Refactor validate_event into helper, use issubset method

unicorn_contracts/src/contracts_service/create_contract.py

@@ -11,13 +11,11 @@
 
 from contracts_service.contract_status import ContractStatus
 from contracts_service.exceptions import EventValidationException
-from contracts_service.helper import get_current_date, get_event_body, publish_event
+from contracts_service.helper import get_current_date, get_event_body, validate_event, publish_event, get_env
 
 # Initialise Environment variables
-if (SERVICE_NAMESPACE := os.environ.get("SERVICE_NAMESPACE")) is None:
-    raise EnvironmentError("SERVICE_NAMESPACE environment variable is undefined")
-if (DYNAMODB_TABLE := os.environ.get("DYNAMODB_TABLE")) is None:
-    raise EnvironmentError("DYNAMODB_TABLE environment variable is undefined")
+SERVICE_NAMESPACE = get_env("SERVICE_NAMESPACE")
+DYNAMODB_TABLE = get_env("DYNAMODB_TABLE")
 
 # Initialise PowerTools
 logger: Logger = Logger()
@@ -50,7 +48,7 @@ def lambda_handler(event, context):
     """
     # Get contract and property details from the event
     try:
-        event_json = validate_event(event)
+        event_json = validate_event(event, {"property_id", "address", "seller_name"})
     except EventValidationException as ex:
         return ex.apigw_return
 
@@ -98,37 +96,3 @@ def create_contract(contract) -> dict:
     """
     # TODO: create entry in DDB for new contract
     return table.put_item(Item=contract,)
-
-
-@tracer.capture_method
-def validate_event(event):
-    """Validates the body of the API Gateway event
-
-    Parameters
-    ----------
-    event : dict
-        API Gateway event
-
-    Returns
-    -------
-    dict
-        The body of the API
-
-    Raises
-    ------
-    EventValidationException
-        The ``Raises`` section is a list of all exceptions
-        that are relevant to the interface.
-    """
-
-    try:
-        event_json = get_event_body(event)
-    except Exception as ex:
-        logger.exception(ex)
-        raise EventValidationException() from ex
-
-    for i in ["property_id", "address", "seller_name"]:
-        if i not in event_json.keys():
-            raise EventValidationException()
-
-    return event_json

unicorn_contracts/src/contracts_service/helper.py

@@ -124,3 +124,43 @@ def publish_event(contract, request_id):
                 }
             ]
         )
+
+@tracer.capture_method
+def validate_event(event, required_keys):
+    """Validates the body of the API Gateway event
+
+    Parameters
+    ----------
+    event : dict
+        API Gateway event
+    required_keys: set
+        Set of required field names
+
+    Returns
+    -------
+    dict
+        The body of the API
+
+    Raises
+    ------
+    EventValidationException
+        The ``Raises`` section is a list of all exceptions
+        that are relevant to the interface.
+    """
+
+    try:
+        event_json = get_event_body(event)
+    except Exception as ex:
+        logger.exception(ex)
+        raise EventValidationException() from ex
+
+    if not required_keys.issubset(event_json.keys()):
+        raise EventValidationException()
+
+    return event_json
+
+def get_env(name):
+  try:
+    return os.environ[name]
+  except KeyError:
+    raise EnvironmentError("%s environment variable is undefined" % name)

unicorn_contracts/src/contracts_service/update_contract.py

@@ -13,14 +13,11 @@
 from contracts_service.contract_status import ContractStatus
 from contracts_service.exceptions import (ContractNotFoundException,
                                   EventValidationException)
-from contracts_service.helper import get_current_date, get_event_body, publish_event
+from contracts_service.helper import get_current_date, get_event_body, publish_event, validate_event, get_env
 
 # Initialise Environment variables
-if (SERVICE_NAMESPACE := os.environ.get("SERVICE_NAMESPACE")) is None:
-    raise EnvironmentError("SERVICE_NAMESPACE environment variable is undefined")
-
-if (DYNAMODB_TABLE := os.environ.get("DYNAMODB_TABLE")) is None:
-    raise EnvironmentError("DYNAMODB_TABLE environment variable is undefined")
+SERVICE_NAMESPACE = get_env("SERVICE_NAMESPACE")
+DYNAMODB_TABLE = get_env("DYNAMODB_TABLE")
 
 # Initialise PowerTools
 logger: Logger = Logger()
@@ -53,7 +50,7 @@ def lambda_handler(event, context):
 
     # Get contract and property details from the event
     try:
-        event_json = validate_event(event)
+        event_json = validate_event(event, {"property_id"})
     except EventValidationException as ex:
         return ex.apigw_return
 
@@ -155,36 +152,3 @@ def get_existing_contract(property_id: str) -> dict:
         raise error
     except KeyError as _:
         raise ContractNotFoundException() from _
-
-
-@tracer.capture_method
-def validate_event(event):
-    """Validates the body of the API Gateway event
-
-    Parameters
-    ----------
-    event : dict
-        API Gateway event
-
-    Returns
-    -------
-    dict
-        The body of the API
-
-    Raises
-    ------
-    EventValidationException
-        The ``Raises`` section is a list of all exceptions
-        that are relevant to the interface.
-    """
-    try:
-        event_json = get_event_body(event)
-    except Exception as ex:
-        logger.exception(ex)
-        raise EventValidationException() from ex
-
-    for i in ["property_id"]:
-        if i not in event_json.keys():
-            raise EventValidationException()
-
-    return event_json