From 5fecab1d06495bd848bf203fa10c2b98e63cfd22 Mon Sep 17 00:00:00 2001
From: dormando <dormando@rydia.net>
Date: Thu, 1 Dec 2011 18:39:37 -0800
Subject: [PATCH] provide a server setting cache via monitor worker

---
 lib/MogileFS/Config.pm         | 14 ++++++++++++--
 lib/MogileFS/Store.pm          | 16 ----------------
 lib/MogileFS/Util.pm           |  7 +++++++
 lib/MogileFS/Worker/Monitor.pm | 14 ++++++++++++--
 4 files changed, 31 insertions(+), 20 deletions(-)

diff --git a/lib/MogileFS/Config.pm b/lib/MogileFS/Config.pm
index 8f215c4..3b9c394 100644
--- a/lib/MogileFS/Config.pm
+++ b/lib/MogileFS/Config.pm
@@ -21,6 +21,7 @@ use constant REBAL_QUEUE => 2;
 use constant DEVICE_SUMMARY_CACHE_TIMEOUT => 15;
 
 my %conf;
+my %server_settings;
 sub set_config {
     shift if @_ == 3;
     my ($k, $v) = @_;
@@ -269,9 +270,18 @@ sub server_setting {
     return Mgd::get_store()->server_setting($key);
 }
 
+sub cache_server_setting {
+    my ($class, $key, $val) = @_;
+    if (! defined $val) {
+        delete $server_settings{$key}
+            if exists $server_settings{$key};
+    }
+    $server_settings{$key} = $val;
+}
+
 sub server_setting_cached {
-    my ($class, $key, $timeout) = @_;
-    return Mgd::get_store()->server_setting_cached($key, $timeout);
+    my ($class, $key) = @_;
+    return $server_settings{$key};
 }
 
 my $memc;
diff --git a/lib/MogileFS/Store.pm b/lib/MogileFS/Store.pm
index 9c44909..7a0fe60 100644
--- a/lib/MogileFS/Store.pm
+++ b/lib/MogileFS/Store.pm
@@ -54,7 +54,6 @@ sub new_from_dsn_user_pass {
         recheck_req_gen  => 0,  # incremented generation, of recheck of dbh being requested
         recheck_done_gen => 0,  # once recheck is done, copy of what the request generation was
         handles_left     => 0,  # amount of times this handle can still be verified
-        server_setting_cache => {}, # value-agnostic db setting cache.
     }, $subclass;
     $self->init;
     return $self;
@@ -875,21 +874,6 @@ sub server_setting {
                                        undef, $key);
 }
 
-# generic server setting cache.
-# note that you can call the same server setting with different timeouts, but
-# the timeout specified at the time of ... timeout, wins.
-sub server_setting_cached {
-    my ($self, $key, $timeout) = @_;
-    $self->{server_setting_cache}->{$key} ||= {val => '', refresh => 0};
-    my $cache = $self->{server_setting_cache}->{$key};
-    my $now = time();
-    if ($now > $cache->{refresh}) {
-        $cache->{val}     = $self->server_setting($key);
-        $cache->{refresh} = $now + $timeout;
-    }
-    return $cache->{val};
-}
-
 sub server_settings {
     my ($self) = @_;
     my $ret = {};
diff --git a/lib/MogileFS/Util.pm b/lib/MogileFS/Util.pm
index c164a7d..882d7e1 100644
--- a/lib/MogileFS/Util.pm
+++ b/lib/MogileFS/Util.pm
@@ -35,6 +35,13 @@ sub apply_state_events {
         my $type = delete $args->{ev_type};
         my $id   = delete $args->{ev_id};
 
+        # This special case feels gross, but that's what it is.
+        if ($type eq 'srvset') {
+            my $val = $mode eq 'set' ? $args->{value} : undef;
+            MogileFS::Config->cache_server_setting($args->{field}, $val);
+            next;
+        }
+
         my $old = $factories{$type}->get_by_id($id);
         if ($mode eq 'setstate') {
             # Host/Device only.
diff --git a/lib/MogileFS/Worker/Monitor.pm b/lib/MogileFS/Worker/Monitor.pm
index 9280380..924974d 100644
--- a/lib/MogileFS/Worker/Monitor.pm
+++ b/lib/MogileFS/Worker/Monitor.pm
@@ -215,7 +215,9 @@ sub diff_data {
             my $id = $type eq 'domain' ? $item->{dmid}
                 : $type eq 'class'     ? $item->{dmid} . '-' . $item->{classid}
                 : $type eq 'host'      ? $item->{hostid}
-                : $type eq 'device'    ? $item->{devid} : die "Unknown type";
+                : $type eq 'device'    ? $item->{devid}
+                : $type eq 'srvset'    ? $item->{field}
+                : die "Unknown type";
             my $old = delete $p_data->{$id};
             # Special case: for devices, we don't care if mb_asof changes.
             # FIXME: Change the grab routine (or filter there?).
@@ -262,10 +264,18 @@ sub grab_all_data {
     while (my ($name, $id) = each %dom) {
         push(@fixed_dom, { namespace => $name, dmid => $id });
     }
+
+    my $set = $sto->server_settings;
+    my @fixed_set = ();
+    while (my ($field, $value) = each %$set) {
+        push(@fixed_set, { field => $field, value => $value });
+    }
+
     my %ret = ( domain => \@fixed_dom,
         class  => [$sto->get_all_classes],
         host   => [$sto->get_all_hosts],
-        device => [$sto->get_all_devices], );
+        device => [$sto->get_all_devices],
+        srvset => \@fixed_set, );
     return \%ret;
 }
 
-- 
2.11.4.GIT