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_ */