--- /dev/null
+/**
+ * collectd - src/write_prometheus.c
+ * Copyright (C) 2016 Florian octo Forster
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * Authors:
+ * Florian octo Forster <octo at collectd.org>
+ */
+
+#include "collectd.h"
+
+#include "common.h"
+#include "plugin.h"
+#include "utils_avltree.h"
+#include "utils_complain.h"
+#include "utils_time.h"
+
+#include "prometheus.pb-c.h"
+
+#include <microhttpd.h>
+
+#ifndef PROMETHEUS_DEFAULT_STALENESS_DELTA
+#define PROMETHEUS_DEFAULT_STALENESS_DELTA TIME_T_TO_CDTIME_T(300)
+#endif
+
+#define VARINT_UINT32_BYTES 5
+
+#define CONTENT_TYPE_PROTO \
+ "application/vnd.google.protobuf; proto=io.prometheus.client.MetricFamily; " \
+ "encoding=delimited"
+#define CONTENT_TYPE_TEXT "text/plain; version=0.0.4"
+
+static c_avl_tree_t *metrics;
+static pthread_mutex_t metrics_lock = PTHREAD_MUTEX_INITIALIZER;
+
+static unsigned short httpd_port = 9103;
+static struct MHD_Daemon *httpd;
+
+static cdtime_t staleness_delta = PROMETHEUS_DEFAULT_STALENESS_DELTA;
+
+/* Unfortunately, protoc-c doesn't export it's implementation of varint, so we
+ * need to implement our own. */
+static size_t varint(uint8_t buffer[static VARINT_UINT32_BYTES],
+ uint32_t value) {
+ for (size_t i = 0; i < VARINT_UINT32_BYTES; i++) {
+ buffer[i] = (uint8_t)(value & 0x7f);
+ value >>= 7;
+
+ if (value == 0)
+ return i + 1;
+
+ buffer[i] |= 0x80;
+ }
+
+ return 0;
+}
+
+/* format_protobuf iterates over all metric families in "metrics" and adds them
+ * to a buffer in ProtoBuf format. It prefixes each protobuf with its encoded
+ * size, the so called "delimited" format. */
+static void format_protobuf(ProtobufCBuffer *buffer) {
+ pthread_mutex_lock(&metrics_lock);
+
+ char *unused_name;
+ Io__Prometheus__Client__MetricFamily *fam;
+ c_avl_iterator_t *iter = c_avl_get_iterator(metrics);
+ while (c_avl_iterator_next(iter, (void *)&unused_name, (void *)&fam) == 0) {
+ /* Prometheus uses a message length prefix to determine where one
+ * MetricFamily ends and the next begins. This delimiter is encoded as a
+ * "varint", which is common in Protobufs. */
+ uint8_t delim[VARINT_UINT32_BYTES] = {0};
+ size_t delim_len = varint(
+ delim,
+ (uint32_t)io__prometheus__client__metric_family__get_packed_size(fam));
+ buffer->append(buffer, delim_len, delim);
+
+ io__prometheus__client__metric_family__pack_to_buffer(fam, buffer);
+ }
+ c_avl_iterator_destroy(iter);
+
+ pthread_mutex_unlock(&metrics_lock);
+}
+
+/* format_labels formats a metric's labels in Prometheus-compatible format. This
+ * format looks like this:
+ *
+ * key0="value0",key1="value1"
+ */
+static char *format_labels(char *buffer, size_t buffer_size,
+ Io__Prometheus__Client__Metric const *m) {
+ /* our metrics always have at least one and at most three labels. */
+ assert(m->n_label >= 1);
+ assert(m->n_label <= 3);
+
+#define LABEL_BUFFER_SIZE (2 * DATA_MAX_NAME_LEN + 4)
+
+ char *labels[3] = {
+ (char[LABEL_BUFFER_SIZE]){0}, (char[LABEL_BUFFER_SIZE]){0},
+ (char[LABEL_BUFFER_SIZE]){0},
+ };
+
+ for (size_t i = 0; i < m->n_label; i++)
+ ssnprintf(labels[i], LABEL_BUFFER_SIZE, "%s=\"%s\"", m->label[i]->name,
+ m->label[i]->value);
+
+ strjoin(buffer, buffer_size, labels, m->n_label, ",");
+ return buffer;
+}
+
+/* format_protobuf iterates over all metric families in "metrics" and adds them
+ * to a buffer in plain text format. */
+static void format_text(ProtobufCBuffer *buffer) {
+ pthread_mutex_lock(&metrics_lock);
+
+ char *unused_name;
+ Io__Prometheus__Client__MetricFamily *fam;
+ c_avl_iterator_t *iter = c_avl_get_iterator(metrics);
+ while (c_avl_iterator_next(iter, (void *)&unused_name, (void *)&fam) == 0) {
+ char line[1024]; /* 4x DATA_MAX_NAME_LEN? */
+
+ ssnprintf(line, sizeof(line), "# HELP %s %s\n", fam->name, fam->help);
+ buffer->append(buffer, strlen(line), (uint8_t *)line);
+
+ ssnprintf(line, sizeof(line), "# TYPE %s %s\n", fam->name,
+ (fam->type == IO__PROMETHEUS__CLIENT__METRIC_TYPE__GAUGE)
+ ? "gauge"
+ : "counter");
+ buffer->append(buffer, strlen(line), (uint8_t *)line);
+
+ for (size_t i = 0; i < fam->n_metric; i++) {
+ Io__Prometheus__Client__Metric *m = fam->metric[i];
+
+ char labels[1024];
+
+ char timestamp_ms[24] = "";
+ if (m->has_timestamp_ms)
+ ssnprintf(timestamp_ms, sizeof(timestamp_ms), " %" PRIi64,
+ m->timestamp_ms);
+
+ if (fam->type == IO__PROMETHEUS__CLIENT__METRIC_TYPE__GAUGE)
+ ssnprintf(line, sizeof(line), "%s{%s} " GAUGE_FORMAT "%s\n", fam->name,
+ format_labels(labels, sizeof(labels), m), m->gauge->value,
+ timestamp_ms);
+ else /* if (fam->type == IO__PROMETHEUS__CLIENT__METRIC_TYPE__COUNTER) */
+ ssnprintf(line, sizeof(line), "%s{%s} %.0f%s\n", fam->name,
+ format_labels(labels, sizeof(labels), m), m->counter->value,
+ timestamp_ms);
+
+ buffer->append(buffer, strlen(line), (uint8_t *)line);
+ }
+ }
+ c_avl_iterator_destroy(iter);
+
+ char server[1024];
+ ssnprintf(server, sizeof(server), "\n# collectd/write_prometheus %s at %s\n",
+ PACKAGE_VERSION, hostname_g);
+ buffer->append(buffer, strlen(server), (uint8_t *)server);
+
+ pthread_mutex_unlock(&metrics_lock);
+}
+
+/* http_handler is the callback called by the microhttpd library. It essentially
+ * handles all HTTP request aspects and creates an HTTP response. */
+static int http_handler(void *cls, struct MHD_Connection *connection,
+ const char *url, const char *method,
+ const char *version, const char *upload_data,
+ size_t *upload_data_size, void **connection_state) {
+ if (strcmp(method, MHD_HTTP_METHOD_GET) != 0) {
+ return MHD_NO;
+ }
+
+ /* On the first call for each connection, return without anything further.
+ * Apparently not everything has been initialized yet or so; the docs are not
+ * very specific on the issue. */
+ if (*connection_state == NULL) {
+ /* set to a random non-NULL pointer. */
+ *connection_state = &(int){42};
+ return MHD_YES;
+ }
+
+ char const *accept = MHD_lookup_connection_value(connection, MHD_HEADER_KIND,
+ MHD_HTTP_HEADER_ACCEPT);
+ _Bool want_proto =
+ (accept != NULL) &&
+ (strstr(accept, "application/vnd.google.protobuf") != NULL);
+
+ uint8_t scratch[4096] = {0};
+ ProtobufCBufferSimple simple = PROTOBUF_C_BUFFER_SIMPLE_INIT(scratch);
+ ProtobufCBuffer *buffer = (ProtobufCBuffer *)&simple;
+
+ if (want_proto)
+ format_protobuf(buffer);
+ else
+ format_text(buffer);
+
+ struct MHD_Response *res = MHD_create_response_from_data(
+ simple.len, simple.data, /* must_free = */ 0, /* must_copy = */ 1);
+ MHD_add_response_header(res, MHD_HTTP_HEADER_CONTENT_TYPE,
+ want_proto ? CONTENT_TYPE_PROTO : CONTENT_TYPE_TEXT);
+
+ int status = MHD_queue_response(connection, MHD_HTTP_OK, res);
+
+ MHD_destroy_response(res);
+ PROTOBUF_C_BUFFER_SIMPLE_CLEAR(&simple);
+ return status;
+}
+
+/*
+ * Functions for manipulating the global state in "metrics". This is organized
+ * in two tiers: the global "metrics" tree holds "metric families", which are
+ * identified by a name (a string). Each metric family has one or more
+ * "metrics", which are identified by a unique set of key-value-pairs. For
+ * example:
+ *
+ * collectd_cpu_total
+ * {cpu="0",type="idle"}
+ * {cpu="0",type="user"}
+ * ...
+ * collectd_memory
+ * {memory="used"}
+ * {memory="free"}
+ * ...
+ * {{{ */
+/* label_pair_destroy frees the memory used by a label pair. */
+static void label_pair_destroy(Io__Prometheus__Client__LabelPair *msg) {
+ if (msg == NULL)
+ return;
+
+ sfree(msg->name);
+ sfree(msg->value);
+
+ sfree(msg);
+}
+
+/* label_pair_create allocates and initializes a new label pair. */
+static Io__Prometheus__Client__LabelPair *label_pair_create(char const *name,
+ char const *value) {
+ Io__Prometheus__Client__LabelPair *msg = calloc(1, sizeof(*msg));
+ if (msg == NULL)
+ return NULL;
+ io__prometheus__client__label_pair__init(msg);
+
+ msg->name = strdup(name);
+ msg->value = strdup(value);
+ if ((msg->name == NULL) || (msg->value == NULL)) {
+ label_pair_destroy(msg);
+ return NULL;
+ }
+
+ return msg;
+}
+
+/* metric_destroy frees the memory used by a metric. */
+static void metric_destroy(Io__Prometheus__Client__Metric *msg) {
+ if (msg == NULL)
+ return;
+
+ for (size_t i = 0; i < msg->n_label; i++) {
+ label_pair_destroy(msg->label[i]);
+ }
+ sfree(msg->label);
+
+ sfree(msg->gauge);
+ sfree(msg->counter);
+
+ sfree(msg);
+}
+
+/* metric_add_labels adds the labels that identify this metric to m.
+ * The logic is copied from the "collectd_exporter". Essentially, the labels
+ * contain the hostname, the plugin instance and the type instance of a
+ * value_list_t. */
+static int metric_add_labels(Io__Prometheus__Client__Metric *m,
+ value_list_t const *vl) {
+ size_t n_label = 1;
+ if (strlen(vl->plugin_instance) != 0)
+ n_label++;
+ if (strlen(vl->type_instance) != 0)
+ n_label++;
+
+ m->label = calloc(n_label, sizeof(*m->label));
+ if (m->label == NULL)
+ return ENOMEM;
+
+ if (strlen(vl->plugin_instance) != 0) {
+ m->label[m->n_label] = label_pair_create(vl->plugin, vl->plugin_instance);
+ m->n_label++;
+ }
+
+ if (strlen(vl->type_instance) != 0) {
+ char const *name = "type";
+ if (strlen(vl->plugin_instance) == 0)
+ name = vl->plugin;
+
+ m->label[m->n_label] = label_pair_create(name, vl->type_instance);
+ m->n_label++;
+ }
+
+ m->label[m->n_label] = label_pair_create("instance", vl->host);
+ m->n_label++;
+
+ for (size_t i = 0; i < m->n_label; i++) {
+ if (m->label[i] == NULL)
+ return ENOMEM;
+ }
+
+ return 0;
+}
+
+/* metric_cmp compares two metrics. It's prototype makes it easy to use with
+ * qsort(3) and bsearch(3). */
+static int metric_cmp(void const *a, void const *b) {
+ Io__Prometheus__Client__Metric const *m_a =
+ *((Io__Prometheus__Client__Metric **)a);
+ Io__Prometheus__Client__Metric const *m_b =
+ *((Io__Prometheus__Client__Metric **)b);
+
+ if (m_a->n_label < m_b->n_label)
+ return -1;
+ else if (m_a->n_label > m_b->n_label)
+ return 1;
+
+ /* Prometheus does not care about the order of labels. All labels in this
+ * plugin are created by metric_add_labels(), though, and therefore always
+ * appear in the same order. We take advantage of this and simplify the check
+ * by making sure all labels are the same in each position. */
+ for (size_t i = 0; i < m_a->n_label; i++) {
+ int status = strcmp(m_a->label[i]->name, m_b->label[i]->name);
+ if (status != 0)
+ return status;
+
+ status = strcmp(m_a->label[i]->value, m_b->label[i]->value);
+ if (status != 0)
+ return status;
+ }
+
+ return 0;
+}
+
+/* metric_create allocates and initializes a new metric. */
+static Io__Prometheus__Client__Metric *metric_create(value_list_t const *vl) {
+ Io__Prometheus__Client__Metric *msg = calloc(1, sizeof(*msg));
+ if (msg == NULL)
+ return NULL;
+ io__prometheus__client__metric__init(msg);
+
+ if (metric_add_labels(msg, vl) != 0) {
+ metric_destroy(msg);
+ return NULL;
+ }
+
+ return msg;
+}
+
+/* metric_update stores the new value and timestamp in m. */
+static int metric_update(Io__Prometheus__Client__Metric *m, value_t value,
+ int ds_type, cdtime_t t, cdtime_t interval) {
+ if (ds_type == DS_TYPE_GAUGE) {
+ sfree(m->counter);
+ if (m->gauge == NULL) {
+ m->gauge = calloc(1, sizeof(*m->gauge));
+ if (m->gauge == NULL)
+ return ENOMEM;
+ io__prometheus__client__gauge__init(m->gauge);
+ }
+
+ m->gauge->value = (double)value.gauge;
+ m->gauge->has_value = 1;
+ } else { /* not gauge */
+ sfree(m->gauge);
+ if (m->counter == NULL) {
+ m->counter = calloc(1, sizeof(*m->counter));
+ if (m->counter == NULL)
+ return ENOMEM;
+ io__prometheus__client__counter__init(m->counter);
+ }
+
+ switch (ds_type) {
+ case DS_TYPE_ABSOLUTE:
+ m->counter->value = (double)value.absolute;
+ break;
+ case DS_TYPE_COUNTER:
+ m->counter->value = (double)value.counter;
+ break;
+ default:
+ m->counter->value = (double)value.derive;
+ break;
+ }
+ m->counter->has_value = 1;
+ }
+
+ /* Prometheus has a globally configured timeout after which metrics are
+ * considered stale. This causes problems when metrics have an interval
+ * exceeding that limit. We emulate the behavior of "pushgateway" and *not*
+ * send a timestamp value – Prometheus will fill in the current time. */
+ if (interval <= staleness_delta) {
+ m->timestamp_ms = CDTIME_T_TO_MS(t);
+ m->has_timestamp_ms = 1;
+ } else {
+ static c_complain_t long_metric = C_COMPLAIN_INIT_STATIC;
+ c_complain(
+ LOG_NOTICE, &long_metric,
+ "write_prometheus plugin: You have metrics with an interval exceeding "
+ "\"StalenessDelta\" setting (%.3fs). This is suboptimal, please check "
+ "the collectd.conf(5) manual page to understand what's going on.",
+ CDTIME_T_TO_DOUBLE(staleness_delta));
+
+ m->timestamp_ms = 0;
+ m->has_timestamp_ms = 0;
+ }
+
+ return 0;
+}
+
+/* metric_family_add_metric adds m to the metric list of fam. */
+static int metric_family_add_metric(Io__Prometheus__Client__MetricFamily *fam,
+ Io__Prometheus__Client__Metric *m) {
+ Io__Prometheus__Client__Metric **tmp =
+ realloc(fam->metric, (fam->n_metric + 1) * sizeof(*fam->metric));
+ if (tmp == NULL)
+ return ENOMEM;
+ fam->metric = tmp;
+
+ fam->metric[fam->n_metric] = m;
+ fam->n_metric++;
+
+ /* Sort the metrics so that lookup is fast. */
+ qsort(fam->metric, fam->n_metric, sizeof(*fam->metric), metric_cmp);
+
+ return 0;
+}
+
+/* metric_family_delete_metric looks up and deletes the metric corresponding to
+ * vl. */
+static int
+metric_family_delete_metric(Io__Prometheus__Client__MetricFamily *fam,
+ value_list_t const *vl) {
+ Io__Prometheus__Client__Metric *key = metric_create(vl);
+ if (key == NULL)
+ return ENOMEM;
+
+ size_t i;
+ for (i = 0; i < fam->n_metric; i++) {
+ if (metric_cmp(&key, &fam->metric[i]) == 0)
+ break;
+ }
+
+ if (i >= fam->n_metric)
+ return ENOENT;
+
+ metric_destroy(fam->metric[i]);
+ if ((fam->n_metric - 1) > i)
+ memmove(&fam->metric[i], &fam->metric[i + 1],
+ ((fam->n_metric - 1) - i) * sizeof(fam->metric[i]));
+ fam->n_metric--;
+
+ Io__Prometheus__Client__Metric **tmp =
+ realloc(fam->metric, fam->n_metric * sizeof(*fam->metric));
+ if ((tmp != NULL) || (fam->n_metric == 0))
+ fam->metric = tmp;
+
+ return 0;
+}
+
+/* metric_family_get_metric looks up the matching metric in a metric family,
+ * allocating it if necessary. */
+static Io__Prometheus__Client__Metric *
+metric_family_get_metric(Io__Prometheus__Client__MetricFamily *fam,
+ value_list_t const *vl) {
+ Io__Prometheus__Client__Metric *key = metric_create(vl);
+ if (key == NULL)
+ return NULL;
+
+ /* Metrics are sorted in metric_family_add_metric() so that we can do a binary
+ * search here. */
+ Io__Prometheus__Client__Metric **m = bsearch(
+ &key, fam->metric, fam->n_metric, sizeof(*fam->metric), metric_cmp);
+
+ if (m != NULL) {
+ metric_destroy(key);
+ return *m;
+ }
+
+ DEBUG("write_prometheus plugin: created new metric in family");
+ int status = metric_family_add_metric(fam, key);
+ if (status != 0) {
+ metric_destroy(key);
+ return NULL;
+ }
+
+ return key;
+}
+
+/* metric_family_update looks up the matching metric in a metric family,
+ * allocating it if necessary, and updates the metric to the latest value. */
+static int metric_family_update(Io__Prometheus__Client__MetricFamily *fam,
+ data_set_t const *ds, value_list_t const *vl,
+ size_t ds_index) {
+ Io__Prometheus__Client__Metric *m = metric_family_get_metric(fam, vl);
+ if (m == NULL)
+ return -1;
+
+ return metric_update(m, vl->values[ds_index], ds->ds[ds_index].type, vl->time,
+ vl->interval);
+}
+
+/* metric_family_destroy frees the memory used by a metric family. */
+static void metric_family_destroy(Io__Prometheus__Client__MetricFamily *msg) {
+ if (msg == NULL)
+ return;
+
+ sfree(msg->name);
+ sfree(msg->help);
+
+ for (size_t i = 0; i < msg->n_metric; i++) {
+ metric_destroy(msg->metric[i]);
+ }
+ sfree(msg->metric);
+
+ sfree(msg);
+}
+
+/* metric_family_create allocates and initializes a new metric family. */
+static Io__Prometheus__Client__MetricFamily *
+metric_family_create(char *name, data_set_t const *ds, value_list_t const *vl,
+ size_t ds_index) {
+ Io__Prometheus__Client__MetricFamily *msg = calloc(1, sizeof(*msg));
+ if (msg == NULL)
+ return NULL;
+ io__prometheus__client__metric_family__init(msg);
+
+ msg->name = name;
+
+ char help[1024];
+ ssnprintf(
+ help, sizeof(help),
+ "write_prometheus plugin: '%s' Type: '%s', Dstype: '%s', Dsname: '%s'",
+ vl->plugin, vl->type, DS_TYPE_TO_STRING(ds->ds[ds_index].type),
+ ds->ds[ds_index].name);
+ msg->help = strdup(help);
+
+ msg->type = (ds->ds[ds_index].type == DS_TYPE_GAUGE)
+ ? IO__PROMETHEUS__CLIENT__METRIC_TYPE__GAUGE
+ : IO__PROMETHEUS__CLIENT__METRIC_TYPE__COUNTER;
+ msg->has_type = 1;
+
+ return msg;
+}
+
+/* metric_family_name creates a metric family's name from a data source. This is
+ * done in the same way as done by the "collectd_exporter" for best possible
+ * compatibility. In essence, the plugin, type and data source name go in the
+ * metric family name, while hostname, plugin instance and type instance go into
+ * the labels of a metric. */
+static char *metric_family_name(data_set_t const *ds, value_list_t const *vl,
+ size_t ds_index) {
+ char const *fields[5] = {"collectd"};
+ size_t fields_num = 1;
+
+ if (strcmp(vl->plugin, vl->type) != 0) {
+ fields[fields_num] = vl->plugin;
+ fields_num++;
+ }
+ fields[fields_num] = vl->type;
+ fields_num++;
+
+ if (strcmp("value", ds->ds[ds_index].name) != 0) {
+ fields[fields_num] = ds->ds[ds_index].name;
+ fields_num++;
+ }
+
+ /* Prometheus best practices:
+ * cumulative metrics should have a "total" suffix. */
+ if ((ds->ds[ds_index].type == DS_TYPE_COUNTER) ||
+ (ds->ds[ds_index].type == DS_TYPE_DERIVE)) {
+ fields[fields_num] = "total";
+ fields_num++;
+ }
+
+ char name[5 * DATA_MAX_NAME_LEN];
+ strjoin(name, sizeof(name), (char **)fields, fields_num, "_");
+ return strdup(name);
+}
+
+/* metric_family_get looks up the matching metric family, allocating it if
+ * necessary. */
+static Io__Prometheus__Client__MetricFamily *
+metric_family_get(data_set_t const *ds, value_list_t const *vl,
+ size_t ds_index) {
+ char *name = metric_family_name(ds, vl, ds_index);
+ if (name == NULL) {
+ ERROR("write_prometheus plugin: Allocating metric family name failed.");
+ return NULL;
+ }
+
+ Io__Prometheus__Client__MetricFamily *fam = NULL;
+ if (c_avl_get(metrics, name, (void *)&fam) == 0) {
+ sfree(name);
+ assert(fam != NULL);
+ return fam;
+ }
+
+ fam = metric_family_create(name, ds, vl, ds_index);
+ if (fam == NULL) {
+ ERROR("write_prometheus plugin: Allocating metric family failed.");
+ sfree(name);
+ return NULL;
+ }
+
+ /* If successful, "name" is owned by "fam", i.e. don't free it here. */
+ DEBUG("write_prometheus plugin: metric family \"%s\" has been created.",
+ name);
+ name = NULL;
+
+ int status = c_avl_insert(metrics, fam->name, fam);
+ if (status != 0) {
+ ERROR("write_prometheus plugin: Adding \"%s\" failed.", name);
+ metric_family_destroy(fam);
+ return NULL;
+ }
+
+ return fam;
+}
+/* }}} */
+
+/*
+ * collectd callbacks
+ */
+static int prom_config(oconfig_item_t *ci) {
+ for (int i = 0; i < ci->children_num; i++) {
+ oconfig_item_t *child = ci->children + i;
+
+ if (strcasecmp("Port", child->key) == 0) {
+ int status = cf_util_get_port_number(child);
+ if (status > 0)
+ httpd_port = (unsigned short)status;
+ } else if (strcasecmp("StalenessDelta", child->key) == 0) {
+ cf_util_get_cdtime(child, &staleness_delta);
+ } else {
+ WARNING("write_prometheus plugin: Ignoring unknown configuration option "
+ "\"%s\".",
+ child->key);
+ }
+ }
+
+ return 0;
+}
+
+static int prom_init() {
+ if (metrics == NULL) {
+ metrics = c_avl_create((void *)strcmp);
+ if (metrics == NULL) {
+ ERROR("write_prometheus plugin: c_avl_create() failed.");
+ return -1;
+ }
+ }
+
+ if (httpd == NULL) {
+ unsigned int flags = MHD_USE_THREAD_PER_CONNECTION;
+#if MHD_VERSION >= 0x00093300
+ flags |= MHD_USE_DUAL_STACK;
+#endif
+
+ httpd = MHD_start_daemon(flags, httpd_port,
+ /* MHD_AcceptPolicyCallback = */ NULL,
+ /* MHD_AcceptPolicyCallback arg = */ NULL,
+ http_handler, NULL, MHD_OPTION_END);
+ if (httpd == NULL) {
+ ERROR("write_prometheus plugin: MHD_start_daemon() failed.");
+ return -1;
+ }
+ DEBUG("write_prometheus plugin: Successfully started microhttpd %s",
+ MHD_get_version());
+ }
+
+ return 0;
+}
+
+static int prom_write(data_set_t const *ds, value_list_t const *vl,
+ __attribute__((unused)) user_data_t *ud) {
+ pthread_mutex_lock(&metrics_lock);
+
+ for (size_t i = 0; i < ds->ds_num; i++) {
+ Io__Prometheus__Client__MetricFamily *fam = metric_family_get(ds, vl, i);
+ if (fam == NULL)
+ continue;
+
+ int status = metric_family_update(fam, ds, vl, i);
+ if (status != 0) {
+ ERROR("write_prometheus plugin: Updating metric \"%s\" failed with "
+ "status %d",
+ fam->name, status);
+ continue;
+ }
+ }
+
+ pthread_mutex_unlock(&metrics_lock);
+ return 0;
+}
+
+static int prom_missing(value_list_t const *vl,
+ __attribute__((unused)) user_data_t *ud) {
+ data_set_t const *ds = plugin_get_ds(vl->type);
+ if (ds == NULL)
+ return ENOENT;
+
+ pthread_mutex_lock(&metrics_lock);
+
+ for (size_t i = 0; i < ds->ds_num; i++) {
+ Io__Prometheus__Client__MetricFamily *fam = metric_family_get(ds, vl, i);
+ if (fam == NULL)
+ continue;
+
+ int status = metric_family_delete_metric(fam, vl);
+ if (status != 0) {
+ ERROR("write_prometheus plugin: Deleting a metric in family \"%s\" "
+ "failed with status %d",
+ fam->name, status);
+ continue;
+ }
+
+ if (fam->n_metric == 0) {
+ int status = c_avl_remove(metrics, fam->name, NULL, NULL);
+ if (status != 0) {
+ ERROR("write_prometheus plugin: Deleting metric family \"%s\" failed "
+ "with status %d",
+ fam->name, status);
+ continue;
+ }
+ metric_family_destroy(fam);
+ }
+ }
+
+ pthread_mutex_unlock(&metrics_lock);
+ return 0;
+}
+
+static int prom_shutdown() {
+ if (httpd != NULL) {
+ MHD_stop_daemon(httpd);
+ httpd = NULL;
+ }
+
+ pthread_mutex_lock(&metrics_lock);
+ if (metrics != NULL) {
+ char *name;
+ Io__Prometheus__Client__MetricFamily *fam;
+ while (c_avl_pick(metrics, (void *)&name, (void *)&fam) == 0) {
+ assert(name == fam->name);
+ name = NULL;
+
+ metric_family_destroy(fam);
+ }
+ c_avl_destroy(metrics);
+ metrics = NULL;
+ }
+ pthread_mutex_unlock(&metrics_lock);
+
+ return 0;
+}
+
+void module_register() {
+ plugin_register_complex_config("write_prometheus", prom_config);
+ plugin_register_init("write_prometheus", prom_init);
+ plugin_register_write("write_prometheus", prom_write,
+ /* user data = */ NULL);
+ plugin_register_missing("write_prometheus", prom_missing,
+ /* user data = */ NULL);
+ plugin_register_shutdown("write_prometheus", prom_shutdown);
+}
+
+/* vim: set sw=2 sts=2 et fdm=marker : */
projects / collectd.git / commitdiff