apcups plugin: Implement the "PersistentConnection" option.

If set to false, close the connection after each interval. This lets
users chose this method if persistent connections pose a problem.

Fixes: #617

diff --git a/src/apcups.c b/src/apcups.c
index 66fe45e..dc533f1 100644 (file)
--- a/src/apcups.c
+++ b/src/apcups.c
@@ -74,12 +74,12 @@ static char *conf_node = NULL;
 static char *conf_service = NULL;
 /* Defaults to false for backwards compatibility. */
 static _Bool conf_report_seconds = 0;
+static _Bool conf_persistent_conn = 1;
 
 static int global_sockfd = -1;
 
 static int count_retries = 0;
 static int count_iterations = 0;
-static _Bool close_socket = 0;
 
 static int net_shutdown (int *fd)
 {
@@ -314,7 +314,7 @@ static int apc_query_server (char const *node, char const *service,
                                "first %i iterations. Will close the socket "
                                "in future iterations.",
                                count_retries, count_iterations);
-               close_socket = 1;
+               conf_persistent_conn = 0;
        }
 
        while ((n = net_recv (&global_sockfd, recvline, sizeof (recvline) - 1)) > 0)
@@ -367,7 +367,7 @@ static int apc_query_server (char const *node, char const *service,
        }
        status = errno; /* save errno, net_shutdown() may re-set it. */
 
-       if (close_socket)
+       if (!conf_persistent_conn)
                net_shutdown (&global_sockfd);
 
        if (n < 0)
@@ -395,6 +395,8 @@ static int apcups_config (oconfig_item_t *ci)
                        cf_util_get_service (child, &conf_service);
                else if (strcasecmp (child->key, "ReportSeconds") == 0)
                        cf_util_get_boolean (child, &conf_report_seconds);
+               else if (strcasecmp (child->key, "PersistentConnection") == 0)
+                       cf_util_get_boolean (child, &conf_persistent_conn);
                else
                        ERROR ("apcups plugin: Unknown config option \"%s\".", child->key);
        }

diff --git a/src/collectd.conf.in b/src/collectd.conf.in
index 99f879c..5a4c467 100644 (file)
--- a/src/collectd.conf.in
+++ b/src/collectd.conf.in
@@ -264,6 +264,7 @@
 #      Host "localhost"
 #      Port "3551"
 #      ReportSeconds true
+#      PersistentConnection true
 #</Plugin>
 
 #<Plugin aquaero>

diff --git a/src/collectd.conf.pod b/src/collectd.conf.pod
index 1884914..16315ad 100644 (file)
--- a/src/collectd.conf.pod
+++ b/src/collectd.conf.pod
@@ -802,12 +802,22 @@ B<apcupsd> can handle it.
 
 TCP-Port to connect to. Defaults to B<3551>.
 
-=item B<ReportSeconds> B<true|false>
+=item B<ReportSeconds> B<true>|B<false>
 
 If set to B<true>, the time reported in the C<timeleft> metric will be
 converted to seconds. This is the recommended setting. If set to B<false>, the
 default for backwards compatibility, the time will be reported in minutes.
 
+=item B<PersistentConnection> B<true>|B<false>
+
+By default, the plugin will try to keep the connection to UPS open between
+reads. Since this appears to be somewhat brittle (I<apcupsd> appears to close
+the connection due to inactivity quite quickly), the plugin will try to detect
+this problem and switch to an open-read-close mode in such cases.
+
+You can instruct the plugin to close the connection after each read by setting
+this option to B<false>.
+
 =back
 
 =head2 Plugin C<aquaero>