Merge branch '18663-add-keepbalance-support'

[arvados.git] / sdk / python / arvados / retry.py

diff --git a/sdk/python/arvados/retry.py b/sdk/python/arvados/retry.py
index dccd9c875a69ee161923e6fa6818e2d751f92352..ea4095930fc78f7cbbb26c49f45a8fa66fbb4081 100644 (file)
--- a/sdk/python/arvados/retry.py
+++ b/sdk/python/arvados/retry.py
@@ -1,5 +1,9 @@
-#!/usr/bin/env python
+# Copyright (C) The Arvados Authors. All rights reserved.
+#
+# SPDX-License-Identifier: Apache-2.0
 
+from builtins import range
+from builtins import object
 import functools
 import inspect
 import pycurl
@@ -9,7 +13,7 @@ from collections import deque
 
 import arvados.errors
 
-_HTTP_SUCCESSES = set(xrange(200, 300))
+_HTTP_SUCCESSES = set(range(200, 300))
 _HTTP_CAN_RETRY = set([408, 409, 422, 423, 500, 502, 503, 504])
 
 class RetryLoop(object):
@@ -51,7 +55,7 @@ class RetryLoop(object):
         * save_results: Specify a number to save the last N results
           that the loop recorded.  These records are available through
           the results attribute, oldest first.  Default 1.
-        * max_wait: Maximum time to wait between retries.
+        * max_wait: Maximum number of seconds to wait between retries.
         """
         self.tries_left = num_retries + 1
         self.check_result = success_check
@@ -60,6 +64,7 @@ class RetryLoop(object):
         self.max_wait = max_wait
         self.next_start_time = 0
         self.results = deque(maxlen=save_results)
+        self._attempts = 0
         self._running = None
         self._success = None
 
@@ -69,7 +74,7 @@ class RetryLoop(object):
     def running(self):
         return self._running and (self._success is None)
 
-    def next(self):
+    def __next__(self):
         if self._running is None:
             self._running = True
         if (self.tries_left < 1) or not self.running():
@@ -97,6 +102,7 @@ class RetryLoop(object):
                 "recorded a loop result after the loop finished")
         self.results.append(result)
         self._success = self.check_result(result)
+        self._attempts += 1
 
     def success(self):
         """Return the loop's end state.
@@ -114,6 +120,19 @@ class RetryLoop(object):
             raise arvados.errors.AssertionError(
                 "queried loop results before any were recorded")
 
+    def attempts(self):
+        """Return the number of attempts that have been made.
+
+        Includes successes and failures."""
+        return self._attempts
+
+    def attempts_str(self):
+        """Human-readable attempts(): 'N attempts' or '1 attempt'"""
+        if self._attempts == 1:
+            return '1 attempt'
+        else:
+            return '{} attempts'.format(self._attempts)
+
 
 def check_http_response_success(status_code):
     """Convert an HTTP status code to a loop control flag.