From b14dd542a8e220070e218f9b86ece291c6f8df5a Mon Sep 17 00:00:00 2001
From: Victor Pellan <victor.pellan@datadoghq.com>
Date: Thu, 21 Nov 2024 16:16:22 +0100
Subject: [PATCH] Move `_dd.apm.enabled` tag in Tracing Rack Middleware instead
 of AppSec middleware

---
 lib/datadog/appsec/contrib/rack/request_middleware.rb | 2 --
 lib/datadog/appsec/ext.rb                             | 1 -
 lib/datadog/tracing/contrib/rack/middlewares.rb       | 5 +++++
 lib/datadog/tracing/metadata/ext.rb                   | 4 ++++
 sig/datadog/appsec/ext.rbs                            | 1 -
 sig/datadog/tracing/metadata/ext.rbs                  | 2 ++
 6 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/lib/datadog/appsec/contrib/rack/request_middleware.rb b/lib/datadog/appsec/contrib/rack/request_middleware.rb
index cbb232c00e3..bd27505c4da 100644
--- a/lib/datadog/appsec/contrib/rack/request_middleware.rb
+++ b/lib/datadog/appsec/contrib/rack/request_middleware.rb
@@ -151,8 +151,6 @@ def add_appsec_tags(processor, scope)
             return unless trace && span
 
             span.set_metric(Datadog::AppSec::Ext::TAG_APPSEC_ENABLED, 1)
-            # We add this tag when ASM standalone is enabled to make sure we don't bill APM
-            span.set_metric(Datadog::AppSec::Ext::TAG_APM_ENABLED, 0) if Datadog.configuration.appsec.standalone.enabled
             span.set_tag('_dd.runtime_family', 'ruby')
             span.set_tag('_dd.appsec.waf.version', Datadog::AppSec::WAF::VERSION::BASE_STRING)
 
diff --git a/lib/datadog/appsec/ext.rb b/lib/datadog/appsec/ext.rb
index 30c21b7d240..0f8dddd446f 100644
--- a/lib/datadog/appsec/ext.rb
+++ b/lib/datadog/appsec/ext.rb
@@ -7,7 +7,6 @@ module Ext
       SCOPE_KEY = 'datadog.appsec.scope'
 
       TAG_APPSEC_ENABLED = '_dd.appsec.enabled'
-      TAG_APM_ENABLED = '_dd.apm.enabled'
       TAG_DISTRIBUTED_APPSEC_EVENT = '_dd.p.appsec'
     end
   end
diff --git a/lib/datadog/tracing/contrib/rack/middlewares.rb b/lib/datadog/tracing/contrib/rack/middlewares.rb
index fc2662c95ca..e4357dbc0e4 100644
--- a/lib/datadog/tracing/contrib/rack/middlewares.rb
+++ b/lib/datadog/tracing/contrib/rack/middlewares.rb
@@ -134,6 +134,11 @@ def set_request_tags!(trace, request_span, env, status, headers, response, origi
             # Otherwise, the getter method would delegate to its root span
             trace.resource = request_span.resource unless trace.resource_override?
 
+            # We add this metric when ASM standalone is enabled to make sure we don't bill APM
+            if Datadog.configuration.appsec.standalone.enabled
+              request_span.set_metric(Tracing::Metadata::Ext::TAG_APM_ENABLED, 0)
+            end
+
             request_span.set_tag(Tracing::Metadata::Ext::TAG_COMPONENT, Ext::TAG_COMPONENT)
             request_span.set_tag(Tracing::Metadata::Ext::TAG_OPERATION, Ext::TAG_OPERATION_REQUEST)
             request_span.set_tag(Tracing::Metadata::Ext::TAG_KIND, Tracing::Metadata::Ext::SpanKind::TAG_SERVER)
diff --git a/lib/datadog/tracing/metadata/ext.rb b/lib/datadog/tracing/metadata/ext.rb
index 95cf3d4e7f0..a1cffa4f725 100644
--- a/lib/datadog/tracing/metadata/ext.rb
+++ b/lib/datadog/tracing/metadata/ext.rb
@@ -31,6 +31,10 @@ module Ext
         # See Datadog-internal "RFC: Identifying which spans have profiling enabled " for details
         TAG_PROFILING_ENABLED = '_dd.profiling.enabled'
 
+        # Set to '0' if Standalone AppSec is enabled, not present otherwise.
+        # Although this tag is only used by Standalone AppSec for now, it acts on APM and belongs in this file
+        TAG_APM_ENABLED = '_dd.apm.enabled'
+
         # Defines constants for trace analytics
         # @public_api
         module Analytics
diff --git a/sig/datadog/appsec/ext.rbs b/sig/datadog/appsec/ext.rbs
index 2ac545ba1d3..94021af2f29 100644
--- a/sig/datadog/appsec/ext.rbs
+++ b/sig/datadog/appsec/ext.rbs
@@ -5,7 +5,6 @@ module Datadog
       SCOPE_KEY: String
 
       TAG_APPSEC_ENABLED: String
-      TAG_APM_ENABLED: String
       TAG_DISTRIBUTED_APPSEC_EVENT: String
     end
   end
diff --git a/sig/datadog/tracing/metadata/ext.rbs b/sig/datadog/tracing/metadata/ext.rbs
index 9820be2b123..d347c7abb48 100644
--- a/sig/datadog/tracing/metadata/ext.rbs
+++ b/sig/datadog/tracing/metadata/ext.rbs
@@ -8,6 +8,8 @@ module Datadog
         TAG_PEER_SERVICE: ::String
         TAG_KIND: ::String
         TAG_TOP_LEVEL: ::String
+        TAG_PROFILING_ENABLED: ::String
+        TAG_APM_ENABLED: ::String
 
         module Analytics
           DEFAULT_SAMPLE_RATE: ::Float