res/prometheus/endpoints.c

Go to the documentation of this file.

/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2019 Sangoma, Inc.
 *
 * Matt Jordan <[email protected]>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*!
 * \file
 * \brief Prometheus Endpoint Metrics
 *
 * \author Matt Jordan <[email protected]>
 *
 */

#include "asterisk.h"

#include "asterisk/stasis_endpoints.h"
#include "asterisk/res_prometheus.h"
#include "prometheus_internal.h"

#define ENDPOINTS_STATE_HELP "Individual endpoint states. 0=unknown; 1=offline; 2=online."

#define ENDPOINTS_CHANNELS_COUNT_HELP "Count of the number of channels currently existing that are associated with the endpoint."

/*!
 * \internal
 * \brief Callback function to get an endpoint's current state
 *
 * \param metric The metric to populate
 * \snapshot Endpoint snapshot
 */
static void get_endpoint_state(struct prometheus_metric *metric, struct ast_endpoint_snapshot *snapshot)
{
   snprintf(metric->value, sizeof(metric->value), "%d", snapshot->state);
}

/*!
 * \internal
 * \brief Callback function to get the current number of channel's associated with an endpoint
 *
 * \param metric The metric to populate
 * \param snapshot Endpoint snapshot
 */
static void get_endpoint_channel_count(struct prometheus_metric *metric, struct ast_endpoint_snapshot *snapshot)
{
   snprintf(metric->value, sizeof(metric->value), "%d", snapshot->num_channels);
}

/*!
 * \internal
 * \brief Helper struct for generating individual endpoint stats
 */
struct endpoint_metric_defs {
   /*!
    * \brief Help text to display
    */
   const char *help;
   /*!
    * \brief Name of the metric
    */
   const char *name;
   /*!
    * \brief Callback function to generate a metric value for a given endpoint
    */
   void (* const get_value)(struct prometheus_metric *metric, struct ast_endpoint_snapshot *snapshot);
} endpoint_metric_defs[] = {
   {
      .help = ENDPOINTS_STATE_HELP,
      .name = "asterisk_endpoints_state",
      .get_value = get_endpoint_state,
   },
   {
      .help = ENDPOINTS_CHANNELS_COUNT_HELP,
      .name = "asterisk_endpoints_channels_count",
      .get_value = get_endpoint_channel_count,
   },
};

/*!
 * \internal
 * \brief Callback invoked when Prometheus scrapes the server
 *
 * \param response The response to populate with formatted metrics
 */
static void endpoints_scrape_cb(struct ast_str **response)
{
   struct ao2_container *endpoint_cache;
   struct ao2_container *endpoints;
   struct ao2_iterator it_endpoints;
   struct stasis_message *message;
   struct prometheus_metric *endpoint_metrics;
   char eid_str[32];
   int i, j, num_endpoints;
   struct prometheus_metric endpoint_count = PROMETHEUS_METRIC_STATIC_INITIALIZATION(
      PROMETHEUS_METRIC_GAUGE,
      "asterisk_endpoints_count",
      "Current endpoint count.",
      NULL
   );

   ast_eid_to_str(eid_str, sizeof(eid_str), &ast_eid_default);

   endpoint_cache = stasis_cache_dump(ast_endpoint_cache(), ast_endpoint_snapshot_type());
   if (!endpoint_cache) {
      return;
   }
   endpoints = ao2_container_clone(endpoint_cache, 0);
   ao2_ref(endpoint_cache, -1);
   if (!endpoints) {
      return;
   }

   num_endpoints = ao2_container_count(endpoints);

   /* Current endpoint count */
   PROMETHEUS_METRIC_SET_LABEL(&endpoint_count, 0, "eid", eid_str);
   snprintf(endpoint_count.value, sizeof(endpoint_count.value), "%d", num_endpoints);
   prometheus_metric_to_string(&endpoint_count, response);

   if (num_endpoints == 0) {
      ao2_ref(endpoints, -1);
      return;
   }

   endpoint_metrics = ast_calloc(ARRAY_LEN(endpoint_metric_defs) * num_endpoints, sizeof(*endpoint_metrics));
   if (!endpoint_metrics) {
      ao2_ref(endpoints, -1);
      return;
   }

   /* Endpoint dependent values */
   it_endpoints = ao2_iterator_init(endpoints, 0);
   for (i = 0; (message = ao2_iterator_next(&it_endpoints)); ao2_ref(message, -1), i++) {
      struct ast_endpoint_snapshot *snapshot = stasis_message_data(message);

      for (j = 0; j < ARRAY_LEN(endpoint_metric_defs); j++) {
         int index = i * ARRAY_LEN(endpoint_metric_defs) + j;

         endpoint_metrics[index].type = PROMETHEUS_METRIC_GAUGE;
         ast_copy_string(endpoint_metrics[index].name, endpoint_metric_defs[j].name, sizeof(endpoint_metrics[index].name));
         endpoint_metrics[index].help = endpoint_metric_defs[j].help;
         PROMETHEUS_METRIC_SET_LABEL(&endpoint_metrics[index], 0, "eid", eid_str);
         PROMETHEUS_METRIC_SET_LABEL(&endpoint_metrics[index], 1, "id", (snapshot->id));
         PROMETHEUS_METRIC_SET_LABEL(&endpoint_metrics[index], 2, "tech", (snapshot->tech));
         PROMETHEUS_METRIC_SET_LABEL(&endpoint_metrics[index], 3, "resource", (snapshot->resource));
         endpoint_metric_defs[j].get_value(&endpoint_metrics[index], snapshot);

         if (i != 0) {
            AST_LIST_INSERT_TAIL(&endpoint_metrics[j].children, &endpoint_metrics[index], entry);
         }
      }
   }
   ao2_iterator_destroy(&it_endpoints);

   for (j = 0; j < ARRAY_LEN(endpoint_metric_defs); j++) {
      prometheus_metric_to_string(&endpoint_metrics[j], response);
   }

   ast_free(endpoint_metrics);
   ao2_ref(endpoints, -1);
}

struct prometheus_callback endpoints_callback = {
   .name = "Endpoints callback",
   .callback_fn = endpoints_scrape_cb,
};

/*!
 * \internal
 * \brief Callback invoked when the core module is unloaded
 */
static void endpoint_metrics_unload_cb(void)
{
   prometheus_callback_unregister(&endpoints_callback);
}

/*!
 * \internal
 * \brief Metrics provider definition
 */
static struct prometheus_metrics_provider provider = {
   .name = "endpoints",
   .unload_cb = endpoint_metrics_unload_cb,
};

int endpoint_metrics_init(void)
{
   prometheus_metrics_provider_register(&provider);
   prometheus_callback_register(&endpoints_callback);

   return 0;
}