fix(api) support HTTP/2 status and metrics requests

kong/api/routes/health.lua

@@ -1,5 +1,6 @@
 local utils = require "kong.tools.utils"
 local declarative = require "kong.db.declarative"
+local http = require "resty.http"
 
 local find = string.find
 local select = select
@@ -14,6 +15,7 @@ local tonumber = tonumber
 local kong = kong
 local dbless = kong.configuration.database == "off"
 local data_plane_role = kong.configuration.role == "data_plane"
+local nginx_status_sock = "unix:" .. ngx.config.prefix() .. "nginx_status.sock"
 
 
 return {
@@ -42,14 +44,27 @@ return {
 
       -- nginx stats
 
-      local r = ngx.location.capture "/nginx_status"
+      local httpc = http.new()
+      local _, err = httpc:connect(nginx_status_sock)
+      if err ~= nil then
+        kong.log.err("failed to retrieve status: ", err)
+        return kong.response.exit(500, { message = "An unexpected error happened" })
+      end
+      local r, err = httpc:request({ method = "GET", path = "/nginx_status",
+          headers = { ["Host"] = "localhost" } })
+      local nginx_status_body = r:read_body()
+      httpc:close()
+      if err ~= nil then
+        kong.log.err("failed to retrieve status: ", err)
+        return kong.response.exit(500, { message = "An unexpected error happened" })
+      end
       if r.status ~= 200 then
-        kong.log.err(r.body)
+        kong.log.err("failed to retrieve status: ", nginx_status_body)
         return kong.response.exit(500, { message = "An unexpected error happened" })
       end
 
       local var = ngx.var
-      local accepted, handled, total = select(3, find(r.body, "accepts handled requests\n (%d*) (%d*) (%d*)"))
+      local accepted, handled, total = select(3, find(nginx_status_body, "accepts handled requests\n (%d*) (%d*) (%d*)"))
 
       local status_response = {
         memory = knode.get_memory_stats(unit, scale),

kong/plugins/prometheus/exporter.lua

@@ -4,6 +4,7 @@ local find = string.find
 local lower = string.lower
 local concat = table.concat
 local select = select
+local http = require "resty.http"
 local ngx_timer_pending_count = ngx.timer.pending_count
 local ngx_timer_running_count = ngx.timer.running_count
 local balancer = require("kong.runloop.balancer")
@@ -12,6 +13,8 @@ if not balancer.get_all_upstreams then -- API changed since after Kong 2.5
   get_all_upstreams = require("kong.runloop.balancer.upstreams").get_all_upstreams
 end
 
+local nginx_status_sock = "unix:" .. ngx.config.prefix() .. "nginx_status.sock"
+
 local CLUSTERING_SYNC_STATUS = require("kong.constants").CLUSTERING_SYNC_STATUS
 
 local stream_available, stream_api = pcall(require, "kong.tools.stream_api")
@@ -298,18 +301,31 @@ local function metric_data()
   end
 
   if ngx.location then
-    local r = ngx.location.capture "/nginx_status"
-
-    if r.status ~= 200 then
+    local httpc = http.new()
+    local _, err = httpc:connect(nginx_status_sock)
+    if err ~= nil then
       kong.log.warn("prometheus: failed to retrieve /nginx_status ",
-        "while processing /metrics endpoint")
-
+        "while processing /metrics endpoint: ", err)
     else
-      local accepted, handled, total = select(3, find(r.body,
-        "accepts handled requests\n (%d*) (%d*) (%d*)"))
-      metrics.connections:set(accepted, { "accepted" })
-      metrics.connections:set(handled, { "handled" })
-      metrics.connections:set(total, { "total" })
+      local r, err = httpc:request({ method = "GET", path = "/nginx_status",
+          headers = { ["Host"] = "localhost" } })
+      local nginx_status_body = r:read_body()
+      httpc:close()
+      if err ~= nil then
+        kong.log.warn("prometheus: failed to retrieve /nginx_status ",
+          "while processing /metrics endpoint: ", err)
+
+      elseif r.status ~= 200 then
+        kong.log.warn("prometheus: failed to retrieve /nginx_status ",
+          "while processing /metrics endpoint")
+
+      else
+        local accepted, handled, total = select(3, find(nginx_status_body,
+          "accepts handled requests\n (%d*) (%d*) (%d*)"))
+        metrics.connections:set(accepted, { "accepted" })
+        metrics.connections:set(handled, { "handled" })
+        metrics.connections:set(total, { "total" })
+      end
     end
   end
 

kong/templates/nginx_kong.lua

@@ -363,12 +363,6 @@ server {
         }
     }
 
-    location /nginx_status {
-        internal;
-        access_log off;
-        stub_status;
-    }
-
     location /robots.txt {
         return 200 'User-agent: *\nDisallow: /';
     }
@@ -408,18 +402,24 @@ server {
         }
     }
 
-    location /nginx_status {
-        internal;
-        access_log off;
-        stub_status;
-    }
-
     location /robots.txt {
         return 200 'User-agent: *\nDisallow: /';
     }
 }
 > end
 
+> if #status_listeners > 0 or (#admin_listeners > 0 and (role == "control_plane" or role == "traditional")) then
+server {
+    server_name nginx_status;
+    listen unix:${{PREFIX}}/nginx_status.sock;
+    error_log  ${{ADMIN_ERROR_LOG}} ${{LOG_LEVEL}};
+    location /nginx_status {
+        access_log off;
+        stub_status;
+    }
+}
+> end -- #status_listeners > 0 or (#admin_listeners > 0 and (role == "control_plane" or role == "traditional"))
+
 > if role == "control_plane" then
 server {
     server_name kong_cluster_listener;

spec/02-integration/02-cmd/02-start_stop_spec.lua

@@ -1,4 +1,5 @@
 local helpers = require "spec.helpers"
+local pl_path = require "pl.path"
 
 
 for _, strategy in helpers.each_strategy() do
@@ -11,6 +12,14 @@ describe("kong start/stop #" .. strategy, function()
     }) -- runs migrations
     helpers.prepare_prefix()
   end)
+  before_each(function()
+    helpers.wait_until(function()
+      if pl_path.exists(helpers.test_conf.prefix .. "/nginx_status.sock") then
+        return false
+      end
+      return true
+    end, 10)
+  end)
   after_each(function()
     helpers.kill_all()
   end)

spec/02-integration/04-admin_api/01-admin_api_spec.lua

@@ -55,7 +55,7 @@ describe("Admin API listeners", function()
       admin_listen = "127.0.0.1:9001, 127.0.0.1:9002",
     }))
 
-    assert.equals(2, count_server_blocks(helpers.test_conf.nginx_kong_conf))
+    assert.equals(3, count_server_blocks(helpers.test_conf.nginx_kong_conf))
     assert.same({
       ["127.0.0.1:9001"] = 1,
       ["127.0.0.1:9002"] = 2,

spec/02-integration/05-proxy/01-proxy_spec.lua

@@ -43,7 +43,7 @@ describe("Proxy interface listeners", function()
       proxy_listen = "off",
       admin_listen = "0.0.0.0:9001",
     }))
-    assert.equals(1, count_server_blocks(helpers.test_conf.nginx_kong_conf))
+    assert.equals(2, count_server_blocks(helpers.test_conf.nginx_kong_conf))
     assert.is_nil(get_listeners(helpers.test_conf.nginx_kong_conf).kong)
   end)
 
@@ -53,7 +53,7 @@ describe("Proxy interface listeners", function()
       admin_listen = "0.0.0.0:9000",
     }))
 
-    assert.equals(2, count_server_blocks(helpers.test_conf.nginx_kong_conf))
+    assert.equals(3, count_server_blocks(helpers.test_conf.nginx_kong_conf))
     assert.same({
       ["127.0.0.1:9001"] = 1,
       ["127.0.0.1:9002"] = 2,

spec/fixtures/custom_nginx.template

@@ -385,12 +385,6 @@ http {
             }
         }
 
-        location /nginx_status {
-            internal;
-            access_log off;
-            stub_status;
-        }
-
         location /robots.txt {
             return 200 'User-agent: *\nDisallow: /';
         }
@@ -430,18 +424,23 @@ http {
             }
         }
 
-        location /nginx_status {
-            internal;
-            access_log off;
-            stub_status;
-        }
-
         location /robots.txt {
             return 200 'User-agent: *\nDisallow: /';
         }
     }
 > end
 
+> if #status_listeners > 0 or (#admin_listeners > 0 and (role == "control_plane" or role == "traditional")) then
+server {
+    listen unix:${{PREFIX}}/nginx_status.sock;
+    error_log  ${{ADMIN_ERROR_LOG}} ${{LOG_LEVEL}};
+    location /nginx_status {
+        access_log off;
+        stub_status;
+    }
+}
+> end -- #status_listeners > 0 or (#admin_listeners > 0 and (role == "control_plane" or role == "traditional"))
+
 > if role == "control_plane" then
     server {
         server_name kong_cluster_listener;