Add tag router functionality for vCon processing

- Introduced a new tag router module that routes vCons to different Redis lists based on tags found in attachments.
- Implemented a run function that processes vCons, extracts tags, and logs routing actions.
- Added comprehensive unit tests to validate the tag routing behavior with various scenarios, including handling of missing tags and different tag formats.

Author: howethomas

server/links/tag_router/__init__.py

@@ -0,0 +1,88 @@
+from lib.logging_utils import init_logger
+from lib.vcon_redis import VconRedis
+from redis_mgr import redis
+
+logger = init_logger(__name__)
+
+default_options = {
+    # Dictionary mapping tags to target Redis lists
+    # e.g., {"important": "important_vcons", "urgent": "urgent_vcons"}
+    "tag_routes": {},
+    # Whether to continue normal processing after routing
+    "forward_original": True,
+}
+
+def run(vcon_uuid, link_name, opts=default_options):
+    """Tag Router link that routes vCons to different Redis lists based on tags in attachments.
+    
+    Args:
+        vcon_uuid: UUID of the vCon to process
+        link_name: Name of this link instance
+        opts: Link options containing:
+            tag_routes: Dictionary mapping tags to target Redis lists
+            forward_original: Whether to continue normal processing after routing
+            
+    Returns:
+        vcon_uuid if the vCon should continue normal processing, None otherwise
+    """
+    logger.debug(f"Starting {__name__}::run")
+
+    # Merge options
+    merged_opts = default_options.copy()
+    merged_opts.update(opts)
+    opts = merged_opts
+
+    # Get the vCon
+    vcon_redis = VconRedis()
+    vcon = vcon_redis.get_vcon(vcon_uuid)
+    if not vcon:
+        logger.error(f"Could not find vCon {vcon_uuid}")
+        return None
+
+    # Check if there are any tag routes configured
+    if not opts.get("tag_routes"):
+        logger.warning(f"No tag routes configured for {link_name}, skipping")
+        return vcon_uuid
+
+    # Extract all tags from attachments
+    tags = []
+    for attachment in vcon.attachments:
+        # Handle only plural "tags" format
+        if attachment['type'] == "tags" and 'body' in attachment:
+            if isinstance(attachment['body'], list):
+                # Process each tag string in the list
+                for tag_str in attachment['body']:
+                    if isinstance(tag_str, str) and ":" in tag_str:
+                        # Split on first colon to get tag name
+                        tag_name = tag_str.split(":", 1)[0]
+                        if tag_name:
+                            tags.append(tag_name)
+            elif isinstance(attachment['body'], dict):
+                # If body is a dict, use the keys as tags
+                for tag_name in attachment['body'].keys():
+                    if tag_name:
+                        tags.append(tag_name)
+    
+    if not tags:
+        logger.debug(f"No tags found in vCon {vcon_uuid}")
+        return vcon_uuid if opts.get("forward_original") else None
+
+    # Route the vCon to the appropriate Redis lists based on tags
+    routed = False
+    for tag in tags:
+        if tag in opts["tag_routes"]:
+            target_list = opts["tag_routes"][tag]
+            logger.info(f"Routing vCon {vcon_uuid} to list '{target_list}' based on tag '{tag}'")
+            # Push the vCon UUID to the target Redis list
+            redis.rpush(target_list, str(vcon_uuid))
+            routed = True
+        else:
+            logger.debug(f"No route configured for tag '{tag}'")
+    
+    if routed:
+        logger.info(f"Successfully routed vCon {vcon_uuid} based on tags")
+    else:
+        logger.info(f"No applicable routes found for vCon {vcon_uuid}")
+    
+    # Return based on forward_original setting
+    return vcon_uuid if opts.get("forward_original") else None