logging: Reduce create_logger to new log_to_file.

The name `create_logger` suggests something much bigger than what this
function actually does -- the logger doesn't any more or less exist
after the function is called than before.  Its one real function is to
send logs to a specific file.

So, pull out that logic to an appropriately-named function just for
it.  We already use `logging.getLogger` in a number of places to
simply get a logger by name, and the old `create_logger` callsites can
do the same.

analytics/lib/counts.py

@@ -1,6 +1,7 @@
 import time
 from collections import OrderedDict, defaultdict
 from datetime import datetime, timedelta
+import logging
 from typing import Any, Callable, Dict, List, \
     Optional, Text, Tuple, Type, Union
 
@@ -11,7 +12,7 @@ from django.db.models import F
 from analytics.models import Anomaly, BaseCount, \
     FillState, InstallationCount, RealmCount, StreamCount, \
     UserCount, installation_epoch, last_successful_fill
-from zerver.lib.logging_util import create_logger
+from zerver.lib.logging_util import log_to_file
 from zerver.lib.timestamp import ceiling_to_day, \
     ceiling_to_hour, floor_to_hour, verify_UTC
 from zerver.models import Message, Realm, RealmAuditLog, \
@@ -19,7 +20,8 @@ from zerver.models import Message, Realm, RealmAuditLog, \
 
 ## Logging setup ##
 
-logger = create_logger('zulip.management', settings.ANALYTICS_LOG_PATH)
+logger = logging.getLogger('zulip.management')
+log_to_file(logger, settings.ANALYTICS_LOG_PATH)
 
 # You can't subtract timedelta.max from a datetime, so use this instead
 TIMEDELTA_MAX = timedelta(days=365*1000)

zerver/decorator.py

@@ -31,7 +31,7 @@ from io import BytesIO
 import urllib
 
 from typing import Union, Any, Callable, Sequence, Dict, Optional, TypeVar, Text, Tuple, cast
-from zerver.lib.logging_util import create_logger
+from zerver.lib.logging_util import log_to_file
 
 # This is a hack to ensure that RemoteZulipServer always exists even
 # if Zilencer isn't enabled.
@@ -45,8 +45,8 @@ else:
 ViewFuncT = TypeVar('ViewFuncT', bound=Callable[..., HttpResponse])
 ReturnT = TypeVar('ReturnT')
 
-## logger setup
-webhook_logger = create_logger("zulip.zerver.webhooks", settings.API_KEY_ONLY_WEBHOOK_LOG_PATH)
+webhook_logger = logging.getLogger("zulip.zerver.webhooks")
+log_to_file(webhook_logger, settings.API_KEY_ONLY_WEBHOOK_LOG_PATH)
 
 class _RespondAsynchronously:
     pass

zerver/lib/digest.py

@@ -2,6 +2,7 @@ from typing import Any, Callable, Dict, Iterable, List, Set, Tuple, Text
 
 from collections import defaultdict
 import datetime
+import logging
 import pytz
 
 from django.db.models import Q, QuerySet
@@ -17,9 +18,10 @@ from zerver.models import UserProfile, UserMessage, Recipient, Stream, \
     Realm
 from zerver.context_processors import common_context
 from zerver.lib.queue import queue_json_publish
-from zerver.lib.logging_util import create_logger
+from zerver.lib.logging_util import log_to_file
 
-logger = create_logger(__name__, settings.DIGEST_LOG_PATH)
+logger = logging.getLogger(__name__)
+log_to_file(logger, settings.DIGEST_LOG_PATH)
 
 VALID_DIGEST_DAY = 1  # Tuesdays
 DIGEST_CUTOFF = 5

zerver/lib/logging_util.py

@@ -185,24 +185,12 @@ class ZulipFormatter(logging.Formatter):
             setattr(record, 'zulip_decorated', True)
         return super().format(record)
 
-def create_logger(name: str,
-                  log_file: str,
-                  log_format: str="%(asctime)s%(levelname)-8s%(message)s") -> Logger:
-    """Creates a named logger for use in logging content to a certain
-    file.  A few notes:
-
-    * "name" is used in determining what gets logged to which files;
-    see "loggers" in zproject/settings.py for details.  Don't use `""`
-    -- that's the root logger.
-    * "log_file" should be declared in zproject/settings.py in ZULIP_PATHS.
-
-    """
-    logger = logging.getLogger(name)
-
-    if log_file:
-        formatter = logging.Formatter(log_format)
-        file_handler = logging.FileHandler(log_file)
-        file_handler.setFormatter(formatter)
-        logger.addHandler(file_handler)
-
-    return logger
+def log_to_file(logger: Logger,
+                filename: str,
+                log_format: str="%(asctime)s%(levelname)-8s%(message)s",
+                ) -> None:
+    """Note: `filename` should be declared in zproject/settings.py in ZULIP_PATHS."""
+    formatter = logging.Formatter(log_format)
+    handler = logging.FileHandler(filename)
+    handler.setFormatter(formatter)
+    logger.addHandler(handler)

zerver/lib/send_email.py

@@ -8,16 +8,18 @@ from zerver.models import UserProfile, ScheduledEmail, get_user_profile_by_id, \
 
 import datetime
 from email.utils import parseaddr, formataddr
+import logging
 import ujson
 
 import os
 from typing import Any, Dict, Iterable, List, Mapping, Optional, Text
 
-from zerver.lib.logging_util import create_logger
+from zerver.lib.logging_util import log_to_file
 
 ## Logging setup ##
 
-logger = create_logger('zulip.send_email', settings.EMAIL_LOG_PATH)
+logger = logging.getLogger('zulip.send_email')
+log_to_file(logger, settings.EMAIL_LOG_PATH)
 
 class FromAddress:
     SUPPORT = parseaddr(settings.ZULIP_ADMINISTRATOR)[1]

zerver/lib/soft_deactivation.py

@@ -1,6 +1,7 @@
 
-from zerver.lib.logging_util import create_logger
+from zerver.lib.logging_util import log_to_file
 from collections import defaultdict
+import logging
 from django.db import transaction
 from django.db.models import Max
 from django.conf import settings
@@ -10,7 +11,8 @@ from typing import DefaultDict, List, Union, Any
 from zerver.models import UserProfile, UserMessage, RealmAuditLog, \
     Subscription, Message, Recipient, UserActivity, Realm
 
-logger = create_logger("zulip.soft_deactivation", settings.SOFT_DEACTIVATION_LOG_PATH)
+logger = logging.getLogger("zulip.soft_deactivation")
+log_to_file(logger, settings.SOFT_DEACTIVATION_LOG_PATH)
 
 def filter_by_subscription_history(user_profile: UserProfile,
                                    all_stream_messages: DefaultDict[int, List[Message]],

zerver/management/commands/deliver_email.py

@@ -9,7 +9,7 @@ condition.  (Alternatively, you can set `EMAIL_DELIVERER_DISABLED=True`
 on all but one machine to make the command have no effect.)
 """
 
-
+import logging
 import time
 from typing import Any
 
@@ -19,12 +19,13 @@ from django.utils.timezone import now as timezone_now
 from ujson import loads
 
 from zerver.lib.context_managers import lockfile
-from zerver.lib.logging_util import create_logger
+from zerver.lib.logging_util import log_to_file
 from zerver.lib.send_email import EmailNotDeliveredException, send_email
 from zerver.models import ScheduledEmail
 
 ## Setup ##
-logger = create_logger(__name__, settings.EMAIL_DELIVERER_LOG_PATH)
+logger = logging.getLogger(__name__)
+log_to_file(logger, settings.EMAIL_DELIVERER_LOG_PATH)
 
 class Command(BaseCommand):
     help = """Deliver emails queued by various parts of Zulip

zerver/management/commands/enqueue_digest_emails.py

@@ -1,4 +1,5 @@
 import datetime
+import logging
 from typing import Any, List
 
 from django.conf import settings
@@ -6,10 +7,11 @@ from django.core.management.base import BaseCommand
 from django.utils.timezone import now as timezone_now
 
 from zerver.lib.digest import DIGEST_CUTOFF, enqueue_emails
-from zerver.lib.logging_util import create_logger
+from zerver.lib.logging_util import log_to_file
 
 ## Logging setup ##
-logger = create_logger(__name__, settings.DIGEST_LOG_PATH)
+logger = logging.getLogger(__name__)
+log_to_file(logger, settings.DIGEST_LOG_PATH)
 
 class Command(BaseCommand):
     help = """Enqueue digest emails for users that haven't checked the app

zerver/management/commands/sync_ldap_user_data.py

@@ -1,16 +1,18 @@
 
+import logging
 from typing import Any
 
 from django.conf import settings
 from django.core.management.base import BaseCommand
 from django.db.utils import IntegrityError
 
-from zerver.lib.logging_util import create_logger
+from zerver.lib.logging_util import log_to_file
 from zerver.models import UserProfile
 from zproject.backends import ZulipLDAPUserPopulator
 
 ## Setup ##
-logger = create_logger(__name__, settings.LDAP_SYNC_LOG_PATH)
+logger = logging.getLogger(__name__)
+log_to_file(logger, settings.LDAP_SYNC_LOG_PATH)
 
 # Run this on a cronjob to pick up on name changes.
 def sync_ldap_user_data() -> None: