channels.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2019 Sangoma, Inc.
 *
 * Matt Jordan <mjordan@digium.com>
 *
 * 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 <mjordan@digium.com>
 *
 */
 
#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
 * \param 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;
}