Error handling tweaks

Makefile.PL

@@ -21,6 +21,7 @@ WriteMakefile(
         'LWP::Simple'     => 0,
         fields            => 0,
         'Test::More'      => 0,
+        'List::Util'      => 0,
     },
 );
 

lib/MogileFS/Backend.pm

@@ -9,6 +9,7 @@ use Socket qw( MSG_NOSIGNAL PF_INET IPPROTO_TCP SOCK_STREAM );
 use Errno qw( EINPROGRESS EWOULDBLOCK EISCONN );
 use POSIX ();
 use MogileFS::Client;
+use List::Util qw/ shuffle /;
 
 use fields ('hosts',        # arrayref of "$host:$port" of mogilefsd servers
             'host_dead',    # "$host:$port" -> $time  (of last connect failure)
@@ -18,6 +19,7 @@ use fields ('hosts',        # arrayref of "$host:$port" of mogilefsd servers
             'pref_ip',      # hashref; { ip => preferred ip }
             'timeout',      # time in seconds to allow sockets to become readable
             'last_host_connected',  # "ip:port" of last host connected to
+            'last_host_idx', # array index of the last host we connected to
             'hooks',        # hash: hookname -> coderef
             );
 
@@ -59,6 +61,8 @@ sub _init {
         $self->{timeout} = $args{timeout} || 3;
     }
 
+    $self->{hosts} = [ shuffle(@{ $self->{hosts} }) ];
+
     $self->{host_dead} = {};
 
     return $self;
@@ -220,6 +224,12 @@ sub err {
     return $self->{lasterr} ? 1 : 0;
 }
 
+sub force_disconnect {
+    my MogileFS::Backend $self = shift;
+    undef $self->{sock_cache};
+    return;
+}
+
 ################################################################################
 # MogileFS::Backend class methods
 #
@@ -310,12 +320,16 @@ sub _get_sock {
 
     my $size = scalar(@{$self->{hosts}});
     my $tries = $size > 15 ? 15 : $size;
-    my $idx = int(rand() * $size);
+
+    unless (defined($self->{last_host_idx})) {
+        $self->{last_host_idx} = int(rand() * $size);
+    }
 
     my $now = time();
     my $sock;
     foreach (1..$tries) {
-        my $host = $self->{hosts}->[$idx++ % $size];
+        $self->{last_host_idx} = ($self->{last_host_idx}+1) % $size;
+        my $host = $self->{hosts}->[$self->{last_host_idx}];
 
         # try dead hosts every 5 seconds
         next if $self->{host_dead}->{$host} &&

lib/MogileFS/Client.pm

@@ -185,6 +185,20 @@ sub errcode {
     return $self->{backend}->errcode;
 }
 
+=head2 force_disconnect
+
+Forces the client to disconnect from the tracker, causing it to reconnect
+when the next request is made.  It will reconnect to a different tracker if
+possible.  A paranoid application may wish to do to this before retrying a
+failed command, on the off chance that another tracker may be working better.
+
+=cut
+
+sub force_disconnect {
+    my MogileFS::Client $self = shift;
+    return $self->{backend}->force_disconnect();
+}
+
 =head2 readonly
 
   $is_readonly = $mogc->readonly

t/30-disconnect.t

@@ -0,0 +1,20 @@
+#!/usr/bin/perl -w
+
+use strict;
+use Test::More;
+use MogileFS::Client;
+
+my $obj = bless({
+    backend => bless({
+    }, 'MogileFS::Backend')
+}, 'MogileFS::Client');
+
+isa_ok($obj, 'MogileFS::Client');
+
+$obj->{backend}->{sock_cache} = 'x';
+is($obj->{backend}->{sock_cache}, 'x');
+
+$obj->force_disconnect();
+is($obj->{backend}->{sock_cache}, undef);
+
+done_testing();