toolhead: Report the current extruder from the get_status() method

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

docs/Command_Templates.md

@@ -142,8 +142,9 @@ The following are common printer attributes:
 - `printer["gcode_macro <macro_name>"].<variable>`: The current value
   of a gcode_macro variable.
 - `printer.<heater>.temperature`: The last reported temperature (in
-  Celsius as a float) for the given heater. Available heaters are:
-  `heater_bed` and `heater_generic <config_name>`.
+  Celsius as a float) for the given heater. Example heaters are:
+  `extruder`, `extruder1`, `heater_bed`, `heater_generic
+  <config_name>`.
 - `printer.<heater>.target`: The current target temperature (in
   Celsius as a float) for the given heater.
 - `printer.pause_resume.is_paused`: Returns true if a PAUSE command
@@ -152,6 +153,10 @@ The following are common printer attributes:
   toolhead relative to the coordinate system specified in the config
   file. It is possible to access the x, y, z, and e components of this
   position (eg, `printer.toolhead.position.x`).
+- `printer.toolhead.extruder`: The name of the currently active
+  extruder. For example, one could use
+  `printer[printer.toolhead.extruder].target` to get the target
+  temperature of the current extruder.
 
 The above list is subject to change - if using an attribute be sure to
 review the [Config Changes document](Config_Changes.md) when upgrading

klippy/kinematics/extruder.py

@@ -93,6 +93,8 @@ class PrinterExtruder:
         return dict(self.get_heater().get_status(eventtime),
                     pressure_advance=self.pressure_advance,
                     smooth_time=self.pressure_advance_smooth_time)
+    def get_name(self):
+        return self.name
     def get_heater(self):
         return self.heater
     def set_active(self, print_time, is_active):
@@ -181,6 +183,8 @@ class DummyExtruder:
             move.end_pos, "Extrude when no extruder present")
     def calc_junction(self, prev_move, move):
         return move.max_cruise_v2
+    def get_name(self):
+        return ""
     def get_heater(self):
         raise homing.CommandError("Extruder not configured")
 

klippy/toolhead.py

@@ -484,6 +484,7 @@ class ToolHead:
             status = "Ready"
         return { 'status': status, 'print_time': print_time,
                  'estimated_print_time': estimated_print_time,
+                 'extruder': self.extruder.get_name(),
                  'position': homing.Coord(*self.commanded_pos),
                  'printing_time': print_time - last_print_start_time }
     def _handle_shutdown(self):