class Application(SingletonConfigurable):
"""A singleton application with full configuration support."""
# The name of the application, will usually match the name of the command
# line application
name = Unicode(u'application')
# The description of the application that is printed at the beginning
# of the help.
description = Unicode(u'This is an application.')
# default section descriptions
option_description = Unicode(option_description)
keyvalue_description = Unicode(keyvalue_description)
subcommand_description = Unicode(subcommand_description)
python_config_loader_class = PyFileConfigLoader
json_config_loader_class = JSONFileConfigLoader
# The usage and example string that goes at the end of the help string.
examples = Unicode()
# A sequence of Configurable subclasses whose config=True attributes will
# be exposed at the command line.
classes = []
def _classes_inc_parents(self, classes=None):
"""Iterate through configurable classes, including configurable parents
:param classes:
The list of classes to iterate; if not set, uses :attr:`classes`.
Children should always be after parents, and each class should only be
yielded once.
"""
if classes is None:
classes = self.classes
seen = set()
for c in classes:
# We want to sort parents before children, so we reverse the MRO
for parent in reversed(c.mro()):
if issubclass(parent, Configurable) and (parent not in seen):
seen.add(parent)
yield parent
# The version string of this application.
version = Unicode(u'0.0')
# the argv used to initialize the application
argv = List()
# Whether failing to load config files should prevent startup
raise_config_file_errors = Bool(
TRAITLETS_APPLICATION_RAISE_CONFIG_FILE_ERROR)
# The log level for the application
log_level = Enum(
(0, 10, 20, 30, 40, 50, 'DEBUG', 'INFO', 'WARN', 'ERROR', 'CRITICAL'),
default_value=logging.WARN,
help="Set the log level by value or name.").tag(config=True)
@observe('log_level')
@observe_compat
def _log_level_changed(self, change):
"""Adjust the log level when log_level is set."""
new = change.new
if isinstance(new, str):
new = getattr(logging, new)
self.log_level = new
self.log.setLevel(new)
_log_formatter_cls = LevelFormatter
log_datefmt = Unicode(
"%Y-%m-%d %H:%M:%S",
help="The date format used by logging formatters for %(asctime)s").tag(
config=True)
log_format = Unicode(
"[%(name)s]%(highlevel)s %(message)s",
help="The Logging format template",
).tag(config=True)
@observe('log_datefmt', 'log_format')
@observe_compat
def _log_format_changed(self, change):
"""Change the log formatter when log_format is set."""
_log_handler = self.log.handlers[0]
_log_formatter = self._log_formatter_cls(fmt=self.log_format,
datefmt=self.log_datefmt)
_log_handler.setFormatter(_log_formatter)
@default('log')
def _log_default(self):
"""Start logging for this application.
The default is to log to stderr using a StreamHandler, if no default
handler already exists. The log level starts at logging.WARN, but this
can be adjusted by setting the ``log_level`` attribute.
"""
log = logging.getLogger(self.__class__.__name__)
log.setLevel(self.log_level)
log.propagate = False
_log = log # copied from Logger.hasHandlers() (new in Python 3.2)
while _log:
if _log.handlers:
return log
if not _log.propagate:
break
else:
_log = _log.parent
if sys.executable and sys.executable.endswith('pythonw.exe'):
# this should really go to a file, but file-logging is only
# hooked up in parallel applications
_log_handler = logging.StreamHandler(open(os.devnull, 'w'))
else:
_log_handler = logging.StreamHandler()
_log_formatter = self._log_formatter_cls(fmt=self.log_format,
datefmt=self.log_datefmt)
_log_handler.setFormatter(_log_formatter)
log.addHandler(_log_handler)
return log
#: the alias map for configurables
#: Keys might strings or tuples for additional options; single-letter alias accessed like `-v`.
#: Values might be like "Class.trait" strings of two-tuples: (Class.trait, help-text).
aliases = {'log-level': 'Application.log_level'}
# flags for loading Configurables or store_const style flags
# flags are loaded from this dict by '--key' flags
# this must be a dict of two-tuples, the first element being the Config/dict
# and the second being the help string for the flag
flags = {
'debug': ({
'Application': {
'log_level': logging.DEBUG,
},
}, "Set log-level to debug, for the most verbose logging."),
'show-config': ({
'Application': {
'show_config': True,
},
}, "Show the application's configuration (human-readable format)"),
'show-config-json': ({
'Application': {
'show_config_json': True,
},
}, "Show the application's configuration (json format)"),
}
# subcommands for launching other applications
# if this is not empty, this will be a parent Application
# this must be a dict of two-tuples,
# the first element being the application class/import string
# and the second being the help string for the subcommand
subcommands = Dict()
# parse_command_line will initialize a subapp, if requested
subapp = Instance('traitlets.config.application.Application',
allow_none=True)
# extra command-line arguments that don't set config values
extra_args = List(Unicode())
cli_config = Instance(
Config, (), {},
help="""The subset of our configuration that came from the command-line
We re-load this configuration after loading config files,
to ensure that it maintains highest priority.
""")
_loaded_config_files = List()
show_config = Bool(
help="Instead of starting the Application, dump configuration to stdout"
).tag(config=True)
show_config_json = Bool(
help=
"Instead of starting the Application, dump configuration to stdout (as JSON)"
).tag(config=True)
@observe('show_config_json')
def _show_config_json_changed(self, change):
self.show_config = change.new
@observe('show_config')
def _show_config_changed(self, change):
if change.new:
self._save_start = self.start
self.start = self.start_show_config
def __init__(self, **kwargs):
SingletonConfigurable.__init__(self, **kwargs)
# Ensure my class is in self.classes, so my attributes appear in command line
# options and config files.
cls = self.__class__
if cls not in self.classes:
if self.classes is cls.classes:
# class attr, assign instead of insert
self.classes = [cls] + self.classes
else:
self.classes.insert(0, self.__class__)
@observe('config')
@observe_compat
def _config_changed(self, change):
super(Application, self)._config_changed(change)
self.log.debug('Config changed: %r', change.new)
@catch_config_error
def initialize(self, argv=None):
"""Do the basic steps to configure me.
Override in subclasses.
"""
self.parse_command_line(argv)
def start(self):
"""Start the app mainloop.
Override in subclasses.
"""
if self.subapp is not None:
return self.subapp.start()
def start_show_config(self):
"""start function used when show_config is True"""
config = self.config.copy()
# exclude show_config flags from displayed config
for cls in self.__class__.mro():
if cls.__name__ in config:
cls_config = config[cls.__name__]
cls_config.pop('show_config', None)
cls_config.pop('show_config_json', None)
if self.show_config_json:
json.dump(config,
sys.stdout,
indent=1,
sort_keys=True,
default=repr)
# add trailing newline
sys.stdout.write('\n')
return
if self._loaded_config_files:
print("Loaded config files:")
for f in self._loaded_config_files:
print(' ' + f)
print()
for classname in sorted(config):
class_config = config[classname]
if not class_config:
continue
print(classname)
pformat_kwargs = dict(indent=4, compact=True)
for traitname in sorted(class_config):
value = class_config[traitname]
print(' .{} = {}'.format(
traitname,
pprint.pformat(value, **pformat_kwargs),
))
def print_alias_help(self):
"""Print the alias parts of the help."""
print('\n'.join(self.emit_alias_help()))
def emit_alias_help(self):
"""Yield the lines for alias part of the help."""
if not self.aliases:
return
classdict = {}
for cls in self.classes:
# include all parents (up to, but excluding Configurable) in available names
for c in cls.mro()[:-3]:
classdict[c.__name__] = c
for alias, longname in self.aliases.items():
try:
if isinstance(longname, tuple):
longname, fhelp = longname
else:
fhelp = None
classname, traitname = longname.split('.', 1)
cls = classdict[classname]
trait = cls.class_traits(config=True)[traitname]
fhelp = cls.class_get_trait_help(trait,
helptext=fhelp).splitlines()
if not isinstance(alias, tuple):
alias = (alias, )
alias = sorted(alias, key=len)
alias = ', '.join(
('--%s' if len(m) > 1 else '-%s') % m for m in alias)
# reformat first line
fhelp[0] = fhelp[0].replace('--' + longname, alias)
for l in fhelp:
yield l
yield indent("Equivalent to: [--%s]" % longname)
except Exception as ex:
self.log.error(
'Failed collecting help-message for alias %r, due to: %s',
alias, ex)
raise
def print_flag_help(self):
"""Print the flag part of the help."""
print('\n'.join(self.emit_flag_help()))
def emit_flag_help(self):
"""Yield the lines for the flag part of the help."""
if not self.flags:
return
for flags, (cfg, fhelp) in self.flags.items():
try:
if not isinstance(flags, tuple):
flags = (flags, )
flags = sorted(flags, key=len)
flags = ', '.join(
('--%s' if len(m) > 1 else '-%s') % m for m in flags)
yield flags
yield indent(dedent(fhelp.strip()))
cfg_list = ' '.join('--%s.%s=%s' % (clname, prop, val)
for clname, props_dict in cfg.items()
for prop, val in props_dict.items())
cfg_txt = "Equivalent to: [%s]" % cfg_list
yield indent(dedent(cfg_txt))
except Exception as ex:
self.log.error(
'Failed collecting help-message for flag %r, due to: %s',
flags, ex)
raise
def print_options(self):
"""Print the options part of the help."""
print('\n'.join(self.emit_options_help()))
def emit_options_help(self):
"""Yield the lines for the options part of the help."""
if not self.flags and not self.aliases:
return
header = 'Options'
yield header
yield '=' * len(header)
for p in wrap_paragraphs(self.option_description):
yield p
yield ''
for l in self.emit_flag_help():
yield l
for l in self.emit_alias_help():
yield l
yield ''
def print_subcommands(self):
"""Print the subcommand part of the help."""
print('\n'.join(self.emit_subcommands_help()))
def emit_subcommands_help(self):
"""Yield the lines for the subcommand part of the help."""
if not self.subcommands:
return
header = "Subcommands"
yield header
yield '=' * len(header)
for p in wrap_paragraphs(
self.subcommand_description.format(app=self.name)):
yield p
yield ''
for subc, (cls, help) in self.subcommands.items():
yield subc
if help:
yield indent(dedent(help.strip()))
yield ''
def emit_help_epilogue(self, classes):
"""Yield the very bottom lines of the help message.
If classes=False (the default), print `--help-all` msg.
"""
if not classes:
yield "To see all available configurables, use `--help-all`."
yield ''
def print_help(self, classes=False):
"""Print the help for each Configurable class in self.classes.
If classes=False (the default), only flags and aliases are printed.
"""
print('\n'.join(self.emit_help(classes=classes)))
def emit_help(self, classes=False):
"""Yield the help-lines for each Configurable class in self.classes.
If classes=False (the default), only flags and aliases are printed.
"""
for l in self.emit_description():
yield l
for l in self.emit_subcommands_help():
yield l
for l in self.emit_options_help():
yield l
if classes:
help_classes = self._classes_with_config_traits()
if help_classes:
yield "Class options"
yield "============="
for p in wrap_paragraphs(self.keyvalue_description):
yield p
yield ''
for cls in help_classes:
yield cls.class_get_help()
yield ''
for l in self.emit_examples():
yield l
for l in self.emit_help_epilogue(classes):
yield l
def document_config_options(self):
"""Generate rST format documentation for the config options this application
Returns a multiline string.
"""
return '\n'.join(c.class_config_rst_doc()
for c in self._classes_inc_parents())
def print_description(self):
"""Print the application description."""
print('\n'.join(self.emit_description()))
def emit_description(self):
"""Yield lines with the application description."""
for p in wrap_paragraphs(self.description or self.__doc__):
yield p
yield ''
def print_examples(self):
"""Print usage and examples (see `emit_examples()`). """
print('\n'.join(self.emit_examples()))
def emit_examples(self):
"""Yield lines with the usage and examples.
This usage string goes at the end of the command line help string
and should contain examples of the application's usage.
"""
if self.examples:
yield "Examples"
yield "--------"
yield ''
yield indent(dedent(self.examples.strip()))
yield ''
def print_version(self):
"""Print the version string."""
print(self.version)
@catch_config_error
def initialize_subcommand(self, subc, argv=None):
"""Initialize a subcommand with argv."""
subapp, _ = self.subcommands.get(subc)
if isinstance(subapp, str):
subapp = import_item(subapp)
## Cannot issubclass() on a non-type (SOhttp://stackoverflow.com/questions/8692430)
if isinstance(subapp, type) and issubclass(subapp, Application):
# Clear existing instances before...
self.__class__.clear_instance()
# instantiating subapp...
self.subapp = subapp.instance(parent=self)
elif callable(subapp):
# or ask factory to create it...
self.subapp = subapp(self)
else:
raise AssertionError("Invalid mappings for subcommand '%s'!" %
subc)
# ... and finally initialize subapp.
self.subapp.initialize(argv)
def flatten_flags(self):
"""Flatten flags and aliases for loaders, so cl-args override as expected.
This prevents issues such as an alias pointing to InteractiveShell,
but a config file setting the same trait in TerminalInteraciveShell
getting inappropriate priority over the command-line arg.
Also, loaders expect ``(key: longname)`` and not ````key: (longname, help)`` items.
Only aliases with exactly one descendent in the class list
will be promoted.
"""
# build a tree of classes in our list that inherit from a particular
# it will be a dict by parent classname of classes in our list
# that are descendents
mro_tree = defaultdict(list)
for cls in self.classes:
clsname = cls.__name__
for parent in cls.mro()[1:-3]:
# exclude cls itself and Configurable,HasTraits,object
mro_tree[parent.__name__].append(clsname)
# flatten aliases, which have the form:
# { 'alias' : 'Class.trait' }
aliases = {}
for alias, longname in self.aliases.items():
if isinstance(longname, tuple):
longname, _ = longname
cls, trait = longname.split('.', 1)
children = mro_tree[cls]
if len(children) == 1:
# exactly one descendent, promote alias
cls = children[0]
if not isinstance(aliases, tuple):
alias = (alias, )
for al in alias:
aliases[al] = '.'.join([cls, trait])
# flatten flags, which are of the form:
# { 'key' : ({'Cls' : {'trait' : value}}, 'help')}
flags = {}
for key, (flagdict, help) in self.flags.items():
newflag = {}
for cls, subdict in flagdict.items():
children = mro_tree[cls]
# exactly one descendent, promote flag section
if len(children) == 1:
cls = children[0]
if cls in newflag:
newflag[cls].update(subdict)
else:
newflag[cls] = subdict
if not isinstance(key, tuple):
key = (key, )
for k in key:
flags[k] = (newflag, help)
return flags, aliases
def _create_loader(self, argv, aliases, flags, classes):
return KVArgParseConfigLoader(argv,
aliases,
flags,
classes=classes,
log=self.log)
@catch_config_error
def parse_command_line(self, argv=None):
"""Parse the command line arguments."""
argv = sys.argv[1:] if argv is None else argv
self.argv = [cast_unicode(arg) for arg in argv]
if argv and argv[0] == 'help':
# turn `ipython help notebook` into `ipython notebook -h`
argv = argv[1:] + ['-h']
if self.subcommands and len(argv) > 0:
# we have subcommands, and one may have been specified
subc, subargv = argv[0], argv[1:]
if re.match(r'^\w(\-?\w)*$', subc) and subc in self.subcommands:
# it's a subcommand, and *not* a flag or class parameter
return self.initialize_subcommand(subc, subargv)
# Arguments after a '--' argument are for the script IPython may be
# about to run, not IPython iteslf. For arguments parsed here (help and
# version), we want to only search the arguments up to the first
# occurrence of '--', which we're calling interpreted_argv.
try:
interpreted_argv = argv[:argv.index('--')]
except ValueError:
interpreted_argv = argv
if any(x in interpreted_argv for x in ('-h', '--help-all', '--help')):
self.print_help('--help-all' in interpreted_argv)
self.exit(0)
if '--version' in interpreted_argv or '-V' in interpreted_argv:
self.print_version()
self.exit(0)
# flatten flags&aliases, so cl-args get appropriate priority:
flags, aliases = self.flatten_flags()
classes = tuple(self._classes_with_config_traits())
loader = self._create_loader(argv, aliases, flags, classes=classes)
self.cli_config = deepcopy(loader.load_config())
self.update_config(self.cli_config)
# store unparsed args in extra_args
self.extra_args = loader.extra_args
@classmethod
def _load_config_files(cls,
basefilename,
path=None,
log=None,
raise_config_file_errors=False):
"""Load config files (py,json) by filename and path.
yield each config object in turn.
"""
if not isinstance(path, list):
path = [path]
for path in path[::-1]:
# path list is in descending priority order, so load files backwards:
pyloader = cls.python_config_loader_class(basefilename + '.py',
path=path,
log=log)
if log:
log.debug("Looking for %s in %s", basefilename, path
or os.getcwd())
jsonloader = cls.json_config_loader_class(basefilename + '.json',
path=path,
log=log)
loaded = []
filenames = []
for loader in [pyloader, jsonloader]:
config = None
try:
config = loader.load_config()
except ConfigFileNotFound:
pass
except Exception:
# try to get the full filename, but it will be empty in the
# unlikely event that the error raised before filefind finished
filename = loader.full_filename or basefilename
# problem while running the file
if raise_config_file_errors:
raise
if log:
log.error("Exception while loading config file %s",
filename,
exc_info=True)
else:
if log:
log.debug("Loaded config file: %s",
loader.full_filename)
if config:
for filename, earlier_config in zip(filenames, loaded):
collisions = earlier_config.collisions(config)
if collisions and log:
log.warning(
"Collisions detected in {0} and {1} config files."
" {1} has higher priority: {2}".format(
filename,
loader.full_filename,
json.dumps(collisions, indent=2),
))
yield (config, loader.full_filename)
loaded.append(config)
filenames.append(loader.full_filename)
@property
def loaded_config_files(self):
"""Currently loaded configuration files"""
return self._loaded_config_files[:]
@catch_config_error
def load_config_file(self, filename, path=None):
"""Load config files by filename and path."""
filename, ext = os.path.splitext(filename)
new_config = Config()
for (config, filename) in self._load_config_files(
filename,
path=path,
log=self.log,
raise_config_file_errors=self.raise_config_file_errors,
):
new_config.merge(config)
if filename not in self._loaded_config_files: # only add to list of loaded files if not previously loaded
self._loaded_config_files.append(filename)
# add self.cli_config to preserve CLI config priority
new_config.merge(self.cli_config)
self.update_config(new_config)
def _classes_with_config_traits(self, classes=None):
"""
Yields only classes with configurable traits, and their subclasses.
:param classes:
The list of classes to iterate; if not set, uses :attr:`classes`.
Thus, produced sample config-file will contain all classes
on which a trait-value may be overridden:
- either on the class owning the trait,
- or on its subclasses, even if those subclasses do not define
any traits themselves.
"""
if classes is None:
classes = self.classes
cls_to_config = OrderedDict(
(cls, bool(cls.class_own_traits(config=True)))
for cls in self._classes_inc_parents(classes))
def is_any_parent_included(cls):
return any(b in cls_to_config and cls_to_config[b]
for b in cls.__bases__)
## Mark "empty" classes for inclusion if their parents own-traits,
# and loop until no more classes gets marked.
#
while True:
to_incl_orig = cls_to_config.copy()
cls_to_config = OrderedDict(
(cls, inc_yes or is_any_parent_included(cls))
for cls, inc_yes in cls_to_config.items())
if cls_to_config == to_incl_orig:
break
for cl, inc_yes in cls_to_config.items():
if inc_yes:
yield cl
def generate_config_file(self, classes=None):
"""generate default config file from Configurables"""
lines = ["# Configuration file for %s." % self.name]
lines.append('')
classes = self.classes if classes is None else classes
config_classes = list(self._classes_with_config_traits(classes))
for cls in config_classes:
lines.append(cls.class_config_section(config_classes))
return '\n'.join(lines)
def exit(self, exit_status=0):
self.log.debug("Exiting application: %s" % self.name)
sys.exit(exit_status)
@classmethod
def launch_instance(cls, argv=None, **kwargs):
"""Launch a global instance of this Application
If a global instance already exists, this reinitializes and starts it
"""
app = cls.instance(**kwargs)
app.initialize(argv)
app.start()
