feat: add debug mode to control file logging (#11)

Author: RezwanM

src/mcpcat/__init__.py

@@ -11,7 +11,7 @@
 
 from .modules.compatibility import is_compatible_server, is_fastmcp_server
 from .modules.internal import set_server_tracking_data
-from .modules.logging import write_to_log
+from .modules.logging import write_to_log, set_debug_mode
 from .types import (
     MCPCatData,
     MCPCatOptions,
@@ -43,6 +43,9 @@ def track(
     if options is None:
         options = MCPCatOptions()
 
+    # Update global debug_mode value
+    set_debug_mode(options.debug_mode)
+
     # Validate configuration
     if not project_id and not options.exporters:
         raise ValueError(

src/mcpcat/modules/logging.py

@@ -3,6 +3,22 @@
 import os
 from datetime import datetime, timezone
 
+from mcpcat.types import MCPCatOptions
+
+
+# Initialize debug_mode from environment variable at module load time
+_env_debug = os.getenv("MCPCAT_DEBUG_MODE")
+if _env_debug is not None:
+    debug_mode = _env_debug.lower() in ("true", "1", "yes", "on")
+else:
+    debug_mode = False
+
+
+def set_debug_mode(value: bool) -> None:
+    """Set the global debug_mode value."""
+    global debug_mode
+    debug_mode = value
+
 
 def write_to_log(message: str) -> None:
     timestamp = datetime.now(timezone.utc).isoformat()
@@ -12,9 +28,10 @@ def write_to_log(message: str) -> None:
     log_path = os.path.expanduser("~/mcpcat.log")
 
     try:
-        # Write to log file (no need to ensure directory exists for home directory)
-        with open(log_path, "a") as f:
-            f.write(log_entry)
+        if debug_mode:
+            # Write to log file (no need to ensure directory exists for home directory)
+            with open(log_path, "a") as f:
+                f.write(log_entry)
     except Exception:
         # Silently fail - we don't want logging errors to break the server
         pass

src/mcpcat/types.py

@@ -122,6 +122,8 @@ class MCPCatOptions:
     identify: IdentifyFunction | None = None
     redact_sensitive_information: RedactionFunction | None = None
     exporters: dict[str, ExporterConfig] | None = None
+    debug_mode: bool = False
+
 
 
 @dataclass

tests/test_logging.py

@@ -8,7 +8,7 @@
 
 import pytest
 
-from mcpcat.modules.logging import write_to_log
+from mcpcat.modules.logging import write_to_log, set_debug_mode
 
 
 class TestLogging:
@@ -31,6 +31,38 @@ def cleanup_log_file(self):
 
     def test_write_to_log_creates_file(self, tmp_path):
         """Test that write_to_log creates the log file if it doesn't exist."""
+        # Enable debug mode
+        set_debug_mode(True)
+
+        # Use a unique file name for this test
+        unique_id = str(uuid.uuid4())
+        log_file = tmp_path / f"test_mcpcat_{unique_id}.log"
+
+        # Mock os.path.expanduser to use our temp file
+        with patch(
+            "mcpcat.modules.logging.os.path.expanduser", return_value=str(log_file)
+        ):
+            # Write a test message
+            test_message = f"Test log message {unique_id}"
+            write_to_log(test_message)
+
+            # Check that the file was created
+            assert log_file.exists(), "Log file was not created"
+
+            # Read the file content
+            content = log_file.read_text()
+
+            # Verify the message is in the file
+            assert test_message in content, "Log message not found in file"
+
+            # Verify timestamp format (ISO format)
+            assert "T" in content, "Timestamp not in ISO format"
+
+    def test_write_to_log_checks_debug_mode(self, tmp_path):
+        """Test that write_to_log writes to file when debug mode is enabled."""
+        # Enable debug mode
+        set_debug_mode(True)
+
         # Use a unique file name for this test
         unique_id = str(uuid.uuid4())
         log_file = tmp_path / f"test_mcpcat_{unique_id}.log"
@@ -55,8 +87,29 @@ def test_write_to_log_creates_file(self, tmp_path):
             # Verify timestamp format (ISO format)
             assert "T" in content, "Timestamp not in ISO format"
 
+        # Check that log file is not created when debug mode is disabled
+        set_debug_mode(False)
+
+        # Use a unique file name for this test
+        unique_id = str(uuid.uuid4())
+        log_file = tmp_path / f"test_mcpcat_{unique_id}.log"
+
+        # Mock os.path.expanduser to use our temp file
+        with patch(
+            "mcpcat.modules.logging.os.path.expanduser", return_value=str(log_file)
+        ):
+            # Write a test message
+            test_message = f"Test log message {unique_id}"
+            write_to_log(test_message)
+
+            # Check that the file was created
+            assert not log_file.exists(), "Log file was wrongly created"
+
     def test_write_to_log_appends_messages(self, tmp_path):
         """Test that write_to_log appends to existing log file."""
+        # Enable debug mode
+        set_debug_mode(True)
+
         # Use a unique file name for this test
         unique_id = str(uuid.uuid4())
         log_file = tmp_path / f"test_mcpcat_{unique_id}.log"
@@ -105,6 +158,9 @@ def test_write_to_log_appends_messages(self, tmp_path):
 
     def test_write_to_log_handles_directory_creation(self, tmp_path):
         """Test that write_to_log creates parent directories if needed."""
+        # Enable debug mode
+        set_debug_mode(True)
+
         # Use a unique file name for this test
         unique_id = str(uuid.uuid4())
         log_file = tmp_path / f"test_mcpcat_{unique_id}.log"
@@ -123,6 +179,9 @@ def test_write_to_log_handles_directory_creation(self, tmp_path):
 
     def test_write_to_log_silently_handles_errors(self, tmp_path, monkeypatch):
         """Test that write_to_log doesn't raise exceptions on errors."""
+        # Enable debug mode
+        set_debug_mode(True)
+
         # Use a unique file name for this test
         unique_id = str(uuid.uuid4())
         log_file = tmp_path / f"test_mcpcat_{unique_id}.log"
@@ -146,6 +205,9 @@ def test_write_to_log_silently_handles_errors(self, tmp_path, monkeypatch):
 
     def test_log_format(self, tmp_path):
         """Test the format of log entries."""
+        # Enable debug mode
+        set_debug_mode(True)
+        
         # Use a unique file name for this test
         unique_id = str(uuid.uuid4())
         log_file = tmp_path / f"test_mcpcat_{unique_id}.log"