NGINX Prometheus

gistfile1.txt

#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>
#include <ngx_event.h>

static char *ngx_http_skill(ngx_conf_t *cf, void *post, void *data);
static ngx_conf_post_handler_pt ngx_http_skill_p = ngx_http_skill;


typedef struct {
    ngx_str_t   name;
} ngx_http_skill_loc_conf_t;


static void *
ngx_http_skill_create_loc_conf(ngx_conf_t *cf)
{
    ngx_http_skill_loc_conf_t  *conf;

    conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_skill_loc_conf_t));
    if (conf == NULL) {
        return NULL;
    }
    return conf;
}

static ngx_command_t ngx_http_skill_commands[] = {
    { ngx_string("skill"),
      NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
	  ngx_conf_set_str_slot,
	  NGX_HTTP_LOC_CONF_OFFSET,
	  offsetof(ngx_http_skill_loc_conf_t, name),
	  &ngx_http_skill_p},

    ngx_null_command
};


static ngx_http_module_t ngx_http_skill_module_ctx = {
    NULL,    /* preconfiguration */
    NULL,                          /* postconfiguration */

    NULL,                          /* create main configuration */
    NULL,                          /* init main configuration */

    NULL,                          /* create server configuration */
    NULL,                          /* merge server configuration */

    ngx_http_skill_create_loc_conf, /* create location configuration */
    NULL                           /* merge location configuration */
};


ngx_module_t ngx_http_skill_module = {
    NGX_MODULE_V1,
    &ngx_http_skill_module_ctx,    /* module context */
    ngx_http_skill_commands,       /* module directives */
    NGX_HTTP_MODULE,               /* module type */
    NULL,                          /* init master */
    NULL,                          /* init module */
    NULL,                          /* init process */
    NULL,                          /* init thread */
    NULL,                          /* exit thread */
	NULL,                          /* exit process */
    NULL,                          /* exit master */
    NGX_MODULE_V1_PADDING
};


static ngx_int_t
ngx_http_skill_handler(ngx_http_request_t *r)
{

    size_t	size;
    ngx_int_t    rc;
    ngx_buf_t   *b;
    ngx_chain_t  out;
    ngx_atomic_int_t   ac, hn, ap;

    if (!(r->method & (NGX_HTTP_GET))) {
        return NGX_HTTP_NOT_ALLOWED;
    }

    rc = ngx_http_discard_request_body(r);

    if (rc != NGX_OK) {
        return rc;
    }

    r->headers_out.content_type_len = sizeof("text/plain") - 1;
    ngx_str_set(&r->headers_out.content_type, "text/plain");
    r->headers_out.content_type_lowcase = NULL;


    size = sizeof("# TYPE active gauge\nactive ") + NGX_ATOMIC_T_LEN +
    	   sizeof("# TYPE accepted gauge\naccepted ") + NGX_ATOMIC_T_LEN +
    	   sizeof("# TYPE handled gauge\nhandled ") + NGX_ATOMIC_T_LEN;
		;

    b = ngx_create_temp_buf(r->pool, size);
    if (b == NULL) {
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    out.buf = b;
    out.next = NULL;

    ac = *ngx_stat_active;
    hn = *ngx_stat_handled;
    ap = *ngx_stat_accepted;

    b->last = ngx_sprintf(b->last, "# TYPE accepted gauge\naccepted %uA\n", ap);
    b->last = ngx_sprintf(b->last, "# TYPE handled gauge\nhandled %uA\n", hn);
    b->last = ngx_sprintf(b->last, "# TYPE active gauge\nactive %uA\n", ac);

    r->headers_out.status = NGX_HTTP_OK;
    r->headers_out.content_length_n = b->last - b->pos;

    b->last_buf = (r == r->main) ? 1 : 0;
    b->last_in_chain = 1;

    rc = ngx_http_send_header(r);

    if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) {
        return rc;
    }

    return ngx_http_output_filter(r, &out);
}

static char *
ngx_http_skill(ngx_conf_t *cf, void *post, void *data)
{
    ngx_http_core_loc_conf_t *clcf;

    clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module);
    clcf->handler = ngx_http_skill_handler;

    return NGX_CONF_OK;
}