feat(telemetry): include NGINX flavor in telemetry (#205)

* feat(telemetry): include NGINX flavor in telemetry

This commit enhances telemetry by adding the NGINX flavor into
the integration name reported. This improvement will provide better
insights into how the module is utilized.

Changes:
  - Fix reported flavor for openresty.
  - Report integration name depending of the flavor.

Author: dmehala

Makefile

@@ -153,6 +153,7 @@ build-openresty-aux:
 		-DNGINX_PATCH_AWAY_LIBC=ON \
 		-DCMAKE_BUILD_TYPE=$(BUILD_TYPE) \
 		-DNGINX_SRC_DIR=/tmp/openresty-${RESTY_VERSION}/build/nginx-${NGINX_VERSION} \
+		-DNGINX_DATADOG_FLAVOR="openresty" \
 		-DNGINX_DATADOG_ASM_ENABLED="$(WAF)" . \
 		&& cmake --build .openresty-build -j $(MAKE_JOB_COUNT) -v --target ngx_http_datadog_module \
 

src/nginx_flavors.h

@@ -14,7 +14,7 @@ inline constexpr flavor from_str(std::string_view in) {
   if (in == "nginx") {
     return flavor::vanilla;
   } else if (in == "openresty") {
-    return flavor::vanilla;
+    return flavor::openresty;
   } else if (in == "ingress-nginx") {
     return flavor::ingress_nginx;
   }

src/tracing_library.cpp

@@ -31,12 +31,27 @@ extern "C" {
 namespace datadog {
 namespace nginx {
 
+inline constexpr std::string_view integration_name_from_flavor(
+    flavor nginx_flavor) {
+  switch (nginx_flavor) {
+    case flavor::vanilla:
+      return "nginx";
+    case flavor::openresty:
+      return "nginx:openresty";
+    case flavor::ingress_nginx:
+      return "nginx:ingress-nginx";
+  }
+
+  static_assert(true, "unknown NGINX flavor");
+  std::abort();
+}
+
 dd::Expected<dd::Tracer> TracingLibrary::make_tracer(
     const datadog_main_conf_t &nginx_conf, std::shared_ptr<dd::Logger> logger) {
   dd::TracerConfig config;
   config.logger = std::move(logger);
   config.agent.event_scheduler = std::make_shared<NgxEventScheduler>();
-  config.integration_name = "nginx";
+  config.integration_name = integration_name_from_flavor(kNginx_flavor);
   config.integration_version = NGINX_VERSION;
   config.service = "nginx";