# -*- coding: utf-8 -*-
"""Link Database
===================
The :mod:`darc` project utilises `Redis`_ based database
to provide tele-process communication.
.. note::
In its first implementation, the :mod:`darc` project used
:class:`~multiprocessing.Queue` to support such communication.
However, as noticed when runtime, the :class:`~multiprocessing.Queue`
object will be much affected by the lack of memory.
There will be three databases, all following the save naming
convension with ``queue_`` prefix:
* the hostname database -- ``queue_hostname`` (:class:`~darc.model.tasks.hostname.HostnameQueueModel`)
* the :mod:`requests` database -- ``queue_requests`` (:class:`~darc.model.tasks.requests.RequestsQueueModel`)
* the :mod:`selenium` database -- ``queue_selenium`` (:class:`~darc.model.tasks.selenium.SeleniumQueueModel`)
For ``queue_hostname``, ``queue_requests`` and ``queue_selenium``,
they are all `Redis`_ **sorted set** data type.
If :data:`~darc.const.FLAG_DB` is :data:`True`, then the
module uses the RDS storage described by the :mod:`peewee`
models as backend.
.. _Redis: https://redis.io/
"""
import contextlib
import datetime
import math
import os
import pickle # nosec
import pprint
import shutil
import sys
import textwrap
import time
import warnings
import peewee
import redis.lock as redis_lock
import stem.util.term
import darc.typing as typing
from darc._compat import nullcontext
from darc.const import CHECK
from darc.const import DB as database
from darc.const import FLAG_DB
from darc.const import REDIS as redis
from darc.const import TIME_CACHE, VERBOSE
from darc.error import DatabaseOperaionFailed, LockWarning, RedisCommandFailed, render_error
from darc.link import Link
from darc.model.tasks import HostnameQueueModel, RequestsQueueModel, SeleniumQueueModel
from darc.parse import _check
# use lock?
REDIS_LOCK = bool(int(os.getenv('DARC_REDIS_LOCK', '0')))
# Redis retry interval
RETRY_INTERVAL = float(os.getenv('DARC_RETRY', '10'))
if not math.isfinite(RETRY_INTERVAL):
RETRY_INTERVAL = None # type: ignore
# lock blocking timeout
LOCK_TIMEOUT = float(os.getenv('DARC_LOCK_TIMEOUT', '10'))
if not math.isfinite(LOCK_TIMEOUT):
LOCK_TIMEOUT = None # type: ignore
# bulk size
BULK_SIZE = int(os.getenv('DARC_BULK_SIZE', '100'))
# max pool
MAX_POOL = float(os.getenv('DARC_MAX_POOL', '100'))
if math.isfinite(MAX_POOL):
MAX_POOL = math.floor(MAX_POOL)
[docs]def _gen_arg_msg(*args, **kwargs) -> str:
"""Sanitise arguments representation string.
Args:
*args: Arbitrary arguments.
Keyword Args:
**kwargs: Arbitrary keyword arguments.
Returns:
Sanitised arguments representation string.
"""
_args = ', '.join(map(repr, args))
_kwargs = ', '.join(f'{k}={v!r}' for k, v in kwargs.items())
if _kwargs:
if _args:
_args += ', '
_args += _kwargs
return textwrap.shorten(_args, shutil.get_terminal_size().columns)
[docs]def _redis_command(command: str, *args, **kwargs) -> typing.Any:
"""Wrapper function for Redis command.
Args:
command: Command name.
*args: Arbitrary arguments for the Redis command.
Keyword Args:
**kwargs: Arbitrary keyword arguments for the Redis command.
Return:
Values returned from the Redis command.
Warns:
RedisCommandFailed: Warns at each round when the command failed.
See Also:
Between each retry, the function sleeps for :data:`~darc.db.RETRY_INTERVAL`
second(s) if such value is **NOT** :data:`None`.
"""
_arg_msg = None
method = getattr(redis, command)
while True:
try:
value = method(*args, **kwargs)
except Exception as error:
if _arg_msg is None:
_arg_msg = _gen_arg_msg(*args, **kwargs)
warning = warnings.formatwarning(str(error), RedisCommandFailed, __file__, 131,
f'value = redis.{command}({_arg_msg})')
print(render_error(warning, stem.util.term.Color.YELLOW), end='', file=sys.stderr) # pylint: disable=no-member
if RETRY_INTERVAL is not None:
time.sleep(RETRY_INTERVAL)
continue
break
return value
[docs]def _db_operation(operation: typing.Callable[..., typing.T], *args, **kwargs) -> typing.T:
"""Retry operation on database.
Args:
operation: Callable / method to perform.
*args: Arbitrary positional arguments.
Keyword Args:
**kwargs: Arbitrary keyword arguments.
Returns:
Any return value from a successful
``operation`` call.
"""
_arg_msg = None
while True:
try:
value = operation(*args, **kwargs)
except Exception as error:
if _arg_msg is None:
_arg_msg = _gen_arg_msg(*args, **kwargs)
model = typing.cast(typing.MethodType, operation).__self__.__class__.__name__
warning = warnings.formatwarning(str(error), DatabaseOperaionFailed, __file__, 168,
f'{model}.{operation.__name__}({_arg_msg})')
print(render_error(warning, stem.util.term.Color.YELLOW), end='', file=sys.stderr) # pylint: disable=no-member
if RETRY_INTERVAL is not None:
time.sleep(RETRY_INTERVAL)
continue
break
return value
[docs]def _redis_get_lock(name: str,
timeout: typing.Optional[float] = None,
sleep: float = 0.1,
blocking_timeout: typing.Optional[float] = None,
lock_class: typing.Optional[redis_lock.Lock] = None,
thread_local: bool = True) -> typing.Union[redis_lock.Lock, nullcontext]: # type: ignore
"""Get a lock for Redis operations.
Args:
name: Lock name.
timeout: Maximum life for the lock.
sleep: Amount of time to sleep per loop iteration when the
lock is in blocking mode and another client is currently
holding the lock.
blocking_timeout: Maximum amount of time in seconds to spend
trying to acquire the lock.
lock_class: Lock implementation.
thread_local: Whether the lock token is placed in thread-local
storage.
Returns:
Return a new :class:`redis.lock.Lock` object using key ``name``
that mimics the behavior of :class:`threading.Lock`.
Seel Also:
If :data:`~darc.db.REDIS_LOCK` is :data:`False`, returns a
:class:`contextlib.nullcontext` instead.
"""
if REDIS_LOCK:
return _redis_command('lock', name, timeout, sleep, blocking_timeout, lock_class, thread_local)
return nullcontext()
[docs]def have_hostname(link: Link) -> typing.Tuple[bool, bool]:
"""Check if current link is a new host.
Args:
link: Link to check against.
Returns:
A tuple of two :obj:`bool` values representing
if such link is a known host and needs force
refetch respectively.
See Also:
* :func:`darc.db._have_hostname_db`
* :func:`darc.db._have_hostname_redis`
"""
if FLAG_DB:
with database.connection_context():
try:
return _have_hostname_db(link)
except Exception as error:
warning = warnings.formatwarning(str(error), DatabaseOperaionFailed, __file__, 238,
f'_have_hostname_db({link})')
print(render_error(warning, stem.util.term.Color.YELLOW), end='', file=sys.stderr) # pylint: disable=no-member
return False, False
return _have_hostname_redis(link)
[docs]def _have_hostname_db(link: Link) -> typing.Tuple[bool, bool]:
"""Check if current link is a new host.
The function checks the :class:`~darc.models.tasks.hostname.HostnameQueueModel` table.
Args:
link: Link to check against.
Returns:
A tuple of two :obj:`bool` values representing
if such link is a known host and needs force
refetch respectively.
"""
timestamp = datetime.datetime.now()
if TIME_CACHE is None:
threshold = math.inf
else:
threshold = timestamp - TIME_CACHE
model, created = _db_operation(HostnameQueueModel.get_or_create, hostname=link.host, defaults=dict(
timestamp=timestamp,
))
if created:
return False, False
return True, model.timestamp < threshold
[docs]def _have_hostname_redis(link: Link) -> typing.Tuple[bool, bool]:
"""Check if current link is a new host.
The function checks the ``queue_hostname`` database.
Args:
link: Link to check against.
Returns:
A tuple of two :obj:`bool` values representing
if such link is a known host and needs force
refetch respectively.
"""
new_score = time.time()
if TIME_CACHE is None:
threshold = math.inf
else:
threshold = new_score - TIME_CACHE.total_seconds()
with _redis_get_lock('lock_queue_hostname'): # type: ignore
score = _redis_command('zscore', 'queue_hostname', link.name)
_redis_command('zadd', 'queue_hostname', {
link.host: new_score,
})
if score is None:
return False, False
return True, score < threshold
[docs]def drop_hostname(link: Link): # pylint: disable=inconsistent-return-statements
"""Remove link from the hostname database.
Args:
link: Link to be removed.
See Also:
* :func:`darc.db._drop_hostname_db`
* :func:`darc.db._drop_hostname_redis`
"""
if FLAG_DB:
with database.connection_context():
try:
return _drop_hostname_db(link)
except Exception as error:
warning = warnings.formatwarning(str(error), DatabaseOperaionFailed, __file__, 318,
f'_drop_hostname_db({link})')
print(render_error(warning, stem.util.term.Color.YELLOW), end='', file=sys.stderr) # pylint: disable=no-member
return
return _drop_hostname_redis(link)
[docs]def _drop_hostname_db(link: Link):
"""Remove link from the hostname database.
The function updates the :class:`~darc.models.tasks.hostname.HostnameQueueModel` table.
Args:
link: Link to be removed.
"""
model: HostnameQueueModel = _db_operation(HostnameQueueModel.get_or_none,
HostnameQueueModel.hostname == link.host)
if model is None:
return
model.delete_instance()
[docs]def _drop_hostname_redis(link: Link):
"""Remove link from the hostname database.
The function updates the ``queue_hostname`` database.
Args:
link: Link to be removed.
"""
with _redis_get_lock('lock_queue_hostname'): # type: ignore
_redis_command('zrem', 'queue_hostname', link.host)
[docs]def drop_requests(link: Link): # pylint: disable=inconsistent-return-statements
"""Remove link from the :mod:`requests` database.
Args:
link: Link to be removed.
See Also:
* :func:`darc.db._drop_requests_db`
* :func:`darc.db._drop_requests_redis`
"""
if FLAG_DB:
with database.connection_context():
try:
return _drop_requests_db(link)
except Exception as error:
warning = warnings.formatwarning(str(error), DatabaseOperaionFailed, __file__, 370,
f'_drop_requests_db({link})')
print(render_error(warning, stem.util.term.Color.YELLOW), end='', file=sys.stderr) # pylint: disable=no-member
return
return _drop_requests_redis(link)
[docs]def _drop_requests_db(link: Link):
"""Remove link from the :mod:`requests` database.
The function updates the :class:`~darc.model.tasks.requests.RequestsQueueModel` table.
Args:
link: Link to be removed.
"""
model: RequestsQueueModel = _db_operation(RequestsQueueModel.get_or_none,
RequestsQueueModel.text == link.url)
if model is None:
return
model.delete_instance()
[docs]def _drop_requests_redis(link: Link):
"""Remove link from the :mod:`requests` database.
The function updates the ``queue_requests`` database.
Args:
link: Link to be removed.
"""
with _redis_get_lock('lock_queue_requests'): # type: ignore
_redis_command('zrem', 'queue_requests', link.name)
[docs]def drop_selenium(link: Link): # pylint: disable=inconsistent-return-statements
"""Remove link from the :mod:`selenium` database.
Args:
link: Link to be removed.
See Also:
* :func:`darc.db._drop_selenium_db`
* :func:`darc.db._drop_selenium_redis`
"""
if FLAG_DB:
with database.connection_context():
try:
return _drop_selenium_db(link)
except Exception as error:
warning = warnings.formatwarning(str(error), DatabaseOperaionFailed, __file__, 422,
f'_drop_selenium_db({link})')
print(render_error(warning, stem.util.term.Color.YELLOW), end='', file=sys.stderr) # pylint: disable=no-member
return
return _drop_selenium_redis(link)
[docs]def _drop_selenium_db(link: Link):
"""Remove link from the :mod:`selenium` database.
The function updates the :class:`~darc.model.tasks.selenium.SeleniumQueueModel` table.
Args:
link: Link to be removed.
"""
model: SeleniumQueueModel = _db_operation(SeleniumQueueModel.get_or_none,
SeleniumQueueModel.text == link.url)
if model is None:
return
model.delete_instance()
[docs]def _drop_selenium_redis(link: Link):
"""Remove link from the :mod:`selenium` database.
The function updates the ``queue_selenium`` database.
Args:
link: Link to be removed.
"""
with _redis_get_lock('lock_queue_selenium'): # type: ignore
_redis_command('zrem', 'queue_selenium', link.name)
[docs]def save_requests(entries: typing.Union[Link, typing.List[Link]], single: bool = False, # pylint: disable=inconsistent-return-statements
score=None, nx=False, xx=False):
"""Save link to the :mod:`requests` database.
The function updates the ``queue_requests`` database.
Args:
entries: Links to be added to the :mod:`requests` database.
It can be either a :obj:`list` of links, or a single
link string (if ``single`` set as :data:`True`).
single: Indicate if ``entries`` is a :obj:`list` of links
or a single link string.
score: Score to for the Redis sorted set.
nx: Only create new elements and not to
update scores for elements that already exist.
xx: Only update scores of elements that
already exist. New elements will not be added.
Notes:
The ``entries`` will be dumped through :mod:`pickle` so that
:mod:`darc` do not need to parse them again.
When ``entries`` is a list of :class:`~darc.link.Link` instances,
we tries to perform *bulk* update to easy the memory consumption.
The *bulk* size is defined by :data:`~darc.db.BULK_SIZE`.
See Also:
* :func:`darc.db._save_requests_db`
* :func:`darc.db._save_requests_redis`
"""
if FLAG_DB:
with database.connection_context():
try:
return _save_requests_db(entries, single, score, nx, xx)
except Exception as error:
warning = warnings.formatwarning(str(error), DatabaseOperaionFailed, __file__, 494,
'_save_requests_db(...)')
print(render_error(warning, stem.util.term.Color.YELLOW), end='', file=sys.stderr) # pylint: disable=no-member
return
return _save_requests_redis(entries, single, score, nx, xx)
[docs]def _save_requests_db(entries: typing.Union[Link, typing.List[Link]], single: bool = False,
score=None, nx=False, xx=False):
"""Save link to the :mod:`requests` database.
The function updates the :class:`~darc.model.tasks.requests.RequestsQueueModel` table.
Args:
entries: Links to be added to the :mod:`requests` database.
It can be either a :obj:`list` of links, or a single
link string (if ``single`` set as :data:`True`).
single: Indicate if ``entries`` is a :obj:`list` of links
or a single link string.
score: Score to for the Redis sorted set.
nx: Only create new elements and not to
update scores for elements that already exist.
xx: Only update scores of elements that
already exist. New elements will not be added.
"""
if not entries:
return
if score is None:
score = datetime.datetime.now()
if not single:
if typing.TYPE_CHECKING:
entries = typing.cast(typing.List[Link], entries)
if nx:
with database.atomic():
insert_many = [dict(
text=link.url,
hash=link.name,
link=link,
timestamp=score,
) for link in entries]
for batch in peewee.chunked(insert_many, BULK_SIZE):
_db_operation(RequestsQueueModel
.insert_many(insert_many)
.on_conflict_ignore()
.execute)
return
if xx:
entries_text = [link.url for link in entries]
_db_operation(RequestsQueueModel
.update(timestamp=score)
.where(typing.cast(peewee.TextField, RequestsQueueModel.text).in_(entries_text))
.execute)
return
with database.atomic():
replace_many = [dict(
text=link.url,
hash=link.name,
link=link,
timestamp=score
) for link in entries]
for batch in peewee.chunked(replace_many, BULK_SIZE):
_db_operation(RequestsQueueModel.replace_many(batch).execute)
return
if typing.TYPE_CHECKING:
entries = typing.cast(Link, entries)
if nx:
_db_operation(RequestsQueueModel.get_or_create,
text=entries.url,
defaults=dict(
hash=entries.name,
link=entries,
timestamp=score,
))
return
if xx:
with contextlib.suppress(peewee.DoesNotExist):
model = _db_operation(RequestsQueueModel.get, RequestsQueueModel.text == entries.url)
model.timestamp = score
_db_operation(model.save)
return
_db_operation(RequestsQueueModel.replace(
text=entries.url,
hash=entries.name,
link=entries,
timestamp=score
).execute)
[docs]def _save_requests_redis(entries: typing.Union[Link, typing.List[Link]], single: bool = False,
score=None, nx=False, xx=False):
"""Save link to the :mod:`requests` database.
The function updates the ``queue_requests`` database.
Args:
entries: Links to be added to the :mod:`requests` database.
It can be either a :obj:`list` of links, or a single
link string (if ``single`` set as :data:`True`).
single: Indicate if ``entries`` is a :obj:`list` of links
or a single link string.
score: Score to for the Redis sorted set.
nx: Forces ``ZADD`` to only create new elements and not to
update scores for elements that already exist.
xx: Forces ``ZADD`` to only update scores of elements that
already exist. New elements will not be added.
"""
if score is None:
score = time.time()
if not single:
if typing.TYPE_CHECKING:
entries = typing.cast(typing.List[Link], entries)
for chunk in peewee.chunked(entries, BULK_SIZE):
pool = list(filter(lambda link: isinstance(link, Link), chunk))
for link in pool:
_redis_command('set', link.name, pickle.dumps(link), nx=True)
mapping = {
link.name: score for link in pool
}
with _redis_get_lock('lock_queue_requests'): # type: ignore
_redis_command('zadd', 'queue_requests', mapping, nx=nx, xx=xx)
return
if typing.TYPE_CHECKING:
entries = typing.cast(Link, entries)
_redis_command('set', entries.name, pickle.dumps(entries), nx=True)
mapping = {
entries.name: score,
}
with _redis_get_lock('lock_queue_requests'): # type: ignore
_redis_command('zadd', 'queue_requests', mapping, nx=nx, xx=xx)
[docs]def save_selenium(entries: typing.Union[Link, typing.List[Link]], single: bool = False, # pylint: disable=inconsistent-return-statements
score=None, nx=False, xx=False):
"""Save link to the :mod:`selenium` database.
Args:
entries: Links to be added to the :mod:`selenium` database.
It can be either a :obj:`list` of links, or a single
link string (if ``single`` set as :data:`True`).
single: Indicate if ``entries`` is a :obj:`list` of links
or a single link string.
score: Score to for the Redis sorted set.
nx: Only create new elements and not to
update scores for elements that already exist.
xx: Only update scores of elements that
already exist. New elements will not be added.
Notes:
The ``entries`` will be dumped through :mod:`pickle` so that
:mod:`darc` do not need to parse them again.
When ``entries`` is a list of :class:`~darc.link.Link` instances,
we tries to perform *bulk* update to easy the memory consumption.
The *bulk* size is defined by :data:`~darc.db.BULK_SIZE`.
See Also:
* :func:`darc.db._save_selenium_db`
* :func:`darc.db._save_selenium_redis`
"""
if FLAG_DB:
with database.connection_context():
try:
return _save_selenium_db(entries, single, score, nx, xx)
except Exception as error:
warning = warnings.formatwarning(str(error), DatabaseOperaionFailed, __file__, 673,
'_save_selenium_db(...)')
print(render_error(warning, stem.util.term.Color.YELLOW), end='', file=sys.stderr) # pylint: disable=no-member
return
return _save_selenium_redis(entries, single, score, nx, xx)
[docs]def _save_selenium_db(entries: typing.Union[Link, typing.List[Link]], single: bool = False,
score=None, nx=False, xx=False):
"""Save link to the :mod:`selenium` database.
The function updates the :class:`~darc.model.tasks.selenium.SeleniumQueueModel` table.
Args:
entries: Links to be added to the :mod:`selenium` database.
It can be either a :obj:`list` of links, or a single
link string (if ``single`` set as :data:`True`).
single: Indicate if ``entries`` is a :obj:`list` of links
or a single link string.
score: Score to for the Redis sorted set.
nx: Only create new elements and not to
update scores for elements that already exist.
xx: Only update scores of elements that
already exist. New elements will not be added.
"""
if not entries:
return
if score is None:
score = datetime.datetime.now()
if not single:
if typing.TYPE_CHECKING:
entries = typing.cast(typing.List[Link], entries)
if nx:
with database.atomic():
insert_many = [dict(
text=link.url,
hash=link.name,
link=link,
timestamp=score,
) for link in entries]
for batch in peewee.chunked(insert_many, BULK_SIZE):
_db_operation(SeleniumQueueModel
.insert_many(insert_many)
.on_conflict_ignore()
.execute)
return
if xx:
entries_text = [link.url for link in entries]
_db_operation(SeleniumQueueModel
.update(timestamp=score)
.where(typing.cast(peewee.TextField, SeleniumQueueModel.text).in_(entries_text))
.execute)
return
with database.atomic():
replace_many = [dict(
text=link.url,
hash=link.name,
link=link,
timestamp=score
) for link in entries]
for batch in peewee.chunked(replace_many, BULK_SIZE):
_db_operation(SeleniumQueueModel.replace_many(batch).execute)
return
if typing.TYPE_CHECKING:
entries = typing.cast(Link, entries)
if nx:
_db_operation(SeleniumQueueModel.get_or_create,
text=entries.url,
defaults=dict(
hash=entries.name,
link=entries,
timestamp=score,
))
return
if xx:
with contextlib.suppress(peewee.DoesNotExist):
model = _db_operation(SeleniumQueueModel.get, SeleniumQueueModel.text == entries.url)
model.timestamp = score
_db_operation(model.save)
return
_db_operation(SeleniumQueueModel.replace(
text=entries.url,
hash=entries.name,
link=entries,
timestamp=score
).execute)
[docs]def _save_selenium_redis(entries: typing.Union[Link, typing.List[Link]], single: bool = False,
score=None, nx=False, xx=False):
"""Save link to the :mod:`selenium` database.
The function updates the ``queue_selenium`` database.
Args:
entries: Links to be added to the :mod:`selenium` database.
It can be either an *iterable* of links, or a single
link string (if ``single`` set as :data:`True`).
single: Indicate if ``entries`` is an *iterable* of links
or a single link string.
score: Score to for the Redis sorted set.
nx: Forces ``ZADD`` to only create new elements and not to
update scores for elements that already exist.
xx: Forces ``ZADD`` to only update scores of elements that
already exist. New elements will not be added.
When ``entries`` is a list of :class:`~darc.link.Link` instances,
we tries to perform *bulk* update to easy the memory consumption.
The *bulk* size is defined by :data:`~darc.db.BULK_SIZE`.
Notes:
The ``entries`` will be dumped through :mod:`pickle` so that
:mod:`darc` do not need to parse them again.
"""
if not entries:
return
if score is None:
score = time.time()
if not single:
if typing.TYPE_CHECKING:
entries = typing.cast(typing.List[Link], entries)
for chunk in peewee.chunked(entries, BULK_SIZE):
pool = list(filter(lambda link: isinstance(link, Link), chunk))
for link in pool:
_redis_command('set', link.name, pickle.dumps(link), nx=True)
mapping = {
link.name: score for link in pool
}
with _redis_get_lock('lock_queue_selenium'): # type: ignore
_redis_command('zadd', 'queue_selenium', mapping, nx=nx, xx=xx)
return
if typing.TYPE_CHECKING:
entries = typing.cast(Link, entries)
_redis_command('set', entries.name, pickle.dumps(entries), nx=True)
mapping = {
entries.name: score,
}
with _redis_get_lock('lock_queue_selenium'): # type: ignore
_redis_command('zadd', 'queue_selenium', mapping, nx=nx, xx=xx)
[docs]def load_requests(check: bool = CHECK) -> typing.List[Link]:
"""Load link from the :mod:`requests` database.
Args:
check: If perform checks on loaded links,
default to :data:`~darc.const.CHECK`.
Returns:
List of loaded links from the :mod:`requests` database.
Note:
At runtime, the function will load links with maximum number
at :data:`~darc.db.MAX_POOL` to limit the memory usage.
See Also:
* :func:`darc.db._load_requests_db`
* :func:`darc.db._load_requests_redis`
"""
if FLAG_DB:
with database.connection_context():
try:
link_pool = _load_requests_db()
except Exception as error:
warning = warnings.formatwarning(str(error), DatabaseOperaionFailed, __file__, 852,
'_load_requests_db()')
print(render_error(warning, stem.util.term.Color.YELLOW), end='', file=sys.stderr) # pylint: disable=no-member
link_pool = list()
else:
link_pool = _load_requests_redis()
if check:
link_pool = _check(link_pool)
if VERBOSE:
print(stem.util.term.format('-*- [REQUESTS] LINK POOL -*-',
stem.util.term.Color.MAGENTA)) # pylint: disable=no-member
print(render_error(pprint.pformat(sorted(link.url for link in link_pool)),
stem.util.term.Color.MAGENTA)) # pylint: disable=no-member
print(stem.util.term.format('-' * shutil.get_terminal_size().columns,
stem.util.term.Color.MAGENTA)) # pylint: disable=no-member
return link_pool
[docs]def _load_requests_db() -> typing.List[Link]:
"""Load link from the :mod:`requests` database.
The function reads the :class:`~darc.model.tasks.requests.RequestsQueueModel` table.
Returns:
List of loaded links from the :mod:`requests` database.
Note:
At runtime, the function will load links with maximum number
at :data:`~darc.db.MAX_POOL` to limit the memory usage.
"""
now = datetime.datetime.now()
if TIME_CACHE is None:
sec_delta = 0
max_score = now
else:
sec_delta = TIME_CACHE
max_score = now - sec_delta
with database.atomic():
query: typing.List[RequestsQueueModel] = _db_operation(
RequestsQueueModel
.select(RequestsQueueModel.link)
.where(RequestsQueueModel.timestamp <= max_score)
.order_by(RequestsQueueModel.timestamp)
.limit(MAX_POOL)
.execute
)
link_pool = [model.link for model in query]
if TIME_CACHE is not None:
new_score = now + sec_delta
_save_requests_db(link_pool, score=new_score) # force update records
return link_pool
[docs]def _load_requests_redis() -> typing.List[Link]:
"""Load link from the :mod:`requests` database.
The function reads the ``queue_requests`` database.
Returns:
List of loaded links from the :mod:`requests` database.
Note:
At runtime, the function will load links with maximum number
at :data:`~darc.db.MAX_POOL` to limit the memory usage.
"""
now = time.time()
if TIME_CACHE is None:
sec_delta = 0
max_score = now
else:
sec_delta = TIME_CACHE.total_seconds()
max_score = now - sec_delta
try:
with _redis_get_lock('lock_queue_requests', blocking_timeout=LOCK_TIMEOUT): # type: ignore
temp_pool: typing.List[bytes] = [_redis_command('get', name) for name in _redis_command('zrangebyscore', 'queue_requests', # pylint: disable=line-too-long
min=0, max=max_score, start=0, num=MAX_POOL)] # pylint: disable=line-too-long
link_pool = [pickle.loads(link) for link in filter(None, temp_pool)] # nosec
if TIME_CACHE is not None:
new_score = now + sec_delta
_save_requests_redis(link_pool, score=new_score) # force update records
except redis_lock.LockError:
warning = warnings.formatwarning(f'[REQUESTS] Failed to acquire Redis lock after {LOCK_TIMEOUT} second(s)',
LockWarning, __file__, 250, "_redis_get_lock('lock_queue_requests')")
print(render_error(warning, stem.util.term.Color.YELLOW), end='', file=sys.stderr) # pylint: disable=no-member
link_pool = list()
return link_pool
[docs]def load_selenium(check: bool = CHECK) -> typing.List[Link]:
"""Load link from the :mod:`selenium` database.
Args:
check: If perform checks on loaded links,
default to :data:`~darc.const.CHECK`.
Returns:
List of loaded links from the :mod:`selenium` database.
Note:
At runtime, the function will load links with maximum number
at :data:`~darc.db.MAX_POOL` to limit the memory usage.
See Also:
* :func:`darc.db._load_selenium_db`
* :func:`darc.db._load_selenium_redis`
"""
if FLAG_DB:
with database.connection_context():
try:
link_pool = _load_selenium_db()
except Exception as error:
warning = warnings.formatwarning(str(error), DatabaseOperaionFailed, __file__, 971,
'_load_selenium_db()')
print(render_error(warning, stem.util.term.Color.YELLOW), end='', file=sys.stderr) # pylint: disable=no-member
link_pool = list()
else:
link_pool = _load_selenium_redis()
if check:
link_pool = _check(link_pool)
if VERBOSE:
print(stem.util.term.format('-*- [SELENIUM] LINK POOL -*-',
stem.util.term.Color.MAGENTA)) # pylint: disable=no-member
print(render_error(pprint.pformat(sorted(link.url for link in link_pool)),
stem.util.term.Color.MAGENTA)) # pylint: disable=no-member
print(stem.util.term.format('-' * shutil.get_terminal_size().columns,
stem.util.term.Color.MAGENTA)) # pylint: disable=no-member
return link_pool
[docs]def _load_selenium_db() -> typing.List[Link]:
"""Load link from the :mod:`selenium` database.
The function reads the :class:`~darc.model.tasks.selenium.SeleniumQueueModel` table.
Returns:
List of loaded links from the :mod:`selenium` database.
Note:
At runtime, the function will load links with maximum number
at :data:`~darc.db.MAX_POOL` to limit the memory usage.
"""
now = datetime.datetime.now()
if TIME_CACHE is None:
sec_delta = 0
max_score = now
else:
sec_delta = TIME_CACHE
max_score = now - sec_delta
with database.atomic():
query: typing.List[SeleniumQueueModel] = _db_operation(
SeleniumQueueModel
.select(SeleniumQueueModel.link)
.where(SeleniumQueueModel.timestamp <= max_score)
.order_by(SeleniumQueueModel.timestamp)
.limit(MAX_POOL)
.query
)
link_pool = [model.link for model in query]
if TIME_CACHE is not None:
new_score = now + sec_delta
_save_selenium_db(link_pool, score=new_score) # force update records
return link_pool
[docs]def _load_selenium_redis() -> typing.List[Link]:
"""Load link from the :mod:`selenium` database.
The function reads the ``queue_selenium`` database.
Args:
check: If perform checks on loaded links,
default to :data:`~darc.const.CHECK`.
Returns:
List of loaded links from the :mod:`selenium` database.
Note:
At runtime, the function will load links with maximum number
at :data:`~darc.db.MAX_POOL` to limit the memory usage.
"""
now = time.time()
if TIME_CACHE is None:
sec_delta = 0
max_score = now
else:
sec_delta = TIME_CACHE.total_seconds()
max_score = now - sec_delta
try:
with _redis_get_lock('lock_queue_selenium', blocking_timeout=LOCK_TIMEOUT): # type: ignore
temp_pool: typing.List[bytes] = [_redis_command('get', name) for name in _redis_command('zrangebyscore', 'queue_selenium', # pylint: disable=line-too-long
min=0, max=max_score, start=0, num=MAX_POOL)] # pylint: disable=line-too-long
link_pool = [pickle.loads(link) for link in filter(None, temp_pool)] # nosec
if TIME_CACHE is not None:
new_score = now + sec_delta
_save_selenium_redis(link_pool, score=new_score) # force update records
except redis_lock.LockError:
warning = warnings.formatwarning(f'[SELENIUM] Failed to acquire Redis lock after {LOCK_TIMEOUT} second(s)',
LockWarning, __file__, 299, "_redis_get_lock('lock_queue_selenium')")
print(render_error(warning, stem.util.term.Color.YELLOW), end='', file=sys.stderr) # pylint: disable=no-member
link_pool = list()
return link_pool