Source code for google.appengine.api.request_info

#!/usr/bin/env python
#
# Copyright 2007 Google Inc.
#
# 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.
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"""Allows API stubs to access request and system state when handling calls.

Certain API stubs require access to information about the request that triggered
the API call (e.g. user_service_stub needs to know the host name of the request
to generate continuation URLs) or system state (e.g. modules_stub).

Other stubs (e.g. taskqueue_stub, channel_stub) need to be able to dispatch
requests within the system.

An instance of a RequestInfo subclass is passed to stubs that require these
capabilities.
"""

import logging
import operator
import os
import urllib


[docs]class Error(Exception): pass
[docs]class ModuleDoesNotExistError(Error): """The provided module does not exist."""
[docs]class VersionDoesNotExistError(Error): """The provided version does not exist."""
[docs]class InvalidInstanceIdError(Error): """The provided instance ID is invalid."""
[docs]class NotSupportedWithAutoScalingError(Error): """The requested operation is not supported for auto-scaling modules."""
[docs]class VersionAlreadyStartedError(Error): """The version is already started."""
[docs]class VersionAlreadyStoppedError(Error): """The version is already stopped."""
[docs]class BackgroundThreadLimitReachedError(Error): """The instance is at its background thread capacity."""
[docs]class ResponseTuple(tuple): 'ResponseTuple(status, headers, content)' __slots__ = () _fields = ('status', 'headers', 'content') def __new__(cls, status, headers, content): return tuple.__new__(cls, (status, headers, content)) @classmethod def _make(cls, iterable, new=tuple.__new__, len=len): result = new(cls, iterable) if len(result) != 3: raise TypeError('Expected 3 arguments, got %d' % len(result)) return result def __repr__(self): return 'ResponseTuple(status=%r, headers=%r, content=%r)' % self def _asdict(self): return dict(zip(self._fields, self)) __dict__ = property(_asdict) def _replace(self, **kwds): result = self._make(map(kwds.pop, ('status', 'headers', 'content'), self)) if kwds: raise ValueError('Got unexpected field names: %r' % kwds.keys()) return result def __getnewargs__(self): return tuple(self) status = property(operator.itemgetter(0), doc='Alias for field number 0') headers = property(operator.itemgetter(1), doc='Alias for field number 1') content = property(operator.itemgetter(2), doc='Alias for field number 2')
[docs]class Dispatcher(object): """Provides information about and dispatches requests to modules."""
[docs] def get_module_names(self): """Returns a list of module names.""" raise NotImplementedError()
[docs] def get_versions(self, module): """Returns a list of versions for a module. Args: module: A str containing the name of the module. Returns: A list of str containing the versions for the specified module. Raises: ModuleDoesNotExistError: The module does not exist. """ raise NotImplementedError()
[docs] def get_default_version(self, module): """Returns the default version for a module. Args: module: A str containing the name of the module. Returns: A str containing the default version for the specified module. Raises: ModuleDoesNotExistError: The module does not exist. """ raise NotImplementedError()
[docs] def get_hostname(self, module, version, instance=None): """Returns the hostname for a (module, version, instance) tuple. If instance is set, this will return a hostname for that particular instances. Otherwise, it will return the hostname for load-balancing. Args: module: A str containing the name of the module. version: A str containing the version. instance: An optional str containing the instance ID. Returns: A str containing the hostname. Raises: ModuleDoesNotExistError: The module does not exist. VersionDoesNotExistError: The version does not exist. InvalidInstanceIdError: The instance ID is not valid for the module/version or the module/version uses automatic scaling. """ raise NotImplementedError()
[docs] def set_num_instances(self, module, version, instances): """Sets the number of instances to run for a version of a module. Args: module: A str containing the name of the module. version: A str containing the version. instances: An int containing the number of instances to run. Raises: ModuleDoesNotExistError: The module does not exist. VersionDoesNotExistError: The version does not exist. NotSupportedWithAutoScalingError: The provided module/version uses automatic scaling. """ raise NotImplementedError()
[docs] def get_num_instances(self, module, version): """Gets the number of instances running for a version of a module. Args: module: A str containing the name of the module. version: A str containing the version. Raises: ModuleDoesNotExistError: The module does not exist. VersionDoesNotExistError: The version does not exist. NotSupportedWithAutoScalingError: The provided module/version uses automatic scaling. """ raise NotImplementedError()
[docs] def start_version(self, module, version): """Starts a version. Args: module: A str containing the name of the module. version: A str containing the version. Raises: ModuleDoesNotExistError: The module does not exist. VersionDoesNotExistError: The version does not exist. NotSupportedWithAutoScalingError: The provided module/version uses automatic scaling. """ raise NotImplementedError()
[docs] def stop_version(self, module, version): """Stops a version. Args: module: A str containing the name of the module. version: A str containing the version. Raises: ModuleDoesNotExistError: The module does not exist. VersionDoesNotExistError: The version does not exist. NotSupportedWithAutoScalingError: The provided module/version uses automatic scaling. """ raise NotImplementedError()
[docs] def add_event(self, runnable, eta, service=None, event_id=None): """Add a callable to be run at the specified time. Args: runnable: A callable object to call at the specified time. eta: An int containing the time to run the event, in seconds since the epoch. service: A str containing the name of the service that owns this event. This should be set if event_id is set. event_id: A str containing the id of the event. If set, this can be passed to update_event to change the time at which the event should run. """ raise NotImplementedError()
[docs] def update_event(self, eta, service, event_id): """Update the eta of a scheduled event. Args: eta: An int containing the time to run the event, in seconds since the epoch. service: A str containing the name of the service that owns this event. event_id: A str containing the id of the event to update. """ raise NotImplementedError()
[docs] def add_request(self, method, relative_url, headers, body, source_ip, module_name=None, version=None, instance_id=None): """Process an HTTP request. Args: method: A str containing the HTTP method of the request. relative_url: A str containing path and query string of the request. headers: A list of (key, value) tuples where key and value are both str. body: A str containing the request body. source_ip: The source ip address for the request. module_name: An optional str containing the module name to service this request. If unset, the request will be dispatched to the default module. version: An optional str containing the version to service this request. If unset, the request will be dispatched to the default version. instance_id: An optional str containing the instance_id of the instance to service this request. If unset, the request will be dispatched to according to the load-balancing for the module and version. Returns: A ResponseTuple containing the response information for the HTTP request. """ raise NotImplementedError()
[docs] def add_async_request(self, method, relative_url, headers, body, source_ip, module_name=None, version=None, instance_id=None): """Dispatch an HTTP request asynchronously. Args: method: A str containing the HTTP method of the request. relative_url: A str containing path and query string of the request. headers: A list of (key, value) tuples where key and value are both str. body: A str containing the request body. source_ip: The source ip address for the request. module_name: An optional str containing the module name to service this request. If unset, the request will be dispatched to the default module. version: An optional str containing the version to service this request. If unset, the request will be dispatched to the default version. instance_id: An optional str containing the instance_id of the instance to service this request. If unset, the request will be dispatched to according to the load-balancing for the module and version. """ raise NotImplementedError()
[docs] def send_background_request(self, module_name, version, instance, background_request_id): """Dispatch a background thread request. Args: module_name: A str containing the module name to service this request. version: A str containing the version to service this request. instance: The instance to service this request. background_request_id: A str containing the unique background thread request identifier. Raises: NotSupportedWithAutoScalingError: The provided module/version uses automatic scaling. BackgroundThreadLimitReachedError: The instance is at its background thread capacity. """ raise NotImplementedError()
class _LocalFakeDispatcher(Dispatcher): """A fake Dispatcher implementation usable by tests.""" def __init__(self, module_names=None, module_name_to_versions=None, module_name_to_default_versions=None, module_name_to_version_to_hostname=None): super(_LocalFakeDispatcher, self).__init__() if module_names is None: module_names = ['default'] if module_name_to_versions is None: module_name_to_versions = {'default': ['1']} if module_name_to_default_versions is None: module_name_to_default_versions = {'default': '1'} if module_name_to_version_to_hostname is None: module_name_to_version_to_hostname = {'default': {'1': 'localhost:8080'}} self._module_names = module_names self._module_name_to_versions = module_name_to_versions self._module_name_to_default_versions = module_name_to_default_versions self._module_name_to_version_to_hostname = ( module_name_to_version_to_hostname) def get_module_names(self): """Returns a list of module names.""" return self._module_names def get_versions(self, module): """Returns a list of versions for a module. Args: module: A str containing the name of the module. Returns: A list of str containing the versions for the specified module. Raises: ModuleDoesNotExistError: The module does not exist. """ if module not in self._module_name_to_versions: raise ModuleDoesNotExistError() return self._module_name_to_versions[module] def get_default_version(self, module): """Returns the default version for a module. Args: module: A str containing the name of the module. Returns: A str containing the default version for the specified module. Raises: ModuleDoesNotExistError: The module does not exist. """ if module not in self._module_name_to_default_versions: raise ModuleDoesNotExistError() return self._module_name_to_default_versions[module] def get_hostname(self, module, version, instance=None): """Returns the hostname for a (module, version, instance) tuple. If instance is set, this will return a hostname for that particular instances. Otherwise, it will return the hostname for load-balancing. Args: module: A str containing the name of the module. version: A str containing the version. instance: An optional str containing the instance ID. Returns: A str containing the hostname. Raises: ModuleDoesNotExistError: The module does not exist. VersionDoesNotExistError: The version does not exist. InvalidInstanceIdError: The instance ID is not valid for the module/version or the module/version uses automatic scaling. """ if module not in self._module_name_to_version_to_hostname: raise ModuleDoesNotExistError() if version not in self._module_name_to_version_to_hostname[module]: raise VersionDoesNotExistError() if instance: raise InvalidInstanceIdError() return self._module_name_to_version_to_hostname[module][version] def set_num_instances(self, module, version, instances): """Sets the number of instances to run for a version of a module. Args: module: A str containing the name of the module. version: A str containing the version. instances: An int containing the number of instances to run. Raises: ModuleDoesNotExistError: The module does not exist. VersionDoesNotExistError: The version does not exist. NotSupportedWithAutoScalingError: The provided module/version uses automatic scaling. """ if module not in self._module_name_to_versions: raise ModuleDoesNotExistError() if version not in self._module_name_to_versions[module]: raise VersionDoesNotExistError() raise NotSupportedWithAutoScalingError() def get_num_instances(self, module, version): """Gets the number of instances running for a version of a module. Args: module: A str containing the name of the module. version: A str containing the version. Raises: ModuleDoesNotExistError: The module does not exist. VersionDoesNotExistError: The version does not exist. NotSupportedWithAutoScalingError: The provided module/version uses automatic scaling. """ if module not in self._module_name_to_versions: raise ModuleDoesNotExistError() if version not in self._module_name_to_versions[module]: raise VersionDoesNotExistError() raise NotSupportedWithAutoScalingError() def start_version(self, module, version): """Starts a version. Args: module: A str containing the name of the module. version: A str containing the version. Raises: ModuleDoesNotExistError: The module does not exist. VersionDoesNotExistError: The version does not exist. NotSupportedWithAutoScalingError: The provided module/version uses automatic scaling. """ if module not in self._module_name_to_versions: raise ModuleDoesNotExistError() if version not in self._module_name_to_versions[module]: raise VersionDoesNotExistError() raise NotSupportedWithAutoScalingError() def stop_version(self, module, version): """Stops a version. Args: module: A str containing the name of the module. version: A str containing the version. Raises: ModuleDoesNotExistError: The module does not exist. VersionDoesNotExistError: The version does not exist. NotSupportedWithAutoScalingError: The provided module/version uses automatic scaling. """ if module not in self._module_name_to_versions: raise ModuleDoesNotExistError() if version not in self._module_name_to_versions[module]: raise VersionDoesNotExistError() raise NotSupportedWithAutoScalingError() def add_event(self, runnable, eta, service=None, event_id=None): """Add a callable to be run at the specified time. Args: runnable: A callable object to call at the specified time. eta: An int containing the time to run the event, in seconds since the epoch. service: A str containing the name of the service that owns this event. This should be set if event_id is set. event_id: A str containing the id of the event. If set, this can be passed to update_event to change the time at which the event should run. """ logging.warning('Scheduled events are not supported with ' '_LocalFakeDispatcher') def update_event(self, eta, service, event_id): """Update the eta of a scheduled event. Args: eta: An int containing the time to run the event, in seconds since the epoch. service: A str containing the name of the service that owns this event. event_id: A str containing the id of the event to update. """ logging.warning('Scheduled events are not supported with ' '_LocalFakeDispatcher') def add_request(self, method, relative_url, headers, body, source_ip, module_name=None, version=None, instance_id=None): """Process an HTTP request. Args: method: A str containing the HTTP method of the request. relative_url: A str containing path and query string of the request. headers: A list of (key, value) tuples where key and value are both str. body: A str containing the request body. source_ip: The source ip address for the request. module_name: An optional str containing the module name to service this request. If unset, the request will be dispatched to the default module. version: An optional str containing the version to service this request. If unset, the request will be dispatched to the default version. instance_id: An optional str containing the instance_id of the instance to service this request. If unset, the request will be dispatched to according to the load-balancing for the module and version. Returns: A ResponseTuple containing the response information for the HTTP request. """ logging.warning('Request dispatching is not supported with ' '_LocalFakeDispatcher') return ResponseTuple('501 Not Implemented', [], '') def add_async_request(self, method, relative_url, headers, body, source_ip, module_name=None, version=None, instance_id=None): """Dispatch an HTTP request asynchronously. Args: method: A str containing the HTTP method of the request. relative_url: A str containing path and query string of the request. headers: A list of (key, value) tuples where key and value are both str. body: A str containing the request body. source_ip: The source ip address for the request. module_name: An optional str containing the module name to service this request. If unset, the request will be dispatched to the default module. version: An optional str containing the version to service this request. If unset, the request will be dispatched to the default version. instance_id: An optional str containing the instance_id of the instance to service this request. If unset, the request will be dispatched to according to the load-balancing for the module and version. """ logging.warning('Request dispatching is not supported with ' '_LocalFakeDispatcher') def send_background_request(self, module_name, version, instance, background_request_id): """Dispatch a background thread request. Args: module_name: A str containing the module name to service this request. version: A str containing the version to service this request. instance: The instance to service this request. background_request_id: A str containing the unique background thread request identifier. Raises: NotSupportedWithAutoScalingError: The provided module/version uses automatic scaling. BackgroundThreadLimitReachedError: The instance is at its background thread capacity. """ logging.warning('Request dispatching is not supported with ' '_LocalFakeDispatcher') raise BackgroundThreadLimitReachedError() _local_dispatcher = _LocalFakeDispatcher()
[docs]class RequestInfo(object): """Allows stubs to lookup state linked to the request making the API call."""
[docs] def get_request_url(self, request_id): """Returns the URL the request e.g. 'http://localhost:8080/foo?bar=baz'. Args: request_id: The string id of the request making the API call. Returns: The URL of the request as a string. """ raise NotImplementedError()
[docs] def get_request_environ(self, request_id): """Returns a dict containing the WSGI environ for the request.""" raise NotImplementedError()
[docs] def get_module(self, request_id): """Returns the name of the module serving this request. Args: request_id: The string id of the request making the API call. Returns: A str containing the module name. """ raise NotImplementedError()
[docs] def get_version(self, request_id): """Returns the version of the module serving this request. Args: request_id: The string id of the request making the API call. Returns: A str containing the version. """ raise NotImplementedError()
[docs] def get_instance(self, request_id): """Returns the instance serving this request. Args: request_id: The string id of the request making the API call. Returns: An opaque representation of the instance serving this request. It should only be passed to dispatcher methods expecting an instance. """ raise NotImplementedError()
[docs] def get_dispatcher(self): """Returns the Dispatcher. Returns: The Dispatcher instance. """ raise NotImplementedError()
[docs] def register_request_id(self, environ, request_id): """Registers a simulated HTTP request from the dev_appserver. Subclasses are not required to provide an implementation. Args: environ: An environ dict for the request as defined in PEP-333. request_id: The string id of the request making the API call. """
class _LocalRequestInfo(RequestInfo): """Lookup information about a request using environment variables.""" def get_request_url(self, request_id): """Returns the URL the request e.g. 'http://localhost:8080/foo?bar=baz'. Args: request_id: The string id of the request making the API call. Returns: The URL of the request as a string. """ try: host = os.environ['HTTP_HOST'] except KeyError: host = os.environ['SERVER_NAME'] port = os.environ['SERVER_PORT'] if port != '80': host += ':' + port url = 'http://' + host url += urllib.quote(os.environ.get('PATH_INFO', '/')) if os.environ.get('QUERY_STRING'): url += '?' + os.environ['QUERY_STRING'] return url def get_request_environ(self, request_id): """Returns a dict containing the WSGI environ for the request.""" return os.environ def get_module(self, request_id): """Returns the name of the module serving this request. Args: request_id: The string id of the request making the API call. Returns: A str containing the module name. """ return 'default' def get_version(self, request_id): """Returns the version of the module serving this request. Args: request_id: The string id of the request making the API call. Returns: A str containing the version. """ return '1' def get_instance(self, request_id): """Returns the instance serving this request. Args: request_id: The string id of the request making the API call. Returns: An opaque representation of the instance serving this request. It should only be passed to dispatcher methods expecting an instance. """ return object() def get_dispatcher(self): """Returns the Dispatcher. Returns: The Dispatcher instance. """ return _local_dispatcher _local_request_info = _LocalRequestInfo()

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