Add multiple output formats to nchan_stub_status directive

config

@@ -133,6 +133,7 @@ _NCHAN_UTIL_SRCS=" \
   $_nchan_util_dir/nchan_accumulator.c \
   $_nchan_util_dir/nchan_timequeue.c \
   $_nchan_util_dir/hdr_histogram.c \
+  $_nchan_util_dir/nchan_stub_status_formats.c \
 "
 
 _NCHAN_STORE_SRCS="\

src/nchan_commands.rb

@@ -1074,11 +1074,13 @@
   nchan_stub_status [:loc],
       :nchan_stub_status_directive,
       :loc_conf,
-      args: 0,
-      
+      args: 0..1,
+
       group: "meta",
       tags: ['introspection'],
-      info: "Similar to Nginx's stub_status directive, requests to an `nchan_stub_status` location get a response with some vital Nchan statistics. This data does not account for information from other Nchan instances, and monitors only local connections, published messages, etc.",
+      value: ["plain", "json", "html", "prometheus"],
+      default: "plain",
+      info: "Similar to Nginx's stub_status directive, requests to an `nchan_stub_status` location get a response with some vital Nchan statistics. This data does not account for information from other Nchan instances, and monitors only local connections, published messages, etc. The optional format argument can be 'plain' (default), 'json', 'html', or 'prometheus'.",
       uri: "#nchan_stub_status"
 
   nchan_channel_event_string [:srv, :loc, :if], 

src/nchan_config_commands.c

@@ -912,7 +912,7 @@ static ngx_command_t  nchan_commands[] = {
     NULL } ,
 
   { ngx_string("nchan_stub_status"),
-    NGX_HTTP_LOC_CONF|NGX_CONF_NOARGS,
+    NGX_HTTP_LOC_CONF|NGX_CONF_NOARGS|NGX_CONF_TAKE1,
     nchan_stub_status_directive,
     NGX_HTTP_LOC_CONF_OFFSET,
     0,

src/nchan_module.c

@@ -31,6 +31,7 @@
 //#include <store/memory/store-private.h> //for debugging
 #endif
 #include <util/nchan_output.h>
+#include <util/nchan_stub_status_formats.h>
 #include <nchan_websocket_publisher.h>
 
 ngx_int_t           nchan_worker_processes;
@@ -236,66 +237,23 @@ static ngx_int_t nchan_http_publisher_handler(ngx_http_request_t * r, void (*bod
 }
 
 ngx_int_t nchan_stub_status_handler(ngx_http_request_t *r) {
-  ngx_buf_t           *b;
-  ngx_chain_t          out;
-
   nchan_stats_global_t global;
   nchan_stats_worker_t worker;
-
   nchan_main_conf_t   *mcf = ngx_http_get_module_main_conf(r, ngx_nchan_module);
-
-  float                shmem_used, shmem_max;
-
-  char     *buf_fmt = "total published messages: %ui\n"
-                      "stored messages: %ui\n"
-                      "shared memory used: %fK\n"
-                      "shared memory limit: %fK\n"
-                      "channels: %ui\n"
-                      "subscribers: %ui\n"
-                      "redis pending commands: %ui\n"
-                      "redis connected servers: %ui\n"
-                      "redis unhealthy upstreams: %ui\n"
-                      "total redis commands sent: %ui\n"
-                      "total interprocess alerts received: %ui\n"
-                      "interprocess alerts in transit: %ui\n"
-                      "interprocess queued alerts: %ui\n"
-                      "total interprocess send delay: %ui\n"
-                      "total interprocess receive delay: %ui\n"
-                      "nchan version: %s\n";
-
-  if ((b = ngx_pcalloc(r->pool, sizeof(*b) + 800)) == NULL) {
-    nchan_log_request_error(r, "Failed to allocate response buffer for nchan_stub_status.");
-    return NGX_HTTP_INTERNAL_SERVER_ERROR;
-  }
-
-  shmem_used = (float )((float )nchan_get_used_shmem() / 1024.0);
-  shmem_max = (float )((float )mcf->shm_size / 1024.0);
-
-  if(nchan_stats_get_all(&worker, &global) != NGX_OK) {
-    nchan_log_request_error(r, "Failed to get stub status stats.");
-    return NGX_HTTP_INTERNAL_SERVER_ERROR;
-  }
-
-  b->start = (u_char *)&b[1];
-  b->pos = b->start;
-
-  b->end = ngx_snprintf(b->start, 800, buf_fmt, global.total_published_messages, worker.messages, shmem_used, shmem_max, worker.channels, worker.subscribers, worker.redis_pending_commands, worker.redis_connected_servers, worker.redis_unhealthy_upstreams, global.total_redis_commands_sent, global.total_ipc_alerts_received, global.total_ipc_alerts_sent - global.total_ipc_alerts_received, worker.ipc_queue_size, global.total_ipc_send_delay, global.total_ipc_receive_delay, NCHAN_VERSION);
-  b->last = b->end;
+  nchan_loc_conf_t    *lcf = ngx_http_get_module_loc_conf(r, ngx_nchan_module);
 
-  b->memory = 1;
-  b->last_buf = 1;
-
-  r->headers_out.status = NGX_HTTP_OK;
-  r->headers_out.content_type.len = sizeof("text/plain") - 1;
-  r->headers_out.content_type.data = (u_char *) "text/plain";
-
-  r->headers_out.content_length_n = b->end - b->start;
-  ngx_http_send_header(r);
-
-  out.buf = b;
-  out.next = NULL;
-
-  return ngx_http_output_filter(r, &out);
+  // Dispatch to format-specific handler based on stub_status_format
+  switch(lcf->stub_status_format) {
+    case 1: // json
+      return nchan_stub_status_json(r, &worker, &global, mcf);
+    case 2: // html
+      return nchan_stub_status_html(r, &worker, &global, mcf);
+    case 3: // prometheus
+      return nchan_stub_status_prometheus(r, &worker, &global, mcf);
+    case 0: // plain (default)
+    default:
+      return nchan_stub_status_plain(r, &worker, &global, mcf);
+  }
 }
 
 static ngx_int_t redis_stats_callback(ngx_int_t rc, void *d, void *pd) {

src/nchan_setup.c

@@ -317,6 +317,9 @@ static void *nchan_create_loc_conf(ngx_conf_t *cf) {
   lcf->benchmark.subscribers_per_channel = NGX_CONF_UNSET;
   lcf->benchmark.subscriber_distribution = NCHAN_BENCHMARK_SUBSCRIBER_DISTRIBUTION_UNSET;
   lcf->benchmark.publisher_distribution = NCHAN_BENCHMARK_PUBLISHER_DISTRIBUTION_UNSET;
+
+  lcf->stub_status_format = NGX_CONF_UNSET;
+
   return lcf;
 }
 
@@ -614,7 +617,9 @@ static char * nchan_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child) {
   ngx_conf_merge_value(conf->benchmark.subscribers_per_channel, prev->benchmark.subscribers_per_channel, 100);
   MERGE_UNSET_CONF(conf->benchmark.subscriber_distribution, prev->benchmark.subscriber_distribution, NCHAN_BENCHMARK_SUBSCRIBER_DISTRIBUTION_UNSET, NCHAN_BENCHMARK_SUBSCRIBER_DISTRIBUTION_RANDOM);
   MERGE_UNSET_CONF(conf->benchmark.publisher_distribution, prev->benchmark.publisher_distribution, NCHAN_BENCHMARK_PUBLISHER_DISTRIBUTION_UNSET, NCHAN_BENCHMARK_PUBLISHER_DISTRIBUTION_RANDOM);
-
+
+  ngx_conf_merge_value(conf->stub_status_format, prev->stub_status_format, 0);
+
   return NGX_CONF_OK;
 }
 
@@ -1427,6 +1432,26 @@ static char *nchan_stub_status_directive(ngx_conf_t *cf, ngx_command_t *cmd, voi
   nchan_loc_conf_t    *lcf = conf;
   nchan_stub_status_enabled = 1;
   lcf->request_handler = &nchan_stub_status_handler;
+
+  // Parse format argument if provided
+  if (cf->args->nelts > 1) {
+    ngx_str_t *val = &((ngx_str_t *) cf->args->elts)[1];
+    if (ngx_strncmp(val->data, "plain", val->len) == 0) {
+      lcf->stub_status_format = 0;
+    } else if (ngx_strncmp(val->data, "json", val->len) == 0) {
+      lcf->stub_status_format = 1;
+    } else if (ngx_strncmp(val->data, "html", val->len) == 0) {
+      lcf->stub_status_format = 2;
+    } else if (ngx_strncmp(val->data, "prometheus", val->len) == 0) {
+      lcf->stub_status_format = 3;
+    } else {
+      ngx_conf_log_error(NGX_LOG_ERR, cf, 0,
+        "invalid nchan_stub_status format: %V (valid: plain, json, html, prometheus)", val);
+      return NGX_CONF_ERROR;
+    }
+  } else {
+    lcf->stub_status_format = 0; // default: plain
+  }
   return NGX_CONF_OK;
 }
 

src/nchan_types.h

@@ -437,6 +437,8 @@ struct nchan_loc_conf_s { //nchan_loc_conf_t
   nchan_benchmark_conf_t          benchmark;
 
   ngx_int_t                     (*request_handler)(ngx_http_request_t *r);
+
+  ngx_int_t                     stub_status_format;  // 0=plain, 1=json, 2=html, 3=prometheus
 };// nchan_loc_conf_t;
 
 typedef struct nchan_llist_timed_s {