metrics.c File Reference

Advanced Prometheus metrics middleware with dimensional labels and histograms. More...

#include <stdarg.h>
#include <stdatomic.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <uv.h>
#include "csilk/csilk.h"

Include dependency graph for metrics.c:

Data Structures
struct	csilk_route_metric_t
	Data structure for a specific combination of labels. More...

Macros
#define	CSILK_METRICS_MAX_ENTRIES   1024
	Maximum unique combinations of {method, route, status} tracked.
#define	CSILK_METRICS_BUCKET_COUNT   6
	Number of latency histogram buckets.

Functions
static uint32_t	metrics_hash (const char *method, const char *route, int status)
	Computes a hash for the metric dimension triple.
static csilk_route_metric_t *	get_metric_slot (const char *method, const char *route, int status)
	Finds or allocates a thread-safe slot in the metrics hash table.
void	csilk_security_get_stats (csilk_security_stats_t *stats)
void	csilk_process_get_stats (csilk_process_stats_t *stats)
void	_csilk_metrics_inc_rate_limit_blocks (void)
void	_csilk_metrics_inc_csrf_violations (void)
void	_csilk_metrics_inc_auth_failures (void)
void	csilk_metrics_middleware (csilk_ctx_t *c, const char *arg)
	Dimensional metrics middleware.
static void	append_metric (char **buf, size_t *size, size_t *offset, const char *fmt,...)
	Dynamic string builder for Prometheus text format.
void	csilk_metrics_handler (csilk_ctx_t *c)
	Handler for the /metrics endpoint.
uint64_t	csilk_metrics_get_total_requests (void)
uint64_t	csilk_metrics_get_total_duration (void)

Variables
static const double	CSILK_METRICS_BUCKETS [CSILK_METRICS_BUCKET_COUNT]
	Latency buckets in seconds for P99/P95 analysis.
static _Atomic uint64_t	http_requests_total = 0
	Atomic counter for total HTTP requests across all workers.
static _Atomic uint64_t	http_request_duration_microseconds = 0
	Atomic counter for cumulative request duration in microseconds.
static _Atomic uint64_t	security_rate_limit_blocks = 0
static _Atomic uint64_t	security_csrf_violations = 0
static _Atomic uint64_t	security_auth_failures = 0
static csilk_route_metric_t	route_metrics [CSILK_METRICS_MAX_ENTRIES] = {0}
	Fixed-size hash table for route metrics using open addressing.

Detailed Description

Advanced Prometheus metrics middleware with dimensional labels and histograms.

This module implements a high-performance metrics collection system for the csilk framework. It supports:

• Aggregated global metrics (requests, duration).
• Dimensional metrics with labels (method, route, status).
• Latency histograms for P99/P95 analysis.
• Lock-free atomic updates using a fixed-size hash table.
• System-wide telemetry (CPU, Memory, MQ, AI, DB, Security).

Copyright

MIT License

---

Data Structure Documentation

csilk_route_metric_t

struct csilk_route_metric_t

Data structure for a specific combination of labels.

Tracks requests that match a specific HTTP method, status code, and route pattern (e.g., GET 200 /api/users/:id).

Data Fields
_Atomic uint64_t	buckets[CSILK_METRICS_BUCKET_COUNT+1]	Histogram bucket counts
_Atomic uint64_t	count	Total requests for this dimension
_Atomic uint64_t	duration_us	Total duration in microseconds
_Atomic int	in_use	Lock-free flag for slot occupation
char	method[12]	HTTP method (GET, POST, etc.)
char	route[128]	Matched route pattern (e.g., "/users/:id")
int	status	HTTP response status code

Macro Definition Documentation

CSILK_METRICS_BUCKET_COUNT

#define CSILK_METRICS_BUCKET_COUNT   6

Number of latency histogram buckets.

CSILK_METRICS_MAX_ENTRIES

#define CSILK_METRICS_MAX_ENTRIES   1024

Maximum unique combinations of {method, route, status} tracked.

Once this limit is reached, new combinations will not be tracked to prevent memory exhaustion. 1024 is typically sufficient for most APIs.

Function Documentation

_csilk_metrics_inc_auth_failures()

void _csilk_metrics_inc_auth_failures

(

void

)

_csilk_metrics_inc_csrf_violations()

void _csilk_metrics_inc_csrf_violations

(

void

)

_csilk_metrics_inc_rate_limit_blocks()

void _csilk_metrics_inc_rate_limit_blocks

(

void

)

append_metric()

static void append_metric ( char **  buf, size_t *  size, size_t *  offset, const char *  fmt,   ...  )

static

Dynamic string builder for Prometheus text format.

Automatically reallocates the buffer as needed.

csilk_metrics_get_total_duration()

uint64_t csilk_metrics_get_total_duration

(

void

)

csilk_metrics_get_total_requests()

uint64_t csilk_metrics_get_total_requests

(

void

)

csilk_metrics_handler()

void csilk_metrics_handler

(

csilk_ctx_t *

c

)

Handler for the /metrics endpoint.

Prometheus /metrics endpoint handler.

Renders full system telemetry in standard Prometheus text-based format.

csilk_metrics_middleware()

void csilk_metrics_middleware	(	csilk_ctx_t *	c,
		const char *	arg
	)

Dimensional metrics middleware.

Prometheus metrics middleware.

Wraps the request execution to measure latency and update atomic counters.

csilk_process_get_stats()

void csilk_process_get_stats

(

csilk_process_stats_t *

stats

)

csilk_security_get_stats()

void csilk_security_get_stats

(

csilk_security_stats_t *

stats

)

get_metric_slot()

static csilk_route_metric_t * get_metric_slot ( const char *  method, const char *  route, int  status  )

static

Finds or allocates a thread-safe slot in the metrics hash table.

Implements a lock-free "claim" mechanism using atomic_compare_exchange.

Parameters

method	The HTTP method.
route	The route pattern.
status	The status code.

Returns

Pointer to the metric slot, or NULL if the table is saturated.

metrics_hash()

static uint32_t metrics_hash ( const char *  method, const char *  route, int  status  )

static

Computes a hash for the metric dimension triple.

Uses the djb2 algorithm for stable distribution across the hash table.

Parameters

method	The HTTP method string.
route	The route pattern string.
status	The HTTP status code.

Returns

A hash index within [0, CSILK_METRICS_MAX_ENTRIES).

Variable Documentation

CSILK_METRICS_BUCKETS

const double CSILK_METRICS_BUCKETS[CSILK_METRICS_BUCKET_COUNT]

static

Initial value:

= {
    0.01, 0.05, 0.1, 0.5, 1.0, 5.0}

Latency buckets in seconds for P99/P95 analysis.

These values define the upper bounds (le="...") for Prometheus histogram buckets.

http_request_duration_microseconds

_Atomic uint64_t http_request_duration_microseconds = 0

static

Atomic counter for cumulative request duration in microseconds.

http_requests_total

_Atomic uint64_t http_requests_total = 0

static

Atomic counter for total HTTP requests across all workers.

route_metrics

csilk_route_metric_t route_metrics[CSILK_METRICS_MAX_ENTRIES] = {0}

static

Fixed-size hash table for route metrics using open addressing.

Statically allocated to ensure zero heap allocation during request processing. Initialized to zero (all slots available).

security_auth_failures

_Atomic uint64_t security_auth_failures = 0

static

security_csrf_violations

_Atomic uint64_t security_csrf_violations = 0

static

security_rate_limit_blocks

_Atomic uint64_t security_rate_limit_blocks = 0

static