feat(zipkin) add support to include http path to span name (#8150)

Co-authored-by: Mayo <i@shoujo.io>

CHANGELOG.md

@@ -91,6 +91,14 @@
 - Bumped inspect from 3.1.2 to 3.1.3
   [#8589](https://github.com/Kong/kong/pull/8589)
 
+### Additions
+
+#### Plugins
+
+- **Zipkin**: add support for including HTTP path in span name 
+  through configuration property `http_span_name`.
+  [#8150](https://github.com/Kong/kong/pull/8150)
+
 ### Fixes
 
 #### Core

kong/plugins/zipkin/handler.lua

@@ -127,9 +127,15 @@ if subsystem == "http" then
       trace_id = rand_bytes(conf.traceid_byte_count)
     end
 
+    local span_name = method
+    local path = req.get_path()
+    if conf.http_span_name == "method_path" then
+      span_name = method .. ' ' .. path
+    end
+
     local request_span = new_span(
       "SERVER",
-      method,
+      span_name,
       ngx_req_start_time_mu(),
       should_sample,
       trace_id,
@@ -146,7 +152,7 @@ if subsystem == "http" then
     request_span:set_tag("lc", "kong")
     request_span:set_tag("http.method", method)
     request_span:set_tag("http.host", req.get_host())
-    request_span:set_tag("http.path", req.get_path())
+    request_span:set_tag("http.path", path)
     if protocol then
       request_span:set_tag("http.protocol", protocol)
     end

kong/plugins/zipkin/schema.lua

@@ -61,6 +61,7 @@ return {
           { tags_header = { type = "string", required = true, default = "Zipkin-Tags" } },
           { static_tags = { type = "array", elements = static_tag,
                             custom_validator = validate_static_tags } },
+          { http_span_name = { type = "string", required = true, default = "method", one_of = { "method", "method_path" } } },
         },
     }, },
   },

spec/03-plugins/34-zipkin/zipkin_spec.lua

@@ -280,6 +280,72 @@ for _, strategy in helpers.each_strategy() do
 end
 
 
+for _, strategy in helpers.each_strategy() do
+  describe("http_span_name configuration", function()
+    local proxy_client, zipkin_client, service
+
+    setup(function()
+      local bp = helpers.get_db_utils(strategy, { "services", "routes", "plugins" })
+
+      service = bp.services:insert {
+        name = string.lower("http-" .. utils.random_string()),
+      }
+
+      -- kong (http) mock upstream
+      bp.routes:insert({
+        name = string.lower("route-" .. utils.random_string()),
+        service = service,
+        hosts = { "http-route" },
+        preserve_host = true,
+      })
+
+      -- enable zipkin plugin globally, with sample_ratio = 1
+      bp.plugins:insert({
+        name = "zipkin",
+        config = {
+          sample_ratio = 1,
+          http_endpoint = fmt("http://%s:%d/api/v2/spans", ZIPKIN_HOST, ZIPKIN_PORT),
+          default_header_type = "b3-single",
+          http_span_name = "method_path",
+        }
+      })
+
+      helpers.start_kong({
+        database = strategy,
+        nginx_conf = "spec/fixtures/custom_nginx.template",
+        stream_listen = helpers.get_proxy_ip(false) .. ":19000",
+      })
+
+      proxy_client = helpers.proxy_client()
+      zipkin_client = helpers.http_client(ZIPKIN_HOST, ZIPKIN_PORT)
+    end)
+
+    teardown(function()
+      helpers.stop_kong()
+    end)
+
+    it("http_span_name = 'method_path' includes path to span name", function()
+      local start_s = ngx.now()
+
+      local r = proxy_client:get("/", {
+        headers = {
+          ["x-b3-sampled"] = "1",
+          host  = "http-route",
+          ["zipkin-tags"] = "foo=bar; baz=qux"
+        },
+      })
+
+      assert.response(r).has.status(200)
+
+      local _, proxy_span, request_span =
+        wait_for_spans(zipkin_client, 3, service.name)
+      -- common assertions for request_span and proxy_span
+      assert_span_invariants(request_span, proxy_span, "get /", 16 * 2, start_s, "kong")
+    end)
+  end)
+end
+
+
 for _, strategy in helpers.each_strategy() do
 for _, traceid_byte_count in ipairs({ 8, 16 }) do
 describe("http integration tests with zipkin server [#"