1 files changed, 76 insertions, 0 deletions
diff --git a/glances/plugins/containers/stats_streamer.py b/glances/plugins/containers/stats_streamer.py
new file mode 100644
index 00000000..0bf7d38e
--- /dev/null
+++ b/glances/plugins/containers/stats_streamer.py
@@ -0,0 +1,76 @@
+import threading
+import time
+
+from glances.logger import logger
+
+
+class StatsStreamer:
+    """
+    Utility class to stream an iterable using a background / daemon Thread
+
+    Use `StatsStreamer.stats` to access the latest streamed results
+    """
+
+    def __init__(self, iterable, initial_stream_value=None):
+        """
+        iterable: an Iterable instance that needs to be streamed
+        """
+        self._iterable = iterable
+        # Iterable results are stored here
+        self._raw_result = initial_stream_value
+        # Use a Thread to stream iterable (daemon=True to automatically kill thread when main process dies)
+        self._thread = threading.Thread(target=self._stream_results, daemon=True)
+        # Event needed to stop the thread manually
+        self._stopper = threading.Event()
+        # Lock to avoid the daemon thread updating stats when main thread reads the stats
+        self.result_lock = threading.Lock()
+        # Last result streamed time (initial val 0)
+        self._last_update_time = 0
+
+        self._thread.start()
+
+    def stop(self):
+        """Stop the thread."""
+        self._stopper.set()
+
+    def stopped(self):
+        """Return True is the thread is stopped."""
+        return self._stopper.is_set()
+
+    def _stream_results(self):
+        """Grab the stats.
+
+        Infinite loop, should be stopped by calling the stop() method
+        """
+        try:
+            for res in self._iterable:
+                self._pre_update_hook()
+                self._raw_result = res
+                self._post_update_hook()
+
+                time.sleep(0.1)
+                if self.stopped():
+                    break
+
+        except Exception as e:
+            logger.debug("docker plugin - Exception thrown during run ({})".format(e))
+            self.stop()
+
+    def _pre_update_hook(self):
+        """Hook that runs before worker thread updates the raw_stats"""
+        self.result_lock.acquire()
+
+    def _post_update_hook(self):
+        """Hook that runs after worker thread updates the raw_stats"""
+        self._last_update_time = time.time()
+        self.result_lock.release()
+
+    @property
+    def stats(self):
+        """Raw Stats getter."""
+        return self._raw_result
+
+    @property
+    def last_update_time(self):
+        """Raw Stats getter."""
+        return self._last_update_time