From 5d969709de939f29c16ee1db87aff5a84245576d Mon Sep 17 00:00:00 2001
From: Anamandla <anamandla38@gmail.com>
Date: Mon, 8 Jun 2026 14:16:39 +0200
Subject: [PATCH] feat: add structured JSON logging using structlog (closes
 #19)

---
 Assignment 12/api/logging_config.py           | 23 +++++++++++++++++++
 Assignment 12/handlers/routes/transactions.py | 15 ++++++++++++
 2 files changed, 38 insertions(+)
 create mode 100644 Assignment 12/api/logging_config.py

diff --git a/Assignment 12/api/logging_config.py b/Assignment 12/api/logging_config.py
new file mode 100644
index 0000000..ff0fb73
--- /dev/null
+++ b/Assignment 12/api/logging_config.py	
@@ -0,0 +1,23 @@
+import structlog
+import logging
+import sys
+
+def configure_logging():
+    """Configure structlog for JSON output to stdout."""
+
+    structlog.configure(
+        processors=[
+            structlog.stdlib.add_log_level,
+            structlog.stdlib.add_logger_name,
+            structlog.processors.TimeStamper(fmt="iso"),
+            structlog.processors.StackInfoRenderer(),
+            structlog.processors.format_exc_info,
+            structlog.processors.JSONRenderer(),
+        ],
+        wrapper_class=structlog.stdlib.BoundLogger,
+        context_class=dict,
+        logger_factory=structlog.PrintLoggerFactory(file=sys.stdout),
+    )
+
+def get_logger(name: str = __name__):
+    return structlog.get_logger(name)
\ No newline at end of file
diff --git a/Assignment 12/handlers/routes/transactions.py b/Assignment 12/handlers/routes/transactions.py
index 5707a79..d6d935e 100644
--- a/Assignment 12/handlers/routes/transactions.py	
+++ b/Assignment 12/handlers/routes/transactions.py	
@@ -32,6 +32,9 @@
     DuplicateEntityError, BusinessRuleViolationError,
     InvalidStateTransitionError,
 )
+from api.logging_config import get_logger
+
+logger = get_logger("sentinelpay.transactions")
 
 router = APIRouter(prefix="/api/transactions", tags=["Transactions"])
 
@@ -45,6 +48,7 @@ def _handle_service_errors(exc: Exception) -> HTTPException:
         return HTTPException(status_code=422, detail=str(exc))
     if isinstance(exc, InvalidStateTransitionError):
         return HTTPException(status_code=409, detail=str(exc))
+    logger.error("unhandled_error", error=str(exc), exc_info=True)
     return HTTPException(status_code=500, detail=f"Internal error: {exc}")
 
 
@@ -82,6 +86,12 @@ def submit_transaction(
             longitude=body.longitude,
             is_international=body.is_international,
         )
+        logger.info(
+            "transaction_submitted",
+            transaction_id=str(txn.transaction_id),
+            amount=body.amount,
+            currency=body.currency,
+        )
         return TransactionResponse.from_domain(txn)
     except Exception as e:
         raise _handle_service_errors(e)
@@ -166,6 +176,11 @@ def apply_decision(
             model_scores=[s.model_dump() for s in body.model_scores],
             account_tier=body.account_tier,
         )
+        logger.info(
+            "fraud_decision_applied",
+            transaction_id=transaction_id,
+            fraud_score=body.fraud_score,
+        )
         return TransactionResponse.from_domain(txn)
     except Exception as e:
         raise _handle_service_errors(e)