feat(cli): Add log level configuration with flag and environment variable.

- Add --log-level flag with LEGGEN_LOG_LEVEL environment variable support
- Configure loguru to respect log level setting across the application
- Pass log level to uvicorn server for consistent logging
- Log GoCardless API responses and transaction data at debug level
- Supported levels: TRACE, DEBUG, INFO, WARNING, ERROR, CRITICAL

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

leggen/commands/server.py

@@ -133,12 +133,14 @@ def create_app() -> FastAPI:
 def server(ctx: click.Context, reload: bool, host: str, port: int):
     """Start the Leggen API server"""
 
-    # Get config_dir and database from main CLI context
+    # Get config_dir, database, and log_level from main CLI context
     config_dir = None
     database = None
+    log_level = "info"
     if ctx.parent:
         config_dir = ctx.parent.params.get("config_dir")
         database = ctx.parent.params.get("database")
+        log_level = ctx.parent.params.get("log_level", "info").lower()
 
     # Set up path manager with user-provided paths
     if config_dir:
@@ -153,7 +155,7 @@ def server(ctx: click.Context, reload: bool, host: str, port: int):
             factory=True,
             host=host,
             port=port,
-            log_level="info",
+            log_level=log_level,
             access_log=True,
             reload=True,
             reload_dirs=["leggen"],  # Watch leggen directory
@@ -164,6 +166,6 @@ def server(ctx: click.Context, reload: bool, host: str, port: int):
             app,
             host=host,
             port=port,
-            log_level="info",
+            log_level=log_level,
             access_log=True,
         )

leggen/main.py

@@ -4,6 +4,7 @@ from gettext import gettext as _
 from pathlib import Path
 
 import click
+from loguru import logger
 
 from leggen.utils.config import load_config
 from leggen.utils.paths import path_manager
@@ -109,13 +110,25 @@ class Group(click.Group):
     show_envvar=True,
     help="URL of the leggen API service",
 )
+@click.option(
+    "--log-level",
+    type=click.Choice(
+        ["TRACE", "DEBUG", "INFO", "WARNING", "ERROR", "CRITICAL"], case_sensitive=False
+    ),
+    default="INFO",
+    envvar="LEGGEN_LOG_LEVEL",
+    show_envvar=True,
+    help="Set the logging level",
+)
 @click.group(
     cls=Group,
     context_settings={"help_option_names": ["-h", "--help"]},
 )
 @click.version_option(package_name="leggen")
 @click.pass_context
-def cli(ctx: click.Context, config_dir: Path, database: Path, api_url: str):
+def cli(
+    ctx: click.Context, config_dir: Path, database: Path, api_url: str, log_level: str
+):
     """
     Leggen: An Open Banking CLI
     """
@@ -124,11 +137,20 @@ def cli(ctx: click.Context, config_dir: Path, database: Path, api_url: str):
     if "--help" in sys.argv[1:] or "-h" in sys.argv[1:]:
         return
 
+    # Configure loguru log level
+    logger.remove()  # Remove default handler
+    logger.add(
+        sys.stderr,
+        level=log_level.upper(),
+        format="<green>{time:YYYY-MM-DD HH:mm:ss}</green> | <level>{level: <8}</level> | <cyan>{name}</cyan>:<cyan>{function}</cyan>:<cyan>{line}</cyan> - <level>{message}</level>",
+    )
+
     # Set up path manager with user-provided paths
     if config_dir:
         path_manager.set_config_dir(config_dir)
     if database:
         path_manager.set_database_path(database)
 
-    # Store API URL in context for commands to use
+    # Store API URL and log level in context for commands to use
     ctx.obj["api_url"] = api_url
+    ctx.obj["log_level"] = log_level.lower()

leggen/services/data_processors/transaction_processor.py

@@ -1,6 +1,8 @@
 from datetime import datetime
 from typing import Any, Dict, List
 
+from loguru import logger
+
 
 class TransactionProcessor:
     """Handles processing and transformation of raw transaction data"""
@@ -13,6 +15,7 @@ class TransactionProcessor:
     ) -> List[Dict[str, Any]]:
         """Process raw transaction data into standardized format"""
         transactions = []
+        logger.debug(transaction_data)
 
         # Process booked transactions
         for transaction in transaction_data.get("transactions", {}).get("booked", []):

leggen/services/gocardless_service.py

@@ -57,7 +57,9 @@ class GoCardlessService:
                 _log_rate_limits(response, method, url)
 
             response.raise_for_status()
-            return response.json()
+            response_data = response.json()
+            logger.debug(f"{method} {url} response: {response_data}")
+            return response_data
 
     async def _get_auth_headers(self) -> Dict[str, str]:
         """Get authentication headers for GoCardless API"""