncio.subprocess.DEVNULL, stdin=asyncio.subprocess.DEVNULL)
+            while True:
+                data = await j.process.stdout.readline ()
+                if not data:
+                    break
+
+                # job is marked running after the first message is received from it
+                if j.status == Status.pending:
+                    j.status = Status.running
+
+                data = json.loads (data)
+                msgid = data.get ('uuid')
+                if msgid == '24d92d16-770e-4088-b769-4020e127a7ff':
+                    j.stats = data
+                elif msgid == '5b8498e4-868d-413c-a67e-004516b8452c':
+                    j.rstats = data
+            code = await j.process.wait ()
 
         if j.status == Status.running:
             j.status = Status.finished