feat(promethues): add ngx.shared.DICT status

apisix/plugins/prometheus/exporter.lua

@@ -33,6 +33,7 @@ local get_services = require("apisix.http.service").services
 local get_consumers = require("apisix.consumer").consumers
 local get_upstreams = require("apisix.upstream").upstreams
 local clear_tab = core.table.clear
+local concat_tab = core.table.concat
 local get_stream_routes = router.stream_routes
 local get_protos = require("apisix.plugins.grpc-transcode.proto").protos
 local service_fetch = require("apisix.http.service").get
@@ -122,6 +123,10 @@ function _M.http_init(prometheus_enabled_in_stream)
             "Etcd modify index for APISIX keys",
             {"key"})
 
+    metrics.shared_dict = prometheus:gauge("shared_dict",
+            "nginx shared DICT of APISIX",
+            {"key"})
+
     -- per service
 
     -- The consumer label indicates the name of consumer corresponds to the
@@ -351,6 +356,42 @@ local function etcd_modify_index()
 
 end
 
+local key = {}
+local combine_param = {}
+
+local function shared_dict_status()
+    local header_of_shared_dict = core.request.header(ngx.ctx, "shared_dict")
+    if not header_of_shared_dict then
+        return
+    end
+
+    local set_shared_dict_param = function (shared_dict_name)
+        if type(shared_dict_name) ~= "string" then
+            return
+        end
+        local share_dict = ngx.shared[shared_dict_name]
+        if share_dict then
+            combine_param[1] = shared_dict_name
+            combine_param[2] = "capacity"
+            key[1] = concat_tab(combine_param, "_")
+            metrics.shared_dict:set(share_dict:capacity(), key)
+
+            combine_param[2] = "free_space"
+            key[1] = concat_tab(combine_param, "_")
+            metrics.shared_dict:set(share_dict:free_space(), key)
+        end
+    end
+
+    if type(header_of_shared_dict) == "string" then
+        set_shared_dict_param(header_of_shared_dict)
+    end
+
+    if type(header_of_shared_dict) == "table" then
+        for _, shared_dict_name in ipairs(header_of_shared_dict) do
+            set_shared_dict_param(shared_dict_name)
+        end
+    end
+end
 
 local function collect(ctx, stream_only)
     if not prometheus or not metrics then
@@ -359,6 +400,9 @@ local function collect(ctx, stream_only)
         return 500, {message = "An unexpected error occurred"}
     end
 
+    -- collect ngx.shared.DICT status
+    shared_dict_status()
+
     -- across all services
     nginx_status()
 

docs/en/latest/plugins/prometheus.md

@@ -201,6 +201,7 @@ The following metrics are exported by the `prometheus` Plugin:
   | node     | IP address of the Upstream node.                                                                                                    |
 
 - Info: Information about the APISIX node.
+- Shared dict: capacity and free space of ngx.shared.DICT, this param uses the request header `Shared_DICT` to carry the shared memory name to be fetched.
 
 Here are the original metrics from APISIX:
 
@@ -272,6 +273,10 @@ apisix_http_latency_bucket{type="upstream",route="1",service="",consumer="",node
 # HELP apisix_node_info Info of APISIX node
 # TYPE apisix_node_info gauge
 apisix_node_info{hostname="desktop-2022q8f-wsl"} 1
+# HELP apisix_shared_dict nginx shared DICT of APISIX
+# TYPE apisix_shared_dict gauge
+apisix_shared_dict{key="internal-status_capacity"} 10485760
+apisix_shared_dict{key="internal-status_free_space"} 10407936
 ```
 
 ## Disable Plugin

docs/zh/latest/plugins/prometheus.md

@@ -198,14 +198,15 @@ scrape_configs:
     | node         | 上游节点的 IP 地址。                                                                      |
 
 - Info: 当前 APISIX 节点信息。
+- Shared dict: 共享内存的大小以及剩余可用空间，该指标使用请求头 `Shared_DICT` 携带需要查询的共享内存名称。
 
 以下是 APISIX 的原始的指标数据集：
 
 ```shell
-curl http://127.0.0.1:9091/apisix/prometheus/metrics
+curl http://127.0.0.1:9091/apisix/prometheus/metrics -H "Shared_DICT:internal-status"
 ```
 
-```
+```shell
 # HELP apisix_bandwidth Total bandwidth in bytes consumed per service in Apisix
 # TYPE apisix_bandwidth counter
 apisix_bandwidth{type="egress",route="",service="",consumer="",node=""} 8417
@@ -269,6 +270,10 @@ apisix_http_latency_bucket{type="upstream",route="1",service="",consumer="",node
 # HELP apisix_node_info Info of APISIX node
 # TYPE apisix_node_info gauge
 apisix_node_info{hostname="APISIX"} 1
+# HELP apisix_shared_dict nginx shared DICT of APISIX
+# TYPE apisix_shared_dict gauge
+apisix_shared_dict{key="internal-status_capacity"} 10485760
+apisix_shared_dict{key="internal-status_free_space"} 10407936
 ```
 
 ## 禁用插件

t/plugin/prometheus.t

@@ -632,3 +632,39 @@ GET /apisix/prometheus/metrics
 qr/apisix_/
 --- response_body_unlike eval
 qr/etcd/
+
+
+
+=== TEST 42: fetch the prometheus one shared dict data
+--- request
+GET /apisix/prometheus/metrics
+--- more_headers
+Shared_DICT: worker-events
+--- response_body_like
+.*TYPE apisix_shared_dict gauge.*worker-events_capacity.*worker-events_free_space.*
+
+
+
+=== TEST 43: fetch the prometheus multiple shared dict data
+--- request eval
+["GET /apisix/prometheus/metrics", "GET /apisix/prometheus/metrics", "GET /apisix/prometheus/metrics"]
+--- more_headers
+Shared_DICT: worker-events
+Shared_DICT: upstream-healthcheck
+Shared_DICT: internal-status
+--- response_body_like eval
+[".*TYPE apisix_shared_dict gauge.*upstream-healthcheck_capacity.*upstream-healthcheck_free_space.*",
+".*TYPE apisix_shared_dict gauge.*internal-status_capacity.*internal-status_free_space.*",
+".*TYPE apisix_shared_dict gauge.*worker-events_capacity.*worker-events_free_space.*"]
+
+
+
+=== TEST 44: fetch the prometheus multiple shared dict data contain not exist shared dict
+--- request
+GET /apisix/prometheus/metrics
+--- more_headers
+Shared_DICT: worker-events
+Shared_DICT: upstream-healthcheck
+Shared_DICT: not-exist-shared-dict
+--- response_body_unlike
+.*TYPE apisix_shared_dict gauge.*not-exist-shared-dict_capacity.*not-exist-shared-dict_free_space.*