collector.h

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/*
 * Copyright (c) 2024 Mustafa Abdullah Kus, Sparse Technology
 * Copyright (c) 2024 Nordic Semiconductor
 *
 * SPDX-License-Identifier: Apache-2.0
 */
 
#ifndef ZEPHYR_INCLUDE_PROMETHEUS_COLLECTOR_H_
#define ZEPHYR_INCLUDE_PROMETHEUS_COLLECTOR_H_
 
#include <zephyr/kernel.h>
#include <zephyr/sys/iterable_sections.h>
#include <zephyr/net/prometheus/metric.h>
 
#include <stddef.h>
 
struct prometheus_collector;
 
typedef int (*prometheus_scrape_cb_t)(struct prometheus_collector *collector,
                                      struct prometheus_metric *metric,
                                      void *user_data);
 
struct prometheus_collector {
        const char *name;
        sys_slist_t metrics;
        struct k_mutex lock;
        prometheus_scrape_cb_t user_cb;
        void *user_data;
};
 
#define PROMETHEUS_COLLECTOR_DEFINE(_name, ...) \
        STRUCT_SECTION_ITERABLE(prometheus_collector, _name) = {        \
                .name = STRINGIFY(_name),                               \
                .metrics = SYS_SLIST_STATIC_INIT(&_name.metrics),       \
                .lock = Z_MUTEX_INITIALIZER(_name.lock),                \
                .user_cb = COND_CODE_0(                                 \
                        NUM_VA_ARGS_LESS_1(                             \
                                LIST_DROP_EMPTY(__VA_ARGS__, _)),       \
                        (NULL),                                         \
                        (GET_ARG_N(1, __VA_ARGS__))),                   \
                .user_data = COND_CODE_0(                               \
                        NUM_VA_ARGS_LESS_1(__VA_ARGS__), (NULL),        \
                        (GET_ARG_N(1,                                   \
                                   GET_ARGS_LESS_N(1, __VA_ARGS__)))),  \
        }
 
int prometheus_collector_register_metric(struct prometheus_collector *collector,
                                         struct prometheus_metric *metric);
 
const void *prometheus_collector_get_metric(struct prometheus_collector *collector,
                                            const char *name);
 
enum prometheus_walk_state {
        PROMETHEUS_WALK_START,
        PROMETHEUS_WALK_CONTINUE,
        PROMETHEUS_WALK_STOP,
};
 
struct prometheus_collector_walk_context {
        struct prometheus_collector *collector;
        struct prometheus_metric *metric;
        struct prometheus_metric *tmp;
        enum prometheus_walk_state state;
};
 
int prometheus_collector_walk_metrics(struct prometheus_collector_walk_context *ctx,
                                      uint8_t *buffer, size_t buffer_size);
 
static inline int prometheus_collector_walk_init(struct prometheus_collector_walk_context *ctx,
                                                 struct prometheus_collector *collector)
{
        if (collector == NULL) {
                return -EINVAL;
        }
 
        ctx->collector = collector;
        ctx->state = PROMETHEUS_WALK_START;
        ctx->metric = NULL;
        ctx->tmp = NULL;
 
        return 0;
}
 
#endif /* ZEPHYR_INCLUDE_PROMETHEUS_COLLECTOR_H_ */