From 7bd5b53686e103e9219ddc81fd870d2d8d8fa074 Mon Sep 17 00:00:00 2001
From: Bruce Duncan <bwduncan@gmail.com>
Date: Sun, 19 Feb 2023 21:10:46 +0000
Subject: [PATCH 1/2] Add a property for the config filename

---
 src/emonhub_setup.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/emonhub_setup.py b/src/emonhub_setup.py
index 05467538..fae4d9c8 100644
--- a/src/emonhub_setup.py
+++ b/src/emonhub_setup.py
@@ -96,6 +96,10 @@ def __init__(self, filename):
             raise EmonHubSetupInitError(
                 'Configuration file error - section: ' + str(e))
 
+    @property
+    def filename(self):
+        return self._filename
+
     def check_settings(self):
         """Check settings
 

From 78a069ba54a45a21793ebaa06504dd840fad4195 Mon Sep 17 00:00:00 2001
From: Bruce Duncan <bwduncan@gmail.com>
Date: Sun, 19 Feb 2023 21:17:06 +0000
Subject: [PATCH 2/2] Use inotify for config file changes

Instead of polling and reparsing the config file every 0.2s, use inotify
to reparse only when the file is written to, moved into place, or
symlinked.

Signed-off-by: Bruce Duncan <bwduncan@gmail.com>
---
 src/emonhub.py | 34 ++++++++++++++++++++++++++++------
 1 file changed, 28 insertions(+), 6 deletions(-)

diff --git a/src/emonhub.py b/src/emonhub.py
index e9a5e1fa..e9b3797e 100755
--- a/src/emonhub.py
+++ b/src/emonhub.py
@@ -19,8 +19,10 @@
 import pprint
 import glob
 import os
+import os.path
 import getpass
 from collections import defaultdict
+import inotify.adapters
 
 import emonhub_setup as ehs
 import emonhub_coder as ehc
@@ -108,13 +110,36 @@ def run(self):
         # Initialise thread restart counters
         restart_count = defaultdict(int)
 
+        # Watch for config file changes
+        inotify_setup = inotify.adapters.Inotify()
+        inotify_setup.add_watch(os.path.dirname(self._setup.filename))
+        # config file could be a symlink, so watch that for writes too
+        inotify_setup.add_watch(os.path.realpath(self._setup.filename))
+
         # Until asked to stop
         while not self._exit:
 
             # Run setup and update settings if modified
-            self._setup.run()
-            if self._setup.check_settings():
-                self._update_settings(self._setup.settings)
+            events = list(inotify_setup.event_gen(yield_nones=False, timeout_s=0.2))
+            for (_, type_names, path, filename) in events:
+                self._log.debug('type_names=%s filename=%s', type_names, filename)
+                # If a symlink is created we have to watch that too
+                if 'IN_CREATE' in type_names:
+                    try:
+                        target = os.readlink(os.path.join(path, filename))
+                        inotify_setup.add_watch(target)
+                    except OSError:
+                        pass
+
+                # We'll reload for any file changes in this directory. There is probably only one anyway.
+                if 'IN_CLOSE_WRITE' not in type_names and 'IN_MOVED_TO' not in type_names and 'IN_CREATE' not in type_names:
+                    continue
+
+                self._log.info('Reloading setup because type_names=%s for filename=%s', type_names, filename)
+                self._setup.run()
+                if self._setup.check_settings():
+                    self._update_settings(self._setup.settings)
+                self._log.info('Reload complete')
 
             # Auto conf populate nodelist 
             if eha.auto_conf_enabled and ehc.nodelist != self._setup.settings['nodes']:
@@ -158,9 +183,6 @@ def run(self):
                 restart_count[name] += 1
                 self._update_settings(self._setup.settings)
 
-            # Sleep until next iteration
-            time.sleep(0.2)
-
     def close(self):
         """Close hub. Do some cleanup before leaving."""