| author |
Steve Losh <steve@stevelosh.com> |
| date |
Tue, 02 Mar 2010 19:45:54 -0500 |
| parents |
(none) |
| children |
(none) |
"""Configuration system for CherryPy.
Configuration in CherryPy is implemented via dictionaries. Keys are strings
which name the mapped value, which may be of any type.
Architecture
------------
CherryPy Requests are part of an Application, which runs in a global context,
and configuration data may apply to any of those three scopes:
Global: configuration entries which apply everywhere are stored in
cherrypy.config.
Application: entries which apply to each mounted application are stored
on the Application object itself, as 'app.config'. This is a two-level
dict where each key is a path, or "relative URL" (for example, "/" or
"/path/to/my/page"), and each value is a config dict. Usually, this
data is provided in the call to tree.mount(root(), config=conf),
although you may also use app.merge(conf).
Request: each Request object possesses a single 'Request.config' dict.
Early in the request process, this dict is populated by merging global
config entries, Application entries (whose path equals or is a parent
of Request.path_info), and any config acquired while looking up the
page handler (see next).
Declaration
-----------
Configuration data may be supplied as a Python dictionary, as a filename,
or as an open file object. When you supply a filename or file, CherryPy
uses Python's builtin ConfigParser; you declare Application config by
writing each path as a section header:
[/path/to/my/page]
request.stream = True
To declare global configuration entries, place them in a [global] section.
You may also declare config entries directly on the classes and methods
(page handlers) that make up your CherryPy application via the '_cp_config'
attribute. For example:
class Demo:
_cp_config = {'tools.gzip.on': True}
def index(self):
return "Hello world"
index.exposed = True
index._cp_config = {'request.show_tracebacks': False}
Note, however, that this behavior is only guaranteed for the default
dispatcher. Other dispatchers may have different restrictions on where
you can attach _cp_config attributes.
Namespaces
----------
Configuration keys are separated into namespaces by the first "." in the key.
Current namespaces:
engine: Controls the 'application engine', including autoreload.
These can only be declared in the global config.
tree: Grafts cherrypy.Application objects onto cherrypy.tree.
These can only be declared in the global config.
hooks: Declares additional request-processing functions.
log: Configures the logging for each application.
These can only be declared in the global or / config.
request: Adds attributes to each Request.
response: Adds attributes to each Response.
server: Controls the default HTTP server via cherrypy.server.
These can only be declared in the global config.
tools: Runs and configures additional request-processing packages.
wsgi: Adds WSGI middleware to an Application's "pipeline".
These can only be declared in the app's root config ("/").
checker: Controls the 'checker', which looks for common errors in
app state (including config) when the engine starts.
Global config only.
The only key that does not exist in a namespace is the "environment" entry.
This special entry 'imports' other config entries from a template stored in
cherrypy._cpconfig.environments[environment]. It only applies to the global
config, and only when you use cherrypy.config.update.
You can define your own namespaces to be called at the Global, Application,
or Request level, by adding a named handler to cherrypy.config.namespaces,
app.namespaces, or app.request_class.namespaces. The name can
be any string, and the handler must be either a callable or a (Python 2.5
style) context manager.
"""
try:
set
except NameError:
from sets import Set as set
import cherrypy
from cherrypy.lib import reprconf
# Deprecated in CherryPy 3.2--remove in 3.3
NamespaceSet = reprconf.NamespaceSet
def merge(base, other):
"""Merge one app config (from a dict, file, or filename) into another.
If the given config is a filename, it will be appended to
the list of files to monitor for "autoreload" changes.
"""
if isinstance(other, basestring):
cherrypy.engine.autoreload.files.add(other)
# Load other into base
for section, value_map in reprconf.as_dict(other).items():
if not isinstance(value_map, dict):
raise ValueError(
"Application config must include section headers, but the "
"config you tried to merge doesn't have any sections. "
"Wrap your config in another dict with paths as section "
"headers, for example: {'/': config}.")
base.setdefault(section, {}).update(value_map)
class Config(reprconf.Config):
"""The 'global' configuration data for the entire CherryPy process."""
def update(self, config):
"""Update self from a dict, file or filename."""
if isinstance(config, basestring):
# Filename
cherrypy.engine.autoreload.files.add(config)
reprconf.Config.update(self, config)
def _apply(self, config):
"""Update self from a dict."""
if isinstance(config.get("global", None), dict):
if len(config) > 1:
cherrypy.checker.global_config_contained_paths = True
config = config["global"]
if 'tools.staticdir.dir' in config:
config['tools.staticdir.section'] = "global"
reprconf.Config._apply(self, config)
def __call__(self, *args, **kwargs):
"""Decorator for page handlers to set _cp_config."""
if args:
raise TypeError(
"The cherrypy.config decorator does not accept positional "
"arguments; you must use keyword arguments.")
def tool_decorator(f):
if not hasattr(f, "_cp_config"):
f._cp_config = {}
for k, v in kwargs.items():
f._cp_config[k] = v
return f
return tool_decorator
Config.environments = environments = {
"staging": {
'engine.autoreload_on': False,
'checker.on': False,
'tools.log_headers.on': False,
'request.show_tracebacks': False,
'request.show_mismatched_params': False,
},
"production": {
'engine.autoreload_on': False,
'checker.on': False,
'tools.log_headers.on': False,
'request.show_tracebacks': False,
'request.show_mismatched_params': False,
'log.screen': False,
},
"embedded": {
# For use with CherryPy embedded in another deployment stack.
'engine.autoreload_on': False,
'checker.on': False,
'tools.log_headers.on': False,
'request.show_tracebacks': False,
'request.show_mismatched_params': False,
'log.screen': False,
'engine.SIGHUP': None,
'engine.SIGTERM': None,
},
"test_suite": {
'engine.autoreload_on': False,
'checker.on': False,
'tools.log_headers.on': False,
'request.show_tracebacks': True,
'request.show_mismatched_params': True,
'log.screen': False,
},
}
def _server_namespace_handler(k, v):
"""Config handler for the "server" namespace."""
atoms = k.split(".", 1)
if len(atoms) > 1:
# Special-case config keys of the form 'server.servername.socket_port'
# to configure additional HTTP servers.
if not hasattr(cherrypy, "servers"):
cherrypy.servers = {}
servername, k = atoms
if servername not in cherrypy.servers:
from cherrypy import _cpserver
cherrypy.servers[servername] = _cpserver.Server()
# On by default, but 'on = False' can unsubscribe it (see below).
cherrypy.servers[servername].subscribe()
if k == 'on':
if v:
cherrypy.servers[servername].subscribe()
else:
cherrypy.servers[servername].unsubscribe()
else:
setattr(cherrypy.servers[servername], k, v)
else:
setattr(cherrypy.server, k, v)
Config.namespaces["server"] = _server_namespace_handler
def _engine_namespace_handler(k, v):
"""Backward compatibility handler for the "engine" namespace."""
engine = cherrypy.engine
if k == 'autoreload_on':
if v:
engine.autoreload.subscribe()
else:
engine.autoreload.unsubscribe()
elif k == 'autoreload_frequency':
engine.autoreload.frequency = v
elif k == 'autoreload_match':
engine.autoreload.match = v
elif k == 'reload_files':
engine.autoreload.files = set(v)
elif k == 'deadlock_poll_freq':
engine.timeout_monitor.frequency = v
elif k == 'SIGHUP':
engine.listeners['SIGHUP'] = set([v])
elif k == 'SIGTERM':
engine.listeners['SIGTERM'] = set([v])
elif "." in k:
plugin, attrname = k.split(".", 1)
plugin = getattr(engine, plugin)
if attrname == 'on':
if v and hasattr(getattr(plugin, 'subscribe', None), '__call__'):
plugin.subscribe()
return
elif (not v) and hasattr(getattr(plugin, 'unsubscribe', None), '__call__'):
plugin.unsubscribe()
return
setattr(plugin, attrname, v)
else:
setattr(engine, k, v)
Config.namespaces["engine"] = _engine_namespace_handler
def _tree_namespace_handler(k, v):
"""Namespace handler for the 'tree' config namespace."""
cherrypy.tree.graft(v, v.script_name)
cherrypy.engine.log("Mounted: %s on %s" % (v, v.script_name or "/"))
Config.namespaces["tree"] = _tree_namespace_handler