mypy type annotations for zerver/lib/utils

zerver/lib/utils.py

@@ -2,6 +2,8 @@
 from __future__ import absolute_import
 from __future__ import division
 
+from typing import Any, Callable, Optional, Sequence, TypeVar
+from six import text_type, binary_type
 import base64
 import hashlib
 import os
@@ -10,7 +12,10 @@ from time import sleep
 from django.conf import settings
 from six.moves import range
 
+T = TypeVar('T')
+
 def statsd_key(val, clean_periods=False):
+    # type: (Any, bool) -> str
     if not isinstance(val, str):
         val = str(val)
 
@@ -30,15 +35,17 @@ class StatsDWrapper(object):
     # as our statsd server supports them but supporting
     # pystatsd is not released yet
     def _our_gauge(self, stat, value, rate=1, delta=False):
+            # type: (str, float, float, bool) -> str
             """Set a gauge value."""
             from django_statsd.clients import statsd
             if delta:
-                value = '%+g|g' % (value,)
+                value_str = '%+g|g' % (value,)
             else:
-                value = '%g|g' % (value,)
-            statsd._send(stat, value, rate)
+                value_str = '%g|g' % (value,)
+            statsd._send(stat, value_str, rate)
 
     def __getattr__(self, name):
+        # type: (str) -> Any
         # Hand off to statsd if we have it enabled
         # otherwise do nothing
         if name in ['timer', 'timing', 'incr', 'decr', 'gauge']:
@@ -57,6 +64,7 @@ statsd = StatsDWrapper()
 
 # Runs the callback with slices of all_list of a given batch_size
 def run_in_batches(all_list, batch_size, callback, sleep_time = 0, logger = None):
+    # type: (Sequence[T], int, Callable[[Sequence[T]], None], int, Optional[Callable[[str], None]]) ->  None
     if len(all_list) == 0:
         return
 
@@ -77,6 +85,7 @@ def run_in_batches(all_list, batch_size, callback, sleep_time = 0, logger = None
             sleep(sleep_time)
 
 def make_safe_digest(string, hash_func=hashlib.sha1):
+    # type: (text_type, Callable[[binary_type], Any]) -> str
     """
     return a hex digest of `string`.
     """
@@ -86,6 +95,7 @@ def make_safe_digest(string, hash_func=hashlib.sha1):
 
 
 def log_statsd_event(name):
+    # type: (str) -> None
     """
     Sends a single event to statsd with the desired name and the current timestamp
 
@@ -100,4 +110,5 @@ def log_statsd_event(name):
     statsd.incr(event_name)
 
 def generate_random_token(length):
+    # type: (int) -> str
     return base64.b16encode(os.urandom(length // 2)).lower()