channels.c

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/*
 * 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 Channel Metrics
 *
 * \author Matt Jordan <[email protected]>
 *
 */

#include "asterisk.h"
#include "asterisk/res_prometheus.h"
#include "asterisk/stasis_channels.h"
#include "asterisk/pbx.h"
#include "prometheus_internal.h"

#define CHANNELS_STATE_HELP "Individual channel states. 0=down; 1=reserved; 2=offhook; 3=dialing; 4=ring; 5=ringing; 6=up; 7=busy; 8=dialing_offhook; 9=prering."

#define CHANNELS_DURATION_HELP "Individual channel durations (in seconds)."

/*!
 * \internal
 * \brief Callback function to get a channel's current state
 *
 * \param metric The metric to populate
 * \snapshot Channel snapshot
 */
static void get_channel_state(struct prometheus_metric *metric, struct ast_channel_snapshot *snapshot)
{
   snprintf(metric->value, sizeof(metric->value), "%d", snapshot->state);
}

/*!
 * \internal
 * \brief Callback function to get a channel's current duration
 *
 * \param metric The metric to populate
 * \param snapshot Channel snapshot
 */
static void get_channel_duration(struct prometheus_metric *metric, struct ast_channel_snapshot *snapshot)
{
   struct timeval now = ast_tvnow();
   int64_t duration = ast_tvdiff_sec(now, snapshot->base->creationtime);

   snprintf(metric->value, sizeof(metric->value), "%" PRIu64, duration);
}

/*!
 * \internal
 * \brief Helper struct for generating individual channel stats
 */
struct channel_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 channel
    */
   void (* const get_value)(struct prometheus_metric *metric, struct ast_channel_snapshot *snapshot);
} channel_metric_defs[] = {
   {
      .help = CHANNELS_STATE_HELP,
      .name = "asterisk_channels_state",
      .get_value = get_channel_state,
   },
   {
      .help = CHANNELS_DURATION_HELP,
      .name = "asterisk_channels_duration_seconds",
      .get_value = get_channel_duration,
   },
};

static void get_total_call_count(struct prometheus_metric *metric)
{
   snprintf(metric->value, sizeof(metric->value), "%d", ast_processed_calls());
}

static void get_current_call_count(struct prometheus_metric *metric)
{
   snprintf(metric->value, sizeof(metric->value), "%d", ast_active_calls());
}

/*!
 * \internal
 * \brief Channel based metrics that are always available
 */
static struct prometheus_metric global_channel_metrics[] = {
   PROMETHEUS_METRIC_STATIC_INITIALIZATION(
      PROMETHEUS_METRIC_COUNTER,
      "asterisk_calls_sum",
      "Total call count.",
      &get_total_call_count
   ),
   PROMETHEUS_METRIC_STATIC_INITIALIZATION(
      PROMETHEUS_METRIC_GAUGE,
      "asterisk_calls_count",
      "Current call count.",
      &get_current_call_count
   ),
};

/*!
 * \internal
 * \brief Callback invoked when Prometheus scrapes the server
 *
 * \param response The response to populate with formatted metrics
 */
static void channels_scrape_cb(struct ast_str **response)
{
   struct ao2_container *channel_cache;
   struct ao2_container *channels;
   struct ao2_iterator it_chans;
   struct ast_channel_snapshot *snapshot;
   struct prometheus_metric *channel_metrics;
   char eid_str[32];
   int num_channels;
   int i, j;
   struct prometheus_metric channel_count = PROMETHEUS_METRIC_STATIC_INITIALIZATION(
      PROMETHEUS_METRIC_GAUGE,
      "asterisk_channels_count",
      "Current channel count.",
      NULL
   );

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

   channel_cache = ast_channel_cache_all();
   if (!channel_cache) {
      return;
   }

   channels = ao2_container_clone(channel_cache, 0);
   ao2_ref(channel_cache, -1);
   if (!channels) {
      return;
   }

   num_channels = ao2_container_count(channels);

   /* Channel count */
   PROMETHEUS_METRIC_SET_LABEL(&channel_count, 0, "eid", eid_str);
   snprintf(channel_count.value, sizeof(channel_count.value), "%d", num_channels);
   prometheus_metric_to_string(&channel_count, response);

   /* Global call values */
   for (i = 0; i < ARRAY_LEN(global_channel_metrics); i++) {
      PROMETHEUS_METRIC_SET_LABEL(&global_channel_metrics[i], 0, "eid", eid_str);
      global_channel_metrics[i].get_metric_value(&global_channel_metrics[i]);
      prometheus_metric_to_string(&global_channel_metrics[i], response);
   }

   if (num_channels == 0) {
      ao2_ref(channels, -1);
      return;
   }

   /* Channel dependent values */
   channel_metrics = ast_calloc(ARRAY_LEN(channel_metric_defs) * num_channels, sizeof(*channel_metrics));
   if (!channel_metrics) {
      ao2_ref(channels, -1);
      return;
   }

   it_chans = ao2_iterator_init(channels, 0);
   for (i = 0; (snapshot = ao2_iterator_next(&it_chans)); ao2_ref(snapshot, -1), i++) {
      for (j = 0; j < ARRAY_LEN(channel_metric_defs); j++) {
         int index = i * ARRAY_LEN(channel_metric_defs) + j;

         channel_metrics[index].type = PROMETHEUS_METRIC_GAUGE;
         ast_copy_string(channel_metrics[index].name, channel_metric_defs[j].name, sizeof(channel_metrics[index].name));
         channel_metrics[index].help = channel_metric_defs[j].help;
         PROMETHEUS_METRIC_SET_LABEL(&channel_metrics[index], 0, "eid", eid_str);
         PROMETHEUS_METRIC_SET_LABEL(&channel_metrics[index], 1, "name", (snapshot->base->name));
         PROMETHEUS_METRIC_SET_LABEL(&channel_metrics[index], 2, "id", (snapshot->base->uniqueid));
         PROMETHEUS_METRIC_SET_LABEL(&channel_metrics[index], 3, "type", (snapshot->base->type));
         if (snapshot->peer) {
            PROMETHEUS_METRIC_SET_LABEL(&channel_metrics[index], 4, "linkedid", (snapshot->peer->linkedid));
         }
         channel_metric_defs[j].get_value(&channel_metrics[index], snapshot);

         if (i > 0) {
            AST_LIST_INSERT_TAIL(&channel_metrics[j].children, &channel_metrics[index], entry);
         }
      }
   }
   ao2_iterator_destroy(&it_chans);

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

   ast_free(channel_metrics);
   ao2_ref(channels, -1);
}

struct prometheus_callback channels_callback = {
   .name = "Channels callback",
   .callback_fn = channels_scrape_cb,
};

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

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

int channel_metrics_init(void)
{
   prometheus_metrics_provider_register(&provider);
   prometheus_callback_register(&channels_callback);

   return 0;
}