add custom trace attributes

config/plano_config_schema.yaml

@@ -382,8 +382,27 @@ properties:
         type: integer
       trace_arch_internal:
         type: boolean
-      opentracing_grpc_endpoint:
-        type: string
+    custom_attributes:
+      type: array
+      items:
+        type: object
+        properties:
+          key:
+            type: string
+          type:
+            type: string
+            enum:
+              - str
+              - bool
+              - float
+              - int
+          header:
+            type: string
+        additionalProperties: false
+        required:
+          - key
+          - type
+          - header
       additionalProperties: false
   mode:
     type: string