update

docs/architecture.md

@@ -395,10 +395,25 @@ function smartsend(
   receiver_id::String = "",
   reply_to::String = "",
   reply_to_msg_id::String = "",
-  is_publish::Bool = true   # Whether to automatically publish to NATS
+  is_publish::Bool = true,   # Whether to automatically publish to NATS
+  NATS_connection::Union{NATS.Connection, Nothing} = nothing  # Pre-existing NATS connection (optional, saves connection overhead)
 )
 ```
 
+**New Keyword Parameter:**
+- `NATS_connection::Union{NATS.Connection, Nothing} = nothing` - Pre-existing NATS connection. When provided, `smartsend` uses this connection instead of creating a new one, avoiding the overhead of connection establishment. This is useful for high-frequency publishing scenarios where connection reuse provides performance benefits.
+
+**Connection Handling Logic:**
+```julia
+if is_publish == false
+  # skip publish a message
+elseif is_publish == true && NATS_connection === nothing
+  publish_message(broker_url, subject, env_json_str, cid)  # Creates new connection
+elseif is_publish == true && NATS_connection !== nothing
+  publish_message(NATS_connection, subject, env_json_str, cid)  # Uses provided connection
+end
+```
+
 **Return Value:**
 - Returns a tuple `(env, env_json_str)` where:
   - `env::msg_envelope_v1` - The envelope object containing all metadata and payloads
@@ -459,6 +474,53 @@ end
 
 **Note:** The `fileserver_download_handler` receives `(url::String, max_retries::Int, base_delay::Int, max_delay::Int, correlation_id::String)` and returns `Vector{UInt8}`.
 
+#### publish_message Function
+
+The `publish_message` function provides two overloads for publishing messages to NATS:
+
+**Overload 1 - URL-based publishing (creates new connection):**
+```julia
+function publish_message(broker_url::String, subject::String, message::String, correlation_id::String)
+  conn = NATS.connect(broker_url)  # Create NATS connection
+  publish_message(conn, subject, message, correlation_id)
+end
+```
+
+**Overload 2 - Connection-based publishing (uses pre-existing connection):**
+```julia
+function publish_message(conn::NATS.Connection, subject::String, message::String, correlation_id::String)
+  try
+    NATS.publish(conn, subject, message)  # Publish message to NATS
+    log_trace(correlation_id, "Message published to $subject")  # Log successful publish
+  finally
+    NATS.drain(conn)  # Ensure connection is closed properly
+  end
+end
+```
+
+**Use Case:** Use the connection-based overload when you already have an established NATS connection and want to publish multiple messages without the overhead of creating a new connection for each publish.
+
+**Integration with smartsend:**
+```julia
+# When NATS_connection is provided to smartsend, it uses the connection-based publish_message
+env, env_json_str = smartsend(
+    "my.subject",
+    [("data", payload_data, "type")],
+    NATS_connection=my_connection,  # Pre-existing connection
+    is_publish=true
+)
+# Uses: publish_message(NATS_connection, subject, env_json_str, cid)
+
+# When NATS_connection is not provided, it uses the URL-based publish_message
+env, env_json_str = smartsend(
+    "my.subject",
+    [("data", payload_data, "type")],
+    broker_url="nats://localhost:4222",
+    is_publish=true
+)
+# Uses: publish_message(broker_url, subject, env_json_str, cid)
+```
+
 ### JavaScript Implementation
 
 #### Dependencies