Implement endpoint renaming

src/datadog_conf.h

@@ -107,6 +107,15 @@ struct datadog_main_conf_t {
   // `agent_url` is set by the `datadog_agent_url` directive.
   std::optional<std::string> agent_url;
 
+  // DD_APM_RESOURCE_RENAMING_ENABLED
+  // Whether generation of http.endpoint is enabled.
+  ngx_flag_t resource_renaming_enabled{NGX_CONF_UNSET};
+
+  // DD_APM_RESOURCE_RENAMING_ALWAYS_SIMPLIFIED_ENDPOINT
+  // Whether http.endpoint is always calculated, even when http.route is
+  // present.
+  ngx_flag_t resource_renaming_always_simplified_endpoint{NGX_CONF_UNSET};
+
 #ifdef WITH_WAF
   // DD_APPSEC_ENABLED
   ngx_flag_t appsec_enabled{NGX_CONF_UNSET};

src/tracing/directives.h

@@ -165,6 +165,25 @@ constexpr datadog::nginx::directive tracing_directives[] = {
         nullptr,
     },
 
+    {
+        "datadog_resource_renaming_enabled",
+        NGX_HTTP_MAIN_CONF | NGX_CONF_TAKE1,
+        ngx_conf_set_flag_slot,
+        NGX_HTTP_MAIN_CONF_OFFSET,
+        offsetof(datadog_main_conf_t, resource_renaming_enabled),
+        nullptr,
+    },
+
+    {
+        "datadog_resource_renaming_always_simplified_endpoint",
+        NGX_HTTP_MAIN_CONF | NGX_CONF_TAKE1,
+        ngx_conf_set_flag_slot,
+        NGX_HTTP_MAIN_CONF_OFFSET,
+        offsetof(datadog_main_conf_t,
+                 resource_renaming_always_simplified_endpoint),
+        nullptr,
+    },
+
     // aliases opentracing (legacy)
     ALIAS_COMMAND("datadog_tracing", "opentracing", anywhere | NGX_CONF_TAKE1),
     ALIAS_COMMAND("datadog_operation_name", "opentracing_operation_name",

src/tracing_library.cpp

@@ -68,6 +68,29 @@ dd::Expected<dd::Tracer> TracingLibrary::make_tracer(
     config.agent.url = nginx_conf.agent_url;
   }
 
+  if (nginx_conf.resource_renaming_enabled != NGX_CONF_UNSET) {
+    config.resource_renaming_enabled = {nginx_conf.resource_renaming_enabled ==
+                                        1};
+  }
+#ifdef WITH_WAF
+  else {
+    // we don't have it, in config
+    // if we also don't have in the environment it defaults to whether appsec
+    // is enabled
+    const char *env_renaming =
+        std::getenv("DD_TRACE_RESOURCE_RENAMING_ENABLED");
+    if (!env_renaming || !env_renaming[0]) {
+      config.resource_renaming_enabled = {nginx_conf.appsec_enabled == 1};
+    }
+  }
+#endif
+
+  if (nginx_conf.resource_renaming_always_simplified_endpoint !=
+      NGX_CONF_UNSET) {
+    config.resource_renaming_always_simplified_endpoint = {
+        nginx_conf.resource_renaming_always_simplified_endpoint == 1};
+  }
+
   // Set sampling rules based on any `datadog_sample_rate` directives.
   std::vector<sampling_rule_t> rules = nginx_conf.sampling_rules;
   // Sort by descending depth, so that rules in a `location` block come before

test/cases/configuration/test_apm_tracing_enabled.py

@@ -277,17 +277,26 @@ def test_distributed_tracing_waf(self):
             expected_headers = {
                 "x-datadog-sampling-priority": "2",
                 "x-datadog-origin": "rum",
-                "x-datadog-tags": "_dd.p.dm=-5,_dd.p.ts=02",
+                "x-datadog-tags": ["_dd.p.dm=-5", "_dd.p.ts=02"],
             }
 
             for header_name, expected_value in expected_headers.items():
                 self.assertIn(header_name, forwarded_headers,
                               f"Missing header: {header_name}")
-                self.assertEqual(
-                    forwarded_headers[header_name],
-                    expected_value,
-                    f"Header {header_name} mismatch: expected {expected_value}, got {forwarded_headers[header_name]}",
-                )
+                gotten_value = forwarded_headers[header_name]
+                if isinstance(expected_value, list):
+                    for ev in expected_value:
+                        self.assertIn(
+                            ev,
+                            gotten_value,
+                            f"Header {header_name} missing expected value: {ev}",
+                        )
+                else:
+                    self.assertEqual(
+                        gotten_value,
+                        expected_value,
+                        f"Header {header_name} mismatch: expected {expected_value}, got {forwarded_headers[header_name]}",
+                    )
 
             # Check traceparent format (trace ID should match, span ID should be different)
             self.assertIn("traceparent", forwarded_headers,
@@ -327,12 +336,17 @@ def test_distributed_tracing_waf(self):
             tracestate = forwarded_headers["tracestate"]
             # The tracestate should contain the new span ID (same as in traceparent)
             expected_span_id = traceparent_parts[2]
-            expected_tracestate = f"dd=s:2;p:{expected_span_id};o:rum;t.dm:-5;t.ts:02"
-            self.assertEqual(
-                tracestate,
-                expected_tracestate,
-                f"tracestate mismatch: expected {expected_tracestate}, got {tracestate}",
-            )
+            expected_tracestate = [
+                "dd=s:2", f"p:{expected_span_id}", "o:rum", "t.dm:-5",
+                "t.ts:02"
+            ]
+            split_tracestate = tracestate.split(";")
+            for expected_part in expected_tracestate:
+                self.assertIn(
+                    expected_part,
+                    split_tracestate,
+                    f"tracestate missing expected part: {expected_part}. Got {tracestate}",
+                )
 
         span_count = 0
 

test/cases/endpoint_renaming/__init__.py

@@ -0,0 +1 @@
+# Endpoint renaming integration tests

test/cases/endpoint_renaming/conf/always.conf

@@ -0,0 +1,38 @@
+# Test configuration for endpoint renaming always mode
+# This configuration tests that endpoint renaming works even when http.route is present
+
+load_module /datadog-tests/ngx_http_datadog_module.so;
+
+events {
+    worker_connections 1024;
+}
+
+http {
+    datadog_agent_url http://agent:8126;
+    datadog_service_name test-service;
+
+    datadog_resource_renaming_enabled on;
+    datadog_resource_renaming_always_simplified_endpoint on;
+
+    server {
+        listen 80;
+        server_name localhost;
+
+        location / {
+            return 200 "$datadog_config_json";
+        }
+
+        location /api/users {
+            return 200 "User endpoint";
+        }
+
+        location /api/products {
+            return 200 "Product endpoint";
+        }
+
+        location /api/orders {
+            datadog_tag "http.route" "/api/orders/:id";
+            return 200 "Order endpoint";
+        }
+    }
+}

test/cases/endpoint_renaming/conf/appsec_enabled.conf

@@ -0,0 +1,45 @@
+# Test configuration for endpoint renaming with appsec enabled
+# This configuration tests that endpoint renaming defaults to enabled (fallback mode)
+# when appsec is enabled, without explicit resource_renaming_enabled directive
+
+thread_pool waf_thread_pool threads=2 max_queue=5;
+
+load_module /datadog-tests/ngx_http_datadog_module.so;
+
+events {
+    worker_connections 1024;
+}
+
+http {
+    datadog_agent_url http://agent:8126;
+    datadog_service_name test-service;
+
+    # Enable appsec - this should enable endpoint renaming by default
+    datadog_appsec_enabled on;
+    datadog_waf_thread_pool_name waf_thread_pool;
+
+    # No explicit datadog_resource_renaming_enabled directive
+    # Should default to on (fallback mode) because appsec is enabled
+
+    server {
+        listen 80;
+        server_name localhost;
+
+        location / {
+            return 200 "$datadog_config_json";
+        }
+
+        location /api/users {
+            return 200 "User endpoint";
+        }
+
+        location /api/products {
+            return 200 "Product endpoint";
+        }
+
+        location /api/orders {
+            datadog_tag "http.route" "/api/orders/:id";
+            return 200 "Order endpoint";
+        }
+    }
+}

test/cases/endpoint_renaming/conf/disabled.conf

@@ -0,0 +1,33 @@
+# Test configuration for endpoint renaming disabled (default)
+# This configuration tests that endpoint renaming is disabled by default
+
+load_module /datadog-tests/ngx_http_datadog_module.so;
+
+events {
+    worker_connections 1024;
+}
+
+http {
+    datadog_agent_url http://agent:8126;
+    datadog_service_name test-service;
+
+    # Endpoint renaming should be disabled by default
+    # No datadog_resource_renaming_enabled directive
+
+    server {
+        listen 80;
+        server_name localhost;
+
+        location / {
+            return 200 "$datadog_config_json";
+        }
+
+        location /api/users {
+            return 200 "User endpoint";
+        }
+
+        location /api/products {
+            return 200 "Product endpoint";
+        }
+    }
+}

test/cases/endpoint_renaming/conf/fallback.conf

@@ -0,0 +1,38 @@
+# Test configuration for endpoint renaming enabled
+# This configuration tests that endpoint renaming works when enabled
+
+load_module /datadog-tests/ngx_http_datadog_module.so;
+
+events {
+    worker_connections 1024;
+}
+
+http {
+    datadog_agent_url http://agent:8126;
+    datadog_service_name test-service;
+
+    # Enable endpoint renaming (fallback mode)
+    datadog_resource_renaming_enabled on;
+
+    server {
+        listen 80;
+        server_name localhost;
+
+        location / {
+            return 200 "$datadog_config_json";
+        }
+
+        location /api/users {
+            return 200 "User endpoint";
+        }
+
+        location /api/products {
+            return 200 "Product endpoint";
+        }
+
+        location /api/orders {
+            datadog_tag "http.route" "/api/orders/:id";
+            return 200 "Order endpoint";
+        }
+    }
+}