1 /* 2 * Copyright (c) 2024 Mustafa Abdullah Kus, Sparse Technology 3 * Copyright (c) 2024 Nordic Semiconductor 4 * 5 * SPDX-License-Identifier: Apache-2.0 6 */ 7 8 #ifndef ZEPHYR_INCLUDE_PROMETHEUS_GAUGE_H_ 9 #define ZEPHYR_INCLUDE_PROMETHEUS_GAUGE_H_ 10 11 /** 12 * @file 13 * 14 * @brief Prometheus gauge APIs. 15 * 16 * @addtogroup prometheus 17 * @{ 18 */ 19 20 #include <zephyr/sys/iterable_sections.h> 21 #include <zephyr/net/prometheus/metric.h> 22 23 /** 24 * @brief Type used to represent a Prometheus gauge metric. 25 * 26 * * References 27 * * See https://prometheus.io/docs/concepts/metric_types/#gauge 28 */ 29 struct prometheus_gauge { 30 /** Base of the Prometheus gauge metric */ 31 struct prometheus_metric base; 32 /** Value of the Prometheus gauge metric */ 33 double value; 34 /** User data */ 35 void *user_data; 36 }; 37 38 /** 39 * @brief Prometheus Gauge definition. 40 * 41 * This macro defines a Gauge metric. If you want to make the gauge static, 42 * then add "static" keyword before the PROMETHEUS_GAUGE_DEFINE. 43 * 44 * @param _name The gauge metric name. 45 * @param _desc Gauge description 46 * @param _label Label for the metric. Additional labels can be added at runtime. 47 * @param _collector Collector to map this metric. Can be set to NULL if it not yet known. 48 * @param ... Optional user data specific to this metric instance. 49 * 50 * Example usage: 51 * @code{.c} 52 * 53 * PROMETHEUS_GAUGE_DEFINE(http_request_gauge, "HTTP request gauge", 54 * ({ .key = "http_request", .value = "request_count" }), 55 * NULL); 56 * 57 * @endcode 58 */ 59 #define PROMETHEUS_GAUGE_DEFINE(_name, _desc, _label, _collector, ...) \ 60 STRUCT_SECTION_ITERABLE(prometheus_gauge, _name) = { \ 61 .base.name = STRINGIFY(_name), \ 62 .base.type = PROMETHEUS_GAUGE, \ 63 .base.description = _desc, \ 64 .base.labels[0] = __DEBRACKET _label, \ 65 .base.num_labels = 1, \ 66 .base.collector = _collector, \ 67 .value = 0.0, \ 68 .user_data = COND_CODE_0( \ 69 NUM_VA_ARGS_LESS_1(LIST_DROP_EMPTY(__VA_ARGS__, _)), \ 70 (NULL), \ 71 (GET_ARG_N(1, __VA_ARGS__))), \ 72 } 73 74 /** 75 * @brief Set the value of a Prometheus gauge metric 76 * 77 * Sets the value of the specified gauge metric to the given value. 78 * 79 * @param gauge Pointer to the gauge metric to set. 80 * @param value Value to set the gauge metric to. 81 * 82 * @return 0 on success, -EINVAL if the value is negative. 83 */ 84 int prometheus_gauge_set(struct prometheus_gauge *gauge, double value); 85 86 /** 87 * @} 88 */ 89 90 #endif /* ZEPHYR_INCLUDE_PROMETHEUS_GAUGE_H_ */ 91
