feat(datadog): add include_method option

Currently there is no way to distinguish Datadog metrics for e.g. GET &
POST requests for the same endpoint within a single Apisix route,
although their performance characteristics are likely to be quite
different.

With these changes, if `include_method` is set to true, HTTP method is
included as a metric tag with the `method:` key, enabling such requests
to be differentiated.

Author: deiwin

apisix/plugins/datadog.lua

@@ -38,7 +38,8 @@ local schema = {
     type = "object",
     properties = {
         prefer_name = {type = "boolean", default = true},
-        include_path = {type = "boolean", default = false}
+        include_path = {type = "boolean", default = false},
+        include_method = {type = "boolean", default = false}
     }
 }
 
@@ -89,6 +90,10 @@ local function generate_tag(entry, const_tags)
         core.table.insert(tags, "path:" .. entry.path)
     end
 
+    if entry.method and entry.method ~= "" then
+        core.table.insert(tags, "method:" .. entry.method)
+    end
+
     if entry.service_id and entry.service_id ~= "" then
         core.table.insert(tags, "service_name:" .. entry.service_id)
     end
@@ -252,6 +257,10 @@ function _M.log(conf, ctx)
         end
     end
 
+    if conf.include_method then
+        entry.method = ctx.var.method
+    end
+
     if batch_processor_manager:add_entry(conf, entry) then
         return
     end

docs/en/latest/plugins/datadog.md

@@ -41,10 +41,11 @@ 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. |
-| include_path | boolean | False    | false   | [true,false] | When set to `true`, includes the path pattern in 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.                          |
+| include_method | boolean | False    | false   | [true,false] | When set to `true`, includes the HTTP method 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.
 
@@ -117,6 +118,7 @@ The metrics will be sent to the DogStatsD agent with the following tags:
 - `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.
+- `method`: The HTTP method. Only available if the attribute `include_method` is set to true.
 
 :::note
 

t/plugin/datadog.t

@@ -538,7 +538,7 @@ message received: apisix\.egress\.size:[\d]+\|ms\|#source:apisix,route_name:data
 
 
 
-=== TEST 11: testing behaviour with include_path
+=== TEST 11: testing behaviour with include_path and include_method
 --- apisix_yaml
 routes:
   - uri: /articles/*/comments
@@ -551,6 +551,7 @@ routes:
         batch_max_size: 1
         max_retry_count: 0
         include_path: true
+        include_method: true
       proxy-rewrite:
         uri: /opentracing
 #END
@@ -562,10 +563,10 @@ opentracing
 --- 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
+qr/message received: apisix\.request\.counter:1\|c\|#source:apisix,route_name:datadog,path:\/articles\/\*\/comments,method:GET,balancer_ip:[\d.]+,response_status:200,scheme:http
+message received: apisix\.request\.latency:[\d.]+\|h\|#source:apisix,route_name:datadog,path:\/articles\/\*\/comments,method:GET,balancer_ip:[\d.]+,response_status:200,scheme:http
+message received: apisix\.upstream\.latency:[\d.]+\|h\|#source:apisix,route_name:datadog,path:\/articles\/\*\/comments,method:GET,balancer_ip:[\d.]+,response_status:200,scheme:http
+message received: apisix\.apisix\.latency:[\d.]+\|h\|#source:apisix,route_name:datadog,path:\/articles\/\*\/comments,method:GET,balancer_ip:[\d.]+,response_status:200,scheme:http
+message received: apisix\.ingress\.size:[\d]+\|ms\|#source:apisix,route_name:datadog,path:\/articles\/\*\/comments,method:GET,balancer_ip:[\d.]+,response_status:200,scheme:http
+message received: apisix\.egress\.size:[\d]+\|ms\|#source:apisix,route_name:datadog,path:\/articles\/\*\/comments,method:GET,balancer_ip:[\d.]+,response_status:200,scheme:http
 /