treewide: use designated initializers for user_data
[collectd.git] / src / write_http.c
index bbd94af..95132cf 100644 (file)
@@ -2,7 +2,7 @@
  * collectd - src/write_http.c
  * Copyright (C) 2009       Paul Sadauskas
  * Copyright (C) 2009       Doug MacEachern
- * Copyright (C) 2007-2009  Florian octo Forster
+ * Copyright (C) 2007-2014  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
  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  *
  * Authors:
- *   Florian octo Forster <octo at verplant.org>
+ *   Florian octo Forster <octo at collectd.org>
  *   Doug MacEachern <dougm@hyperic.com>
  *   Paul Sadauskas <psadauskas@gmail.com>
  **/
 
 #include "collectd.h"
+
 #include "plugin.h"
 #include "common.h"
-#include "utils_cache.h"
-#include "utils_parse_option.h"
 #include "utils_format_json.h"
-
-#if HAVE_PTHREAD_H
-# include <pthread.h>
-#endif
+#include "utils_format_kairosdb.h"
 
 #include <curl/curl.h>
 
+#ifndef WRITE_HTTP_DEFAULT_BUFFER_SIZE
+# define WRITE_HTTP_DEFAULT_BUFFER_SIZE 4096
+#endif
+
 /*
  * Private variables
  */
 struct wh_callback_s
 {
-        char *location;
+        char *name;
 
+        char *location;
         char *user;
         char *pass;
         char *credentials;
-        int   verify_peer;
-        int   verify_host;
+        _Bool verify_peer;
+        _Bool verify_host;
         char *cacert;
-        int   store_rates;
-
-#define WH_FORMAT_COMMAND 0
-#define WH_FORMAT_JSON    1
+        char *capath;
+        char *clientkey;
+        char *clientcert;
+        char *clientkeypass;
+        long sslversion;
+        _Bool store_rates;
+        _Bool log_http_error;
+        int   low_speed_limit;
+        time_t low_speed_time;
+        int timeout;
+
+#define WH_FORMAT_COMMAND  0
+#define WH_FORMAT_JSON     1
+#define WH_FORMAT_KAIROSDB 2
         int format;
+        _Bool send_metrics;
+        _Bool send_notifications;
 
         CURL *curl;
-       struct curl_slist *headers;
+        struct curl_slist *headers;
         char curl_errbuf[CURL_ERROR_SIZE];
 
-        char   send_buffer[4096];
+        char  *send_buffer;
+        size_t send_buffer_size;
         size_t send_buffer_free;
         size_t send_buffer_fill;
         cdtime_t send_buffer_init_time;
@@ -68,14 +82,30 @@ struct wh_callback_s
 };
 typedef struct wh_callback_s wh_callback_t;
 
+static void wh_log_http_error (wh_callback_t *cb)
+{
+        if (!cb->log_http_error)
+                return;
+
+        long http_code = 0;
+
+        curl_easy_getinfo (cb->curl, CURLINFO_RESPONSE_CODE, &http_code);
+
+        if (http_code != 200)
+                INFO ("write_http plugin: HTTP Error code: %lu", http_code);
+}
+
 static void wh_reset_buffer (wh_callback_t *cb)  /* {{{ */
 {
-        memset (cb->send_buffer, 0, sizeof (cb->send_buffer));
-        cb->send_buffer_free = sizeof (cb->send_buffer);
+        if ((cb == NULL) || (cb->send_buffer == NULL))
+                return;
+
+        memset (cb->send_buffer, 0, cb->send_buffer_size);
+        cb->send_buffer_free = cb->send_buffer_size;
         cb->send_buffer_fill = 0;
         cb->send_buffer_init_time = cdtime ();
 
-        if (cb->format == WH_FORMAT_JSON)
+        if (cb->format == WH_FORMAT_JSON || cb->format == WH_FORMAT_KAIROSDB)
         {
                 format_json_initialize (cb->send_buffer,
                                 &cb->send_buffer_fill,
@@ -83,12 +113,16 @@ static void wh_reset_buffer (wh_callback_t *cb)  /* {{{ */
         }
 } /* }}} wh_reset_buffer */
 
-static int wh_send_buffer (wh_callback_t *cb) /* {{{ */
+/* must hold cb->send_lock when calling */
+static int wh_post_nolock (wh_callback_t *cb, char const *data) /* {{{ */
 {
         int status = 0;
 
-        curl_easy_setopt (cb->curl, CURLOPT_POSTFIELDS, cb->send_buffer);
+        curl_easy_setopt (cb->curl, CURLOPT_POSTFIELDS, data);
         status = curl_easy_perform (cb->curl);
+
+        wh_log_http_error (cb);
+
         if (status != CURLE_OK)
         {
                 ERROR ("write_http plugin: curl_easy_perform failed with "
@@ -96,7 +130,7 @@ static int wh_send_buffer (wh_callback_t *cb) /* {{{ */
                                 status, cb->curl_errbuf);
         }
         return (status);
-} /* }}} wh_send_buffer */
+} /* }}} wh_post_nolock */
 
 static int wh_callback_init (wh_callback_t *cb) /* {{{ */
 {
@@ -110,12 +144,24 @@ static int wh_callback_init (wh_callback_t *cb) /* {{{ */
                 return (-1);
         }
 
+        if (cb->low_speed_limit > 0 && cb->low_speed_time > 0)
+        {
+                curl_easy_setopt (cb->curl, CURLOPT_LOW_SPEED_LIMIT,
+                                  (long) (cb->low_speed_limit * cb->low_speed_time));
+                curl_easy_setopt (cb->curl, CURLOPT_LOW_SPEED_TIME,
+                                  (long) cb->low_speed_time);
+        }
+
+#ifdef HAVE_CURLOPT_TIMEOUT_MS
+        if (cb->timeout > 0)
+                curl_easy_setopt (cb->curl, CURLOPT_TIMEOUT_MS, (long) cb->timeout);
+#endif
+
         curl_easy_setopt (cb->curl, CURLOPT_NOSIGNAL, 1L);
-        curl_easy_setopt (cb->curl, CURLOPT_USERAGENT, PACKAGE_NAME"/"PACKAGE_VERSION);
+        curl_easy_setopt (cb->curl, CURLOPT_USERAGENT, COLLECTD_USERAGENT);
 
-       cb->headers = NULL;
         cb->headers = curl_slist_append (cb->headers, "Accept:  */*");
-        if (cb->format == WH_FORMAT_JSON)
+        if (cb->format == WH_FORMAT_JSON || cb->format == WH_FORMAT_KAIROSDB)
                 cb->headers = curl_slist_append (cb->headers, "Content-Type: application/json");
         else
                 cb->headers = curl_slist_append (cb->headers, "Content-Type: text/plain");
@@ -124,16 +170,23 @@ static int wh_callback_init (wh_callback_t *cb) /* {{{ */
 
         curl_easy_setopt (cb->curl, CURLOPT_ERRORBUFFER, cb->curl_errbuf);
         curl_easy_setopt (cb->curl, CURLOPT_URL, cb->location);
+        curl_easy_setopt (cb->curl, CURLOPT_FOLLOWLOCATION, 1L);
+        curl_easy_setopt (cb->curl, CURLOPT_MAXREDIRS, 50L);
 
         if (cb->user != NULL)
         {
+#ifdef HAVE_CURLOPT_USERNAME
+                curl_easy_setopt (cb->curl, CURLOPT_USERNAME, cb->user);
+                curl_easy_setopt (cb->curl, CURLOPT_PASSWORD,
+                        (cb->pass == NULL) ? "" : cb->pass);
+#else
                 size_t credentials_size;
 
                 credentials_size = strlen (cb->user) + 2;
                 if (cb->pass != NULL)
                         credentials_size += strlen (cb->pass);
 
-                cb->credentials = (char *) malloc (credentials_size);
+                cb->credentials = malloc (credentials_size);
                 if (cb->credentials == NULL)
                 {
                         ERROR ("curl plugin: malloc failed.");
@@ -143,14 +196,27 @@ static int wh_callback_init (wh_callback_t *cb) /* {{{ */
                 ssnprintf (cb->credentials, credentials_size, "%s:%s",
                                 cb->user, (cb->pass == NULL) ? "" : cb->pass);
                 curl_easy_setopt (cb->curl, CURLOPT_USERPWD, cb->credentials);
+#endif
                 curl_easy_setopt (cb->curl, CURLOPT_HTTPAUTH, CURLAUTH_ANY);
         }
 
         curl_easy_setopt (cb->curl, CURLOPT_SSL_VERIFYPEER, (long) cb->verify_peer);
         curl_easy_setopt (cb->curl, CURLOPT_SSL_VERIFYHOST,
                         cb->verify_host ? 2L : 0L);
+        curl_easy_setopt (cb->curl, CURLOPT_SSLVERSION, cb->sslversion);
         if (cb->cacert != NULL)
                 curl_easy_setopt (cb->curl, CURLOPT_CAINFO, cb->cacert);
+        if (cb->capath != NULL)
+                curl_easy_setopt (cb->curl, CURLOPT_CAPATH, cb->capath);
+
+        if (cb->clientkey != NULL && cb->clientcert != NULL)
+        {
+            curl_easy_setopt (cb->curl, CURLOPT_SSLKEY, cb->clientkey);
+            curl_easy_setopt (cb->curl, CURLOPT_SSLCERT, cb->clientcert);
+
+            if (cb->clientkeypass != NULL)
+                curl_easy_setopt (cb->curl, CURLOPT_SSLKEYPASSWD, cb->clientkeypass);
+        }
 
         wh_reset_buffer (cb);
 
@@ -178,16 +244,16 @@ static int wh_flush_nolock (cdtime_t timeout, wh_callback_t *cb) /* {{{ */
 
         if (cb->format == WH_FORMAT_COMMAND)
         {
-                if (cb->send_buffer_fill <= 0)
+                if (cb->send_buffer_fill == 0)
                 {
                         cb->send_buffer_init_time = cdtime ();
                         return (0);
                 }
 
-                status = wh_send_buffer (cb);
+                status = wh_post_nolock (cb, cb->send_buffer);
                 wh_reset_buffer (cb);
         }
-        else if (cb->format == WH_FORMAT_JSON)
+        else if (cb->format == WH_FORMAT_JSON || cb->format == WH_FORMAT_KAIROSDB)
         {
                 if (cb->send_buffer_fill <= 2)
                 {
@@ -206,7 +272,7 @@ static int wh_flush_nolock (cdtime_t timeout, wh_callback_t *cb) /* {{{ */
                         return (status);
                 }
 
-                status = wh_send_buffer (cb);
+                status = wh_post_nolock (cb, cb->send_buffer);
                 wh_reset_buffer (cb);
         }
         else
@@ -234,15 +300,11 @@ static int wh_flush (cdtime_t timeout, /* {{{ */
 
         pthread_mutex_lock (&cb->send_lock);
 
-        if (cb->curl == NULL)
+        if (wh_callback_init (cb) != 0)
         {
-                status = wh_callback_init (cb);
-                if (status != 0)
-                {
-                        ERROR ("write_http plugin: wh_callback_init failed.");
-                        pthread_mutex_unlock (&cb->send_lock);
-                        return (-1);
-                }
+                ERROR ("write_http plugin: wh_callback_init failed.");
+                pthread_mutex_unlock (&cb->send_lock);
+                return (-1);
         }
 
         status = wh_flush_nolock (timeout, cb);
@@ -260,21 +322,32 @@ static void wh_callback_free (void *data) /* {{{ */
 
         cb = data;
 
-        wh_flush_nolock (/* timeout = */ 0, cb);
+        if (cb->send_buffer != NULL)
+                wh_flush_nolock (/* timeout = */ 0, cb);
 
-        curl_easy_cleanup (cb->curl);
+        if (cb->curl != NULL)
+        {
+                curl_easy_cleanup (cb->curl);
+                cb->curl = NULL;
+        }
 
-       if (cb->headers != NULL)
-       {
-               curl_slist_free_all (cb->headers);
-               cb->headers = NULL;
-       }
+        if (cb->headers != NULL)
+        {
+                curl_slist_free_all (cb->headers);
+                cb->headers = NULL;
+        }
 
+        sfree (cb->name);
         sfree (cb->location);
         sfree (cb->user);
         sfree (cb->pass);
         sfree (cb->credentials);
         sfree (cb->cacert);
+        sfree (cb->capath);
+        sfree (cb->clientkey);
+        sfree (cb->clientcert);
+        sfree (cb->clientkeypass);
+        sfree (cb->send_buffer);
 
         sfree (cb);
 } /* }}} void wh_callback_free */
@@ -324,16 +397,11 @@ static int wh_write_command (const data_set_t *ds, const value_list_t *vl, /* {{
         }
 
         pthread_mutex_lock (&cb->send_lock);
-
-        if (cb->curl == NULL)
+        if (wh_callback_init (cb) != 0)
         {
-                status = wh_callback_init (cb);
-                if (status != 0)
-                {
-                        ERROR ("write_http plugin: wh_callback_init failed.");
-                        pthread_mutex_unlock (&cb->send_lock);
-                        return (-1);
-                }
+                ERROR ("write_http plugin: wh_callback_init failed.");
+                pthread_mutex_unlock (&cb->send_lock);
+                return (-1);
         }
 
         if (command_len >= cb->send_buffer_free)
@@ -356,8 +424,8 @@ static int wh_write_command (const data_set_t *ds, const value_list_t *vl, /* {{
 
         DEBUG ("write_http plugin: <%s> buffer %zu/%zu (%g%%) \"%s\"",
                         cb->location,
-                        cb->send_buffer_fill, sizeof (cb->send_buffer),
-                        100.0 * ((double) cb->send_buffer_fill) / ((double) sizeof (cb->send_buffer)),
+                        cb->send_buffer_fill, cb->send_buffer_size,
+                        100.0 * ((double) cb->send_buffer_fill) / ((double) cb->send_buffer_size),
                         command);
 
         /* Check if we have enough space for this command. */
@@ -372,6 +440,55 @@ static int wh_write_json (const data_set_t *ds, const value_list_t *vl, /* {{{ *
         int status;
 
         pthread_mutex_lock (&cb->send_lock);
+        if (wh_callback_init (cb) != 0)
+        {
+                ERROR ("write_http plugin: wh_callback_init failed.");
+                pthread_mutex_unlock (&cb->send_lock);
+                return (-1);
+        }
+
+        status = format_json_value_list (cb->send_buffer,
+                        &cb->send_buffer_fill,
+                        &cb->send_buffer_free,
+                        ds, vl, cb->store_rates);
+        if (status == -ENOMEM)
+        {
+                status = wh_flush_nolock (/* timeout = */ 0, cb);
+                if (status != 0)
+                {
+                        wh_reset_buffer (cb);
+                        pthread_mutex_unlock (&cb->send_lock);
+                        return (status);
+                }
+
+                status = format_json_value_list (cb->send_buffer,
+                                &cb->send_buffer_fill,
+                                &cb->send_buffer_free,
+                                ds, vl, cb->store_rates);
+        }
+        if (status != 0)
+        {
+                pthread_mutex_unlock (&cb->send_lock);
+                return (status);
+        }
+
+        DEBUG ("write_http plugin: <%s> buffer %zu/%zu (%g%%)",
+                        cb->location,
+                        cb->send_buffer_fill, cb->send_buffer_size,
+                        100.0 * ((double) cb->send_buffer_fill) / ((double) cb->send_buffer_size));
+
+        /* Check if we have enough space for this command. */
+        pthread_mutex_unlock (&cb->send_lock);
+
+        return (0);
+} /* }}} int wh_write_json */
+
+static int wh_write_kairosdb (const data_set_t *ds, const value_list_t *vl, /* {{{ */
+                wh_callback_t *cb)
+{
+        int status;
+
+        pthread_mutex_lock (&cb->send_lock);
 
         if (cb->curl == NULL)
         {
@@ -384,11 +501,11 @@ static int wh_write_json (const data_set_t *ds, const value_list_t *vl, /* {{{ *
                 }
         }
 
-        status = format_json_value_list (cb->send_buffer,
+        status = format_kairosdb_value_list (cb->send_buffer,
                         &cb->send_buffer_fill,
                         &cb->send_buffer_free,
                         ds, vl, cb->store_rates);
-        if (status == (-ENOMEM))
+        if (status == -ENOMEM)
         {
                 status = wh_flush_nolock (/* timeout = */ 0, cb);
                 if (status != 0)
@@ -398,7 +515,7 @@ static int wh_write_json (const data_set_t *ds, const value_list_t *vl, /* {{{ *
                         return (status);
                 }
 
-                status = format_json_value_list (cb->send_buffer,
+                status = format_kairosdb_value_list (cb->send_buffer,
                                 &cb->send_buffer_fill,
                                 &cb->send_buffer_free,
                                 ds, vl, cb->store_rates);
@@ -411,14 +528,14 @@ static int wh_write_json (const data_set_t *ds, const value_list_t *vl, /* {{{ *
 
         DEBUG ("write_http plugin: <%s> buffer %zu/%zu (%g%%)",
                         cb->location,
-                        cb->send_buffer_fill, sizeof (cb->send_buffer),
-                        100.0 * ((double) cb->send_buffer_fill) / ((double) sizeof (cb->send_buffer)));
+                        cb->send_buffer_fill, cb->send_buffer_size,
+                        100.0 * ((double) cb->send_buffer_fill) / ((double) cb->send_buffer_size));
 
         /* Check if we have enough space for this command. */
         pthread_mutex_unlock (&cb->send_lock);
 
         return (0);
-} /* }}} int wh_write_json */
+} /* }}} int wh_write_kairosdb */
 
 static int wh_write (const data_set_t *ds, const value_list_t *vl, /* {{{ */
                 user_data_t *user_data)
@@ -430,55 +547,54 @@ static int wh_write (const data_set_t *ds, const value_list_t *vl, /* {{{ */
                 return (-EINVAL);
 
         cb = user_data->data;
+        assert (cb->send_metrics);
 
-        if (cb->format == WH_FORMAT_JSON)
+        switch(cb->format) {
+            case WH_FORMAT_JSON:
                 status = wh_write_json (ds, vl, cb);
-        else
+                break;
+            case WH_FORMAT_KAIROSDB:
+                status = wh_write_kairosdb (ds, vl, cb);
+                break;
+            default:
                 status = wh_write_command (ds, vl, cb);
-
+                break;
+        }
         return (status);
 } /* }}} int wh_write */
 
-static int config_set_string (char **ret_string, /* {{{ */
-                oconfig_item_t *ci)
+static int wh_notify (notification_t const *n, user_data_t *ud) /* {{{ */
 {
-        char *string;
+        wh_callback_t *cb;
+        char alert[4096];
+        int status;
 
-        if ((ci->values_num != 1)
-                        || (ci->values[0].type != OCONFIG_TYPE_STRING))
-        {
-                WARNING ("write_http plugin: The `%s' config option "
-                                "needs exactly one string argument.", ci->key);
-                return (-1);
-        }
+        if ((ud == NULL) || (ud->data == NULL))
+                return (EINVAL);
+
+        cb = ud->data;
+        assert (cb->send_notifications);
 
-        string = strdup (ci->values[0].value.string);
-        if (string == NULL)
+        status = format_json_notification (alert, sizeof (alert), n);
+        if (status != 0)
         {
-                ERROR ("write_http plugin: strdup failed.");
-                return (-1);
+                ERROR ("write_http plugin: formatting notification failed");
+                return status;
         }
 
-        if (*ret_string != NULL)
-                free (*ret_string);
-        *ret_string = string;
-
-        return (0);
-} /* }}} int config_set_string */
-
-static int config_set_boolean (int *dest, oconfig_item_t *ci) /* {{{ */
-{
-        if ((ci->values_num != 1) || (ci->values[0].type != OCONFIG_TYPE_BOOLEAN))
+        pthread_mutex_lock (&cb->send_lock);
+        if (wh_callback_init (cb) != 0)
         {
-                WARNING ("write_http plugin: The `%s' config option "
-                                "needs exactly one boolean argument.", ci->key);
+                ERROR ("write_http plugin: wh_callback_init failed.");
+                pthread_mutex_unlock (&cb->send_lock);
                 return (-1);
         }
 
-        *dest = ci->values[0].value.boolean ? 1 : 0;
+        status = wh_post_nolock (cb, alert);
+        pthread_mutex_unlock (&cb->send_lock);
 
-        return (0);
-} /* }}} int config_set_boolean */
+        return (status);
+} /* }}} int wh_notify */
 
 static int config_set_format (wh_callback_t *cb, /* {{{ */
                 oconfig_item_t *ci)
@@ -498,6 +614,8 @@ static int config_set_format (wh_callback_t *cb, /* {{{ */
                 cb->format = WH_FORMAT_COMMAND;
         else if (strcasecmp ("JSON", string) == 0)
                 cb->format = WH_FORMAT_JSON;
+        else if (strcasecmp ("KAIROSDB", string) == 0)
+                cb->format = WH_FORMAT_KAIROSDB;
         else
         {
                 ERROR ("write_http plugin: Invalid format string: %s",
@@ -506,90 +624,233 @@ static int config_set_format (wh_callback_t *cb, /* {{{ */
         }
 
         return (0);
-} /* }}} int config_set_string */
+} /* }}} int config_set_format */
 
-static int wh_config_url (oconfig_item_t *ci) /* {{{ */
+static int wh_config_append_string (const char *name, struct curl_slist **dest, /* {{{ */
+    oconfig_item_t *ci)
+{
+  struct curl_slist *temp = NULL;
+  if ((ci->values_num != 1) || (ci->values[0].type != OCONFIG_TYPE_STRING))
+  {
+    WARNING ("write_http plugin: `%s' needs exactly one string argument.", name);
+    return (-1);
+  }
+
+  temp = curl_slist_append(*dest, ci->values[0].value.string);
+  if (temp == NULL)
+    return (-1);
+
+  *dest = temp;
+
+  return (0);
+} /* }}} int wh_config_append_string */
+
+static int wh_config_node (oconfig_item_t *ci) /* {{{ */
 {
         wh_callback_t *cb;
-        user_data_t user_data;
+        int buffer_size = 0;
         char callback_name[DATA_MAX_NAME_LEN];
-        int i;
+        int status = 0;
 
-        cb = malloc (sizeof (*cb));
+        cb = calloc (1, sizeof (*cb));
         if (cb == NULL)
         {
-                ERROR ("write_http plugin: malloc failed.");
+                ERROR ("write_http plugin: calloc failed.");
                 return (-1);
         }
-        memset (cb, 0, sizeof (*cb));
-        cb->location = NULL;
-        cb->user = NULL;
-        cb->pass = NULL;
-        cb->credentials = NULL;
         cb->verify_peer = 1;
         cb->verify_host = 1;
-        cb->cacert = NULL;
         cb->format = WH_FORMAT_COMMAND;
-        cb->curl = NULL;
-       cb->headers = NULL;
+        cb->sslversion = CURL_SSLVERSION_DEFAULT;
+        cb->low_speed_limit = 0;
+        cb->timeout = 0;
+        cb->log_http_error = 0;
+        cb->headers = NULL;
+        cb->send_metrics = 1;
+        cb->send_notifications = 0;
 
         pthread_mutex_init (&cb->send_lock, /* attr = */ NULL);
 
-        config_set_string (&cb->location, ci);
-        if (cb->location == NULL)
-                return (-1);
+        cf_util_get_string (ci, &cb->name);
+
+        /* FIXME: Remove this legacy mode in version 6. */
+        if (strcasecmp ("URL", ci->key) == 0)
+                cf_util_get_string (ci, &cb->location);
 
-        for (i = 0; i < ci->children_num; i++)
+        for (int i = 0; i < ci->children_num; i++)
         {
                 oconfig_item_t *child = ci->children + i;
 
-                if (strcasecmp ("User", child->key) == 0)
-                        config_set_string (&cb->user, child);
+                if (strcasecmp ("URL", child->key) == 0)
+                        status = cf_util_get_string (child, &cb->location);
+                else if (strcasecmp ("User", child->key) == 0)
+                        status = cf_util_get_string (child, &cb->user);
                 else if (strcasecmp ("Password", child->key) == 0)
-                        config_set_string (&cb->pass, child);
+                        status = cf_util_get_string (child, &cb->pass);
                 else if (strcasecmp ("VerifyPeer", child->key) == 0)
-                        config_set_boolean (&cb->verify_peer, child);
+                        status = cf_util_get_boolean (child, &cb->verify_peer);
                 else if (strcasecmp ("VerifyHost", child->key) == 0)
-                        config_set_boolean (&cb->verify_host, child);
+                        status = cf_util_get_boolean (child, &cb->verify_host);
                 else if (strcasecmp ("CACert", child->key) == 0)
-                        config_set_string (&cb->cacert, child);
+                        status = cf_util_get_string (child, &cb->cacert);
+                else if (strcasecmp ("CAPath", child->key) == 0)
+                        status = cf_util_get_string (child, &cb->capath);
+                else if (strcasecmp ("ClientKey", child->key) == 0)
+                        status = cf_util_get_string (child, &cb->clientkey);
+                else if (strcasecmp ("ClientCert", child->key) == 0)
+                        status = cf_util_get_string (child, &cb->clientcert);
+                else if (strcasecmp ("ClientKeyPass", child->key) == 0)
+                        status = cf_util_get_string (child, &cb->clientkeypass);
+                else if (strcasecmp ("SSLVersion", child->key) == 0)
+                {
+                        char *value = NULL;
+
+                        status = cf_util_get_string (child, &value);
+                        if (status != 0)
+                                break;
+
+                        if (value == NULL || strcasecmp ("default", value) == 0)
+                                cb->sslversion = CURL_SSLVERSION_DEFAULT;
+                        else if (strcasecmp ("SSLv2", value) == 0)
+                                cb->sslversion = CURL_SSLVERSION_SSLv2;
+                        else if (strcasecmp ("SSLv3", value) == 0)
+                                cb->sslversion = CURL_SSLVERSION_SSLv3;
+                        else if (strcasecmp ("TLSv1", value) == 0)
+                                cb->sslversion = CURL_SSLVERSION_TLSv1;
+#if (LIBCURL_VERSION_MAJOR > 7) || (LIBCURL_VERSION_MAJOR == 7 && LIBCURL_VERSION_MINOR >= 34)
+                        else if (strcasecmp ("TLSv1_0", value) == 0)
+                                cb->sslversion = CURL_SSLVERSION_TLSv1_0;
+                        else if (strcasecmp ("TLSv1_1", value) == 0)
+                                cb->sslversion = CURL_SSLVERSION_TLSv1_1;
+                        else if (strcasecmp ("TLSv1_2", value) == 0)
+                                cb->sslversion = CURL_SSLVERSION_TLSv1_2;
+#endif
+                        else
+                        {
+                                ERROR ("write_http plugin: Invalid SSLVersion "
+                                                "option: %s.", value);
+                                status = EINVAL;
+                        }
+
+                        sfree(value);
+                }
                 else if (strcasecmp ("Format", child->key) == 0)
-                        config_set_format (cb, child);
+                        status = config_set_format (cb, child);
+                else if (strcasecmp ("Metrics", child->key) == 0)
+                        cf_util_get_boolean (child, &cb->send_metrics);
+                else if (strcasecmp ("Notifications", child->key) == 0)
+                        cf_util_get_boolean (child, &cb->send_notifications);
                 else if (strcasecmp ("StoreRates", child->key) == 0)
-                        config_set_boolean (&cb->store_rates, child);
+                        status = cf_util_get_boolean (child, &cb->store_rates);
+                else if (strcasecmp ("BufferSize", child->key) == 0)
+                        status = cf_util_get_int (child, &buffer_size);
+                else if (strcasecmp ("LowSpeedLimit", child->key) == 0)
+                        status = cf_util_get_int (child, &cb->low_speed_limit);
+                else if (strcasecmp ("Timeout", child->key) == 0)
+                        status = cf_util_get_int (child, &cb->timeout);
+                else if (strcasecmp ("LogHttpError", child->key) == 0)
+                        status = cf_util_get_boolean (child, &cb->log_http_error);
+                else if (strcasecmp ("Header", child->key) == 0)
+                        status = wh_config_append_string ("Header", &cb->headers, child);
                 else
                 {
                         ERROR ("write_http plugin: Invalid configuration "
                                         "option: %s.", child->key);
+                        status = EINVAL;
                 }
+
+                if (status != 0)
+                        break;
         }
 
+        if (status != 0)
+        {
+                wh_callback_free (cb);
+                return (status);
+        }
+
+        if (cb->location == NULL)
+        {
+                ERROR ("write_http plugin: no URL defined for instance '%s'",
+                        cb->name);
+                wh_callback_free (cb);
+                return (-1);
+        }
+
+        if (!cb->send_metrics && !cb->send_notifications)
+        {
+                ERROR ("write_http plugin: Neither metrics nor notifications "
+                       "are enabled for \"%s\".", cb->name);
+                wh_callback_free (cb);
+                return (-1);
+        }
+
+        if (cb->low_speed_limit > 0)
+                cb->low_speed_time = CDTIME_T_TO_TIME_T(plugin_get_interval());
+
+        /* Determine send_buffer_size. */
+        cb->send_buffer_size = WRITE_HTTP_DEFAULT_BUFFER_SIZE;
+        if (buffer_size >= 1024)
+                cb->send_buffer_size = (size_t) buffer_size;
+        else if (buffer_size != 0)
+                ERROR ("write_http plugin: Ignoring invalid BufferSize setting (%d).",
+                                buffer_size);
+
+        /* Allocate the buffer. */
+        cb->send_buffer = malloc (cb->send_buffer_size);
+        if (cb->send_buffer == NULL)
+        {
+                ERROR ("write_http plugin: malloc(%zu) failed.", cb->send_buffer_size);
+                wh_callback_free (cb);
+                return (-1);
+        }
+        /* Nulls the buffer and sets ..._free and ..._fill. */
+        wh_reset_buffer (cb);
+
         ssnprintf (callback_name, sizeof (callback_name), "write_http/%s",
-                        cb->location);
+                        cb->name);
         DEBUG ("write_http: Registering write callback '%s' with URL '%s'",
                         callback_name, cb->location);
 
-        memset (&user_data, 0, sizeof (user_data));
-        user_data.data = cb;
-        user_data.free_func = NULL;
+        user_data_t user_data = {
+                .data = cb
+        };
+
         plugin_register_flush (callback_name, wh_flush, &user_data);
 
         user_data.free_func = wh_callback_free;
-        plugin_register_write (callback_name, wh_write, &user_data);
+
+        if (cb->send_metrics)
+        {
+                plugin_register_write (callback_name, wh_write, &user_data);
+                user_data.free_func = NULL;
+
+                plugin_register_flush (callback_name, wh_flush, &user_data);
+        }
+
+        if (cb->send_notifications)
+        {
+                plugin_register_notification (callback_name, wh_notify, &user_data);
+                user_data.free_func = NULL;
+        }
 
         return (0);
-} /* }}} int wh_config_url */
+} /* }}} int wh_config_node */
 
 static int wh_config (oconfig_item_t *ci) /* {{{ */
 {
-        int i;
-
-        for (i = 0; i < ci->children_num; i++)
+        for (int i = 0; i < ci->children_num; i++)
         {
                 oconfig_item_t *child = ci->children + i;
 
-                if (strcasecmp ("URL", child->key) == 0)
-                        wh_config_url (child);
+                if (strcasecmp ("Node", child->key) == 0)
+                        wh_config_node (child);
+                /* FIXME: Remove this legacy mode in version 6. */
+                else if (strcasecmp ("URL", child->key) == 0) {
+                        WARNING ("write_http plugin: Legacy <URL> block found. "
+                                "Please use <Node> instead.");
+                        wh_config_node (child);
+                }
                 else
                 {
                         ERROR ("write_http plugin: Invalid configuration "