#!/usr/bin/env python3
-"""Global configuration driven by commandline arguments (even across
-different modules). Usage:
+"""Global configuration driven by commandline arguments, environment variables
+and saved configuration files. This works across several modules.
+
+Usage:
module.py:
----------
config.parse() # Very important, this must be invoked!
If you set this up and remember to invoke config.parse(), all commandline
- arguments will play nicely together:
+ arguments will play nicely together. This is done automatically for you
+ if you're using the bootstrap module's initialize wrapper.
% main.py -h
usage: main.py [-h]
--dry_run
Should we really do the thing?
- Arguments themselves should be accessed via config.config['arg_name']. e.g.
+ Arguments themselves should be accessed via
+ config.config['arg_name']. e.g.
if not config.config['dry_run']:
module.do_the_thing()
+
"""
import argparse
+import logging
+import os
import pprint
-import re
import sys
-from typing import Dict, Any
-
-# Note: at this point in time, logging hasn't been configured and
-# anything we log will come out the root logger.
-
-
-class LoadFromFile(argparse.Action):
- """Helper to load a config file into argparse."""
- def __call__ (self, parser, namespace, values, option_string = None):
- with values as f:
- buf = f.read()
- argv = []
- for line in buf.split(','):
- line = line.strip()
- line = line.strip('{')
- line = line.strip('}')
- m = re.match(r"^'([a-zA-Z_\-]+)'\s*:\s*(.*)$", line)
- if m:
- key = m.group(1)
- value = m.group(2)
- value = value.strip("'")
- if value not in ('None', 'True', 'False'):
- argv.append(f'--{key}')
- argv.append(value)
- parser.parse_args(argv, namespace)
+from typing import Any, Dict, List, Optional
+
+# This module is commonly used by others in here and should avoid
+# taking any unnecessary dependencies back on them.
+
+# Defer logging messages until later when logging has been initialized.
+saved_messages: List[str] = []
+
+# Make a copy of the original program arguments.
+program_name = os.path.basename(sys.argv[0])
+original_argv = [arg for arg in sys.argv]
# A global parser that we will collect arguments into.
args = argparse.ArgumentParser(
- description=f"This program uses config.py ({__file__}) for global, cross-module configuration.",
+ description=None,
formatter_class=argparse.ArgumentDefaultsHelpFormatter,
- fromfile_prefix_chars="@"
+ fromfile_prefix_chars="@",
+ epilog=f'{program_name} uses config.py ({__file__}) for global, cross-module configuration setup and parsing.'
)
+
+# Keep track of if we've been called and prevent being called more
+# than once.
config_parse_called = False
-# A global configuration dictionary that will contain parsed arguments
-# It is also this variable that modules use to access parsed arguments
-config: Dict[str, Any] = {}
+
+# A global configuration dictionary that will contain parsed arguments.
+# It is also this variable that modules use to access parsed arguments.
+# This is the data that is most interesting to our callers; it will hold
+# the configuration result.
+config = {}
+# It would be really nice if this shit worked from interactive python
def add_commandline_args(title: str, description: str = ""):
)
group.add_argument(
'--config_loadfile',
- type=open,
- action=LoadFromFile,
metavar='FILENAME',
default=None,
- help='Config file from which to read args in lieu or in addition to commandline.',
+ help='Config file (populated via --config_savefile) from which to read args in lieu or in addition to commandline.',
)
group.add_argument(
'--config_dump',
default=False,
action='store_true',
- help='Display the global configuration on STDERR at program startup.',
+ help='Display the global configuration (possibly derived from multiple sources) on STDERR at program startup.',
)
group.add_argument(
'--config_savefile',
type=str,
metavar='FILENAME',
default=None,
- help='Populate config file compatible --config_loadfile to save config for later use.',
+ help='Populate config file compatible with --config_loadfile to save global config for later use.',
)
-def parse() -> Dict[str, Any]:
- """Main program should call this early in main()"""
- global config_parse_called
- config_parse_called = True
- config.update(vars(args.parse_args()))
+def is_flag_already_in_argv(var: str):
+ """Is a particular flag passed on the commandline?"""
+ for _ in sys.argv:
+ if var in _:
+ return True
+ return False
- if config['config_savefile']:
- with open(config['config_savefile'], 'w') as wf:
- wf.write("\n".join(sys.argv[1:]))
+def parse(entry_module: Optional[str]) -> Dict[str, Any]:
+ """Main program should call this early in main(). Note that the
+ bootstrap.initialize wrapper takes care of this automatically.
+
+ """
+ global config_parse_called
+ if config_parse_called:
+ return config
+
+ global saved_messages
+
+ # If we're about to do the usage message dump, put the main module's
+ # argument group last in the list (if possible) so that when the user
+ # passes -h or --help, it will be visible on the screen w/o scrolling.
+ reordered_action_groups = []
+ global prog
+ for arg in sys.argv:
+ if arg == '--help' or arg == '-h':
+ for group in args._action_groups:
+ if entry_module is not None and entry_module in group.title:
+ reordered_action_groups.append(group)
+ elif program_name in group.title:
+ reordered_action_groups.append(group)
+ else:
+ reordered_action_groups.insert(0, group)
+ args._action_groups = reordered_action_groups
+
+ # Examine the environment for variables that match known flags.
+ # For a flag called --example_flag the corresponding environment
+ # variable would be called EXAMPLE_FLAG.
+ usage_message = args.format_usage()
+ optional = False
+ var = ''
+ for x in usage_message.split():
+ if x[0] == '[':
+ optional = True
+ if optional:
+ var += f'{x} '
+ if x[-1] == ']':
+ optional = False
+ var = var.strip()
+ var = var.strip('[')
+ var = var.strip(']')
+ chunks = var.split()
+ if len(chunks) > 1:
+ var = var.split()[0]
+
+ # Environment vars the same as flag names without
+ # the initial -'s and in UPPERCASE.
+ env = var.strip('-').upper()
+ if env in os.environ:
+ if not is_flag_already_in_argv(var):
+ value = os.environ[env]
+ saved_messages.append(
+ f'Initialized from environment: {var} = {value}'
+ )
+ from string_utils import to_bool
+ if len(chunks) == 1 and to_bool(value):
+ sys.argv.append(var)
+ elif len(chunks) > 1:
+ sys.argv.append(var)
+ sys.argv.append(value)
+ var = ''
+ env = ''
+ else:
+ next
+
+ # Look for loadfile and read/parse it if present.
+ loadfile = None
+ saw_other_args = False
+ grab_next_arg = False
+ for arg in sys.argv[1:]:
+ if 'config_loadfile' in arg:
+ pieces = arg.split('=')
+ if len(pieces) > 1:
+ loadfile = pieces[1]
+ else:
+ grab_next_arg = True
+ elif grab_next_arg:
+ loadfile = arg
+ else:
+ saw_other_args = True
+
+ if loadfile is not None:
+ if saw_other_args:
+ msg = f'Augmenting commandline arguments with those from {loadfile}.'
+ print(msg, file=sys.stderr)
+ saved_messages.append(msg)
+ if not os.path.exists(loadfile):
+ print(f'ERROR: --config_loadfile argument must be a file, {loadfile} not found.',
+ file=sys.stderr)
+ sys.exit(-1)
+ with open(loadfile, 'r') as rf:
+ newargs = rf.readlines()
+ newargs = [arg.strip('\n') for arg in newargs if 'config_savefile' not in arg]
+ sys.argv += newargs
+
+ # Parse (possibly augmented, possibly completely overwritten)
+ # commandline args with argparse normally and populate config.
+ known, unknown = args.parse_known_args()
+ config.update(vars(known))
+
+ # Reconstruct the argv with unrecognized flags for the benefit of
+ # future argument parsers. For example, unittest_main in python
+ # has some of its own flags. If we didn't recognize it, maybe
+ # someone else will.
+ sys.argv = sys.argv[:1] + unknown
+
+ # Check for savefile and populate it if requested.
+ savefile = config['config_savefile']
+ if savefile and len(savefile) > 0:
+ with open(savefile, 'w') as wf:
+ wf.write(
+ "\n".join(original_argv[1:])
+ )
+
+ # Also dump the config on stderr if requested.
if config['config_dump']:
dump_config()
+ config_parse_called = True
return config
def has_been_parsed() -> bool:
+ """Has the global config been parsed yet?"""
global config_parse_called
return config_parse_called
"""Print the current config to stdout."""
print("Global Configuration:", file=sys.stderr)
pprint.pprint(config, stream=sys.stderr)
+ print()
+
+
+def late_logging():
+ """Log messages saved earlier now that logging has been initialized."""
+ logger = logging.getLogger(__name__)
+ global saved_messages
+ for _ in saved_messages:
+ logger.debug(_)
projects / python_utils.git / blobdiff