fix cpu_count is NOT correct under container environment! omnilib#110

aiomultiprocess/pool.py

@@ -163,7 +163,7 @@ def __init__(
         self.context = get_context()
 
         self.scheduler = scheduler or RoundRobin()
-        self.process_count = max(1, processes or os.cpu_count() or 2)
+        self.process_count = max(1, processes or self._cpu_count() or 2)
         self.queue_count = max(1, queuecount or 1)
 
         if self.queue_count > self.process_count:
@@ -214,6 +214,39 @@ def init(self) -> None:
             self.processes[self.create_worker(qid)] = qid
             self.scheduler.register_process(qid)
 
+    def _cpu_count(self):
+
+        """get the real cpu count considering container environment"""
+
+        def get_cpu_use_cgroup(cgroup_file_dir):
+            """use cgroup"""
+            with open(cgroup_file_dir + '/cpu/cpu.cfs_quota_us') as f:
+                use_cpu_time = int(f.read())
+            if use_cpu_time == -1:
+                core_num = os.cpu_count()
+            else:
+                with open(cgroup_file_dir + '/cpu/cpu.cfs_period_us') as file:
+                    per_cpu_time = int(file.read())
+                core_num = use_cpu_time / per_cpu_time
+            return round(core_num)
+
+        def get_cpu_use_os():
+            """use os.cpu_count"""
+            return os.cpu_count()
+
+        cgroup_file_dir = '/sys/fs/cgroup'
+        docker_judge = '/.dockerenv'
+        if os.path.exists(docker_judge) and os.path.exists(cgroup_file_dir):
+            # under container environment
+            try:
+                core_num = get_cpu_use_cgroup(cgroup_file_dir)
+            except Exception:
+                core_num = get_cpu_use_os()
+        else:
+            core_num = get_cpu_use_os()
+
+        return core_num
+
     async def loop(self) -> None:
         """
         Maintain the pool of workers while open.