[catapult] - Copy Telemetry's gsutilz over to third_party.

third_party/gsutil/third_party/retry-decorator/retry_decorator/retry_decorator.py

Index: third_party/gsutil/third_party/retry-decorator/retry_decorator/retry_decorator.py
diff --git a/third_party/gsutil/third_party/retry-decorator/retry_decorator/retry_decorator.py b/third_party/gsutil/third_party/retry-decorator/retry_decorator/retry_decorator.py
new file mode 100755
index 0000000000000000000000000000000000000000..466396a3b9199c1b49089bf833f0088dfbabbf3b
--- /dev/null
+++ b/third_party/gsutil/third_party/retry-decorator/retry_decorator/retry_decorator.py
@@ -0,0 +1,37 @@
+#!/usr/bin/env python
+
+from __future__ import print_function
+
+import traceback
+import logging
+import time
+import random
+import sys
+
+def retry(ExceptionToCheck, tries=10, timeout_secs=1.0, logger=None):
+    """
+    Retry calling the decorated function using an exponential backoff.
+    """
+    def deco_retry(f):
+        def f_retry(*args, **kwargs):
+            mtries, mdelay = tries, timeout_secs
+            while mtries > 1:
+                try:
+                    return f(*args, **kwargs)
+                except ExceptionToCheck as e:
+                    #traceback.print_exc()
+                    half_interval = mdelay * 0.10 #interval size
+                    actual_delay = random.uniform(mdelay - half_interval, mdelay + half_interval)
+                    msg = "Retrying in %.2f seconds ..." % actual_delay
+                    if logger is None:
+                        logging.exception(msg)
+                    else:
+                        logger.exception(msg)
+                    time.sleep(actual_delay)
+                    mtries -= 1
+                    mdelay *= 2
+            return f(*args, **kwargs)
+        return f_retry  # true decorator
+    return deco_retry
+
+