Handle missing FastAPI dependencies gracefully

README.md

@@ -137,6 +137,34 @@ For unstable multi-agent version, you also can run:
 python run_flow.py
 ```
 
+### Web interface (experimental)
+
+Before launching the server ensure the optional web dependencies are installed:
+
+```bash
+pip install fastapi uvicorn pydantic
+# or install everything from requirements.txt
+pip install -r requirements.txt
+```
+
+To try the browser-based experience, start the FastAPI server:
+
+```bash
+uvicorn app.web.server:app --reload
+```
+
+Then open <http://localhost:8000> to access the chat UI. Each browser tab keeps its
+own session and conversations are stored in memory while the server is running.
+
+Alternatively, you can launch the bundled runner which wraps `uvicorn`:
+
+```bash
+python -m app.web.server --host 0.0.0.0 --port 8000
+```
+
+Pass `--reload` for auto-reload in development environments.
+
+
 ### Custom Adding Multiple Agents
 
 Currently, besides the general OpenManus Agent, we have also integrated the DataAnalysis Agent, which is suitable for data analysis and data visualization tasks. You can add this agent to `run_flow` in `config.toml`.

app/logger.py

@@ -1,28 +1,70 @@
+import logging
 import sys
 from datetime import datetime
+from importlib.util import find_spec
+from pathlib import Path
 
-from loguru import logger as _logger
+PROJECT_ROOT = Path(__file__).resolve().parents[1]
 
-from app.config import PROJECT_ROOT
+
+if find_spec("loguru") is not None:
+    from loguru import logger as _logger  # type: ignore[import-not-found]
+
+    _loguru_available = True
+else:  # pragma: no cover - loguru expected in production environments
+    _loguru_available = False
+    _logger = logging.getLogger("app")
 
 
 _print_level = "INFO"
 
 
-def define_log_level(print_level="INFO", logfile_level="DEBUG", name: str = None):
-    """Adjust the log level to above level"""
+def define_log_level(
+    print_level: str = "INFO", logfile_level: str = "DEBUG", name: str | None = None
+):
+    """Configure the application logger with sane defaults.
+
+    Uses *loguru* when available for richer logging capabilities while
+    gracefully falling back to the standard :mod:`logging` module when the
+    dependency is missing (for example in lightweight environments).
+    """
+
     global _print_level
     _print_level = print_level
 
     current_date = datetime.now()
     formatted_date = current_date.strftime("%Y%m%d%H%M%S")
-    log_name = (
-        f"{name}_{formatted_date}" if name else formatted_date
-    )  # name a log with prefix name
+    log_name = f"{name}_{formatted_date}" if name else formatted_date
+
+    log_dir: Path = PROJECT_ROOT / "logs"
+    log_dir.mkdir(parents=True, exist_ok=True)
+
+    if _loguru_available:
+        _logger.remove()
+        _logger.add(sys.stderr, level=print_level)
+        _logger.add(log_dir / f"{log_name}.log", level=logfile_level)
+    else:
+        _logger.setLevel(getattr(logging, logfile_level.upper(), logging.DEBUG))
+
+        for handler in list(_logger.handlers):
+            _logger.removeHandler(handler)
+
+        formatter = logging.Formatter(
+            "%(asctime)s | %(levelname)s | %(name)s | %(message)s",
+            datefmt="%Y-%m-%d %H:%M:%S",
+        )
+
+        stream_handler = logging.StreamHandler(sys.stderr)
+        stream_handler.setLevel(getattr(logging, print_level.upper(), logging.INFO))
+        stream_handler.setFormatter(formatter)
+
+        file_handler = logging.FileHandler(log_dir / f"{log_name}.log")
+        file_handler.setLevel(getattr(logging, logfile_level.upper(), logging.DEBUG))
+        file_handler.setFormatter(formatter)
+
+        _logger.addHandler(stream_handler)
+        _logger.addHandler(file_handler)
 
-    _logger.remove()
-    _logger.add(sys.stderr, level=print_level)
-    _logger.add(PROJECT_ROOT / f"logs/{log_name}.log", level=logfile_level)
     return _logger