bridges.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 Bridge Metrics
 *
 * \author Matt Jordan <mjordan@digium.com>
 *
 */
 
#include "asterisk.h"
 
#include "asterisk/stasis_bridges.h"
#include "asterisk/res_prometheus.h"
#include "prometheus_internal.h"
 
#define BRIDGES_CHANNELS_COUNT_HELP "Number of channels in the bridge."
 
/*!
 * \internal
 * \brief Callback function to get the number of channels in a bridge
 *
 * \param metric The metric to populate
 * \param snapshot Bridge snapshot
 */
static void get_bridge_channel_count(struct prometheus_metric *metric, struct ast_bridge_snapshot *snapshot)
{
    snprintf(metric->value, sizeof(metric->value), "%d", snapshot->num_channels);
}
 
/*!
 * \internal
 * \brief Helper struct for generating individual bridge stats
 */
struct bridge_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 bridge
     */
    void (* const get_value)(struct prometheus_metric *metric, struct ast_bridge_snapshot *snapshot);
} bridge_metric_defs[] = {
    {
        .help = BRIDGES_CHANNELS_COUNT_HELP,
        .name = "asterisk_bridges_channels_count",
        .get_value = get_bridge_channel_count,
    },
};
 
/*!
 * \internal
 * \brief Callback invoked when Prometheus scrapes the server
 *
 * \param response The response to populate with formatted metrics
 */
static void bridges_scrape_cb(struct ast_str **response)
{
    struct ao2_container *bridge_cache;
    struct ao2_container *bridges;
    struct ao2_iterator it_bridges;
    struct ast_bridge *bridge;
    struct prometheus_metric *metrics;
    struct prometheus_metric **bridge_metrics;
    char eid_str[32];
    int i, j, num_bridges, num_outputs = 0;
    struct prometheus_metric bridge_count = PROMETHEUS_METRIC_STATIC_INITIALIZATION(
        PROMETHEUS_METRIC_GAUGE,
        "asterisk_bridges_count",
        "Current bridge count.",
        NULL
    );
 
    ast_eid_to_str(eid_str, sizeof(eid_str), &ast_eid_default);
 
    bridge_cache = ast_bridges();
    if (!bridge_cache) {
        return;
    }
 
    bridges = ao2_container_clone(bridge_cache, 0);
    ao2_ref(bridge_cache, -1);
    if (!bridges) {
        return;
    }
 
    num_bridges = ao2_container_count(bridges);
 
    /* Current endpoint count */
    PROMETHEUS_METRIC_SET_LABEL(&bridge_count, 0, "eid", eid_str);
    snprintf(bridge_count.value, sizeof(bridge_count.value), "%d", num_bridges);
    prometheus_metric_to_string(&bridge_count, response);
 
    if (num_bridges == 0) {
        ao2_ref(bridges, -1);
        return;
    }
 
    metrics = ast_calloc(ARRAY_LEN(bridge_metric_defs) * num_bridges, sizeof(*metrics));
    if (!metrics) {
        ao2_ref(bridges, -1);
        return;
    }
 
    bridge_metrics = ast_calloc(ARRAY_LEN(bridge_metric_defs), sizeof(bridge_metrics));
    if (!bridge_metrics) {
        ast_free(metrics);
        ao2_ref(bridges, -1);
        return;
    }
 
    /* Bridge dependent values */
    it_bridges = ao2_iterator_init(bridges, 0);
    for (i = 0; (bridge = ao2_iterator_next(&it_bridges)); ao2_ref(bridge, -1), i++) {
        struct ast_bridge_snapshot *snapshot;
 
        /* Invisible bridges don't get shown externally and have no snapshot */
        if (ast_test_flag(&bridge->feature_flags, AST_BRIDGE_FLAG_INVISIBLE)) {
            continue;
        }
 
        snapshot = ast_bridge_get_snapshot(bridge);
        if (!snapshot) {
            continue;
        }
 
        for (j = 0; j < ARRAY_LEN(bridge_metric_defs); j++) {
            int index = num_outputs++;
 
            metrics[index].type = PROMETHEUS_METRIC_GAUGE;
            ast_copy_string(metrics[index].name, bridge_metric_defs[j].name, sizeof(metrics[index].name));
            metrics[index].help = bridge_metric_defs[j].help;
            PROMETHEUS_METRIC_SET_LABEL(&metrics[index], 0, "eid", eid_str);
            PROMETHEUS_METRIC_SET_LABEL(&metrics[index], 1, "id", (snapshot->uniqueid));
            PROMETHEUS_METRIC_SET_LABEL(&metrics[index], 2, "tech", (snapshot->technology));
            PROMETHEUS_METRIC_SET_LABEL(&metrics[index], 3, "subclass", (snapshot->subclass));
            PROMETHEUS_METRIC_SET_LABEL(&metrics[index], 4, "creator", (snapshot->creator));
            PROMETHEUS_METRIC_SET_LABEL(&metrics[index], 5, "name", (snapshot->name));
            bridge_metric_defs[j].get_value(&metrics[index], snapshot);
 
            if (bridge_metrics[j] == NULL) {
                bridge_metrics[j] = &metrics[index];
            } else {
                AST_LIST_INSERT_TAIL(&bridge_metrics[j]->children, &metrics[index], entry);
            }
        }
        ao2_ref(snapshot, -1);
    }
    ao2_iterator_destroy(&it_bridges);
 
    for (j = 0; j < ARRAY_LEN(bridge_metric_defs); j++) {
        if (bridge_metrics[j]) {
            prometheus_metric_to_string(bridge_metrics[j], response);
        }
    }
 
    ast_free(bridge_metrics);
    ast_free(metrics);
    ao2_ref(bridges, -1);
}
 
struct prometheus_callback bridges_callback = {
    .name = "bridges callback",
    .callback_fn = bridges_scrape_cb,
};
 
/*!
 * \internal
 * \brief Callback invoked when the core module is unloaded
 */
static void bridge_metrics_unload_cb(void)
{
    prometheus_callback_unregister(&bridges_callback);
}
 
/*!
 * \internal
 * \brief Metrics provider definition
 */
static struct prometheus_metrics_provider provider = {
    .name = "bridges",
    .unload_cb = bridge_metrics_unload_cb,
};
 
int bridge_metrics_init(void)
{
    prometheus_metrics_provider_register(&provider);
    prometheus_callback_register(&bridges_callback);
 
    return 0;
}