{GPL, other}: Relicense to MIT license.
[collectd.git] / src / plugin.c
index 894b0e5..30a1ff1 100644 (file)
@@ -1,19 +1,24 @@
 /**
  * collectd - src/plugin.c
- * Copyright (C) 2005-2013  Florian octo Forster
+ * Copyright (C) 2005-2014  Florian octo Forster
  *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License as published by the
- * Free Software Foundation; only version 2 of the License is applicable.
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
  *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License for more details.
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
  *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
  *
  * Authors:
  *   Florian octo Forster <octo at collectd.org>
@@ -31,6 +36,7 @@
 #include "utils_llist.h"
 #include "utils_heap.h"
 #include "utils_time.h"
+#include "utils_random.h"
 
 #if HAVE_PTHREAD_H
 # include <pthread.h>
@@ -108,6 +114,7 @@ static int             read_threads_num = 0;
 
 static write_queue_t  *write_queue_head;
 static write_queue_t  *write_queue_tail;
+static long            write_queue_length = 0;
 static _Bool           write_loop = 1;
 static pthread_mutex_t write_lock = PTHREAD_MUTEX_INITIALIZER;
 static pthread_cond_t  write_cond = PTHREAD_COND_INITIALIZER;
@@ -117,6 +124,9 @@ static size_t          write_threads_num = 0;
 static pthread_key_t   plugin_ctx_key;
 static _Bool           plugin_ctx_key_initialized = 0;
 
+static long            write_limit_high = 0;
+static long            write_limit_low = 0;
+
 /*
  * Static functions
  */
@@ -670,11 +680,13 @@ static int plugin_write_enqueue (value_list_t const *vl) /* {{{ */
        {
                write_queue_head = q;
                write_queue_tail = q;
+               write_queue_length = 1;
        }
        else
        {
                write_queue_tail->next = q;
                write_queue_tail = q;
+               write_queue_length += 1;
        }
 
        pthread_cond_signal (&write_cond);
@@ -701,8 +713,11 @@ static value_list_t *plugin_write_dequeue (void) /* {{{ */
 
        q = write_queue_head;
        write_queue_head = q->next;
-       if (write_queue_head == NULL)
+       write_queue_length -= 1;
+       if (write_queue_head == NULL) {
                write_queue_tail = NULL;
+               assert(0 == write_queue_length);
+               }
 
        pthread_mutex_unlock (&write_lock);
 
@@ -805,6 +820,7 @@ static void stop_write_threads (void) /* {{{ */
        }
        write_queue_head = NULL;
        write_queue_tail = NULL;
+       write_queue_length = 0;
        pthread_mutex_unlock (&write_lock);
 
        if (i > 0)
@@ -1206,6 +1222,27 @@ int plugin_register_shutdown (const char *name,
                                (void *) callback, /* user_data = */ NULL));
 } /* int plugin_register_shutdown */
 
+static void plugin_free_data_sets (void)
+{
+       void *key;
+       void *value;
+
+       if (data_sets == NULL)
+               return;
+
+       while (c_avl_pick (data_sets, &key, &value) == 0)
+       {
+               data_set_t *ds = value;
+               /* key is a pointer to ds->type */
+
+               sfree (ds->ds);
+               sfree (ds);
+       }
+
+       c_avl_destroy (data_sets);
+       data_sets = NULL;
+} /* void plugin_free_data_sets */
+
 int plugin_register_data_set (const data_set_t *ds)
 {
        data_set_t *ds_copy;
@@ -1423,7 +1460,8 @@ int plugin_unregister_notification (const char *name)
 
 void plugin_init_all (void)
 {
-       const char *chain_name;
+       char const *chain_name;
+       long write_threads_num;
        llentry_t *le;
        int status;
 
@@ -1436,16 +1474,38 @@ void plugin_init_all (void)
        chain_name = global_option_get ("PostCacheChain");
        post_cache_chain = fc_chain_get_by_name (chain_name);
 
+       write_limit_high = global_option_get_long ("WriteQueueLimitHigh",
+                       /* default = */ 0);
+       if (write_limit_high < 0)
        {
-               char const *tmp = global_option_get ("WriteThreads");
-               int num = atoi (tmp);
+               ERROR ("WriteQueueLimitHigh must be positive or zero.");
+               write_limit_high = 0;
+       }
 
-               if (num < 1)
-                       num = 5;
+       write_limit_low = global_option_get_long ("WriteQueueLimitLow",
+                       /* default = */ write_limit_high / 2);
+       if (write_limit_low < 0)
+       {
+               ERROR ("WriteQueueLimitLow must be positive or zero.");
+               write_limit_low = write_limit_high / 2;
+       }
+       else if (write_limit_low > write_limit_high)
+       {
+               ERROR ("WriteQueueLimitLow must not be larger than "
+                               "WriteQueueLimitHigh.");
+               write_limit_low = write_limit_high;
+       }
 
-               start_write_threads ((size_t) num);
+       write_threads_num = global_option_get_long ("WriteThreads",
+                       /* default = */ 5);
+       if (write_threads_num < 1)
+       {
+               ERROR ("WriteThreads must be positive.");
+               write_threads_num = 5;
        }
 
+       start_write_threads ((size_t) write_threads_num);
+
        if ((list_init == NULL) && (read_heap == NULL))
                return;
 
@@ -1730,6 +1790,7 @@ void plugin_shutdown_all (void)
        destroy_all_callbacks (&list_log);
 
        plugin_free_loaded ();
+       plugin_free_data_sets ();
 } /* void plugin_shutdown_all */
 
 int plugin_dispatch_missing (const value_list_t *vl) /* {{{ */
@@ -1950,10 +2011,76 @@ static int plugin_dispatch_values_internal (value_list_t *vl)
        return (0);
 } /* int plugin_dispatch_values_internal */
 
+static double get_drop_probability (void) /* {{{ */
+{
+       long pos;
+       long size;
+       long wql;
+
+       pthread_mutex_lock (&write_lock);
+       wql = write_queue_length;
+       pthread_mutex_unlock (&write_lock);
+
+       if (wql < write_limit_low)
+               return (0.0);
+       if (wql >= write_limit_high)
+               return (1.0);
+
+       pos = 1 + wql - write_limit_low;
+       size = 1 + write_limit_high - write_limit_low;
+
+       return (((double) pos) / ((double) size));
+} /* }}} double get_drop_probability */
+
+static _Bool check_drop_value (void) /* {{{ */
+{
+       static cdtime_t last_message_time = 0;
+       static pthread_mutex_t last_message_lock = PTHREAD_MUTEX_INITIALIZER;
+
+       double p;
+       double q;
+       int status;
+
+       if (write_limit_high == 0)
+               return (0);
+
+       p = get_drop_probability ();
+       if (p == 0.0)
+               return (0);
+
+       status = pthread_mutex_trylock (&last_message_lock);
+       if (status == 0)
+       {
+               cdtime_t now;
+
+               now = cdtime ();
+               if ((now - last_message_time) > TIME_T_TO_CDTIME_T (1))
+               {
+                       last_message_time = now;
+                       ERROR ("plugin_dispatch_values: Low water mark "
+                                       "reached. Dropping %.0f%% of metrics.",
+                                       100.0 * p);
+               }
+               pthread_mutex_unlock (&last_message_lock);
+       }
+
+       if (p == 1.0)
+               return (1);
+
+       q = cdrand_d ();
+       if (q > p)
+               return (1);
+       else
+               return (0);
+} /* }}} _Bool check_drop_value */
+
 int plugin_dispatch_values (value_list_t const *vl)
 {
        int status;
 
+       if (check_drop_value ())
+               return (0);
+
        status = plugin_write_enqueue (vl);
        if (status != 0)
        {
@@ -1967,6 +2094,65 @@ int plugin_dispatch_values (value_list_t const *vl)
        return (0);
 }
 
+__attribute__((sentinel))
+int plugin_dispatch_multivalue (value_list_t const *template, /* {{{ */
+               _Bool store_percentage, ...)
+{
+       value_list_t *vl;
+       int failed = 0;
+       gauge_t sum = 0.0;
+       va_list ap;
+
+       assert (template->values_len == 1);
+
+       va_start (ap, store_percentage);
+       while (42)
+       {
+               char const *name;
+               gauge_t value;
+
+               name = va_arg (ap, char const *);
+               if (name == NULL)
+                       break;
+
+               value = va_arg (ap, gauge_t);
+               if (!isnan (value))
+                       sum += value;
+       }
+       va_end (ap);
+
+       vl = plugin_value_list_clone (template);
+       /* plugin_value_list_clone makes sure vl->time is set to non-zero. */
+       if (store_percentage)
+               sstrncpy (vl->type, "percent", sizeof (vl->type));
+
+       va_start (ap, store_percentage);
+       while (42)
+       {
+               char const *name;
+               int status;
+
+               /* Set the type instance. */
+               name = va_arg (ap, char const *);
+               if (name == NULL)
+                       break;
+               sstrncpy (vl->type_instance, name, sizeof (vl->type_instance));
+
+               /* Set the value. */
+               vl->values[0].gauge = va_arg (ap, gauge_t);
+               if (store_percentage)
+                       vl->values[0].gauge *= 100.0 / sum;
+
+               status = plugin_write_enqueue (vl);
+               if (status != 0)
+                       failed++;
+       }
+       va_end (ap);
+
+       plugin_value_list_free (vl);
+       return (failed);
+} /* }}} int plugin_dispatch_multivalue */
+
 int plugin_dispatch_notification (const notification_t *notif)
 {
        llentry_t *le;