Differential D2348 Diff 8390 swh/lister/core/lister_transports.py

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swh/lister/core/lister_transports.py

# Copyright (C) 2017-2018 the Software Heritage developers		# Copyright (C) 2017-2019 the Software Heritage developers
# License: GNU General Public License version 3, or any later version		# License: GNU General Public License version 3, or any later version
# See top-level LICENSE file for more information		# See top-level LICENSE file for more information

import abc		import abc
import random		import random
from datetime import datetime		from datetime import datetime
from email.utils import parsedate		from email.utils import parsedate
from pprint import pformat		from pprint import pformat
import logging		import logging

import requests		import requests
import xmltodict		import xmltodict

from typing import Optional, Union		from typing import Any, Dict, Mapping, Optional, Tuple, Union

from swh.lister import USER_AGENT_TEMPLATE, __version__		from swh.lister import USER_AGENT_TEMPLATE, __version__

from .abstractattribute import AbstractAttribute		from .abstractattribute import AbstractAttribute
from .lister_base import FetchError		from .lister_base import FetchError


logger = logging.getLogger(__name__)		logger = logging.getLogger(__name__)


class ListerHttpTransport(abc.ABC):		class ListerHttpTransport(abc.ABC):
"""Use the Requests library for making Lister endpoint requests.		"""Use the Requests library for making Lister endpoint requests.

To be used in conjunction with ListerBase or a subclass of it.		To be used in conjunction with ListerBase or a subclass of it.
"""		"""
DEFAULT_URL = None # type: Optional[str]		DEFAULT_URL = None # type: Optional[str]
PATH_TEMPLATE = \		PATH_TEMPLATE = \
AbstractAttribute(		AbstractAttribute(
'string containing a python string format pattern that produces'		'string containing a python string format pattern that produces'
' the API endpoint path for listing stored repositories when given'		' the API endpoint path for listing stored repositories when given'
' an index, e.g., "/repositories?after=%s". To be implemented in'		' an index, e.g., "/repositories?after=%s". To be implemented in'
' the API-specific class inheriting this.'		' the API-specific class inheriting this.'
) # type: Union[AbstractAttribute, Optional[str]]		) # type: Union[AbstractAttribute, Optional[str]]

EXPECTED_STATUS_CODES = (200, 429, 403, 404)		EXPECTED_STATUS_CODES = (200, 429, 401, 403, 404)
		# All instance credentials to use
		creds: Optional[Dict[str, Any]] = None
		# The current elected authentication tuple
		auth: Optional[Tuple[str, str]] = None

def request_headers(self):		def request_headers(self):
"""Returns dictionary of any request headers needed by the server.		"""Returns dictionary of any request headers needed by the server.

MAY BE OVERRIDDEN if request headers are needed.		MAY BE OVERRIDDEN if request headers are needed.
"""		"""
return {		return {
'User-Agent': USER_AGENT_TEMPLATE % self.lister_version		'User-Agent': USER_AGENT_TEMPLATE % self.lister_version
}		}

def request_instance_credentials(self):		def request_instance_credentials(self) -> Mapping[str, Any]:
"""Returns dictionary of any credentials configuration needed by the		"""Returns dictionary of any credentials configuration needed by the
forge instance to list.		forge instance to list.

The 'credentials' configuration is expected to be a dict of multiple		The 'credentials' configuration is expected to be a dict of multiple
levels. The first level is the lister's name, the second is the		levels. The first level is the lister's name, the second is the
lister's instance name, which value is expected to be a list of		lister's instance name, which value is expected to be a list of
credential structures (typically a couple username/password).		credential structures (typically a couple username/password).

For example:		For example:

credentials:		credentials:
github: # github lister		github: # github lister
github: # has only one instance (so far)		github: # has only one instance (so far)
- username: some		- username: some
password: somekey		password: somekey
- username: one		- username: one
password: onekey		password: onekey
- ...		- ...
gitlab: # gitlab lister		gitlab: # gitlab lister
riseup: # has many instances		riseup: # has many instances
- username: someone		- username: someone
password: ...		password: ...
- ...		- username: another
		...
gitlab:		gitlab:
- username: someone		- username: someone
password: ...		password: ...
- ...

Returns:		Returns:
list of credential dicts for the current lister.		Dict of credential dicts (key: login, value: dict) for the current
		lister. For example, for lister 'gitlab', instance 'riseup':

		{
		someone: {'username': 'someone', "password": ...},
		another: {'username': 'another', "password": ...},
		...
		}


"""		"""
all_creds = self.config.get('credentials')		if self.creds is None:
		ardumontAuthorUnsubmitted Done Inline Actions `type: ignore` because otherwise it complains about the `config` not being declared for that class... which is also true... but... let's refactor this another day. (same goes for the other `type: ignore` below) ardumont: `type: ignore` because otherwise it complains about the `config` not being declared for that…
		all_creds = self.config.get('credentials') # type: ignore
if not all_creds:		if not all_creds:
return []		return {}
lister_creds = all_creds.get(self.LISTER_NAME, {})		lister_creds = all_creds.get(self.LISTER_NAME, {}) # type: ignore
creds = lister_creds.get(self.instance, [])		instance_creds = lister_creds.get(
return creds		self.instance, []) # type: ignore
		creds = {}
		for cred in instance_creds:
		creds[cred['username']] = cred
		self.creds = creds

		return self.creds

def request_uri(self, identifier):		def request_uri(self, identifier):
"""Get the full request URI given the transport_request identifier.		"""Get the full request URI given the transport_request identifier.

MAY BE OVERRIDDEN if something more complex than the PATH_TEMPLATE is		MAY BE OVERRIDDEN if something more complex than the PATH_TEMPLATE is
required.		required.
"""		"""
path = self.PATH_TEMPLATE % identifier		path = self.PATH_TEMPLATE % identifier
Show All 10 Lines	def request_params(self, identifier):
is needed.		is needed.

"""		"""
params = {}		params = {}
params['headers'] = self.request_headers() or {}		params['headers'] = self.request_headers() or {}
creds = self.request_instance_credentials()		creds = self.request_instance_credentials()
if not creds:		if not creds:
return params		return params
auth = random.choice(creds) if creds else None		if self.auth: # Already elected token, reuse
if auth:		params['auth'] = self.auth
params['auth'] = (auth['username'], auth['password'])		else:
		login = random.choice(list(creds)) if creds else None
		if login:
		auth = creds[login]
		self.auth = (auth['username'], auth['password'])
		params['auth'] = self.auth
return params		return params

		douarddaUnsubmitted Not Done Inline Actions I don't really understand the semantic of 'reset' in the method (at first glance). Why this 'reset' does remove a token? Remove from what? Why/when is this useful or needed? I mean credentials are loaded by the 'request_instance_credentials' method. Now this method (I guess called when a credential usage generated errors ; not yet read the remaining of the code), will gradually remove entries from the list of known credentials. So each time an error occurs this list will be pop'd. Not sure I like this behavior very much. It might be better to be able to temporarily disable a credential. Then check on a regular base if the credential can be enabled again. Also, the credential 'status' is kept local to the class. Whereas we have many workers. It might be useful to think about a solution for this state to be shared among workers (using memcache, etcd or similar). Not to be done right now in this diff, obviously :D douardda: I don't really understand the semantic of 'reset' in the method (at first glance). Why this…
		ardumontAuthorUnsubmitted Done Inline Actions Why this 'reset' does remove a token? yes, `remove_authentication_token` sounds better now. Remove from what? From the current setup initially loaded (from the configuration file) at the task startup. Why/when is this useful or needed? That'd be the task linked in the description T2099. ardumont: > Why this 'reset' does remove a token? yes,` remove_authentication_token` sounds better now.
		def reset_authentication_token(self) -> bool:
		"""Reset the current authentication token if any.

		Returns
		True if the reset is actually effective (token has been removed),
		False otherwise.

		"""
		effective_reset = False
		if self.auth is not None and self.creds:
		login = self.auth[0]
		actual_token = self.creds.get(login)
		if actual_token == self.auth:
		self.creds.pop(login)
		effective_reset = True
		return effective_reset

def transport_quota_check(self, response):		def transport_quota_check(self, response):
"""Implements ListerBase.transport_quota_check with standard 429		"""Implements ListerBase.transport_quota_check with standard 429
code check for HTTP with Requests library.		code check for HTTP with Requests library.

MAY BE OVERRIDDEN if the server notifies about rate limits in a		MAY BE OVERRIDDEN if the server notifies about rate limits in a
non-standard way that doesn't use HTTP 429 and the Retry-After		non-standard way that doesn't use HTTP 429 and the Retry-After
response header. ( https://tools.ietf.org/html/rfc6585#section-4 )		response header. ( https://tools.ietf.org/html/rfc6585#section-4 )

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