feat: log download endpoints

ref: N25B-401

.logging_config.yaml

@@ -48,6 +48,7 @@ handlers:
     class: control_backend.logging.DatedFileHandler
     formatter: experiment
     filters: [partial]
+    # Directory must match config.logging_settings.experiment_log_directory
     file_prefix: experiment_logs/experiment
 
 # Level for external libraries
@@ -59,6 +60,6 @@ loggers:
   control_backend:
     level: LLM
     handlers: [ui]
-  experiment:
+  experiment:  # This name must match config.logging_settings.experiment_logger_name
     level: DEBUG
     handlers: [ui, file]

src/control_backend/api/v1/endpoints/logs.py

@@ -1,8 +1,9 @@
 import logging
+from pathlib import Path
 
 import zmq
-from fastapi import APIRouter
+from fastapi import APIRouter, HTTPException
-from fastapi.responses import StreamingResponse
+from fastapi.responses import FileResponse, StreamingResponse
 from zmq.asyncio import Context
 
 from control_backend.core.config import settings
@@ -38,3 +39,29 @@ async def log_stream():
             yield f"data: {message}\n\n"
 
     return StreamingResponse(gen(), media_type="text/event-stream")
+
+
+LOGGING_DIR = Path(settings.logging_settings.experiment_log_directory).resolve()
+
+
+@router.get("/logs/files")
+@router.get("/api/logs/files")
+async def log_directory():
+    """
+    Get a list of all log files stored in the experiment log file directory.
+    """
+    return [f.name for f in LOGGING_DIR.glob("*.log")]
+
+
+@router.get("/logs/files/{filename}")
+@router.get("/api/logs/files/{filename}")
+async def log_file(filename: str):
+    # Prevent path-traversal
+    file_path = (LOGGING_DIR / filename).resolve()  # This .resolve() is important
+    if not file_path.is_relative_to(LOGGING_DIR):
+        raise HTTPException(status_code=400, detail="Invalid filename.")
+
+    if not file_path.is_file():
+        raise HTTPException(status_code=404, detail="File not found.")
+
+    return FileResponse(file_path, filename=file_path.name)

src/control_backend/core/config.py

@@ -147,10 +147,12 @@ class LoggingSettings(BaseModel):
     Configuration for logging.
 
     :ivar logging_config_file: Path to the logging configuration file.
-    :ivar experiment_logger_name: Name of the experiment logger, should match the logging config.
+    :ivar experiment_log_directory: Location of the experiment logs. Must match the logging config.
+    :ivar experiment_logger_name: Name of the experiment logger. Must match the logging config.
     """
 
     logging_config_file: str = ".logging_config.yaml"
+    experiment_log_directory: str = "experiment_logs"
     experiment_logger_name: str = "experiment"