From: Wilfried Goesgens <dothebart@citadel.org>
Date: Sat, 23 May 2015 13:44:24 +0000 (+0200)
Subject: Filterchain: if we don't find a writer, output the available writers to syslog.
X-Git-Tag: collectd-5.5.0~7
X-Git-Url: https://git.octo.it/?p=collectd.git;a=commitdiff_plain;h=809a89739bd92a5432deb6230a68dd6e6bbb72b3

Filterchain: if we don't find a writer, output the available writers to syslog.
---

diff --git a/src/daemon/filter_chain.c b/src/daemon/filter_chain.c
index b93435fd..32ce7367 100644
--- a/src/daemon/filter_chain.c
+++ b/src/daemon/filter_chain.c
@@ -733,6 +733,8 @@ static int fc_bit_write_invoke (const data_set_t *ds, /* {{{ */
           "all write plugins failed with status %i (ENOENT). "
           "Most likely this means you didn't load any write plugins.",
           status);
+
+      plugin_log_available_writers ();
     }
     else if (status != 0)
     {
@@ -763,6 +765,8 @@ static int fc_bit_write_invoke (const data_set_t *ds, /* {{{ */
             "Filter subsystem: Built-in target `write': Dispatching value to "
             "the `%s' plugin failed with status %i.",
             plugin_list[i].plugin, status);
+
+	plugin_log_available_writers ();
       }
       else
       {
diff --git a/src/daemon/plugin.c b/src/daemon/plugin.c
index 25bd37b8..b69e65b6 100644
--- a/src/daemon/plugin.c
+++ b/src/daemon/plugin.c
@@ -307,6 +307,56 @@ static int register_callback (llist_t **list, /* {{{ */
 	return (0);
 } /* }}} int register_callback */
 
+static void log_list_callbacks (llist_t **list, /* {{{ */
+				const char *comment)
+{
+	char *str;
+	int len;
+	llentry_t *le;
+	int i;
+	int n;
+	char **keys;
+
+	n = llist_size(*list);
+	if (n == 0)
+	{
+		INFO("%s [none]", comment);
+		return;
+	}
+
+	keys = calloc(n, sizeof(char*));
+
+	if (keys == NULL)
+	{
+		ERROR("%s: failed to allocate memory for list of callbacks",
+		      comment);
+
+		return;
+	}
+
+	for (le = llist_head (*list), i = 0, len = 0;
+	     le != NULL;
+	     le = le->next, i++)
+	{
+		keys[i] = le->key;
+		len += strlen(le->key) + 6;
+	}
+	str = malloc(len + 10);
+	if (str == NULL)
+	{
+		ERROR("%s: failed to allocate memory for list of callbacks",
+		      comment);
+	}
+	else
+	{
+		*str = '\0';
+		strjoin(str, len, keys, n, "', '");
+		INFO("%s ['%s']", comment, str);
+		free(str);
+	}
+	free(keys);
+} /* }}} void log_list_callbacks */
+
 static int create_register_callback (llist_t **list, /* {{{ */
 		const char *name, void *callback, user_data_t *ud)
 {
@@ -1398,6 +1448,11 @@ int plugin_unregister_read (const char *name) /* {{{ */
 	return (0);
 } /* }}} int plugin_unregister_read */
 
+void plugin_log_available_writers ()
+{
+	log_list_callbacks (&list_write, "Available writers:");
+}
+
 static int compare_read_func_group (llentry_t *e, void *ud) /* {{{ */
 {
 	read_func_t *rf    = e->value;
diff --git a/src/daemon/plugin.h b/src/daemon/plugin.h
index 86a2d662..beeb5761 100644
--- a/src/daemon/plugin.h
+++ b/src/daemon/plugin.h
@@ -322,6 +322,17 @@ int plugin_unregister_data_set (const char *name);
 int plugin_unregister_log (const char *name);
 int plugin_unregister_notification (const char *name);
 
+/*
+ * NAME
+ *  plugin_log_available_writers
+ *
+ * DESCRIPTION
+ *  This function can be called to output a list of _all_ registered
+ *  writers to the logfacility.
+ *  Since some writers dynamically build their name it can be hard for
+ *  the configuring person to know it. This function will fill this gap. 
+ */
+void plugin_log_available_writers ();
 
 /*
  * NAME