gcode_button: Execute gcode when a button is pressed or released (#1745)

An extra to execute gcode when a hardware button is pressed or released. Uses the jinja2 templating system.

Inspired by pull request #545 from Miguel Moitinho miguel@moitinho.net and pull request #1098 from Paulo Drugos paulodrugos@gmail.com

Signed-off-by: Alec Plumb <alec@etherwalker.com>

2 files changed, 76 insertions, 0 deletions

diff --git a/config/example-extras.cfg b/config/example-extras.cfg
index a17d10db..ebe3b921 100644
--- a/config/example-extras.cfg
+++ b/config/example-extras.cfg
@@ -1618,3 +1618,18 @@
 # Replicape support - see the generic-replicape.cfg file for further
 # details.
 #[replicape]
+
+
+# Execute gcode when a button is pressed or released (or when a pin changes
+# state). You can check the state of the button my using
+# QUERY_BUTTON button=my_gcode_button
+#[gcode_button my_gcode_button]
+#pin:
+#   The pin on which the button is connected. This parameter must be
+#   provided.
+#press_gcode:
+#   A list of G-Code commands to execute when the button is pressed.
+#   G-Code templates are supported.
+#release_gcode:
+#   A list of G-Code commands to execute when the button is released.
+#   G-Code templates are supported.
diff --git a/klippy/extras/gcode_button.py b/klippy/extras/gcode_button.py
new file mode 100644
index 00000000..f6ec5870
--- /dev/null
+++ b/klippy/extras/gcode_button.py
@@ -0,0 +1,61 @@
+# Support for executing gcode when a hardware button is pressed or released.
+#
+# Copyright (C) 2019 Alec Plumb <alec@etherwalker.com>
+#
+# This file may be distributed under the terms of the GNU GPLv3 license.
+import logging
+
+class GCodeButton:
+    def __init__(self, config):
+        self.printer = config.get_printer()
+        self.name = config.get_name().split(' ')[-1]
+        self.pin = config.get('pin')
+        self.last_state = 0
+        self.template_queue = []
+        buttons = self.printer.try_load_module(config, "buttons")
+        buttons.register_buttons([self.pin], self.button_callback)
+        gcode_macro = self.printer.try_load_module(config, 'gcode_macro')
+        self.press_template = gcode_macro.load_template(config, 'press_gcode')
+        self.release_template = gcode_macro.load_template(
+                                        config, 'release_gcode')
+        self.gcode = self.printer.lookup_object('gcode')
+        self.gcode.register_mux_command("QUERY_BUTTON", "BUTTON", self.name,
+                                        self.cmd_QUERY_BUTTON,
+                                        desc=self.cmd_QUERY_BUTTON_help)
+
+    cmd_QUERY_BUTTON_help = "Report on the state of a button"
+
+    def cmd_QUERY_BUTTON(self, params):
+        self.gcode.respond(self.name + ": " + self.get_status()['state'])
+
+    def button_callback(self, eventtime, state):
+        self.last_state = state
+        if state and bool(self.press_template):
+           self.queue_template(self.press_template)
+        if (not state) and bool(self.release_template):
+           self.queue_template(self.release_template)
+
+    def get_status(self, eventtime=None):
+        if self.last_state:
+            return {'state': "PRESSED"}
+        return {'state': "RELEASED"}
+
+    def queue_template(self, template):
+        if template is None:
+            return
+        if not self.template_queue:
+            reactor = self.printer.get_reactor()
+            reactor.register_callback(self.dispatch_templates)
+        self.template_queue.append(template)
+
+    def dispatch_templates(self, eventtime):
+        while self.template_queue:
+            template = self.template_queue[0]
+            try:
+                self.gcode.run_script(template.render())
+            except Exception:
+                logging.exception("Script running error")
+            self.template_queue.pop(0)
+
+def load_config_prefix(config):
+    return GCodeButton(config)