Run PACS and MWL in separate containers

compose.yml

@@ -1,30 +1,46 @@
 services:
-  gateway:
+  pacs:
     build:
       context: .
       dockerfile: Dockerfile
-    container_name: gateway-server
+    container_name: pacs-server
+    command: ["uv", "run", "python", "-m", "pacs_main"]
     ports:
-      - "4243:4243"  # MWL
-      - "4244:4244"  # PACS
+      - "4244:4244"
     volumes:
       - pacs-storage:/var/lib/pacs/storage
       - pacs-db:/var/lib/pacs
     environment:
-      # PACS configuration
       - PACS_AET=SCREENING_PACS
       - PACS_PORT=4244
       - PACS_STORAGE_PATH=/var/lib/pacs/storage
       - PACS_DB_PATH=/var/lib/pacs/pacs.db
-      # MWL configuration
+      - LOG_LEVEL=INFO
+    restart: unless-stopped
+    healthcheck:
+      test: ["CMD", "sqlite3", "/var/lib/pacs/pacs.db", "SELECT 1"]
+      interval: 30s
+      timeout: 5s
+      retries: 3
+
+  mwl:
+    build:
+      context: .
+      dockerfile: Dockerfile
+    container_name: mwl-server
+    command: ["uv", "run", "python", "-m", "mwl_main"]
+    ports:
+      - "4243:4243"
+    volumes:
+      - pacs-db:/var/lib/pacs
+    environment:
       - MWL_AET=MWL_SCP
       - MWL_PORT=4243
       - MWL_DB_PATH=/var/lib/pacs/worklist.db
-      # Logging
       - LOG_LEVEL=INFO
     restart: unless-stopped
     healthcheck:
-      test: ["CMD", "sqlite3", "/var/lib/pacs/pacs.db", "SELECT 1"]
+      test: ["CMD", "sqlite3", "/var/lib/pacs/worklist.db", "SELECT 1"]
       interval: 30s
       timeout: 5s
       retries: 3

docs/adr/ADR-003_Separate_containers_for_PACS_and_MWL.md

@@ -0,0 +1,43 @@
+# ADR-003: Separate containers for PACS and MWL
+
+Date: 2026-01-08
+
+Status: Accepted
+
+## Context
+
+The Gateway needs to provide DICOM services that must run together in production:
+
+1. **PACS Server** - C-STORE operations for receiving medical images (port 4244)
+2. **MWL Server** - C-FIND operations for modality worklist queries (port 4243)
+
+Several deployment architectures were considered, including running both servers in separate threads within a single container. However, the team identified requirements that made separate containers a better fit:
+
+1. **Independent scaling** - PACS may receive more load than MWL (or vice versa) and needs to scale independently
+2. **Independent deployment** - Ability to update one service without restarting the other
+3. **Operational flexibility** - Ability to restart, debug, or maintain one service independently
+4. **Better alignment with container best practices** - One process per container is the standard pattern
+5. **Clearer resource management** - Separate containers make it easier to monitor and allocate resources
+
+## Decision
+
+Run PACS and MWL servers in separate Docker containers using dedicated entry points.
+
+**Implementation:**
+
+Created two entry point modules:
+- `pacs_main.py` - Starts only the PACS server
+- `mwl_main.py` - Starts only the MWL server
+
+## Consequences
+
+### Positive Consequences
+
+- **Independent scaling** - Can scale PACS and MWL based on their individual load patterns
+- **Independent deployment** - Update one service without touching the other
+- **Better observability** - Separate log streams and health checks for each service
+- **Operational flexibility** - Can restart, debug, or maintain services independently
+
+### Negative Consequences
+
+- **Slightly more resource usage** - Two separate processes instead of one (minimal overhead)

docs/mwl/README.md

@@ -9,7 +9,7 @@ The MWL server is a lightweight, production-ready DICOM worklist solution that:
 - Provides scheduled procedure information via DICOM C-FIND protocol
 - Stores worklist items in SQLite database
 - Supports filtering by modality, date, and patient ID
-- Runs alongside ([PACS Server](../pacs/README.md)) in the same Docker container
+- Runs in a separate container alongside the [PACS Server](../pacs/README.md)
 
 ## Architecture
 
@@ -47,14 +47,17 @@ The MWL server is a lightweight, production-ready DICOM worklist solution that:
 
 ## Running the MWL Server
 
-The MWL server runs in the same container as the PACS server:
+The MWL server runs in a separate container:
 
 ```bash
-# Start both servers
+# Start both PACS and MWL servers
 docker compose up -d
 
+# Start only MWL server
+docker compose up -d mwl
+
 # View logs
-docker compose logs -f gateway
+docker compose logs -f mwl
 
 # Stop servers
 docker compose down
@@ -136,6 +139,30 @@ uv run pytest tests/integration/test_c_find_returns_worklist_items.py -v
 uv run pytest tests/integration/test_request_cfind_on_worklist.py -v
 ```
 
-## Multi-server architecture
+## Multi-container architecture
+
+The PACS and MWL servers run in separate containers. See [ADR-003: Separate containers for PACS and MWL](../adr/ADR-003_Separate_containers_for_PACS_and_MWL.md) for the architectural decision and trade-offs.
+
+**Docker Compose services:**
+```yaml
+services:
+  pacs:
+    container_name: pacs-server
+    command: ["uv", "run", "python", "-m", "pacs_main"]
+    ports:
+      - "4244:4244"
+
+  mwl:
+    container_name: mwl-server
+    command: ["uv", "run", "python", "-m", "mwl_main"]
+    ports:
+      - "4243:4243"
+```
+
+Each server:
 
-The gateway container runs both PACS and MWL servers using separate threads. See [ADR-003: Multi-threaded PACS and MWL server architecture](../adr/ADR-003_Multi_threaded_PACS_MWL_server.md) for the architectural decision and trade-offs.
+- Runs in its own container
+- Has its own Application Entity (AE)
+- Uses a separate SQLite database
+- Can be scaled and deployed independently
+- Handles different DICOM operations (C-STORE vs C-FIND)

docs/pacs/README.md

@@ -8,7 +8,7 @@ The PACS server is a lightweight, production-ready DICOM storage solution that:
 - Receives medical images via DICOM C-STORE protocol
 - Stores the images using hash-based directory structure
 - Indexes metadata in SQLite database
-- Runs alongside the [MWL Server](../mwl/README.md) in the same Docker container (see [ADR-003](../adr/ADR-003_Multi_threaded_PACS_MWL_server.md))
+- Runs in a separate container alongside the [MWL Server](../mwl/README.md) (see [ADR-003](../adr/ADR-003_Separate_containers_for_PACS_and_MWL.md))
 
 ## Architecture
 
@@ -74,13 +74,16 @@ CREATE TABLE stored_instances (
 ## Running the PACS Server
 
 ```bash
-# Start the server
+# Start both PACS and MWL servers
 docker compose up -d
 
+# Start only PACS server
+docker compose up -d pacs
+
 # View logs
 docker compose logs -f pacs
 
-# Stop the server
+# Stop servers
 docker compose down
 
 # Reset database and storage

src/mwl_main.py

@@ -0,0 +1,30 @@
+"""Entry point for MWL server."""
+
+import logging
+import os
+
+from server import MWLServer
+
+
+def main():
+    """Main entry point for MWL server."""
+    logging.basicConfig(
+        level=os.getenv("LOG_LEVEL", "INFO").upper(),
+        format=os.getenv("LOG_FORMAT", "%(asctime)s - %(name)s - %(levelname)s - %(message)s"),
+    )
+
+    mwl_aet = os.getenv("MWL_AET", "MWL_SCP")
+    mwl_port = int(os.getenv("MWL_PORT", "4243"))
+    mwl_db_path = os.getenv("MWL_DB_PATH", "/var/lib/pacs/worklist.db")
+
+    mwl_server = MWLServer(mwl_aet, mwl_port, mwl_db_path, block=True)
+
+    try:
+        mwl_server.start()
+    except KeyboardInterrupt:
+        logging.info("Received shutdown signal")
+        mwl_server.stop()
+
+
+if __name__ == "__main__":
+    main()

src/pacs_main.py

@@ -0,0 +1,31 @@
+"""Entry point for PACS server."""
+
+import logging
+import os
+
+from server import PACSServer
+
+
+def main():
+    """Main entry point for PACS server."""
+    logging.basicConfig(
+        level=os.getenv("LOG_LEVEL", "INFO").upper(),
+        format=os.getenv("LOG_FORMAT", "%(asctime)s - %(name)s - %(levelname)s - %(message)s"),
+    )
+
+    pacs_aet = os.getenv("PACS_AET", "SCREENING_PACS")
+    pacs_port = int(os.getenv("PACS_PORT", "4244"))
+    pacs_storage_path = os.getenv("PACS_STORAGE_PATH", "/var/lib/pacs/storage")
+    pacs_db_path = os.getenv("PACS_DB_PATH", "/var/lib/pacs/pacs.db")
+
+    pacs_server = PACSServer(pacs_aet, pacs_port, pacs_storage_path, pacs_db_path, block=True)
+
+    try:
+        pacs_server.start()
+    except KeyboardInterrupt:
+        logging.info("Received shutdown signal")
+        pacs_server.stop()
+
+
+if __name__ == "__main__":
+    main()

src/server.py

@@ -6,8 +6,6 @@
 """
 
 import logging
-import os
-import threading
 
 from pynetdicom import AE, StoragePresentationContexts, evt
 from pynetdicom.sop_class import ModalityWorklistInformationFind  # type: ignore[attr-defined]
@@ -113,48 +111,3 @@ def stop(self):
         if self.ae:
             logger.info("Stopping MWL server")
             self.ae.shutdown()
-
-
-def main():
-    """Main entry point for PACS and MWL servers."""
-    logging.basicConfig(
-        level=os.getenv("LOG_LEVEL", "INFO").upper(),
-        format=os.getenv("LOG_FORMAT", "%(asctime)s - %(name)s - %(levelname)s - %(message)s"),
-    )
-
-    # PACS configuration
-    pacs_aet = os.getenv("PACS_AET", "SCREENING_PACS")
-    pacs_port = int(os.getenv("PACS_PORT", "4244"))
-    pacs_storage_path = os.getenv("PACS_STORAGE_PATH", "/var/lib/pacs/storage")
-    pacs_db_path = os.getenv("PACS_DB_PATH", "/var/lib/pacs/pacs.db")
-
-    # MWL configuration
-    mwl_aet = os.getenv("MWL_AET", "MWL_SCP")
-    mwl_port = int(os.getenv("MWL_PORT", "4243"))
-    mwl_db_path = os.getenv("MWL_DB_PATH", "/var/lib/pacs/worklist.db")
-
-    # Create servers with block=True - each runs in its own thread so they won't block each other
-    pacs_server = PACSServer(pacs_aet, pacs_port, pacs_storage_path, pacs_db_path, block=True)
-    mwl_server = MWLServer(mwl_aet, mwl_port, mwl_db_path, block=True)
-
-    # Start servers in separate threads
-    pacs_thread = threading.Thread(target=pacs_server.start, name="PACSServer", daemon=True)
-    mwl_thread = threading.Thread(target=mwl_server.start, name="MWLServer", daemon=True)
-
-    pacs_thread.start()
-    mwl_thread.start()
-
-    logger.info("Both PACS and MWL servers started")
-
-    try:
-        # Keep main thread alive
-        pacs_thread.join()
-        mwl_thread.join()
-    except KeyboardInterrupt:
-        logger.info("Received shutdown signal")
-        pacs_server.stop()
-        mwl_server.stop()
-
-
-if __name__ == "__main__":
-    main()