feat(datadog): add include_path option

Currently there is no way to distinguish Datadog metrics for different
HTTP endpoints if these endpoints are served through a single Apisix
route.

With these changes, if `include_path` is set to true, the path pattern
by which the HTTP request was matched to a route is included as a metric
tag with the `path:` key. This allows different endpoints to be
distinguished in metrics.

Author: deiwin

apisix/plugins/datadog.lua

@@ -37,7 +37,8 @@ local batch_processor_manager = bp_manager_mod.new(plugin_name)
 local schema = {
     type = "object",
     properties = {
-        prefer_name = {type = "boolean", default = true}
+        prefer_name = {type = "boolean", default = true},
+        include_path = {type = "boolean", default = false}
     }
 }
 
@@ -84,6 +85,10 @@ local function generate_tag(entry, const_tags)
         core.table.insert(tags, "route_name:" .. entry.route_id)
     end
 
+    if entry.path and entry.path ~= "" then
+        core.table.insert(tags, "path:" .. entry.path)
+    end
+
     if entry.service_id and entry.service_id ~= "" then
         core.table.insert(tags, "service_name:" .. entry.service_id)
     end
@@ -241,6 +246,12 @@ function _M.log(conf, ctx)
         end
     end
 
+    if conf.include_path then
+        if ctx.curr_req_matched and ctx.curr_req_matched._path then
+            entry.path = ctx.curr_req_matched._path
+        end
+    end
+
     if batch_processor_manager:add_entry(conf, entry) then
         return
     end

docs/en/latest/plugins/datadog.md

@@ -41,9 +41,10 @@ This Plugin provides the ability to push metrics as a batch to the external Data
 
 ## Attributes
 
-| Name        | Type    | Required | Default | Valid values | Description                                                                            |
-| ----------- | ------- | -------- | ------- | ------------ | -------------------------------------------------------------------------------------- |
-| prefer_name | boolean | False    | true    | [true,false] | When set to `false`, uses Route/Service ID instead of name (default) with metric tags. |
+| Name         | Type    | Required | Default | Valid values | Description                                                                            |
+| ------------ | ------- | -------- | ------- | ------------ | -------------------------------------------------------------------------------------- |
+| prefer_name  | boolean | False    | true    | [true,false] | When set to `false`, uses Route/Service ID instead of name (default) with metric tags. |
+| include_path | boolean | False    | false   | [true,false] | When set to `true`, includes the path pattern in metric tags.                          |
 
 This Plugin supports using batch processors to aggregate and process entries (logs/data) in a batch. This avoids the need for frequently submitting the data. The batch processor submits data every `5` seconds or when the data in the queue reaches `1000`. See [Batch Processor](../batch-processor.md#configuration) for more information or setting your custom configuration.
 
@@ -115,6 +116,7 @@ The metrics will be sent to the DogStatsD agent with the following tags:
 - `balancer_ip`: IP address of the Upstream balancer that processed the current request.
 - `response_status`: HTTP response status code.
 - `scheme`: Request scheme such as HTTP, gRPC, and gRPCs.
+- `path`: The HTTP path pattern. Only available if the attribute `include_path` is set to true.
 
 :::note
 

t/plugin/datadog.t

@@ -535,3 +535,37 @@ message received: apisix\.apisix\.latency:[\d.]+\|h\|#source:apisix,route_name:d
 message received: apisix\.ingress\.size:[\d]+\|ms\|#source:apisix,route_name:datadog,consumer:user0,balancer_ip:[\d.]+,response_status:200,scheme:http
 message received: apisix\.egress\.size:[\d]+\|ms\|#source:apisix,route_name:datadog,consumer:user0,balancer_ip:[\d.]+,response_status:200,scheme:http
 /
+
+
+
+=== TEST 11: testing behaviour with include_path
+--- apisix_yaml
+routes:
+  - uri: /articles/*/comments
+    name: datadog
+    upstream:
+      nodes:
+        "127.0.0.1:1982": 1
+    plugins:
+      datadog:
+        batch_max_size: 1
+        max_retry_count: 0
+        include_path: true
+      proxy-rewrite:
+        uri: /opentracing
+#END
+--- request
+GET /articles/12345/comments?foo=bar
+--- response_body
+opentracing
+--- wait: 0.5
+--- grep_error_log eval
+qr/message received: apisix(.+?(?=, ))/
+--- grep_error_log_out eval
+qr/message received: apisix\.request\.counter:1\|c\|#source:apisix,route_name:datadog,path:\/articles\/\*\/comments,balancer_ip:[\d.]+,response_status:200,scheme:http
+message received: apisix\.request\.latency:[\d.]+\|h\|#source:apisix,route_name:datadog,path:\/articles\/\*\/comments,balancer_ip:[\d.]+,response_status:200,scheme:http
+message received: apisix\.upstream\.latency:[\d.]+\|h\|#source:apisix,route_name:datadog,path:\/articles\/\*\/comments,balancer_ip:[\d.]+,response_status:200,scheme:http
+message received: apisix\.apisix\.latency:[\d.]+\|h\|#source:apisix,route_name:datadog,path:\/articles\/\*\/comments,balancer_ip:[\d.]+,response_status:200,scheme:http
+message received: apisix\.ingress\.size:[\d]+\|ms\|#source:apisix,route_name:datadog,path:\/articles\/\*\/comments,balancer_ip:[\d.]+,response_status:200,scheme:http
+message received: apisix\.egress\.size:[\d]+\|ms\|#source:apisix,route_name:datadog,path:\/articles\/\*\/comments,balancer_ip:[\d.]+,response_status:200,scheme:http
+/