A couple of minor changes:

- Added extra configuration parameter 'only_follow_origins' to only repoint pgbouncer configuration if the origin of the monitored sets changes, which is what we usually want.
- Only write cluster status information file when cluster status has actually changed.

diff --git a/README.md b/README.md
index 0b0fee1141852472d182a0468fd976636621f8f1..33cabba30ef53fe32eec2a9a6fcae683f66fea4d 100644 (file)
--- a/README.md
+++ b/README.md
@@ -43,6 +43,7 @@ $ sudo invoke-rc.d pgbouncer_follower_rw start
 | pgBouncer | sets_to_follow         | text    | *1*                                         | Comma separated list of sets to follow or 'all' to follow all sets
 | pgBouncer | pool_mode              | 'ro/rw' | *'rw'*                                      | Select a read-only subscriber or the origin for read-write
 | pgBouncer | pool_all_databases     | boolean | *'false'*                                   | If true uses wildcard for database name in pgbouncer.ini, false uses slony database
+| pgBouncer | only_follow_origins    | boolean | *'false'*                                   | If true pgbouncer will only be reconfigured and reloaded when sets move origin
 | pgBouncer | status_file            | text    | *'/tmp/pgbouncer_follower_%mode.status'*    | File used to store a hash depicting the state of the cluster
 | pgBouncer | log_file               | text    | *'/tmp/pgbouncer_follower_%mode.log'*       | Log file for the script
 | pgBouncer | pid_file               | text    | *'/tmp/pgbouncer_follower_%mode.log'*       | PID file for the script when run as a daemon

diff --git a/pgbouncer_follower.pl b/pgbouncer_follower.pl
index fefe45ee153ffd6112f40ebf31f1b8b2aec8c44b..0b88b19dfd2f987af14dd3c9a32185ff015bb7c2 100755 (executable)
--- a/pgbouncer_follower.pl
+++ b/pgbouncer_follower.pl
@@ -58,12 +58,17 @@ my ($year, $month, $day, $hour, $min, $sec);
 my $change_time;
 my $g_host = hostname;
 my ($g_addr)=inet_ntoa((gethostbyname(hostname))[4]);
+my $g_origins_only = false;
 
 die $g_usage unless GetOptions(\%opt, 'config_file|f=s', 'daemon|D',) and keys %opt and ! @ARGV;
 
 unless (getConfig($opt{config_file})){
     print ("There was a problem reading the configuration.\n");
 }
+if (!defined($g_status_file)) {
+    $g_status_file = "/tmp/$g_clname.status";
+}
+
  
 if ($g_debug) {
     printLogLn($g_logfile, "DEBUG: Logging to my '$g_logfile'");
@@ -235,7 +240,9 @@ sub generateConfig {
                     }
                     if (defined($target_host)) {
                         $_ = "# Configuration for " . ($target_is_origin ? "origin" : "subscriber") . " of sets $target_sets node #$target_node_id $target_host:$target_port\n" . $_;
-                        printLogLn ($g_logfile, "DEBUG: Configuration for " . ($target_is_origin ? "origin" : "subscriber") . " of sets $target_sets node #$target_node_id $target_host:$target_port");
+                        if ($g_debug) {
+                            printLogLn ($g_logfile, "DEBUG: Configuration for " . ($target_is_origin ? "origin" : "subscriber") . " of sets $target_sets node #$target_node_id $target_host:$target_port");
+                        }
                         if ($all_databases) {
                             $_ =~ s/(\[databases\])/$1\n\* = host=$target_host port=$target_port/;
                         }
@@ -270,9 +277,11 @@ sub checkCluster {
     my $current_cluster;
     my $previous_cluster;
     foreach (@g_cluster) {
-        $current_cluster = md5_hex(($current_cluster // "") . $_->[0] . $_->[2] . (defined($_->[3]) ? 't' : 'f'));
-        if ($g_debug) {
-            printLogLn($g_logfile, "DEBUG: Node " . $_->[0] . " detail = " . $_->[2] . (defined($_->[3]) ? 't' : 'f'));
+        if (!$g_origins_only || defined($_->[3])) {
+            $current_cluster = md5_hex(($current_cluster // "") . $_->[0] . $_->[2] . (defined($_->[3]) ? 't' : 'f'));
+            if ($g_debug) {
+                printLogLn($g_logfile, "DEBUG: Node " . $_->[0] . " detail = " . $_->[2] . (defined($_->[3]) ? 't' : 'f'));
+            }
         }
     }
    
@@ -286,15 +295,20 @@ sub checkCluster {
         }
     }
 
-    if (open(CLUSTERFILE, ">", $infile)) {
-        print CLUSTERFILE $current_cluster;
-        close(CLUSTERFILE);
-    }
-    else {
-        printLogLn ($g_logfile, "ERROR: Can't open file $infile for writing");
+    unless (-f $infile && ($current_cluster eq $previous_cluster)) {
+        if ($g_debug) {
+                printLogLn($g_logfile, "DEBUG: Writing to status file");
+        }
+        if (open(CLUSTERFILE, ">", $infile)) {
+            print CLUSTERFILE $current_cluster;
+            close(CLUSTERFILE);
+        }
+        else {
+            printLogLn ($g_logfile, "ERROR: Can't open file $infile for writing");
+        }
     }
 
-    if ((($previous_cluster // "")ne "") && (($current_cluster // "") ne "") && ($current_cluster ne $previous_cluster)){
+    if ((($previous_cluster // "") ne "") && (($current_cluster // "") ne "") && ($current_cluster ne $previous_cluster)){
         $changed = true;
     }
 
@@ -456,6 +470,9 @@ sub getConfig {
                     when(/\bpool_all_databases\b/i) {
                         $g_all_databases = checkBoolean($value);
                     }
+                    when(/\bonly_follow_origins\b/i) {
+                        $g_origins_only = checkBoolean($value);
+                    }
                 }  
             }
         }

diff --git a/pgbouncer_follower_rw.conf b/pgbouncer_follower_rw.conf
index f0f0d8fe52dfcfa6b619ce6b153e6ecc039e3a29..e780cac6c8988e283a4c0c98f29744248ce31653 100755 (executable)
--- a/pgbouncer_follower_rw.conf
+++ b/pgbouncer_follower_rw.conf
@@ -16,11 +16,15 @@ server_conninfo=dbname=TEST host=localhost port=5435
 #------------------------------------------------------------------------------
 # PgBouncer follower information
 #------------------------------------------------------------------------------
-debug = true
+debug = false
 follower_poll_interval=5000                                                     # Cluster state poll interval (milliseconds)
 
 slony_sets_to_follow=all                                                        # Comma separated list of set id's to follow E.g. "1,2,3,4" or "all"
 
+only_follow_origins=true                                                        # If true pgbouncer will only be reconfigured and reloaded
+                                                                                # when the origin of a set moves. If false any changes to origins,
+                                                                                # providers or subscribers will initiate a reconfigure and reload.
+
 pool_mode=rw                                                                    # Values are rw/ro. "rw" follows the origin node
                                                                                 # whereas "ro" will follow a subscriber  of the sets
                                                                                 # specified in slony_sets_to_follow
@@ -34,7 +38,7 @@ log_file=/var/slony/pgbouncer_follower/pgbouncer_follower_%mode.log
 pid_file=/var/run/pgbouncer_follower_%mode.pid                                  # Pidfile for poll mode 
 pool_conf_template=/etc/pgbouncer/pgbouncer_%mode.template                      # Template configuration file
 pool_conf_target=/etc/pgbouncer/pgbouncer_%mode.ini                             # Target configuration file to be modified
-pool_reload_command=invoke-rc.d pgbouncer_%mode reload                          # Command used to action configuration changes
+pool_reload_command=/etc/init.d/pgbouncer_%mode reload                          # Command used to action configuration changes
                                                                                 # Sepcial values for status_file, log_file, pool_conf_template
                                                                                 # pool_conf_target and pool_reload_command parameters:
                                                                                 #   %mode - Pool Mode