84 lines
2.5 KiB
Python
84 lines
2.5 KiB
Python
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"""
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Request ID Middleware for distributed tracing
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Generates and propagates unique request IDs across all services
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"""
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import uuid
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import structlog
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from fastapi import Request
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from starlette.middleware.base import BaseHTTPMiddleware
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from starlette.responses import Response
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from app.core.header_manager import header_manager
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logger = structlog.get_logger()
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class RequestIDMiddleware(BaseHTTPMiddleware):
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"""
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Middleware to generate and propagate request IDs for distributed tracing.
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Request IDs are:
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- Generated if not provided by client
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- Logged with every request
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- Propagated to all downstream services
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- Returned in response headers
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"""
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def __init__(self, app):
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super().__init__(app)
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async def dispatch(self, request: Request, call_next) -> Response:
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"""Process request with request ID tracking"""
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# Extract or generate request ID
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request_id = request.headers.get("X-Request-ID")
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if not request_id:
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request_id = str(uuid.uuid4())
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# Store in request state for access by routes
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request.state.request_id = request_id
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# Bind request ID to structured logger context
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logger_ctx = logger.bind(request_id=request_id)
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# Inject request ID header for downstream services using HeaderManager
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# Note: This runs early in middleware chain, so we use add_header_for_middleware
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header_manager.add_header_for_middleware(request, "x-request-id", request_id)
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# Log request start
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logger_ctx.info(
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"Request started",
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method=request.method,
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path=request.url.path,
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client_ip=request.client.host if request.client else None
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)
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try:
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# Process request
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response = await call_next(request)
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# Add request ID to response headers
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response.headers["X-Request-ID"] = request_id
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# Log request completion
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logger_ctx.info(
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"Request completed",
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method=request.method,
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path=request.url.path,
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status_code=response.status_code
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)
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return response
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except Exception as e:
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# Log request failure
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logger_ctx.error(
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"Request failed",
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method=request.method,
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path=request.url.path,
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error=str(e),
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error_type=type(e).__name__
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)
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raise
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