Special actions after machine is stopped by the user

#!/usr/bin/python
# ----------------------------------------------------------------------
#  HAL USERSPACE COMPONENT GO_TO_PURGE
#
#
# ----------------------------------------------------------------------

"""
requires: sys, linuxcnc, hal, time, os

If the input pin "gotopurge" is trigerred :

The script shall:
	- stop Gcode execution
	- save the current:
			- program line number : 
				* motion.program-line
			- head position
			- motion status:
				* motion.in-position
				* motion.distance-to-go
			- ...
	- switch to MDI mode
	- move the head to the purge point
	- activate purging signal pin (custom M112 command)
	- copy the Gcode File
	- clean it to the point we are
	- load it in EMC waiting operator to relaunch it

"""


import sys
import linuxcnc
import hal
import time
import os

dumpfilename = "DUMPFILE.txt"
go2purgeSequence = ["G0 Z4000.0 F10000", "G0 X2000.0 Y2000.0", "G0 Z200.0", "M112"]

#                 HAL US COMPONENT INSTANCIATION
myComponent = hal.component("gotopurge")
myComponent.newpin("purge", hal.HAL_BIT, hal.HAL_IN)



#                 STATUS CHANNEL INSTANCIATION
try:
	status = linuxcnc.stat() # create a connection to the status channel
	status.poll() # get current values
except linuxcnc.error, detail:
	print "\nBDE ERROR : in stop_to_purge.py status: ", detail
	sys.exit(1)

#                 COMMAND CHANNEL INSTANCIATION
try:
	command = linuxcnc.command() # create a connection to the command channel

except linuxcnc.error, detail:
	print "\nBDE ERROR : in stop_to_purge.py command: ", detail
	sys.exit(1)


myComponent.ready()






# ######################################################################
#                     UTILITY FUNCTIONS
# ######################################################################

# ----------------------------------------------------------------------
#  Switching to mdi mode, going to purge_point
# ----------------------------------------------------------------------
def go_to_purge(go2purgeSequence):
	if isReady_for_mdi:
		command.mode(linuxcnc.MODE_MDI) # going to MDI mode
		command.wait_complete()         # waits until mode has changed
		time.sleep(0.1)
		print " Going to MDI mode"
		for cmd in go2purgeSequence :
			command.mdi(cmd)   			# sending Gcode to move to purge
			command.wait_complete() 
		print "\nBDE INFO : stop_to_purge.py : Purging Started ...\nPlease stop it when OK...\n"
	else:
		print "\nBDE WARNING : stop_to_purge.py : Machine not ready to go in MDI mode - aborting\n"

   
# ----------------------------------------------------------------------
#  Recovering usefull status information
# ----------------------------------------------------------------------
def grab_status():
	statdict = {}
	status.poll()

	statdict["current_pos"] = status.actual_position
	statdict["traj_position"] = status.position

	statdict["disp_dtg"] = status.distance_to_go
	statdict["xyz_dtg"] = status.dtg

	statdict["actual_jpos"] = status.joint_actual_position
	statdict["desired_jpos"] = status.joint_position

	statdict["current_file"] = status.file
	statdict["current_line"] = status.current_line
	statdict["motion_line"] = status.motion_line
	statdict["read_line"] = status.read_line

	print "\n\nBDE stop_to_purge.py : STATUS IS :"
	for key in statdict:
		print "	", key, " --> ", statdict[key]

	# Dump status to a file :
	f = open(dumpfilename, "a")
	f.write("\n###################################################\n")
	for key in statdict:
		f.write( str(key)+ " = " + str(statdict[key]) +"\n")

	f.write("\n")
	f.close()

	return statdict

# ----------------------------------------------------------------------
#  Is machine state OK to send MDI Commands ?
# ----------------------------------------------------------------------
def isReady_for_mdi():
	status.poll()
	estopOK = not status.estop
	enableOK = status.enabled
	homedOK = status.homed
	idleOK = (status.interp_state == linuxcnc.INTERP_IDLE)
	isReady = estopOK and enableOK and homedOK and idleOK
	return isReady

# ----------------------------------------------------------------------
#  Update a copy of Gcode file to be able to restart
# ----------------------------------------------------------------------
def update_Gcode_file(statdict):
	removeItems = ["g0", "g0 ","g00", "g00 ", "g1", "g1 ", "g01", "g01 "]

	filepath = statdict["current_file"]
	path, filename = os.path.split(filepath)
	basename, ext = filename.split(".")
	if "_STOP_" in basename:
		basenameroot, laststop_number = basename.split("_STOP_")
	else:
		basenameroot = basename
		laststop_number = "0"

	newstop_number = int(laststop_number) + 1
	newfileName = basename + "_STOP_" + str(newstop_number)+"."+ ext
	newfilePath = path + "/" + newfileName
	print "\nNew File Path is : " , newfilePath

	original_file = open(filepath , "r").readlines()
	new_file = open(newfilePath , "w")
	# It seems that "motion line" is the only relevant for restarting
	ml = statdict["motion_line"]
	print "\n motion stopped at line = ", ml 

	# Write relevant Gcode lines from the old file to the new one
        # Note : this only removes all moves before the stop; it should be modified for robustness to cope with modal command which
        # should not be ignored
	new_file.write("; File created for restart from unattended stop : "+ newfilePath)
	for iline, line in enumerate(original_file):
		if iline < ml: # If the line is in the already fabricated part
			# If we do not have any G1 , G01 , G0 , G00 
			OK = True
			#print iline, " --> " , line
			for cmd in ["G0 " , "G00 " , "G1 ", "G01 ", "g0 " , "g00 " , "g1 ", "g01 "]:
				if cmd in line:
					#print "cmd found in :" , cmd
					OK = OK & False
			if OK:
				new_file.write(line)
		else:
			new_file.write(line)
	new_file.close()
	print "\nBDE INFO: gotopurge : new Gcode file saved in :\n", "		-->", newfilePath

	# Resets the current file and load the new one
	command.wait_complete()
	command.reset_interpreter()
	command.wait_complete()
	command.program_open(newfilePath)
	command.wait_complete()
	print "\nBDE INFO: new Gcode file \n(", newfilePath , ")\nloaded..."

# ######################################################################
#                     MAIN LOOP 
#      (should be at the end for the interpreter to read all...)
# ######################################################################
def doActions():
	print "\n\nBDE stop_to_purge.py aborting motion..."
	# Stop motion
	command.abort()
	# Get current status
	statdict = grab_status()
	# Go to PP and start purging
	go_to_purge(go2purgeSequence)
	# Modify Gcode file and loads it
	update_Gcode_file(statdict)

lastState = False
try:
	while 1:
		time.sleep(0.1)
		if (myComponent["purge"] == True and lastState == False):
			lastState = True
			doActions()

except KeyboardInterrupt:
    raise SystemExit