test(opentelemetry): support variable resource attributes

changelog/unreleased/kong/feat-variable-resource-attributes.yml

@@ -0,0 +1,4 @@
+message: | 
+  **Opentelemetry**: Support variable resource attributes
+type: feature
+scope: Plugin

spec/03-plugins/37-opentelemetry/02-schema_spec.lua

@@ -33,4 +33,16 @@ describe("Plugin: OpenTelemetry (schema)", function()
       }
     }, err)
   end)
+
+  it("accepts variable values", function()
+    local ok, err = validate_plugin_config_schema({
+      endpoint = "http://example.dev",
+      resource_attributes = {
+        foo = "$(headers.host)",
+      },
+    }, schema_def)
+
+    assert.truthy(ok)
+    assert.is_nil(err)
+  end)
 end)

spec/03-plugins/37-opentelemetry/04-exporter_spec.lua

@@ -567,6 +567,8 @@ for _, strategy in helpers.each_strategy() do
           resource_attributes = {
             ["service.name"] = "kong_oss",
             ["os.version"] = "debian",
+            ["host.name"] = "$(headers.host)",
+            ["validstr"] = "$($@#)",
           }
         })
         mock = helpers.http_mock(HTTP_SERVER_PORT_TRACES, { timeout = HTTP_MOCK_TIMEOUT })
@@ -608,13 +610,17 @@ for _, strategy in helpers.each_strategy() do
         local res_attr = decoded.resource_spans[1].resource.attributes
         sort_by_key(res_attr)
         -- resource attributes
-        assert.same("os.version", res_attr[1].key)
-        assert.same({string_value = "debian", value = "string_value"}, res_attr[1].value)
-        assert.same("service.instance.id", res_attr[2].key)
-        assert.same("service.name", res_attr[3].key)
-        assert.same({string_value = "kong_oss", value = "string_value"}, res_attr[3].value)
-        assert.same("service.version", res_attr[4].key)
-        assert.same({string_value = kong.version, value = "string_value"}, res_attr[4].value)
+        assert.same("host.name", res_attr[1].key)
+        assert.same({string_value = "0.0.0.0:" .. PROXY_PORT, value = "string_value"}, res_attr[1].value)
+        assert.same("os.version", res_attr[2].key)
+        assert.same({string_value = "debian", value = "string_value"}, res_attr[2].value)
+        assert.same("service.instance.id", res_attr[3].key)
+        assert.same("service.name", res_attr[4].key)
+        assert.same({string_value = "kong_oss", value = "string_value"}, res_attr[4].value)
+        assert.same("service.version", res_attr[5].key)
+        assert.same({string_value = kong.version, value = "string_value"}, res_attr[5].value)
+        assert.same("validstr", res_attr[6].key)
+        assert.same({string_value = "$($@#)", value = "string_value"}, res_attr[6].value)
 
         local scope_spans = decoded.resource_spans[1].scope_spans
         assert.is_true(#scope_spans > 0, scope_spans)

spec/03-plugins/37-opentelemetry/07-utils_spec.lua

@@ -0,0 +1,53 @@
+require("spec.helpers")
+local LOG_PHASE = require("kong.pdk.private.phases").phases.log
+
+describe("compile_resource_attributes()", function()
+    local mock_request
+    local old_ngx
+    local compile_resource_attributes
+
+    setup(function()
+        old_ngx = _G.ngx
+        _G.ngx = {
+            ctx = {
+                KONG_PHASE = LOG_PHASE
+            },
+            req = {
+              get_headers = function() return mock_request.headers end,
+            },
+            get_phase = function() return "log" end,
+        }
+        package.loaded["kong.pdk.request"] = nil
+        package.loaded["kong.plugins.opentelemetry.utils"] = nil
+
+        local pdk_request = require "kong.pdk.request"
+        kong.request = pdk_request.new(kong)
+        compile_resource_attributes = require "kong.plugins.opentelemetry.utils".compile_resource_attributes
+    end)
+
+    lazy_teardown(function()
+        _G.ngx = old_ngx
+    end)
+
+
+    it("accepts valid template and valid string", function()
+        mock_request = {
+            headers = {
+                host = "kong-test",
+            },    
+        }
+        local resource_attributes = {
+            ["valid_variable"] = "$(headers.host)",
+            ["nonexist_variable"] = "$($@#)",
+            ["valid_string"] = "valid",
+        }
+        local rendered_resource_attributes, err = compile_resource_attributes(resource_attributes)
+
+        assert.is_nil(err)
+        assert.same(rendered_resource_attributes["valid_variable"], "kong-test")
+
+        -- take as a normal string if variable does not exist
+        assert.same(rendered_resource_attributes["nonexist_variable"], "$($@#)")
+        assert.same(rendered_resource_attributes["valid_string"], "valid")
+    end)
+end)