3 """Global configuration driven by commandline arguments, environment variables
4 and saved configuration files. This works across several modules.
12 parser = config.add_commandline_args(
14 "Args related to module doing the thing.",
17 "--module_do_the_thing",
20 help="Should the module do the thing?"
28 parser = config.add_commandline_args(
30 "A program that does the thing.",
36 help="Should we really do the thing?"
38 config.parse() # Very important, this must be invoked!
40 If you set this up and remember to invoke config.parse(), all commandline
41 arguments will play nicely together. This is done automatically for you
42 if you're using the bootstrap module's initialize wrapper.
46 [--module_do_the_thing MODULE_DO_THE_THING]
50 Args related to module doing the thing.
52 --module_do_the_thing MODULE_DO_THE_THING
53 Should the module do the thing?
56 A program that does the thing
59 Should we really do the thing?
61 Arguments themselves should be accessed via
62 config.config['arg_name']. e.g.
64 if not config.config['dry_run']:
74 from typing import Any, Dict, List, Optional
76 # This module is commonly used by others in here and should avoid
77 # taking any unnecessary dependencies back on them.
79 # Defer logging messages until later when logging has been initialized.
80 saved_messages: List[str] = []
82 # Make a copy of the original program arguments.
83 program_name = os.path.basename(sys.argv[0])
84 original_argv = [arg for arg in sys.argv]
87 # A global parser that we will collect arguments into.
88 args = argparse.ArgumentParser(
90 formatter_class=argparse.ArgumentDefaultsHelpFormatter,
91 fromfile_prefix_chars="@",
92 epilog=f'{program_name} uses config.py ({__file__}) for global, cross-module configuration setup and parsing.'
95 # Keep track of if we've been called and prevent being called more
97 config_parse_called = False
100 # A global configuration dictionary that will contain parsed arguments.
101 # It is also this variable that modules use to access parsed arguments.
102 # This is the data that is most interesting to our callers; it will hold
103 # the configuration result.
105 # It would be really nice if this shit worked from interactive python
108 def add_commandline_args(title: str, description: str = ""):
109 """Create a new context for arguments and return a handle."""
110 return args.add_argument_group(title, description)
113 group = add_commandline_args(
114 f'Global Config ({__file__})',
115 'Args that control the global config itself; how meta!',
121 help='Config file (populated via --config_savefile) from which to read args in lieu or in addition to commandline.',
127 help='Display the global configuration (possibly derived from multiple sources) on STDERR at program startup.',
134 help='Populate config file compatible with --config_loadfile to save global config for later use.',
138 def is_flag_already_in_argv(var: str):
139 """Is a particular flag passed on the commandline?"""
146 def parse(entry_module: Optional[str]) -> Dict[str, Any]:
147 """Main program should call this early in main(). Note that the
148 bootstrap.initialize wrapper takes care of this automatically.
151 global config_parse_called
152 if config_parse_called:
155 global saved_messages
157 # If we're about to do the usage message dump, put the main module's
158 # argument group last in the list (if possible) so that when the user
159 # passes -h or --help, it will be visible on the screen w/o scrolling.
160 reordered_action_groups = []
163 if arg == '--help' or arg == '-h':
164 for group in args._action_groups:
165 if entry_module is not None and entry_module in group.title:
166 reordered_action_groups.append(group)
167 elif program_name in group.title:
168 reordered_action_groups.append(group)
170 reordered_action_groups.insert(0, group)
171 args._action_groups = reordered_action_groups
173 # Examine the environment for variables that match known flags.
174 # For a flag called --example_flag the corresponding environment
175 # variable would be called EXAMPLE_FLAG.
176 usage_message = args.format_usage()
179 for x in usage_message.split():
193 # Environment vars the same as flag names without
194 # the initial -'s and in UPPERCASE.
195 env = var.strip('-').upper()
196 if env in os.environ:
197 if not is_flag_already_in_argv(var):
198 value = os.environ[env]
199 saved_messages.append(
200 f'Initialized from environment: {var} = {value}'
202 from string_utils import to_bool
203 if len(chunks) == 1 and to_bool(value):
205 elif len(chunks) > 1:
207 sys.argv.append(value)
213 # Look for loadfile and read/parse it if present.
215 saw_other_args = False
216 grab_next_arg = False
217 for arg in sys.argv[1:]:
218 if 'config_loadfile' in arg:
219 pieces = arg.split('=')
227 saw_other_args = True
229 if loadfile is not None:
231 msg = f'Augmenting commandline arguments with those from {loadfile}.'
232 print(msg, file=sys.stderr)
233 saved_messages.append(msg)
234 if not os.path.exists(loadfile):
235 print(f'ERROR: --config_loadfile argument must be a file, {loadfile} not found.',
238 with open(loadfile, 'r') as rf:
239 newargs = rf.readlines()
240 newargs = [arg.strip('\n') for arg in newargs if 'config_savefile' not in arg]
243 # Parse (possibly augmented, possibly completely overwritten)
244 # commandline args with argparse normally and populate config.
245 known, unknown = args.parse_known_args()
246 config.update(vars(known))
248 # Reconstruct the argv with unrecognized flags for the benefit of
249 # future argument parsers. For example, unittest_main in python
250 # has some of its own flags. If we didn't recognize it, maybe
252 sys.argv = sys.argv[:1] + unknown
254 # Check for savefile and populate it if requested.
255 savefile = config['config_savefile']
256 if savefile and len(savefile) > 0:
257 with open(savefile, 'w') as wf:
259 "\n".join(original_argv[1:])
262 # Also dump the config on stderr if requested.
263 if config['config_dump']:
266 config_parse_called = True
270 def has_been_parsed() -> bool:
271 """Has the global config been parsed yet?"""
272 global config_parse_called
273 return config_parse_called
277 """Print the current config to stdout."""
278 print("Global Configuration:", file=sys.stderr)
279 pprint.pprint(config, stream=sys.stderr)
284 """Log messages saved earlier now that logging has been initialized."""
285 logger = logging.getLogger(__name__)
286 global saved_messages
287 for _ in saved_messages: