147 lines
4.5 KiB
Python
147 lines
4.5 KiB
Python
from aws_lambda_powertools.event_handler.api_gateway import (
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APIGatewayHttpResolver,
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Response,
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)
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from aws_lambda_powertools.event_handler.middlewares import (
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BaseMiddlewareHandler,
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NextMiddleware,
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)
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from aws_lambda_powertools.shared.functions import (
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extract_event_from_common_models,
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)
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from layercake.dateutils import now, ttl
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from layercake.dynamodb import ComposeKey, DynamoDBCollection, KeyPair
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from layercake.funcs import pick
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from pydantic import UUID4, BaseModel, EmailStr, Field
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from auth import AuthFlowType
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LOG_RETENTION_DAYS = 365 * 2 # 2 years
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class User(BaseModel):
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id: str
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name: str
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email: EmailStr
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class CognitoUser(User):
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id: str = Field(alias='custom:user_id')
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email_verified: bool
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sub: UUID4
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class AuthorizerMiddleware(BaseMiddlewareHandler):
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def handler(
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self,
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app: APIGatewayHttpResolver,
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next_middleware: NextMiddleware,
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) -> Response:
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# Gets the Lambda authorizer associated with the current API Gateway event.
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# You can check the file `auth.py` for more details.
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context = app.current_event.request_context.authorizer.get_lambda
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auth_flow_type = context.get('auth_flow_type')
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if not auth_flow_type:
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return next_middleware(app)
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cls = {
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AuthFlowType.USER_AUTH: CognitoUser,
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AuthFlowType.API_AUTH: User,
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}.get(auth_flow_type)
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if cls:
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app.append_context(user=cls(**context['user']))
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return next_middleware(app)
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class TenantMiddleware(BaseMiddlewareHandler):
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def handler(
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self,
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app: APIGatewayHttpResolver,
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next_middleware: NextMiddleware,
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) -> Response:
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context = app.current_event.request_context.authorizer.get_lambda
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tenant = app.current_event.headers.get('x-tenant')
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auth_flow_type = context.get('auth_flow_type')
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match auth_flow_type, tenant:
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case AuthFlowType.API_AUTH, None:
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app.append_context(tenant=context['tenant'])
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case AuthFlowType.USER_AUTH, str():
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print(tenant)
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return next_middleware(app)
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class AuditLogMiddleware(BaseMiddlewareHandler):
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"""This middleware logs audit details for successful requests, storing user,
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action, and IP info with a specified retention period.
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Parameters
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----------
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action : str
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The identifier for the audit log action.
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collect : DynamoDBCollection
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The collection instance used to persist the audit log data.
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audit_attrs : tuple of str, optional
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A tuple of attribute names to extract from the response body for logging.
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These represent the specific fields to include in the audit log.
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retention_days : int or None, optional
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The number of days the log is retained on the server.
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If None, no time-to-live (TTL) will be applied.
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"""
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def __init__(
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self,
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action: str,
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/,
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collect: DynamoDBCollection,
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audit_attrs: tuple[str, ...] = (),
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retention_days: int | None = LOG_RETENTION_DAYS,
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) -> None:
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self.action = action
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self.collect = collect
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self.audit_attrs = audit_attrs
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self.retention_days = retention_days
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def handler(
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self,
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app: APIGatewayHttpResolver,
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next_middleware: NextMiddleware,
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) -> Response:
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user = app.context.get('user')
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req_context = app.current_event.request_context
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ip_addr = req_context.http.source_ip
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response = next_middleware(app)
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# Successful response
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# https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Status#successful_responses
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if 200 <= response.status_code < 300 and user:
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now_ = now()
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data = (
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pick(self.audit_attrs, extract_event_from_common_models(response.body))
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if response.is_json()
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else None
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)
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retention_days = (
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ttl(start_dt=now_, days=self.retention_days)
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if self.retention_days
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else None
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)
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self.collect.put_item(
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key=KeyPair(
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# Post-migration: remove `delimiter` from ComposeKey.
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pk=ComposeKey(user.id, prefix='logs', delimiter=':'),
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sk=now_.isoformat(),
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),
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action=self.action,
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data=data,
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ip=ip_addr,
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ttl=retention_days,
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)
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return response
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