Added minimal logging (#6)

Author: frnhr

retrying.py

@@ -11,7 +11,7 @@
 # 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.
-
+import logging
 import random
 import sys
 import time
@@ -82,6 +82,7 @@ def __init__(
         wait_jitter_max=None,
         before_attempts=None,
         after_attempts=None,
+        logger=None,
     ):
 
         self._stop_max_attempt_number = (
@@ -109,6 +110,14 @@ def __init__(
         self._wait_jitter_max = 0 if wait_jitter_max is None else wait_jitter_max
         self._before_attempts = before_attempts
         self._after_attempts = after_attempts
+        
+        if logger in (True, None):
+            self._logger = logging.getLogger(__name__)
+            if logger is None:
+                self._logger.addHandler(logging.NullHandler()) 
+                self._logger.propagate = False
+        elif logger:
+           self._logger = logger
 
         # TODO add chaining of stop behaviors
         # stop behavior
@@ -255,6 +264,7 @@ def call(self, fn, *args, **kwargs):
             if not self.should_reject(attempt):
                 return attempt.get(self._wrap_exception)
 
+            self._logger.warn(attempt)
             if self._after_attempts:
                 self._after_attempts(attempt_number)
 
@@ -270,6 +280,7 @@ def call(self, fn, *args, **kwargs):
                 if self._wait_jitter_max:
                     jitter = random.random() * self._wait_jitter_max
                     sleep = sleep + max(0, jitter)
+                self._logger.info(f"Retrying in {sleep / 1000.0:.2f} seconds.")
                 time.sleep(sleep / 1000.0)
 
             attempt_number += 1