from __future__ import (
nested_scopes,
generators,
division,
absolute_import,
with_statement,
print_function,
unicode_literals,
)
import sys
from multiprocessing import cpu_count, Process, Queue
import time
from xml.etree.ElementTree import fromstring
from grass.exceptions import CalledModuleError, GrassError, ParameterError
from grass.script.core import Popen, PIPE, use_temp_region, del_temp_region
from grass.script.utils import encode, decode
from .docstring import docstring_property
from .parameter import Parameter
from .flag import Flag
from .typedict import TypeDict
from .read import GETFROMTAG, DOC
from .env import G_debug
if sys.version_info[0] == 2:
from itertools import izip_longest as zip_longest
else:
from itertools import zip_longest
unicode = str
def _get_bash(self, *args, **kargs):
return self.get_bash()
[docs]class ParallelModuleQueue(object):
"""This class is designed to run an arbitrary number of pygrass Module or MultiModule
processes in parallel.
Objects of type grass.pygrass.modules.Module or
grass.pygrass.modules.MultiModule can be put into the
queue using put() method. When the queue is full with the maximum
number of parallel processes it will wait for all processes to finish,
sets the stdout and stderr of the Module object and removes it
from the queue when its finished.
To finish the queue before the maximum number of parallel
processes was reached call wait() .
This class will raise a GrassError in case a Module process exits
with a return code other than 0.
Processes that were run asynchronously with the MultiModule class
will not raise a GrassError in case of failure. This must be manually checked
by accessing finished modules by calling get_finished_modules().
Usage:
Check with a queue size of 3 and 5 processes
>>> import copy
>>> from grass.pygrass.modules import Module, MultiModule, ParallelModuleQueue
>>> mapcalc_list = []
Setting run_ to False is important, otherwise a parallel processing is not possible
>>> mapcalc = Module("r.mapcalc", overwrite=True, run_=False)
>>> queue = ParallelModuleQueue(nprocs=3)
>>> for i in range(5):
... new_mapcalc = copy.deepcopy(mapcalc)
... mapcalc_list.append(new_mapcalc)
... m = new_mapcalc(expression="test_pygrass_%i = %i"%(i, i))
... queue.put(m)
>>> queue.wait()
>>> mapcalc_list = queue.get_finished_modules()
>>> queue.get_num_run_procs()
0
>>> queue.get_max_num_procs()
3
>>> for mapcalc in mapcalc_list:
... print(mapcalc.returncode)
0
0
0
0
0
Check with a queue size of 8 and 5 processes
>>> queue = ParallelModuleQueue(nprocs=8)
>>> mapcalc_list = []
>>> for i in range(5):
... new_mapcalc = copy.deepcopy(mapcalc)
... mapcalc_list.append(new_mapcalc)
... m = new_mapcalc(expression="test_pygrass_%i = %i"%(i, i))
... queue.put(m)
>>> queue.wait()
>>> mapcalc_list = queue.get_finished_modules()
>>> queue.get_num_run_procs()
0
>>> queue.get_max_num_procs()
8
>>> for mapcalc in mapcalc_list:
... print(mapcalc.returncode)
0
0
0
0
0
Check MultiModule approach with three by two processes running in a background process
>>> gregion = Module("g.region", flags="p", run_=False)
>>> queue = ParallelModuleQueue(nprocs=3)
>>> proc_list = []
>>> for i in range(3):
... new_gregion = copy.deepcopy(gregion)
... proc_list.append(new_gregion)
... new_mapcalc = copy.deepcopy(mapcalc)
... m = new_mapcalc(expression="test_pygrass_%i = %i"%(i, i))
... proc_list.append(new_mapcalc)
... mm = MultiModule(module_list=[new_gregion, new_mapcalc], sync=False, set_temp_region=True)
... queue.put(mm)
>>> queue.wait()
>>> proc_list = queue.get_finished_modules()
>>> queue.get_num_run_procs()
0
>>> queue.get_max_num_procs()
3
>>> for proc in proc_list:
... print(proc.returncode)
0
0
0
0
0
0
Check with a queue size of 8 and 4 processes
>>> queue = ParallelModuleQueue(nprocs=8)
>>> mapcalc_list = []
>>> new_mapcalc = copy.deepcopy(mapcalc)
>>> mapcalc_list.append(new_mapcalc)
>>> m = new_mapcalc(expression="test_pygrass_1 =1")
>>> queue.put(m)
>>> queue.get_num_run_procs()
1
>>> new_mapcalc = copy.deepcopy(mapcalc)
>>> mapcalc_list.append(new_mapcalc)
>>> m = new_mapcalc(expression="test_pygrass_2 =2")
>>> queue.put(m)
>>> queue.get_num_run_procs()
2
>>> new_mapcalc = copy.deepcopy(mapcalc)
>>> mapcalc_list.append(new_mapcalc)
>>> m = new_mapcalc(expression="test_pygrass_3 =3")
>>> queue.put(m)
>>> queue.get_num_run_procs()
3
>>> new_mapcalc = copy.deepcopy(mapcalc)
>>> mapcalc_list.append(new_mapcalc)
>>> m = new_mapcalc(expression="test_pygrass_4 =4")
>>> queue.put(m)
>>> queue.get_num_run_procs()
4
>>> queue.wait()
>>> mapcalc_list = queue.get_finished_modules()
>>> queue.get_num_run_procs()
0
>>> queue.get_max_num_procs()
8
>>> for mapcalc in mapcalc_list:
... print(mapcalc.returncode)
0
0
0
0
Check with a queue size of 3 and 4 processes
>>> queue = ParallelModuleQueue(nprocs=3)
>>> mapcalc_list = []
>>> new_mapcalc = copy.deepcopy(mapcalc)
>>> mapcalc_list.append(new_mapcalc)
>>> m = new_mapcalc(expression="test_pygrass_1 =1")
>>> queue.put(m)
>>> queue.get_num_run_procs()
1
>>> new_mapcalc = copy.deepcopy(mapcalc)
>>> mapcalc_list.append(new_mapcalc)
>>> m = new_mapcalc(expression="test_pygrass_2 =2")
>>> queue.put(m)
>>> queue.get_num_run_procs()
2
>>> new_mapcalc = copy.deepcopy(mapcalc)
>>> mapcalc_list.append(new_mapcalc)
>>> m = new_mapcalc(expression="test_pygrass_3 =3")
>>> queue.put(m) # Now it will wait until all procs finish and set the counter back to 0
>>> queue.get_num_run_procs()
0
>>> new_mapcalc = copy.deepcopy(mapcalc)
>>> mapcalc_list.append(new_mapcalc)
>>> m = new_mapcalc(expression="test_pygrass_%i = %i"%(i, i))
>>> queue.put(m)
>>> queue.get_num_run_procs()
1
>>> queue.wait()
>>> mapcalc_list = queue.get_finished_modules()
>>> queue.get_num_run_procs()
0
>>> queue.get_max_num_procs()
3
>>> for mapcalc in mapcalc_list:
... print(mapcalc.returncode)
0
0
0
0
"""
def __init__(self, nprocs=1):
"""Constructor
:param nprocs: The maximum number of Module processes that
can be run in parallel, default is 1, if None
then use all the available CPUs.
:type nprocs: int
"""
nprocs = int(nprocs) if nprocs else cpu_count()
self._num_procs = nprocs
self._list = nprocs * [None]
self._proc_count = 0
self._finished_modules = [] # Store all processed modules in a list
[docs] def put(self, module):
"""Put the next Module or MultiModule object in the queue
To run the Module objects in parallel the run\_ and finish\_ options
of the Module must be set to False.
:param module: a preconfigured Module or MultiModule object that were configured
with run\_ and finish\_ set to False,
:type module: Module or MultiModule object
"""
self._list[self._proc_count] = module
# Force that finish is False, otherwise the execution
# will not be parallel
self._list[self._proc_count].finish_ = False
self._list[self._proc_count].run()
self._proc_count += 1
if self._proc_count == self._num_procs:
self.wait()
[docs] def get(self, num):
"""Get a Module object or list of Module objects from the queue
:param num: the number of the object in queue
:type num: int
:returns: the Module object or list of Module objects or None if num is not in the queue
"""
if num < self._num_procs:
return self._list[num]
return None
[docs] def get_num_run_procs(self):
"""Get the number of Module processes that are in the queue running
or finished
:returns: the number fo Module processes running/finished in the queue
"""
return self._proc_count
[docs] def get_max_num_procs(self):
"""Return the maximum number of parallel Module processes
:returns: the maximum number of parallel Module processes
"""
return self._num_procs
[docs] def set_max_num_procs(self, nprocs):
"""Set the maximum number of Module processes that should run
in parallel
:param nprocs: The maximum number of Module processes that can be
run in parallel
:type nprocs: int
"""
self._num_procs = int(nprocs)
self.wait()
[docs] def get_finished_modules(self):
"""Return all finished processes that were run by this queue
:return: A list of Module objects
"""
return self._finished_modules
[docs] def wait(self):
"""Wait for all Module processes that are in the list to finish
and set the modules stdout and stderr output options
:return: A list of modules that were run
"""
for proc in self._list:
if proc:
if isinstance(proc, Module):
self._finished_modules.extend(
[
proc.wait(),
]
)
else:
self._finished_modules.extend(proc.wait())
self._list = self._num_procs * [None]
self._proc_count = 0
[docs]class Module(object):
"""This class is design to wrap/run/interact with the GRASS modules.
The class during the init phase read the XML description generate using
the ``--interface-description`` in order to understand which parameters
are required which optionals. ::
>>> from grass.pygrass.modules import Module
>>> from subprocess import PIPE
>>> import copy
>>> region = Module("g.region")
>>> region.flags.p = True # set flags
>>> region.flags.u = True
>>> region.flags["3"].value = True # set numeric flags
>>> region.get_bash()
'g.region -p -3 -u'
>>> new_region = copy.deepcopy(region)
>>> new_region.inputs.res = "10"
>>> new_region.get_bash()
'g.region res=10 -p -3 -u'
>>> neighbors = Module("r.neighbors")
>>> neighbors.inputs.input = "mapA"
>>> neighbors.outputs.output = "mapB"
>>> neighbors.inputs.size = 5
>>> neighbors.inputs.quantile = 0.5
>>> neighbors.get_bash()
'r.neighbors input=mapA size=5 method=average weighting_function=none quantile=0.5 nprocs=1 memory=300 output=mapB'
>>> new_neighbors1 = copy.deepcopy(neighbors)
>>> new_neighbors1.inputs.input = "mapD"
>>> new_neighbors1.inputs.size = 3
>>> new_neighbors1.inputs.quantile = 0.5
>>> new_neighbors1.get_bash()
'r.neighbors input=mapD size=3 method=average weighting_function=none quantile=0.5 nprocs=1 memory=300 output=mapB'
>>> new_neighbors2 = copy.deepcopy(neighbors)
>>> new_neighbors2(input="mapD", size=3, run_=False)
Module('r.neighbors')
>>> new_neighbors2.get_bash()
'r.neighbors input=mapD size=3 method=average weighting_function=none quantile=0.5 nprocs=1 memory=300 output=mapB'
>>> neighbors = Module("r.neighbors")
>>> neighbors.get_bash()
'r.neighbors size=3 method=average weighting_function=none nprocs=1 memory=300'
>>> new_neighbors3 = copy.deepcopy(neighbors)
>>> new_neighbors3(input="mapA", size=3, output="mapB", run_=False)
Module('r.neighbors')
>>> new_neighbors3.get_bash()
'r.neighbors input=mapA size=3 method=average weighting_function=none nprocs=1 memory=300 output=mapB'
>>> mapcalc = Module("r.mapcalc", expression="test_a = 1",
... overwrite=True, run_=False)
>>> mapcalc.run()
Module('r.mapcalc')
>>> mapcalc.returncode
0
>>> mapcalc = Module("r.mapcalc", expression="test_a = 1",
... overwrite=True, run_=False, finish_=False)
>>> mapcalc.run()
Module('r.mapcalc')
>>> p = mapcalc.wait()
>>> p.returncode
0
>>> mapcalc.run()
Module('r.mapcalc')
>>> p = mapcalc.wait()
>>> p.returncode
0
>>> colors = Module("r.colors", map="test_a", rules="-",
... run_=False, stdout_=PIPE,
... stderr_=PIPE, stdin_="1 red")
>>> colors.run()
Module('r.colors')
>>> p = mapcalc.wait()
>>> p.returncode
0
>>> colors.inputs["stdin"].value
'1 red'
>>> colors.outputs["stdout"].value
''
>>> colors.outputs["stderr"].value.strip()
"Color table for raster map <test_a> set to 'rules'"
>>> colors = Module("r.colors", map="test_a", rules="-",
... run_=False, finish_=False, stdin_=PIPE)
>>> colors.inputs["stdin"].value = "1 red"
>>> colors.run()
Module('r.colors')
>>> colors.wait()
Module('r.colors')
>>> colors.returncode
0
>>> colors = Module("r.colors", map="test_a", rules="-",
... run_=False, finish_=False,
... stdin_=PIPE, stderr_=PIPE)
>>> colors.inputs["stdin"].value = "1 red"
>>> colors.run()
Module('r.colors')
>>> colors.wait()
Module('r.colors')
>>> colors.outputs["stderr"].value.strip()
"Color table for raster map <test_a> set to 'rules'"
>>> colors.returncode
0
Run a second time
>>> colors.inputs["stdin"].value = "1 red"
>>> colors.run()
Module('r.colors')
>>> colors.wait()
Module('r.colors')
>>> colors.outputs["stderr"].value.strip()
"Color table for raster map <test_a> set to 'rules'"
>>> colors.returncode
0
Run many times and change parameters for each run
>>> colors = Module("r.colors", map="test_a", color="ryb", run_=False)
>>> colors.get_bash()
'r.colors map=test_a color=ryb offset=0.0 scale=1.0'
>>> colors.run()
Module('r.colors')
>>> colors.update(color="gyr")
>>> colors.run()
Module('r.colors')
>>> colors.update(color="ryg")
>>> colors.update(stderr_=PIPE)
>>> colors.run()
Module('r.colors')
>>> print(colors.outputs["stderr"].value.strip())
Color table for raster map <test_a> set to 'ryg'
>>> colors.update(color="byg")
>>> colors.update(stdout_=PIPE)
>>> colors.run()
Module('r.colors')
>>> print(colors.outputs["stderr"].value.strip())
Color table for raster map <test_a> set to 'byg'
>>> colors.get_bash()
'r.colors map=test_a color=byg offset=0.0 scale=1.0'
Often in the Module class you can find ``*args`` and ``kwargs`` annotation
in methods, like in the __call__ method.
Python allow developers to not specify all the arguments and
keyword arguments of a method or function. ::
def f(*args):
for arg in args:
print arg
therefore if we call the function like:
>>> f('grass', 'gis', 'modules') # doctest: +SKIP
grass
gis
modules
or we can define a new list:
>>> words = ['grass', 'gis', 'modules'] # doctest: +SKIP
>>> f(*words) # doctest: +SKIP
grass
gis
modules
we can do the same with keyword arguments, rewrite the above function: ::
def f(*args, **kargs):
for arg in args:
print arg
for key, value in kargs.items():
print "%s = %r" % (key, value)
now we can use the new function, with:
>>> f('grass', 'gis', 'modules', os = 'linux', language = 'python')
... # doctest: +SKIP
grass
gis
modules
os = 'linux'
language = 'python'
or, as before we can, define a dictionary and give the dictionary to
the function, like:
>>> keywords = {'os' : 'linux', 'language' : 'python'} # doctest: +SKIP
>>> f(*words, **keywords) # doctest: +SKIP
grass
gis
modules
os = 'linux'
language = 'python'
In the Module class we heavily use this language feature to pass arguments
and keyword arguments to the grass module.
"""
def __init__(self, cmd, *args, **kargs):
if isinstance(cmd, unicode):
self.name = str(cmd)
elif isinstance(cmd, str):
self.name = cmd
else:
raise GrassError("Problem initializing the module {s}".format(s=cmd))
try:
# call the command with --interface-description
get_cmd_xml = Popen([cmd, "--interface-description"], stdout=PIPE)
except OSError as e:
print("OSError error({0}): {1}".format(e.errno, e.strerror))
str_err = "Error running: `%s --interface-description`."
raise GrassError(str_err % self.name)
# get the xml of the module
self.xml = get_cmd_xml.communicate()[0]
# transform and parse the xml into an Element class:
# http://docs.python.org/library/xml.etree.elementtree.html
tree = fromstring(self.xml)
for e in tree:
if e.tag not in ("parameter", "flag"):
self.__setattr__(e.tag, GETFROMTAG[e.tag](e))
#
# extract parameters from the xml
#
self.params_list = [Parameter(p) for p in tree.findall("parameter")]
self.inputs = TypeDict(Parameter)
self.outputs = TypeDict(Parameter)
self.required = []
# Insert parameters into input/output and required
for par in self.params_list:
if par.input:
self.inputs[par.name] = par
else:
self.outputs[par.name] = par
if par.required:
self.required.append(par.name)
#
# extract flags from the xml
#
flags_list = [Flag(f) for f in tree.findall("flag")]
self.flags = TypeDict(Flag)
for flag in flags_list:
self.flags[flag.name] = flag
#
# Add new attributes to the class
#
self.run_ = True
self.finish_ = True
self.check_ = True
self.env_ = None
self.stdin_ = None
self.stdin = None
self.stdout_ = None
self.stderr_ = None
diz = {
"name": "stdin",
"required": False,
"multiple": False,
"type": "all",
"value": None,
}
self.inputs["stdin"] = Parameter(diz=diz)
diz["name"] = "stdout"
self.outputs["stdout"] = Parameter(diz=diz)
diz["name"] = "stderr"
self.outputs["stderr"] = Parameter(diz=diz)
self._popen = None
self.time = None
self.start_time = None # This variable will be set in the run() function
# This variable is set True if wait() was successfully called
self._finished = False
self.returncode = None
if args or kargs:
self.__call__(*args, **kargs)
self.__call__.__func__.__doc__ = self.__doc__
def __call__(self, *args, **kargs):
"""Set module parameters to the class and, if run_ is True execute the
module, therefore valid parameters are all the module parameters
plus some extra parameters that are: run_, stdin_, stdout_, stderr_,
env_ and finish_.
"""
if not args and not kargs:
self.run()
return self
self.update(*args, **kargs)
#
# check if execute
#
if self.run_:
#
# check reqire parameters
#
if self.check_:
self.check()
return self.run()
return self
[docs] def update(self, *args, **kargs):
"""Update module parameters and selected object attributes.
Valid parameters are all the module parameters
and additional parameters, namely: run_, stdin_, stdout_, stderr_,
env_, and finish_.
"""
#
# check for extra kargs, set attribute and remove from dictionary
#
if "flags" in kargs:
for flg in kargs["flags"]:
self.flags[flg].value = True
del kargs["flags"]
# set attributes
for key in ("run_", "env_", "finish_", "stdout_", "stderr_", "check_"):
if key in kargs:
setattr(self, key, kargs.pop(key))
# set inputs
for key in ("stdin_",):
if key in kargs:
self.inputs[key[:-1]].value = kargs.pop(key)
#
# set/update args
#
for param, arg in zip(self.params_list, args):
param.value = arg
for key, val in kargs.items():
key = key.strip("_")
if key in self.inputs:
self.inputs[key].value = val
elif key in self.outputs:
self.outputs[key].value = val
elif key in self.flags:
# we need to add this, because some parameters (overwrite,
# verbose and quiet) work like parameters
self.flags[key].value = val
else:
raise ParameterError("%s is not a valid parameter." % key)
[docs] def get_bash(self):
"""Return a BASH representation of the Module."""
return " ".join(self.make_cmd())
[docs] def get_python(self):
"""Return a Python representation of the Module."""
prefix = self.name.split(".")[0]
name = "_".join(self.name.split(".")[1:])
params = ", ".join(
[par.get_python() for par in self.params_list if par.get_python() != ""]
)
flags = "".join(
[
flg.get_python()
for flg in self.flags.values()
if not flg.special and flg.get_python() != ""
]
)
special = ", ".join(
[
flg.get_python()
for flg in self.flags.values()
if flg.special and flg.get_python() != ""
]
)
# pre name par flg special
if flags and special:
return "%s.%s(%s, flags=%r, %s)" % (prefix, name, params, flags, special)
elif flags:
return "%s.%s(%s, flags=%r)" % (prefix, name, params, flags)
elif special:
return "%s.%s(%s, %s)" % (prefix, name, params, special)
else:
return "%s.%s(%s)" % (prefix, name, params)
def __str__(self):
"""Return the command string that can be executed in a shell"""
return " ".join(self.make_cmd())
def __repr__(self):
return "Module(%r)" % self.name
@docstring_property(__doc__)
def __doc__(self):
"""{cmd_name}({cmd_params})"""
head = DOC["head"].format(
cmd_name=self.name,
# go to a new line
# give space under the function name
cmd_params=("\n" + (" " * (len(self.name) + 1))).join(
[
", ".join(
# transform each parameter in string
[str(param) for param in line if param is not None]
)
# make a list of parameters with only 3 param per line
for line in zip_longest(*[iter(self.params_list)] * 3)
]
),
)
params = "\n".join([par.__doc__ for par in self.params_list])
flags = self.flags.__doc__
return "\n".join([head, params, DOC["flag_head"], flags, DOC["foot"]])
[docs] def check(self):
"""Check the correctness of the provide parameters"""
required = True
for flg in self.flags.values():
if flg and flg.suppress_required:
required = False
if required:
for k in self.required:
if (k in self.inputs and self.inputs[k].value is None) or (
k in self.outputs and self.outputs[k].value is None
):
msg = "Required parameter <%s> not set."
raise ParameterError(msg % k)
[docs] def get_dict(self):
"""Return a dictionary that includes the name, all valid
inputs, outputs and flags
"""
dic = {}
dic["name"] = self.name
dic["inputs"] = [(k, v.value) for k, v in self.inputs.items() if v.value]
dic["outputs"] = [(k, v.value) for k, v in self.outputs.items() if v.value]
dic["flags"] = [flg for flg in self.flags if self.flags[flg].value]
return dic
[docs] def make_cmd(self):
"""Create the command string that can be executed in a shell
:returns: the command string
"""
skip = ["stdin", "stdout", "stderr"]
args = [
self.name,
]
for key in self.inputs:
if (
key not in skip
and self.inputs[key].value is not None
and self.inputs[key].value != ""
):
args.append(self.inputs[key].get_bash())
for key in self.outputs:
if (
key not in skip
and self.outputs[key].value is not None
and self.outputs[key].value != ""
):
args.append(self.outputs[key].get_bash())
for flg in self.flags:
if self.flags[flg].value:
args.append(str(self.flags[flg]))
return args
[docs] def run(self):
"""Run the module
This function will wait for the process to terminate in case
finish_==True and sets up stdout and stderr. If finish_==False this
function will return after starting the process. Use wait() to wait for
the started process
:return: A reference to this object
"""
G_debug(1, self.get_bash())
self._finished = False
if self.inputs["stdin"].value:
self.stdin = self.inputs["stdin"].value
self.stdin_ = PIPE
cmd = self.make_cmd()
self.start_time = time.time()
self._popen = Popen(
cmd,
stdin=self.stdin_,
stdout=self.stdout_,
stderr=self.stderr_,
env=self.env_,
)
if self.finish_ is True:
self.wait()
return self
[docs] def wait(self):
"""Wait for the module to finish. Call this method if
the run() call was performed with self.false_ = False.
:return: A reference to this object
"""
if self._finished is False:
if self.stdin:
self.stdin = encode(self.stdin)
stdout, stderr = self._popen.communicate(input=self.stdin)
self.outputs["stdout"].value = decode(stdout) if stdout else ""
self.outputs["stderr"].value = decode(stderr) if stderr else ""
self.time = time.time() - self.start_time
self.returncode = self._popen.returncode
self._finished = True
if self._popen.poll():
raise CalledModuleError(
returncode=self._popen.returncode,
code=self.get_bash(),
module=self.name,
errors=stderr,
)
self._popen = None
return self
[docs]class MultiModule(object):
"""This class is designed to run a list of modules in serial in the provided order
within a temporary region environment.
Module can be run in serial synchronously or asynchronously.
- Synchronously: When calling run() all modules will run in serial order
until they are finished, The run() method will return until all modules finished.
The modules objects can be accessed by calling get_modules() to check their return
values.
- Asynchronously: When calling run() all modules will run in serial order in a background process.
Method run() will return after starting the modules without waiting for them to finish.
The user must call the wait() method to wait for the modules to finish.
Asynchronously called module can be optionally run in a temporary region
environment, hence invokeing g.region will not alter the current
region or the region of other MultiModule runs.
Note:
Modules run in asynchronous mode can only be accessed via the wait() method.
The wait() method will return all finished module objects as list.
Objects of this class can be passed to the ParallelModuleQueue to run serial stacks
of modules in parallel. This is meaningful if region settings must be applied
to each parallel module run.
>>> from grass.pygrass.modules import Module
>>> from grass.pygrass.modules import MultiModule
>>> from multiprocessing import Process
>>> import copy
Synchronous module run
>>> region_1 = Module("g.region", run_=False)
>>> region_1.flags.p = True
>>> region_2 = copy.deepcopy(region_1)
>>> region_2.flags.p = True
>>> mm = MultiModule(module_list=[region_1, region_2])
>>> mm.run()
>>> m_list = mm.get_modules()
>>> m_list[0].returncode
0
>>> m_list[1].returncode
0
Asynchronous module run, setting finish = False
>>> region_1 = Module("g.region", run_=False)
>>> region_1.flags.p = True
>>> region_2 = copy.deepcopy(region_1)
>>> region_2.flags.p = True
>>> region_3 = copy.deepcopy(region_1)
>>> region_3.flags.p = True
>>> region_4 = copy.deepcopy(region_1)
>>> region_4.flags.p = True
>>> region_5 = copy.deepcopy(region_1)
>>> region_5.flags.p = True
>>> mm = MultiModule(module_list=[region_1, region_2, region_3, region_4, region_5],
... sync=False)
>>> t = mm.run()
>>> isinstance(t, Process)
True
>>> m_list = mm.wait()
>>> m_list[0].returncode
0
>>> m_list[1].returncode
0
>>> m_list[2].returncode
0
>>> m_list[3].returncode
0
>>> m_list[4].returncode
0
Asynchronous module run, setting finish = False and using temporary region
>>> mm = MultiModule(module_list=[region_1, region_2, region_3, region_4, region_5],
... sync=False, set_temp_region=True)
>>> str(mm)
'g.region -p ; g.region -p ; g.region -p ; g.region -p ; g.region -p'
>>> t = mm.run()
>>> isinstance(t, Process)
True
>>> m_list = mm.wait()
>>> m_list[0].returncode
0
>>> m_list[1].returncode
0
>>> m_list[2].returncode
0
>>> m_list[3].returncode
0
>>> m_list[4].returncode
0
"""
def __init__(self, module_list, sync=True, set_temp_region=False):
"""Constructor of the multi module class
:param module_list: A list of pre-configured Module objects that should be run
:param sync: If set True the run() method will wait for all processes to finish -> synchronously run.
If set False, the run() method will return after starting the processes -> asynchronously run.
The wait() method must be called to finish the modules.
:param set_temp_region: Set a temporary region in which the modules should be run, hence
region settings in the process list will not affect the current
computation region.
Note:
This flag is only available in asynchronous mode!
:return:
"""
self.module_list = module_list
self.set_temp_region = set_temp_region
self.finish_ = sync # We use the same variable name a Module
self.p = None
self.q = Queue()
def __str__(self):
"""Return the command string that can be executed in a shell"""
return " ; ".join(str(string) for string in self.module_list)
[docs] def get_modules(self):
"""Return the list of modules that have been run in synchronous mode
Note: Asynchronously run module can only be accessed via the wait() method.
:return: The list of modules
"""
return self.module_list
[docs] def run(self):
"""Start the modules in the list. If self.finished_ is set True
this method will return after all processes finished.
If self.finish_ is set False, this method will return
after the process list was started for execution.
In a background process, the processes in the list will
be run one after the another.
:return: None in case of self.finish_ is True,
otherwise a multiprocessing.Process object that invokes the modules
"""
if self.finish_ is True:
for module in self.module_list:
module.finish_ = True
module.run()
return None
else:
if self.set_temp_region is True:
self.p = Process(
target=run_modules_in_temp_region, args=[self.module_list, self.q]
)
else:
self.p = Process(target=run_modules, args=[self.module_list, self.q])
self.p.start()
return self.p
[docs] def wait(self):
"""Wait for all processes to finish. Call this method
in asynchronous mode, hence if finished was set False.
:return: The process list with finished processes to check their return states
"""
if self.p:
proc_list = self.q.get()
self.p.join()
return proc_list
[docs]def run_modules_in_temp_region(module_list, q):
"""Run the modules in a temporary region environment
This function is the argument for multiprocessing.Process class
in the MultiModule asynchronous execution.
:param module_list: The list of modules to run in serial
:param q: The process queue to put the finished process list
"""
use_temp_region()
try:
for proc in module_list:
proc.run()
proc.wait()
finally:
q.put(module_list)
del_temp_region()
[docs]def run_modules(module_list, q):
"""Run the modules
This function is the argument for multiprocessing.Process class
in the MultiModule asynchronous execution.
:param module_list: The list of modules to run in serial
:param q: The process queue to put the finished process list
"""
try:
for proc in module_list:
proc.run()
proc.wait()
finally:
q.put(module_list)
###############################################################################
if __name__ == "__main__":
import doctest
doctest.testmod()
