X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/5a80356ddc3798f6530e306901d7ea5e19cfe3f9..8c5f2973a5c5f042d1d12aef1c470b37519fd416:/sdk/python/arvados/retry.py

diff --git a/sdk/python/arvados/retry.py b/sdk/python/arvados/retry.py
index 5dc31aefa7..5ba4f4ea41 100644
--- a/sdk/python/arvados/retry.py
+++ b/sdk/python/arvados/retry.py
@@ -1,5 +1,8 @@
 #!/usr/bin/env python
 
+import functools
+import inspect
+import pycurl
 import time
 
 from collections import deque
@@ -28,7 +31,8 @@ class RetryLoop(object):
             return loop.last_result()
     """
     def __init__(self, num_retries, success_check=lambda r: True,
-                 backoff_start=0, backoff_growth=2, save_results=1):
+                 backoff_start=0, backoff_growth=2, save_results=1,
+                 max_wait=60):
         """Construct a new RetryLoop.
 
         Arguments:
@@ -47,11 +51,13 @@ 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 number of seconds to wait between retries.
         """
         self.tries_left = num_retries + 1
         self.check_result = success_check
         self.backoff_wait = backoff_start
         self.backoff_growth = backoff_growth
+        self.max_wait = max_wait
         self.next_start_time = 0
         self.results = deque(maxlen=save_results)
         self._running = None
@@ -73,6 +79,8 @@ class RetryLoop(object):
             wait_time = max(0, self.next_start_time - time.time())
             time.sleep(wait_time)
             self.backoff_wait *= self.backoff_growth
+            if self.backoff_wait > self.max_wait:
+                self.backoff_wait = self.max_wait
         self.next_start_time = time.time() + self.backoff_wait
         self.tries_left -= 1
         return self.tries_left
@@ -107,12 +115,12 @@ class RetryLoop(object):
                 "queried loop results before any were recorded")
 
 
-def check_http_response_success(result):
-    """Convert an httplib2 request result to a loop control flag.
+def check_http_response_success(status_code):
+    """Convert an HTTP status code to a loop control flag.
 
-    Pass this method the 2-tuple returned by httplib2.Http.request.  It
-    returns True if the response indicates success, None if it indicates
-    temporary failure, and False otherwise.  You can use this as the
+    Pass this method a numeric HTTP status code.  It returns True if
+    the code indicates success, None if it indicates temporary
+    failure, and False otherwise.  You can use this as the
     success_check for a RetryLoop.
 
     Implementation details:
@@ -126,15 +134,26 @@ def check_http_response_success(result):
       3xx status codes.  They don't indicate success, and you can't
       retry those requests verbatim.
     """
-    try:
-        status = int(result[0].status)
-    except Exception:
-        return None
-    if status in _HTTP_SUCCESSES:
+    if status_code in _HTTP_SUCCESSES:
         return True
-    elif status in _HTTP_CAN_RETRY:
+    elif status_code in _HTTP_CAN_RETRY:
         return None
-    elif 100 <= status < 600:
+    elif 100 <= status_code < 600:
         return False
     else:
         return None  # Get well soon, server.
+
+def retry_method(orig_func):
+    """Provide a default value for a method's num_retries argument.
+
+    This is a decorator for instance and class methods that accept a
+    num_retries argument, with a None default.  When the method is called
+    without a value for num_retries, it will be set from the underlying
+    instance or class' num_retries attribute.
+    """
+    @functools.wraps(orig_func)
+    def num_retries_setter(self, *args, **kwargs):
+        if kwargs.get('num_retries') is None:
+            kwargs['num_retries'] = self.num_retries
+        return orig_func(self, *args, **kwargs)
+    return num_retries_setter