Line data Source code
1 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_COUNTER_H_
9 : #define ZEPHYR_INCLUDE_PROMETHEUS_COUNTER_H_
10 :
11 : /**
12 : * @file
13 : *
14 : * @brief Prometheus counter APIs.
15 : *
16 : * @addtogroup prometheus
17 : * @{
18 : */
19 :
20 : #include <stdint.h>
21 :
22 : #include <zephyr/sys/iterable_sections.h>
23 : #include <zephyr/net/prometheus/metric.h>
24 :
25 : /**
26 : * @brief Type used to represent a Prometheus counter metric.
27 : *
28 : * * References
29 : * * See https://prometheus.io/docs/concepts/metric_types/#counter
30 : */
31 1 : struct prometheus_counter {
32 : /** Base of the Prometheus counter metric */
33 1 : struct prometheus_metric base;
34 : /** Value of the Prometheus counter metric */
35 1 : uint64_t value;
36 : /** User data */
37 1 : void *user_data;
38 : };
39 :
40 : /**
41 : * @brief Prometheus Counter definition.
42 : *
43 : * This macro defines a Counter metric. If you want to make the counter static,
44 : * then add "static" keyword before the PROMETHEUS_COUNTER_DEFINE.
45 : *
46 : * @param _name The counter metric name
47 : * @param _desc Counter description
48 : * @param _label Label for the metric. Additional labels can be added at runtime.
49 : * @param _collector Collector to map this metric. Can be set to NULL if it not yet known.
50 : * @param ... Optional user data specific to this metric instance.
51 : *
52 : * Example usage:
53 : * @code{.c}
54 : *
55 : * PROMETHEUS_COUNTER_DEFINE(http_request_counter, "HTTP request counter",
56 : * ({ .key = "http_request", .value = "request_count" }),
57 : * NULL);
58 : * @endcode
59 : */
60 1 : #define PROMETHEUS_COUNTER_DEFINE(_name, _desc, _label, _collector, ...) \
61 : STRUCT_SECTION_ITERABLE(prometheus_counter, _name) = { \
62 : .base.name = STRINGIFY(_name), \
63 : .base.type = PROMETHEUS_COUNTER, \
64 : .base.description = _desc, \
65 : .base.labels[0] = __DEBRACKET _label, \
66 : .base.num_labels = 1, \
67 : .base.collector = _collector, \
68 : .value = 0ULL, \
69 : .user_data = COND_CODE_0( \
70 : NUM_VA_ARGS_LESS_1(LIST_DROP_EMPTY(__VA_ARGS__, _)), \
71 : (NULL), \
72 : (GET_ARG_N(1, __VA_ARGS__))), \
73 : }
74 :
75 : /**
76 : * @brief Increment the value of a Prometheus counter metric
77 : * Increments the value of the specified counter metric by arbitrary amount.
78 : * @param counter Pointer to the counter metric to increment.
79 : * @param value Amount to increment the counter by.
80 : * @return 0 on success, negative errno on error.
81 : */
82 1 : int prometheus_counter_add(struct prometheus_counter *counter, uint64_t value);
83 :
84 : /**
85 : * @brief Increment the value of a Prometheus counter metric
86 : * Increments the value of the specified counter metric by one.
87 : * @param counter Pointer to the counter metric to increment.
88 : * @return 0 on success, negative errno on error.
89 : */
90 1 : static inline int prometheus_counter_inc(struct prometheus_counter *counter)
91 : {
92 : return prometheus_counter_add(counter, 1ULL);
93 : }
94 :
95 : /**
96 : * @brief Set the counter value to specific value.
97 : * The new value must be higher than the current value. This function can be used
98 : * if we cannot add individual increments to the counter but need to periodically
99 : * update the counter value. This function will add the difference between the
100 : * new value and the old value to the counter.
101 : * @param counter Pointer to the counter metric to increment.
102 : * @param value New value of the counter.
103 : * @return 0 on success, negative errno on error.
104 : */
105 1 : int prometheus_counter_set(struct prometheus_counter *counter, uint64_t value);
106 :
107 : /**
108 : * @}
109 : */
110 :
111 : #endif /* ZEPHYR_INCLUDE_PROMETHEUS_COUNTER_H_ */
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