feat: Introduce logging context to Tangle

api_server_main.py

@@ -5,21 +5,31 @@
 
 from cloud_pipelines_backend import api_router
 from cloud_pipelines_backend import database_ops
+from cloud_pipelines_backend.instrumentation.request_middleware import RequestContextMiddleware
+from cloud_pipelines_backend.instrumentation import logging_context
 
 app = fastapi.FastAPI(
     title="Cloud Pipelines API",
     version="0.0.1",
     separate_input_output_schemas=False,
 )
 
+# Add request context middleware for automatic request_id generation
+app.add_middleware(RequestContextMiddleware)
+
 
 @app.exception_handler(Exception)
 def handle_error(request: fastapi.Request, exc: BaseException):
     exception_str = traceback.format_exception(type(exc), exc, exc.__traceback__)
-    return fastapi.responses.JSONResponse(
+    response = fastapi.responses.JSONResponse(
         status_code=503,
         content={"exception": exception_str},
     )
+    # Add request_id to error responses for traceability
+    request_id = logging_context.get_context_metadata("request_id")
+    if request_id:
+        response.headers["x-tangle-request-id"] = request_id
+    return response
 
 
 DEFAULT_DATABASE_URI = "sqlite:///db.sqlite"

cloud_pipelines_backend/api_router.py

@@ -15,6 +15,7 @@
 from . import component_library_api_server as components_api
 from . import database_ops
 from . import errors
+from .instrumentation import logging_context
 
 if typing.TYPE_CHECKING:
     from .launchers import interfaces as launcher_interfaces
@@ -95,17 +96,27 @@ def _setup_routes_internal(
 
     @app.exception_handler(errors.ItemNotFoundError)
     def handle_not_found_error(request: fastapi.Request, exc: errors.ItemNotFoundError):
-        return fastapi.responses.JSONResponse(
+        response = fastapi.responses.JSONResponse(
             status_code=404,
             content={"message": str(exc)},
         )
+        # Add request_id to error responses for traceability
+        request_id = logging_context.get_context_metadata("request_id")
+        if request_id:
+            response.headers["x-tangle-request-id"] = request_id
+        return response
 
     @app.exception_handler(errors.PermissionError)
     def handle_permission_error(request: fastapi.Request, exc: errors.PermissionError):
-        return fastapi.responses.JSONResponse(
+        response = fastapi.responses.JSONResponse(
             status_code=403,
             content={"message": str(exc)},
         )
+        # Add request_id to error responses for traceability
+        request_id = logging_context.get_context_metadata("request_id")
+        if request_id:
+            response.headers["x-tangle-request-id"] = request_id
+        return response
 
     get_user_details_dependency = fastapi.Depends(user_details_getter)
 

cloud_pipelines_backend/instrumentation/logging_context.py

@@ -0,0 +1,111 @@
+"""Logging context management for distributed tracing and execution tracking.
+
+This module provides utilities for managing arbitrary metadata in the logging context.
+This metadata is automatically added to all log records for better filtering and correlation.
+
+Common metadata keys:
+- request_id: From API requests - groups all logs from a single API call
+- pipeline_run_id: From PipelineRun.id - tracks the entire pipeline run
+- execution_id: From ExecutionNode.id - tracks individual execution nodes
+- container_execution_id: From ContainerExecution.id - tracks running containers
+- user_id: User who initiated the operation
+- Any other metadata you want to track in logs
+
+Usage:
+    # Set metadata in context
+    with logging_context(request_id="abc123", user_id="user@example.com"):
+        logger.info("Processing")  # Both fields in logs
+"""
+
+import contextvars
+from contextlib import contextmanager
+from typing import Any, Optional
+
+
+# Single context variable to store all metadata as a dictionary
+_context_metadata: contextvars.ContextVar[dict[str, Any]] = contextvars.ContextVar(
+    "context_metadata", default={}
+)
+
+
+def set_context_metadata(key: str, value: Any) -> None:
+    """Set a metadata value in the current context.
+
+    Args:
+        key: The metadata key (e.g., 'execution_id', 'request_id', 'user_id')
+        value: The value to set
+    """
+    metadata = _context_metadata.get().copy()
+    metadata[key] = value
+    _context_metadata.set(metadata)
+
+
+def get_context_metadata(key: str) -> Optional[Any]:
+    """Get a metadata value from the current context.
+
+    Args:
+        key: The metadata key to retrieve
+
+    Returns:
+        The metadata value or None if not set
+    """
+    return _context_metadata.get().get(key)
+
+
+def get_all_context_metadata() -> dict[str, Any]:
+    """Get all metadata from the current context.
+
+    Returns:
+        Dictionary of all context metadata
+    """
+    return _context_metadata.get().copy()
+
+
+def clear_context_metadata() -> None:
+    """Clear all metadata from the current context."""
+    _context_metadata.set({})
+
+
+@contextmanager
+def logging_context(**metadata: Any):
+    """Context manager for setting arbitrary metadata that is automatically cleared.
+
+    This is the recommended way to set logging context. It ensures metadata is
+    always cleaned up, even if an exception occurs.
+
+    You can pass any keyword arguments, and they will be available in log records.
+    Common keys include: request_id, pipeline_run_id, execution_id, container_execution_id, user_id
+
+    Args:
+        **metadata: Arbitrary keyword arguments to add to the context
+
+    Example with IDs:
+        >>> with logging_context(pipeline_run_id="run123", execution_id="exec456"):
+        ...     logger.info("Processing execution")  # Will include both IDs
+
+    Example with custom metadata:
+        >>> with logging_context(
+        ...     execution_id="exec456",
+        ...     user_id="user@example.com",
+        ...     operation="reprocessing"
+        ... ):
+        ...     logger.info("Custom operation")  # All metadata in logs
+
+    Example for API requests:
+        >>> request_id = generate_request_id()
+        >>> with logging_context(request_id=request_id):
+        ...     logger.info("Handling API request")
+    """
+    # Store previous metadata to restore nested contexts
+    prev_metadata = get_all_context_metadata()
+
+    try:
+        # Set all provided metadata
+        for key, value in metadata.items():
+            if value is not None:  # Only set non-None values
+                set_context_metadata(key, value)
+        yield
+    finally:
+        # Restore previous metadata
+        _context_metadata.set(prev_metadata)
+

cloud_pipelines_backend/instrumentation/request_middleware.py

@@ -0,0 +1,64 @@
+"""Request context middleware for FastAPI applications.
+
+This middleware automatically generates a request_id for each incoming HTTP request,
+sets it in the logging context for the duration of the request, and includes it in
+the response headers.
+"""
+
+import logging
+import secrets
+
+from starlette.middleware.base import BaseHTTPMiddleware
+from starlette.requests import Request
+from starlette.responses import Response
+
+from . import logging_context
+
+logger = logging.getLogger(__name__)
+
+
+def generate_request_id() -> str:
+    """Generate a new request ID compatible with OpenTelemetry format.
+
+    OpenTelemetry trace IDs are 16-byte (128-bit) values represented as 
+    32 hexadecimal characters (lowercase). We use the same format for
+    request IDs to maintain compatibility.
+
+    Returns:
+        A 32-character hexadecimal string representing the request ID
+    """
+    return secrets.token_hex(16)
+
+
+class RequestContextMiddleware(BaseHTTPMiddleware):
+    """Middleware to manage request_id for each request.
+
+    For each incoming request:
+    1. Generates a new request_id (32-character hex string)
+    2. Sets it in the logging context (as 'request_id' key)
+    3. Adds it to the response headers as 'x-tangle-request-id'
+    4. Clears it after the request completes
+
+    This ensures all logs during the request processing include the same request_id.
+    """
+
+    async def dispatch(self, request: Request, call_next) -> Response:
+        """Process each request with a new request_id.
+
+        Args:
+            request: The incoming HTTP request
+            call_next: The next middleware or route handler
+
+        Returns:
+            The HTTP response with request_id in headers
+        """
+        # Generate a new request_id for this request
+        request_id = generate_request_id()
+
+        # Use generic logging_context to set request_id
+        with logging_context.logging_context(request_id=request_id):
+            # Process the request
+            response = await call_next(request)
+            # Add request_id to response headers for client reference
+            response.headers["x-tangle-request-id"] = request_id
+            return response