diff --git a/src/flow_service/mod.rs b/src/flow_service/mod.rs
index 1dc35c0..8bd43f7 100644
--- a/src/flow_service/mod.rs
+++ b/src/flow_service/mod.rs
@@ -26,6 +26,7 @@ pub struct FlowUpdateService {
     flow_types: Vec<FlowType>,
     channel: Channel,
     aquila_token: String,
+    definition_source: Option<String>,
 }
 
 impl FlowUpdateService {
@@ -64,9 +65,15 @@ impl FlowUpdateService {
             flow_types,
             channel,
             aquila_token,
+            definition_source: None,
         }
     }
 
+    pub fn with_definition_source(mut self, source: String) -> Self {
+        self.definition_source = Some(source);
+        self
+    }
+
     pub fn with_flow_types(mut self, flow_types: Vec<FlowType>) -> Self {
         self.flow_types = flow_types;
         self
@@ -90,11 +97,11 @@ impl FlowUpdateService {
         self
     }
 
-    pub async fn send(&self) {
+    pub async fn send(&mut self) {
         let _ = self.send_with_status().await;
     }
 
-    pub async fn send_with_status(&self) -> bool {
+    pub async fn send_with_status(&mut self) -> bool {
         let data_types_success = self.update_data_types().await;
         let runtime_functions_success = self.update_runtime_functions().await;
         let functions_success = self.update_functions().await;
@@ -102,12 +109,18 @@ impl FlowUpdateService {
         data_types_success && runtime_functions_success && functions_success && flow_types_success
     }
 
-    async fn update_data_types(&self) -> bool {
+    async fn update_data_types(&mut self) -> bool {
         if self.data_types.is_empty() {
             log::info!("No DataTypes present.");
             return true;
         }
 
+        if let Some(source) = &self.definition_source {
+            for data_type in self.data_types.iter_mut() {
+                data_type.definition_source = source.to_string();
+            }
+        }
+
         log::info!("Updating {} DataTypes.", self.data_types.len());
         let mut client = DataTypeServiceClient::new(self.channel.clone());
         let request = Request::from_parts(
@@ -135,12 +148,18 @@ impl FlowUpdateService {
         }
     }
 
-    async fn update_functions(&self) -> bool {
+    async fn update_functions(&mut self) -> bool {
         if self.functions.is_empty() {
             log::info!("No FunctionDefinitions present.");
             return true;
         }
 
+        if let Some(source) = &self.definition_source {
+            for function in self.functions.iter_mut() {
+                function.definition_source = source.to_string();
+            }
+        };
+
         log::info!("Updating {} FunctionDefinitions.", self.functions.len());
         let mut client = FunctionDefinitionServiceClient::new(self.channel.clone());
         let request = Request::from_parts(
@@ -167,12 +186,18 @@ impl FlowUpdateService {
         }
     }
 
-    async fn update_runtime_functions(&self) -> bool {
+    async fn update_runtime_functions(&mut self) -> bool {
         if self.runtime_functions.is_empty() {
             log::info!("No RuntimeFunctionDefinitions present.");
             return true;
         }
 
+        if let Some(source) = &self.definition_source {
+            for runtime_function in self.runtime_functions.iter_mut() {
+                runtime_function.definition_source = source.to_string();
+            }
+        }
+
         log::info!(
             "Updating {} RuntimeFunctionDefinitions.",
             self.runtime_functions.len()
@@ -202,12 +227,18 @@ impl FlowUpdateService {
         }
     }
 
-    async fn update_flow_types(&self) -> bool {
+    async fn update_flow_types(&mut self) -> bool {
         if self.flow_types.is_empty() {
             log::info!("No FlowTypes present.");
             return true;
         }
 
+        if let Some(source) = &self.definition_source {
+            for flow_type in self.flow_types.iter_mut() {
+                flow_type.definition_source = Some(source.to_string());
+            }
+        }
+
         log::info!("Updating {} FlowTypes.", self.flow_types.len());
         let mut client = FlowTypeServiceClient::new(self.channel.clone());
         let request = Request::from_parts(