sync: cleanup sleep+retry logic a bitv2.14

Make sure we print a message whenever we retry so it's clear to the
user why repo is pausing for a long time, and why repo might have
passed even though it displayed some errors earlier.

Also unify the sleep logic so we don't have two independent methods.
This makes it easier to reason about.

Also don't sleep if we're in the last iteration of the for loop.  It
doesn't make sense to and needlessly slows things down when there are
real errors.

Bug: https://crbug.com/gerrit/12494
Change-Id: Ifceace5b2dde75c2dac39ea5388527dd37376336
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/303402
Reviewed-by: Sam Saccone 🐐 <samccone@google.com>
Tested-by: Mike Frysinger <vapier@google.com>

1 files changed, 18 insertions, 14 deletions

diff --git a/project.py b/project.py
index 9517c5ab..1e31a20a 100644
--- a/project.py
+++ b/project.py
@@ -2175,19 +2175,13 @@ class Project(object):
       elif (gitcmd.stdout and
             'error:' in gitcmd.stdout and
             'HTTP 429' in gitcmd.stdout):
-        if not quiet:
-          print('429 received, sleeping: %s sec' % retry_cur_sleep,
-                file=sys.stderr)
-        time.sleep(retry_cur_sleep)
-        retry_cur_sleep = min(retry_exp_factor * retry_cur_sleep,
-                              MAXIMUM_RETRY_SLEEP_SEC)
-        retry_cur_sleep *= (1 - random.uniform(-RETRY_JITTER_PERCENT,
-                                               RETRY_JITTER_PERCENT))
-        continue
+        # Fallthru to sleep+retry logic at the bottom.
+        pass
 
-      # If this is not last attempt, try 'git remote prune'.
-      elif (try_n < retry_fetches - 1 and
-            gitcmd.stdout and
+      # Try to prune remote branches once in case there are conflicts.
+      # For example, if the remote had refs/heads/upstream, but deleted that and
+      # now has refs/heads/upstream/foo.
+      elif (gitcmd.stdout and
             'error:' in gitcmd.stdout and
             'git remote prune' in gitcmd.stdout and
             not prune_tried):
@@ -2197,6 +2191,8 @@ class Project(object):
         ret = prunecmd.Wait()
         if ret:
           break
+        output_redir.write('retrying fetch after pruning remote branches')
+        # Continue right away so we don't sleep as we shouldn't need to.
         continue
       elif current_branch_only and is_sha1 and ret == 128:
         # Exit code 128 means "couldn't find the ref you asked for"; if we're
@@ -2206,9 +2202,17 @@ class Project(object):
       elif ret < 0:
         # Git died with a signal, exit immediately
         break
+
+      # Figure out how long to sleep before the next attempt, if there is one.
       if not verbose:
-        print('\n%s:\n%s' % (self.name, gitcmd.stdout), file=sys.stderr)
-      time.sleep(random.randint(30, 45))
+        output_redir.write('\n%s:\n%s' % (self.name, gitcmd.stdout), file=sys.stderr)
+      if try_n < retry_fetches - 1:
+        output_redir.write('sleeping %s seconds before retrying' % retry_cur_sleep)
+        time.sleep(retry_cur_sleep)
+        retry_cur_sleep = min(retry_exp_factor * retry_cur_sleep,
+                              MAXIMUM_RETRY_SLEEP_SEC)
+        retry_cur_sleep *= (1 - random.uniform(-RETRY_JITTER_PERCENT,
+                                               RETRY_JITTER_PERCENT))
 
     if initial:
       if alt_dir: