add prometheus output

.gitignore

@@ -7,7 +7,7 @@
 .cproject
 .vscode
 test/test.log
-test/test.output
+test/test.output*
 mod_result_status_counter.so
 autom4te.cache
 Makefile

README.md

@@ -3,7 +3,7 @@ __________________________
 
 [![Build Status](https://travis-ci.org/TheMeier/mod_result_status_counter.svg?branch=master)](https://travis-ci.org/TheMeier/mod_result_status_counter)
 
-This apache module counts the result status of each request handled by apache httpd. The counters can be fetched via a module_hablder wicht outputs a simple json array. This is hand to do some monitoruing.
+This apache module counts the result status of each request handled by apache httpd. The counters can be fetched via a module_hablder wicht outputs a simple json array or prometheus text output if you use query param prometheus. This is handy to do some monitoring.
 
 To use compile with apxs, add a location handler an LoadModule directive to your config:
 
@@ -14,6 +14,25 @@ LoadModule result_status_counter_module modules/mod_result_status_counter.so
 </Location>
 ```
 
+```shell
+~ curl http://localhost/mrsc
+[
+        { "100 Continue": 0 },
+        { "101 Switching Protocols": 0 },
+        { "102 Processing": 0 },
+        { "200 OK": 10 },
+        ...
+
+~ curl http://localhost/mrsc?prometheus
+# HELP http_requests_total The total number of HTTP requests.
+# TYPE http_requests_total counter
+http_requests_total{status="100 Continue"}  0
+http_requests_total{status="101 Switching Protocols"}  0
+http_requests_total{status="102 Processing"}  0
+http_requests_total{status="200 OK"}  11
+...
+```
+
 
 FIXME:
 I could not find a way to translate the apache result-array indices back to status codes and sadly status_lines is not exortet in http_protocol.h so for now in copy&pasted the definition of status_lines[]

debian/changelog

@@ -1,4 +1,11 @@
-libapache2-mod-result-status-counter (1.0.1-1) unstable; urgency=medium
+libapache2-mod-result-status-counter (1.1.0-1) unstable; urgency=medium
+
+  * add simple text only prometheus output
+  * add test
+
+ -- Christoph Maser <[email protected]>  Sat, 05 Sep 2017 09:55:23 +0200
+
+ libapache2-mod-result-status-counter (1.0.1-1) unstable; urgency=medium
 
   * update response code array
 

mod_result_status_counter.c

@@ -289,19 +289,35 @@ static int mrsc_handler(request_rec *r)
         return DECLINED;
     }
 
-    r->content_type = "text/json";
     base = (mrsc_data *)apr_shm_baseaddr_get(mrsc_shm);
 
     if (!r->header_only) {
-        ap_rputs("[\n", r);
-        for (i = 0; i < RESPONSE_CODES; ++i) {
-            if (status_lines[i] == '\0') {
-        	   ap_rprintf(r, "\t{ \"%s apache code %d\": %d },\n", "unknown", i ,base->request_status[i]);
-            } else {
-                ap_rprintf(r, "\t{ \"%s\": %d },\n", status_lines[i] ,base->request_status[i]);
+        if (r->args) {
+            if (ap_strstr_c(r->args, "prometheus")) {
+                r->content_type = "text/plain; version=0.0.4";
+                ap_rputs("# HELP http_requests_total The total number of HTTP requests.\n",r);
+                ap_rputs("# TYPE http_requests_total counter\n",r);
+                for (i = 0; i < RESPONSE_CODES; ++i) {
+                    if (status_lines[i] == '\0') {
+                	   ap_rprintf(r, "http_requests_total{status=\"%s apache code %d\"}  %d\n", "unknown", i ,base->request_status[i]);
+                    } else {
+                        ap_rprintf(r, "http_requests_total{status=\"%s\"}  %d\n", status_lines[i] ,base->request_status[i]);
+                    }
+                }
             }
+        } else {
+            r->content_type = "text/json";
+
+            ap_rputs("[\n", r);
+            for (i = 0; i < RESPONSE_CODES; ++i) {
+                if (status_lines[i] == '\0') {
+            	   ap_rprintf(r, "\t{ \"%s apache code %d\": %d },\n", "unknown", i ,base->request_status[i]);
+                } else {
+                    ap_rprintf(r, "\t{ \"%s\": %d },\n", status_lines[i] ,base->request_status[i]);
+                }
+            }
+            ap_rputs("]", r);
         }
-        ap_rputs("]", r);
 
     }
     return OK;

test.sh

@@ -33,3 +33,7 @@ curl -o test.output -q http://localhost:8080/mrsc
 grep '{ "200 OK": 10 }' test.output
 grep '{ "404 Not Found": 10 }' test.output
 
+curl -o test.output2 http://localhost:8080/mrsc?prometheus
+
+grep 'http_requests_total{status="200 OK"}  11' test.output2
+grep 'http_requests_total{status="404 Not Found"}  10' test.output2