Add a python library for halrun

[hdiethelm]

Many python tools use either subprocess.Popen(["halrun", "-Is", "raster.hal"], stdin=subprocess.PIPE) / os.popen("halrun -Is > /dev/null", "w"), os.spawnvp(os.P_WAIT, "halcmd", ["halcmd", "-f", "touchy.hal"]) or something similar to do hal commands.

All these variants are somewhat non-deterministic. You don't really know when your command will be executed and error handling is not easy.

Some grep'ing:

tests/raster/test:        halrun = subprocess.Popen(["halrun", "-Is", "raster.hal"], stdin=subprocess.PIPE)
src/emc/usr_intf/stepconf/stepconf.py:        self.halrun = halrun = os.popen("halrun -Is", "w")
src/emc/usr_intf/stepconf/stepconf.py:        self.halrun = halrun = os.popen("halrun -Is", "w")
src/emc/usr_intf/pncconf/pncconf.py:            halrun = os.popen("halrun -Is > /dev/null", "w")
src/emc/usr_intf/pncconf/pncconf.py:        halrun = subprocess.Popen("halrun -I", shell=True,stdin=subprocess.PIPE,stdout=subprocess.PIPE, encoding='utf-8' )
src/emc/usr_intf/pncconf/tests.py:        halrun = os.popen("halrun -Is > /dev/null", "w")
src/emc/usr_intf/pncconf/tests.py:        self.halrun = halrun = os.popen("halrun -Is > /dev/null", "w")
src/emc/usr_intf/pncconf/tests.py:        self.halrun = halrun = os.popen("halrun -Is > /dev/null", "w")
src/emc/usr_intf/pncconf/tests.py:        self.halrun = os.popen("halrun -Is > /dev/null", "w")
src/emc/usr_intf/pncconf/tests.py:            a = os.popen("halrun -U > /dev/null", "w")
src/emc/usr_intf/pncconf/tests.py:            a = os.popen("halrun -U > /dev/null", "w")
...
src/hal/user_comps/gladevcp.py:            
            cmd = ["haltcl", opts.halfile]
        else:
            cmd = ["halcmd", "-f", opts.halfile] 
        res = subprocess.call(cmd, stdout=sys.stdout, stderr=sys.stderr)

src/emc/usr_intf/gscreen/gscreen.py:                res = os.spawnvp(os.P_WAIT, "halcmd", ["halcmd", "-i", inifile, "-f", f])
src/emc/usr_intf/touchy/touchy.py:            res = os.spawnvp(os.P_WAIT, "halcmd", ["halcmd", "-f", "touchy.hal"])
src/emc/usr_intf/touchy/touchy.py:                    res = os.spawnvp(os.P_WAIT, "halcmd", ["halcmd", "-i", inifile, "-f", f])
src/emc/usr_intf/axis/scripts/axis.py:        cmd = "halcmd loadusr -Wn {0} gladevcp -c {0}".format(gladename).split()
src/emc/usr_intf/axis/scripts/axis.py:                    res = os.spawnvp(os.P_WAIT, "halcmd", ["halcmd", "-i", vars.emcini.get(), "-f", f])
src/emc/usr_intf/axis/scripts/axis.py:                res = os.spawnvp(os.P_WAIT, "halcmd", ["halcmd"] + f.split())
src/emc/usr_intf/mdro/mdro.py:                halcmd_args = ["halcmd", "-V", "-i", args.ini, "-f", f]
src/emc/usr_intf/mdro/mdro.py:                print("halcmd", halcmd_args)
src/emc/usr_intf/mdro/mdro.py:                halcmd_args = ["halcmd", "-i", args.ini, "-f", f]
src/emc/usr_intf/mdro/mdro.py:        res = os.spawnvp(os.P_WAIT, "halcmd", halcmd_args)
src/emc/usr_intf/gmoccapy/gmoccapy.py:                res = os.spawnvp(os.P_WAIT, "halcmd", ["halcmd", "-i", inifile, "-f", f])
src/emc/usr_intf/gmoccapy/gmoccapy.py:                res = os.spawnvp(os.P_WAIT, "halcmd", ["halcmd"] + f.split())
src/emc/usr_intf/qtvcp/qtvcp.py:                cmd = ["halcmd", "-f", opts.halfile]
src/emc/usr_intf/qtvcp/qtvcp.py:                    res = os.spawnvp(os.P_WAIT, "halcmd", ["halcmd", "-i",self.inipath,"-f", f])
src/emc/usr_intf/qtvcp/qtvcp.py:                res = os.spawnvp(os.P_WAIT, "halcmd", ["halcmd"] + f.split())
...

Using something like:

run=hal.halrun()
[ret, out] = run.load(`raster.hal')
[ret, out] = run.cmd('show')
run.exit()

would look much nicer and also be deterministic.

Just an idea for now to park here. Nothing urgent.

[BsAtHome]

You don't need to invoke external programs when there is a module that can do it for you.

It would make sense to move quite a bit, if not most, of halcmd into a library because multiple programs already need its functionality. Then you make a python wrapper on top of that library. I already did that with the many of the hal library interactions, which is why I could make halquery in just about no time.

There are some more complex operations and interactions in both halcmd and halrun that need to be looked at how they can be wrapped logically and efficiently.