Files
bonobo/bonobo/commands/base.py
2018-08-11 15:29:53 +02:00

133 lines
4.0 KiB
Python

import argparse
import logging
import runpy
import sys
from contextlib import contextmanager
import bonobo.util.environ
from bonobo.util import get_name
from bonobo.util.environ import get_argument_parser, parse_args
from mondrian import humanizer
class BaseCommand:
"""
Base class for CLI commands.
"""
@property
def logger(self):
try:
return self._logger
except AttributeError:
self._logger = logging.getLogger(get_name(self))
return self._logger
def add_arguments(self, parser):
"""
Entry point for subclassed commands to add custom arguments.
"""
pass
def handle(self, *args, **options):
"""
The actual logic of the command. Subclasses must implement this method.
"""
raise NotImplementedError("Subclasses of BaseCommand must provide a handle() method")
class BaseGraphCommand(BaseCommand):
"""
Base class for CLI commands that depends on a graph definition, either from a file or from a module.
"""
required = True
handler = None
def add_arguments(self, parser):
# target arguments (cannot provide both).
source_group = parser.add_mutually_exclusive_group(required=self.required)
source_group.add_argument("file", nargs="?", type=str)
source_group.add_argument("-m", dest="mod", type=str)
# add arguments to enforce system environment.
parser = get_argument_parser(parser)
return parser
def parse_options(self, **options):
return options
def handle(self, file, mod, **options):
with humanizer.humanize():
options = self.parse_options(**options)
with self.read(file, mod, **options) as (graph, graph_execution_options, options):
return self.do_handle(graph, **graph_execution_options, **options)
def do_handle(self, graph, **options):
if not self.handler:
raise RuntimeError("{} has no handler defined.".format(get_name(self)))
return self.handler(graph, **options)
@contextmanager
def read(self, file, mod, **options):
_graph, _graph_execution_options = None, None
def _record(graph, **graph_execution_options):
nonlocal _graph, _graph_execution_options
_graph, _graph_execution_options = graph, graph_execution_options
with _override_runner(_record), parse_args(options) as options:
_argv = sys.argv
try:
if file:
sys.argv = [file]
self._run_path(file)
elif mod:
sys.argv = [mod]
self._run_module(mod)
else:
raise RuntimeError("No target provided.")
finally:
sys.argv = _argv
if _graph is None:
raise RuntimeError("Could not find graph.")
yield _graph, _graph_execution_options, options
def _run_path(self, file):
return runpy.run_path(file, run_name="__main__")
def _run_module(self, mod):
return runpy.run_module(mod, run_name="__main__")
@contextmanager
def _override_runner(runner):
"""
Context manager that monkey patches `bonobo.run` function with our current command logic.
:param runner: the callable that will handle the `run()` logic.
"""
import bonobo
_get_argument_parser = bonobo.util.environ.get_argument_parser
_run = bonobo.run
try:
# Original get_argument_parser would create or update an argument parser with environment options, but here we
# already had them parsed so let's patch with something that creates an empty one instead.
def get_argument_parser(parser=None):
return parser or argparse.ArgumentParser()
bonobo.util.environ.get_argument_parser = get_argument_parser
bonobo.run = runner
yield runner
finally:
# Restore our saved values.
bonobo.util.environ.get_argument_parser = _get_argument_parser
bonobo.run = _run