Re:Re: [PATCH v5] send-email: --batch-size to work around some SMTP server limit

>On Sun, May 21, 2017 at 2:59 PM, xiaoqiang zhao <zxq_yx_007@163.com> wrote:
>> Some email servers (e.g. smtp.163.com) limit the number emails to be
>> sent per session(connection) and this will lead to a faliure when
>> sending many messages.
>
>This OK to me, the nits I had are addressed by Junio's reply.
>
>Looking at this the Nth time now though I wonder about this approach
>in general. In all your E-Mails I don't think you ever said /what/
>sort of error you had from the SMTP server, you just said you had a
>failure or an error, I assume you hit one of the die's in the
>send_message() function. Can you paste the actual error you get
>without this patch?
>

>I wonder if something like this would Just Work for this case without
>any configuration or command-line options, with the added benefit of
>just working for anyone with transitory SMTP issues as well (patch
>posted with -w, full version at
>https://github.com/avar/git/commit/acb60c4bde50bdcb62b71ed46f49617e2caef84e.patch):
>
>diff --git a/git-send-email.perl b/git-send-email.perl
>index 8a1ee0f0d4..c2d85236d1 100755
>--- a/git-send-email.perl
>+++ b/git-send-email.perl
>@@ -1363,6 +1363,10 @@ EOF
>                        die __("The required SMTP server is not
>properly defined.")
>                }
>
>+               my $num_tries = 0;
>+               my $max_tries = 5;
>+       smtp_again:
>+               eval {
>                        if ($smtp_encryption eq 'ssl') {
>                                $smtp_server_port ||= 465; # ssmtp
>                                require Net::SMTP::SSL;
>@@ -1429,6 +1433,22 @@ EOF
>                        }
>                        $smtp->dataend() or die $smtp->message;
>                        $smtp->code =~ /250|200/ or die
>sprintf(__("Failed to send %s\n"), $subject).$smtp->message;
>+                       1;
>+               } or do {
>+                       my $error = $@ || "Zombie Error";
>+
>+                       warn sprintf(__("Failed to send %s due to
>error: %s"), $subject, $error);
>+                       if ($num_tries++ < $max_tries) {
>+                               $smtp->quit if defined $smtp;
>+                               $smtp = undef;
>+                               $auth = undef;
>+                               my $sleep = $num_tries * 3; # 3, 6, 9, ...
>+                               warn sprintf(__("This is retry %d/%d.
>Sleeping %d before trying again"),
>+                                            $num_tries, $max_tries, $sleep);
>+                               sleep($sleep);
>+                               goto smtp_again;
>+                       }
>+               };
>        }
>        if ($quiet) {
>                printf($dry_run ? __("Dry-Sent %s\n") : __("Sent
>%s\n"), $subject);
>
>Now that's very much a WIP and I don't have a server like that to test against.
>
>Having worked with SMTP a lot in a past life/job, I'd say it's *very*
>likely that you're just getting a /^4/ error code from 163.com,
>probably 421, which would make this logic even simpler. I.e. we could
>just adjust this to back-off for /^4/ instead of trying to handle
>arbitrary errors.
>
>Anyway, I'm not interested in pursuing that WIP patch, and I don't
>think perfect should be the enemy of the good here. Your patch works
>for you, doesn't really damage anything else, so if you're not
>interested in hacking up something like the above I think we should
>just take it.
>
>But I do think it would be very good to get a reply to you / details
>in the commit message about what error you get exactly in this
>scenario, see if you get better details with --smtp-debug, and if so
>paste that (sans any secret info like user/password you don't want to
>share).
>
>Then if we're poking at this code in the future we can maybe just fix
>this in some more general fashion while keeping this use-case in mind.