res_prometheus: Add Asterisk endpoint metrics

This patch adds basic Asterisk endpoint statistics to the res_prometheus
module. This includes:

* asterisk_endpoints_state: The current state (unknown, online, offline)
  for each defined endpoint.

* asterisk_endpoints_channels_count: The current number of channels
  associated with a given endpoint.

* asterisk_endpoints_count: The current number of defined endpoints.

In all cases, enough information is provided with each endpoint metric
to determine a unique instance of Asterisk that provided the data, as well
as the underlying technology and resource definition.

ASTERISK-28403

Change-Id: I46443963330c206a7d12722d08dcaabef672310e

diff --git a/res/prometheus/endpoints.c b/res/prometheus/endpoints.c
new file mode 100644 (file)
index 0000000..37ddd81
--- /dev/null
+++ b/res/prometheus/endpoints.c
@@ -0,0 +1,196 @@
+/*
+ * 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 Endpoint Metrics
+ *
+ * \author Matt Jordan <mjordan@digium.com>
+ *
+ */
+
+#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 *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);
+
+       endpoints = stasis_cache_dump(ast_endpoint_cache(), ast_endpoint_snapshot_type());
+       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++) {
+               for (j = 0; j < ARRAY_LEN(endpoint_metric_defs); j++) {
+                       struct ast_endpoint_snapshot *snapshot = stasis_message_data(message);
+                       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;
+}

diff --git a/res/prometheus/prometheus_internal.h b/res/prometheus/prometheus_internal.h
index 06cff989e292a37ce485f820f97deaf509f0d632..7eb4457e438ed3701d23238b4b509efa26ca86b5 100644 (file)
--- a/res/prometheus/prometheus_internal.h
+++ b/res/prometheus/prometheus_internal.h
@@ -38,4 +38,12 @@
  */
 int channel_metrics_init(void);
 
+/*!
+ * \brief Initialize endpoint metrics
+ *
+ * \retval 0 success
+ * \retval -1 error
+ */
+int endpoint_metrics_init(void);
+
 #endif /* #define PROMETHEUS_INTERNAL_H__ */

diff --git a/res/res_prometheus.c b/res/res_prometheus.c
index 4533e1b0dad08602d8fe39ddb7b5fb0c61df8b23..41f449d1609dc620810eca7c84a0a877a5432b47 100644 (file)
--- a/res/res_prometheus.c
+++ b/res/res_prometheus.c
@@ -917,7 +917,7 @@ static int load_module(void)
                goto cleanup;
        }
 
-       if (channel_metrics_init()) {
+       if (channel_metrics_init() || endpoint_metrics_init()) {
                goto cleanup;
        }