healthz.c File Reference

Health probe registry and JSON endpoint generation. More...

#include <cwist/sys/health/healthz.h>
#include <cwist/core/utils/json_builder.h>
#include <cwist/core/sstring/sstring.h>
#include <cwist/core/mem/alloc.h>
#include <string.h>
#include <stdio.h>

Include dependency graph for healthz.c:

Go to the source code of this file.

Macros
#define	CWIST_HEALTHZ_MAX_PROBES   16

Typedefs
typedef struct cwist_healthz_entry	cwist_healthz_entry_t

Functions
bool	cwist_healthz_register (const char *name, cwist_health_probe_fn fn, void *ctx)
	Register or update a health probe.
void	cwist_healthz_unregister (const char *name)
	Deactivate a registered health probe.
void	cwist_healthz_run (cwist_health_probe_t *out_probes, size_t max_probes, size_t *out_count, cwist_health_status_t *out_overall)
	Run all active probes and aggregate their results.
void	cwist_app_healthz (cwist_http_response *res)
	Serve the /healthz HTTP endpoint as a JSON response.

Detailed Description

Health probe registry and JSON endpoint generation.

Definition in file healthz.c.

Macro Definition Documentation

CWIST_HEALTHZ_MAX_PROBES

#define CWIST_HEALTHZ_MAX_PROBES   16

Definition at line 17 of file healthz.c.

Typedef Documentation

cwist_healthz_entry_t

typedef struct cwist_healthz_entry cwist_healthz_entry_t

Function Documentation

cwist_app_healthz()

void cwist_app_healthz

(

cwist_http_response *

res

)

Serve the /healthz HTTP endpoint as a JSON response.

Populate an HTTP response with the healthz JSON payload.

Runs all registered probes and writes a JSON body with an overall "status" field and a "probes" array of per-probe name, status, and optional message. The response Content-Type is set to application/json.

Parameters

res	Response to fill; NULL is a no-op. The body and headers are (re)assigned on success.

Definition at line 168 of file healthz.c.

References cwist_http_response::body, cap, count, CWIST_HEALTH_DEGRADED, CWIST_HEALTH_FAIL, CWIST_HEALTH_OK, CWIST_HEALTHZ_MAX_PROBES, cwist_healthz_run(), cwist_http_header_add(), CWIST_HTTP_OK, CWIST_HTTP_SERVICE_UNAVAILABLE, cwist_json_add_string(), cwist_json_begin_array(), cwist_json_begin_object(), cwist_json_builder_create(), cwist_json_builder_destroy(), cwist_json_end_array(), cwist_json_end_object(), cwist_json_get_raw(), cwist_sstring_assign(), cwist_http_response::headers, and cwist_http_response::status_code.

cwist_healthz_register()

bool cwist_healthz_register	(	const char *	name,
		cwist_health_probe_fn	fn,
		void *	ctx
	)

Register or update a health probe.

Register a custom probe function.

If a probe with the same name is already active, its function and context are replaced in place. Otherwise the probe is appended to the registry.

Parameters

name	Probe name; must be non-NULL and outlive the registration.
fn	Probe function; must be non-NULL.
ctx	Opaque context passed to fn on each evaluation.

Returns

true on success, false if name or fn is NULL or the registry is full.

Definition at line 45 of file healthz.c.

References cap, and CWIST_HEALTHZ_MAX_PROBES.

cwist_healthz_run()

void cwist_healthz_run	(	cwist_health_probe_t *	out_probes,
		size_t	max_probes,
		size_t *	out_count,
		cwist_health_status_t *	out_overall
	)

Run all active probes and aggregate their results.

Evaluate all probes and return the aggregate status.

Probes are evaluated in registration order. The overall status is FAIL if any probe reports FAIL, DEGRADED if at least one reports DEGRADED and none report FAIL, and OK otherwise.

Parameters

out_probes	Optional array receiving per-probe results; at most max_probes entries are written.
max_probes	Capacity of out_probes.
out_count	Optional output receiving the number of active probes evaluated.
out_overall	Optional output receiving the aggregated status.

Definition at line 130 of file healthz.c.

References cap, count, CWIST_HEALTH_DEGRADED, CWIST_HEALTH_FAIL, CWIST_HEALTH_OK, and cwist_health_probe::status.

Referenced by cwist_app_healthz().

cwist_healthz_unregister()

void cwist_healthz_unregister

(

const char *

name

)

Deactivate a registered health probe.

Unregister a previously registered probe.

Marks every active entry with the given name as inactive; inactive entries are skipped by cwist_healthz_run and their slots may be reused by cwist_healthz_register. The name and function pointers are not cleared.

Parameters

name	Probe name to remove; NULL is a no-op.

Definition at line 88 of file healthz.c.

References cap.