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Diffstat (limited to 'charms/trusty/ceilometer-agent/hooks/charmhelpers/cli/__init__.py')
| -rw-r--r-- | charms/trusty/ceilometer-agent/hooks/charmhelpers/cli/__init__.py | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/charms/trusty/ceilometer-agent/hooks/charmhelpers/cli/__init__.py b/charms/trusty/ceilometer-agent/hooks/charmhelpers/cli/__init__.py new file mode 100644 index 0000000..389b490 --- /dev/null +++ b/charms/trusty/ceilometer-agent/hooks/charmhelpers/cli/__init__.py @@ -0,0 +1,189 @@ +# Copyright 2014-2015 Canonical Limited. +# +# Licensed under the Apache License, Version 2.0 (the "License"); +# you may not use this file except in compliance with the License. +# You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. + +import inspect +import argparse +import sys + +from six.moves import zip + +import charmhelpers.core.unitdata + + +class OutputFormatter(object): + def __init__(self, outfile=sys.stdout): + self.formats = ( + "raw", + "json", + "py", + "yaml", + "csv", + "tab", + ) + self.outfile = outfile + + def add_arguments(self, argument_parser): + formatgroup = argument_parser.add_mutually_exclusive_group() + choices = self.supported_formats + formatgroup.add_argument("--format", metavar='FMT', + help="Select output format for returned data, " + "where FMT is one of: {}".format(choices), + choices=choices, default='raw') + for fmt in self.formats: + fmtfunc = getattr(self, fmt) + formatgroup.add_argument("-{}".format(fmt[0]), + "--{}".format(fmt), action='store_const', + const=fmt, dest='format', + help=fmtfunc.__doc__) + + @property + def supported_formats(self): + return self.formats + + def raw(self, output): + """Output data as raw string (default)""" + if isinstance(output, (list, tuple)): + output = '\n'.join(map(str, output)) + self.outfile.write(str(output)) + + def py(self, output): + """Output data as a nicely-formatted python data structure""" + import pprint + pprint.pprint(output, stream=self.outfile) + + def json(self, output): + """Output data in JSON format""" + import json + json.dump(output, self.outfile) + + def yaml(self, output): + """Output data in YAML format""" + import yaml + yaml.safe_dump(output, self.outfile) + + def csv(self, output): + """Output data as excel-compatible CSV""" + import csv + csvwriter = csv.writer(self.outfile) + csvwriter.writerows(output) + + def tab(self, output): + """Output data in excel-compatible tab-delimited format""" + import csv + csvwriter = csv.writer(self.outfile, dialect=csv.excel_tab) + csvwriter.writerows(output) + + def format_output(self, output, fmt='raw'): + fmtfunc = getattr(self, fmt) + fmtfunc(output) + + +class CommandLine(object): + argument_parser = None + subparsers = None + formatter = None + exit_code = 0 + + def __init__(self): + if not self.argument_parser: + self.argument_parser = argparse.ArgumentParser(description='Perform common charm tasks') + if not self.formatter: + self.formatter = OutputFormatter() + self.formatter.add_arguments(self.argument_parser) + if not self.subparsers: + self.subparsers = self.argument_parser.add_subparsers(help='Commands') + + def subcommand(self, command_name=None): + """ + Decorate a function as a subcommand. Use its arguments as the + command-line arguments""" + def wrapper(decorated): + cmd_name = command_name or decorated.__name__ + subparser = self.subparsers.add_parser(cmd_name, + description=decorated.__doc__) + for args, kwargs in describe_arguments(decorated): + subparser.add_argument(*args, **kwargs) + subparser.set_defaults(func=decorated) + return decorated + return wrapper + + def test_command(self, decorated): + """ + Subcommand is a boolean test function, so bool return values should be + converted to a 0/1 exit code. + """ + decorated._cli_test_command = True + return decorated + + def no_output(self, decorated): + """ + Subcommand is not expected to return a value, so don't print a spurious None. + """ + decorated._cli_no_output = True + return decorated + + def subcommand_builder(self, command_name, description=None): + """ + Decorate a function that builds a subcommand. Builders should accept a + single argument (the subparser instance) and return the function to be + run as the command.""" + def wrapper(decorated): + subparser = self.subparsers.add_parser(command_name) + func = decorated(subparser) + subparser.set_defaults(func=func) + subparser.description = description or func.__doc__ + return wrapper + + def run(self): + "Run cli, processing arguments and executing subcommands." + arguments = self.argument_parser.parse_args() + argspec = inspect.getargspec(arguments.func) + vargs = [] + for arg in argspec.args: + vargs.append(getattr(arguments, arg)) + if argspec.varargs: + vargs.extend(getattr(arguments, argspec.varargs)) + output = arguments.func(*vargs) + if getattr(arguments.func, '_cli_test_command', False): + self.exit_code = 0 if output else 1 + output = '' + if getattr(arguments.func, '_cli_no_output', False): + output = '' + self.formatter.format_output(output, arguments.format) + if charmhelpers.core.unitdata._KV: + charmhelpers.core.unitdata._KV.flush() + + +cmdline = CommandLine() + + +def describe_arguments(func): + """ + Analyze a function's signature and return a data structure suitable for + passing in as arguments to an argparse parser's add_argument() method.""" + + argspec = inspect.getargspec(func) + # we should probably raise an exception somewhere if func includes **kwargs + if argspec.defaults: + positional_args = argspec.args[:-len(argspec.defaults)] + keyword_names = argspec.args[-len(argspec.defaults):] + for arg, default in zip(keyword_names, argspec.defaults): + yield ('--{}'.format(arg),), {'default': default} + else: + positional_args = argspec.args + + for arg in positional_args: + yield (arg,), {} + if argspec.varargs: + yield (argspec.varargs,), {'nargs': '*'} |