Add SIGTERM handling to geographic gatherer

pytroll_collectors/geographic_gatherer.py

@@ -25,6 +25,7 @@
 """Geographic segment gathering."""
 
 import logging
+import signal
 import time
 
 from configparser import NoOptionError, ConfigParser
@@ -56,6 +57,8 @@ def __init__(self, opts):
         self.triggers = []
         self.return_status = 0
 
+        self._sigterm_caught = False
+
         self._clean_config()
         self._setup_publisher()
         try:
@@ -103,8 +106,9 @@ def _setup_triggers(self):
 
     def run(self):
         """Run granule triggers."""
+        signal.signal(signal.SIGTERM, self._handle_sigterm)
         try:
-            while True:
+            while self._keep_running():
                 time.sleep(1)
                 for trigger in self.triggers:
                     if not trigger.is_alive():
@@ -119,9 +123,26 @@ def run(self):
 
         return self.return_status
 
+    def _handle_sigterm(self, signum, frame):
+        logger.info("Caught SIGTERM, shutting down when all collections are finished.")
+        self._sigterm_caught = True
+
+    def _keep_running(self):
+        keep_running = True
+        if self._sigterm_caught:
+            keep_running = self._trigger_collectors_have_granules()
+        return keep_running
+
+    def _trigger_collectors_have_granules(self):
+        for t in self.triggers:
+            for c in t.collectors:
+                if c.granules:
+                    return True
+        return False
+
     def stop(self):
         """Stop the gatherer."""
-        logger.info('Ending publication the gathering of granules...')
+        logger.info('Ending the gathering of granules...')
         for trigger in self.triggers:
             trigger.stop()
         self.publisher.stop()

pytroll_collectors/tests/test_geographic_gatherer.py

@@ -527,3 +527,89 @@
             assert snd_msg.data == expected_msg.data
         finally:
             gatherer.stop()
+
+
+def test_sigterm(tmp_config_file, tmp_config_parser):
+    """Test that SIGTERM signal is handled."""
+    import os
+    import signal
+    import time
+    from multiprocessing import Process
+
+    from pytroll_collectors.geographic_gatherer import GeographicGatherer
+
+    with open(tmp_config_file, mode="w") as fp:
+        tmp_config_parser.write(fp)
+
+    opts = arg_parse(["-c", "minimal_config", "-p", "40000", "-n", "false", "-i", "localhost:12345",
+                     str(tmp_config_file)])
+    # We don't need the triggers here. They also interfere with completing the test (the test never exits)
+    with patch("pytroll_collectors.geographic_gatherer.TriggerFactory.create"):
+        gatherer = GeographicGatherer(opts)
+    proc = Process(target=gatherer.run)
+    proc.start()
+    time.sleep(1)
+    os.kill(proc.pid, signal.SIGTERM)
+    proc.join()
+
+    assert proc.exitcode == 0
+
+
+def test_sigterm_with_collection(tmp_config_file, tmp_config_parser):
+    """Test that SIGTERM signal is handled when there is collection ongoing."""
+    import os
+    import signal
+    import time
+    from multiprocessing import Process
+
+    from pytroll_collectors.geographic_gatherer import GeographicGatherer
+
+    with open(tmp_config_file, mode="w") as fp:
+        tmp_config_parser.write(fp)
+
+    opts = arg_parse(["-c", "posttroll_section", "-p", "40000", "-n", "false", "-i", "localhost:12345",
+                     str(tmp_config_file)])
+    # Use a fake trigger that initially sets some granules and after a while clears them
+    with patch("pytroll_collectors.geographic_gatherer.PostTrollTrigger",
+               new=FakeTriggerWithGranules):
+        gatherer = GeographicGatherer(opts)
+    proc = Process(target=gatherer.run)
+    proc.start()
+    time.sleep(1)
+    os.kill(proc.pid, signal.SIGTERM)
+    proc.join()
+
+    assert proc.exitcode == 0
+
+
+class FakeTriggerWithGranules:
+    """Fake trigger class used in testing SIGTERM handling.
+
+    At creation, adds "foo" to collector granules. When is_alive() is called the second time, it clears the granules.
+    """
+
+    def __init__(self, collectors, *args, **kwargs):
+        """Initialize the trigger class."""
+        self.collectors = collectors
+        for col in self.collectors:
+            col.granules.append("foo")
+        self._args = args
+        self._kwargs = kwargs
+        self._counter = 0
+
+    def is_alive(self):
+        """Return True for alive thread."""
+        if self._counter > 0:
+            # On the second call clear the granules
+            for col in self.collectors:
+                col.granules = []
+        self._counter += 1
+        return True
+
+    def start(self):
+        """Start the trigger."""
+        pass
+
+    def stop(self):
+        """Stop the trigger."""
+        pass