add prometheus library

include/zephyr/net/prometheus/collector.h

@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2024 Mustafa Abdullah Kus, Sparse Technology
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_INCLUDE_PROMETHEUS_COLLECTOR_H_
+#define ZEPHYR_INCLUDE_PROMETHEUS_COLLECTOR_H_
+
+/**
+ * @file
+ *
+ * @brief Prometheus collector APIs.
+ *
+ * @defgroup prometheus Prometheus API
+ * @since 4.0
+ * @version 0.1.0
+ * @ingroup networking
+ * @{
+ */
+
+#include <zephyr/sys/iterable_sections.h>
+#include <zephyr/net/prometheus/metric.h>
+
+#include <stddef.h>
+
+/**
+ * @brief Prometheus collector definition
+ *
+ * This structure defines a Prometheus collector.
+ */
+struct prometheus_collector {
+	/** Name of the collector */
+	const char *name;
+	/** Array of metrics associated with the collector */
+	struct prometheus_metric *metric[CONFIG_PROMETHEUS_MAX_METRICS];
+	/** Number of metrics associated with the collector */
+	size_t size;
+};
+
+/**
+ * @brief Prometheus Collector definition.
+ *
+ * This macro defines a Collector.
+ *
+ * @param _name The collector's name.
+ */
+#define PROMETHEUS_COLLECTOR_DEFINE(_name)                                                         \
+	static STRUCT_SECTION_ITERABLE(prometheus_collector, _name) = {                            \
+		.name = STRINGIFY(_name), .size = 0, .metric = {0}}
+
+/**
+ * @brief Register a metric with a Prometheus collector
+ *
+ * Registers the specified metric with the given collector.
+ *
+ * @param collector Pointer to the collector to register the metric with.
+ * @param metric Pointer to the metric to register.
+ *
+ * @return 0 if successful, otherwise a negative error code.
+ * @retval -EINVAL Invalid arguments.
+ * @retval -ENOMEM Not enough memory to register the metric.
+ */
+int prometheus_collector_register_metric(struct prometheus_collector *collector,
+					 struct prometheus_metric *metric);
+
+/**
+ * @brief Get a metric from a Prometheus collector
+ *
+ * Retrieves the metric with the specified name from the given collector.
+ *
+ * @param collector Pointer to the collector to retrieve the metric from.
+ * @param name Name of the metric to retrieve.
+ * @return Pointer to the retrieved metric, or NULL if not found.
+ */
+const void *prometheus_collector_get_metric(const struct prometheus_collector *collector,
+					    const char *name);
+
+/**
+ * @}
+ */
+
+#endif /* ZEPHYR_INCLUDE_PROMETHEUS_COLLECTOR_H_ */

include/zephyr/net/prometheus/counter.h

@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2024 Mustafa Abdullah Kus, Sparse Technology
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_INCLUDE_PROMETHEUS_COUNTER_H_
+#define ZEPHYR_INCLUDE_PROMETHEUS_COUNTER_H_
+
+/**
+ * @file
+ *
+ * @brief Prometheus counter APIs.
+ *
+ * @addtogroup prometheus
+ * @{
+ */
+
+#include <stdint.h>
+
+#include <zephyr/sys/iterable_sections.h>
+#include <zephyr/net/prometheus/metric.h>
+
+/**
+ * @brief Type used to represent a Prometheus counter metric.
+ *
+ * * References
+ * * See https://prometheus.io/docs/concepts/metric_types/#counter
+ */
+struct prometheus_counter {
+	/** Base of the Prometheus counter metric */
+	struct prometheus_metric *base;
+	/** Value of the Prometheus counter metric */
+	uint64_t value;
+};
+
+/**
+ * @brief Prometheus Counter definition.
+ *
+ * This macro defines a Counter metric.
+ *
+ * @param _name The channel's name.
+ * @param _detail The metric base.
+ *
+ * Example usage:
+ * @code{.c}
+ *
+ * struct prometheus_metric http_request_counter = {
+ *	.type = PROMETHEUS_COUNTER,
+ *	.name = "http_request_counter",
+ *	.description = "HTTP request counter",
+ *	.num_labels = 1,
+ *	.labels = {
+ *		{ .key = "http_request", .value = "request_count",}
+ *	},
+ *};
+ *
+ * PROMETHEUS_COUNTER_DEFINE(test_counter, &test_counter_metric);
+ * @endcode
+ */
+#define PROMETHEUS_COUNTER_DEFINE(_name, _detail)                                                  \
+	static STRUCT_SECTION_ITERABLE(prometheus_counter, _name) = {.base = (void *)(_detail),    \
+								     .value = 0}
+
+/**
+ * @brief Increment the value of a Prometheus counter metric
+ * Increments the value of the specified counter metric by one.
+ * @param counter Pointer to the counter metric to increment.
+ * @return 0 on success, negative errno on error.
+ */
+int prometheus_counter_inc(struct prometheus_counter *counter);
+
+/**
+ * @}
+ */
+
+#endif /* ZEPHYR_INCLUDE_PROMETHEUS_COUNTER_H_ */

include/zephyr/net/prometheus/formatter.h

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2024 Mustafa Abdullah Kus, Sparse Technology
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_INCLUDE_PROMETHEUS_FORMATTER_H_
+#define ZEPHYR_INCLUDE_PROMETHEUS_FORMATTER_H_
+
+/**
+ * @file
+ *
+ * @brief Prometheus formatter APIs.
+ *
+ * @addtogroup prometheus
+ * @{
+ */
+
+#include <zephyr/net/prometheus/collector.h>
+
+/**
+ * @brief Format exposition data for Prometheus
+ *
+ * Formats the exposition data collected by the specified collector into the provided buffer.
+ * Function to format metric data according to Prometheus text-based format
+ *
+ * @param collector Pointer to the collector containing the data to format.
+ * @param buffer Pointer to the buffer where the formatted exposition data will be stored.
+ * @param buffer_size Size of the buffer.
+ *
+ * @return 0 on success, negative errno on error.
+ */
+int prometheus_format_exposition(const struct prometheus_collector *collector, char *buffer,
+				 size_t buffer_size);
+
+/**
+ * @}
+ */
+
+#endif /* ZEPHYR_INCLUDE_PROMETHEUS_FORMATTER_H_ */

include/zephyr/net/prometheus/gauge.h

@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) 2024 Mustafa Abdullah Kus, Sparse Technology
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_INCLUDE_PROMETHEUS_GAUGE_H_
+#define ZEPHYR_INCLUDE_PROMETHEUS_GAUGE_H_
+
+/**
+ * @file
+ *
+ * @brief Prometheus gauge APIs.
+ *
+ * @addtogroup prometheus
+ * @{
+ */
+
+#include <zephyr/sys/iterable_sections.h>
+#include <zephyr/net/prometheus/metric.h>
+
+/**
+ * @brief Type used to represent a Prometheus gauge metric.
+ *
+ * * References
+ * * See https://prometheus.io/docs/concepts/metric_types/#gauge
+ */
+struct prometheus_gauge {
+	/** Base of the Prometheus gauge metric */
+	struct prometheus_metric *base;
+	/** Value of the Prometheus gauge metric */
+	double value;
+};
+
+/**
+ * @brief Prometheus Gauge definition.
+ *
+ * This macro defines a Gauge metric.
+ *
+ * @param _name The channel's name.
+ * @param _detail The metric base.
+ *
+ * Example usage:
+ * @code{.c}
+ *
+ * struct prometheus_metric http_request_gauge = {
+ *	.type = PROMETHEUS_GAUGE,
+ *	.name = "http_request_gauge",
+ *	.description = "HTTP request gauge",
+ *	.num_labels = 1,
+ *	.labels = {
+ *		{ .key = "http_request", .value = "request_count",}
+ *	},
+ * };
+ *
+ * PROMETHEUS_GAUGE_DEFINE(test_gauge, &test_gauge_metric);
+ *
+ * @endcode
+ */
+#define PROMETHEUS_GAUGE_DEFINE(_name, _detail)                                                    \
+	static STRUCT_SECTION_ITERABLE(prometheus_gauge, _name) = {.base = (void *)(_detail),      \
+								   .value = 0}
+
+/**
+ * @brief Set the value of a Prometheus gauge metric
+ *
+ * Sets the value of the specified gauge metric to the given value.
+ *
+ * @param gauge Pointer to the gauge metric to set.
+ * @param value Value to set the gauge metric to.
+ *
+ * @return 0 on success, -EINVAL if the value is negative.
+ */
+int prometheus_gauge_set(struct prometheus_gauge *gauge, double value);
+
+/**
+ * @}
+ */
+
+#endif /* ZEPHYR_INCLUDE_PROMETHEUS_GAUGE_H_ */

include/zephyr/net/prometheus/histogram.h

@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2024 Mustafa Abdullah Kus, Sparse Technology
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_INCLUDE_PROMETHEUS_HISTOGRAM_H_
+#define ZEPHYR_INCLUDE_PROMETHEUS_HISTOGRAM_H_
+
+/**
+ * @file
+ *
+ * @brief Prometheus histogram APIs.
+ *
+ * @addtogroup prometheus
+ * @{
+ */
+
+#include <zephyr/sys/iterable_sections.h>
+#include <zephyr/net/prometheus/metric.h>
+
+#include <stddef.h>
+
+/**
+ * @brief Prometheus histogram bucket definition.
+ *
+ * This structure defines a Prometheus histogram bucket.
+ */
+struct prometheus_histogram_bucket {
+	/** Upper bound value of bucket */
+	double upper_bound;
+	/** Cumulative count of observations in the bucket */
+	unsigned long count;
+};
+
+/**
+ * @brief Type used to represent a Prometheus histogram metric.
+ *
+ * * References
+ * * See https://prometheus.io/docs/concepts/metric_types/#histogram
+ */
+struct prometheus_histogram {
+	/** Base of the Prometheus histogram metric */
+	struct prometheus_metric *base;
+	/** Array of buckets in the histogram */
+	struct prometheus_histogram_bucket *buckets;
+	/** Number of buckets in the histogram */
+	size_t num_buckets;
+	/** Sum of all observed values in the histogram */
+	double sum;
+	/** Total count of observations in the histogram */
+	unsigned long count;
+};
+
+/**
+ * @brief Prometheus Histogram definition.
+ *
+ * This macro defines a Histogram metric.
+ *
+ * @param _name The channel's name.
+ * @param _detail The metric base.
+ *
+ * Example usage:
+ * @code{.c}
+ *
+ * struct prometheus_metric http_request_gauge = {
+ *	.type = PROMETHEUS_HISTOGRAM,
+ *	.name = "http_request_histograms",
+ *	.description = "HTTP request histogram",
+ *	.num_labels = 1,
+ *	.labels = {
+ *		{ .key = "request_latency", .value = "request_latency_seconds",}
+ *	},
+ * };
+ *
+ * PROMETHEUS_HISTOGRAM_DEFINE(test_histogram, &test_histogram_metric);
+ *
+ * @endcode
+ */
+#define PROMETHEUS_HISTOGRAM_DEFINE(_name, _detail)                                                \
+	static STRUCT_SECTION_ITERABLE(prometheus_histogram, _name) = {.base = (void *)(_detail),  \
+								       .buckets = NULL,            \
+								       .num_buckets = 0,           \
+								       .sum = 0,                   \
+								       .count = 0}
+
+/**
+ * @brief Observe a value in a Prometheus histogram metric
+ *
+ * Observes the specified value in the given histogram metric.
+ *
+ * @param histogram Pointer to the histogram metric to observe.
+ * @param value Value to observe in the histogram metric.
+ * @return 0 on success, -EINVAL if the value is negative.
+ */
+int prometheus_histogram_observe(struct prometheus_histogram *histogram, double value);
+
+/**
+ * @}
+ */
+
+#endif /* ZEPHYR_INCLUDE_PROMETHEUS_HISTOGRAM_H_ */