idle_timeout: let it be 0 (#165)

Author: rogerlz

README.md

@@ -76,6 +76,8 @@ If I want my printer to light itself on fire, I should be able to make my printe
 
 - [kinematics: independent X & Y acceleration and velocity settings](https://github.com/DangerKlippers/danger-klipper/pull/4)
 
+- [idle_timeout: allow the idle timeout to be disabled](https://github.com/DangerKlippers/danger-klipper/issues/165)
+
 - [canbus: custom CAN bus uuid hash for deterministic uuids](https://github.com/DangerKlippers/danger-klipper/pull/156)
 
 If you're feeling adventurous, take a peek at the extra features in the bleeding-edge branch [feature documentation](docs/Bleeding_Edge.md)

docs/Config_Reference.md

@@ -1649,7 +1649,8 @@ explicit idle_timeout config section to change the default settings.
 #   "TURN_OFF_HEATERS" and "M84".
 #timeout: 600
 #   Idle time (in seconds) to wait before running the above G-Code
-#   commands. The default is 600 seconds.
+#   commands. Set it to 0 to disable the timeout feature.
+#   The default is 600 seconds.
 ```
 
 ## Optional G-Code features

klippy/extras/idle_timeout.py

@@ -23,7 +23,7 @@ def __init__(self, config):
         self.gcode = self.printer.lookup_object("gcode")
         self.toolhead = self.timeout_timer = None
         self.printer.register_event_handler("klippy:ready", self.handle_ready)
-        self.idle_timeout = config.getfloat("timeout", 600.0, above=0.0)
+        self.idle_timeout = config.getfloat("timeout", 600.0, minval=0)
         gcode_macro = self.printer.load_object(config, "gcode_macro")
         self.idle_gcode = gcode_macro.load_template(
             config, "gcode", DEFAULT_IDLE_GCODE
@@ -64,6 +64,9 @@ def transition_idle_state(self, eventtime):
         return self.reactor.NEVER
 
     def check_idle_timeout(self, eventtime):
+        # timeout is disabled
+        if not self.idle_timeout > 0:
+            return eventtime + 60.0
         # Make sure toolhead class isn't busy
         print_time, est_print_time, lookahead_empty = self.toolhead.check_busy(
             eventtime