API Gateway - Error during return : Object of type datetime is not JSON serializable

What were you trying to accomplish?

I’m trying to return the list of quicksight dashboards via an api call.

Expected Behavior

Return the data

Current Behavior

Trace :

[ERROR] TypeError: Object of type datetime is not JSON serializable
Traceback (most recent call last):
  File "/var/task/aws_lambda_powertools/logging/logger.py", line 354, in decorate
    return lambda_handler(event, context)
  File "/var/task/app.py", line 15, in lambda_handler
    return app.resolve(event, context)
  File "/var/task/aws_lambda_powertools/event_handler/api_gateway.py", line 498, in resolve
    return self._resolve().build(self.current_event, self._cors)
  File "/var/task/aws_lambda_powertools/event_handler/api_gateway.py", line 557, in _resolve
    return self._call_route(route, match_results.groupdict())  # pass fn args
  File "/var/task/aws_lambda_powertools/event_handler/api_gateway.py", line 611, in _call_route
    return ResponseBuilder(self._to_response(route.func(**args)), route)
  File "/var/task/aws_lambda_powertools/event_handler/api_gateway.py", line 684, in _to_response
    body=self._json_dump(result),
  File "/var/task/aws_lambda_powertools/event_handler/api_gateway.py", line 688, in _json_dump
    return self._serializer(obj)
  File "/var/lang/lib/python3.9/json/__init__.py", line 234, in dumps
    return cls(
  File "/var/lang/lib/python3.9/json/encoder.py", line 199, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/var/lang/lib/python3.9/json/encoder.py", line 257, in iterencode
    return _iterencode(o, 0)
  File "/var/task/aws_lambda_powertools/shared/json_encoder.py", line 16, in default
    return super().default(obj)
  File "/var/lang/lib/python3.9/json/encoder.py", line 179, in default
    raise TypeError(f'Object of type {o.__class__.__name__} '

Possible Solution

Steps to Reproduce (for bugs)

Object that i try to return (result from : https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/quicksight.html#QuickSight.Client.list_dashboards)

{
   "ResponseMetadata":{
      "RequestId":"xxxxxxx",
      "HTTPStatusCode":200,
      "HTTPHeaders":{
         "date":"Wed, 30 Mar 2022 07:35:02 GMT",
         "content-type":"application/json",
         "content-length":"12119",
         "connection":"keep-alive",
         "x-amzn-requestid":"xxxx"
      },
      "RetryAttempts":0
   },
   "Status":200,
   "DashboardSummaryList":[
      {
         "Arn":"arn:aws:quicksight:eu-west-1:xxxxxx:dashboard/xxxxxx",
         "DashboardId":"079dfe29-8857-43b0-859c-4f1130ccab68",
         "Name":"xxxxxx",
         "CreatedTime":"2022-02-01 18:51:13.217000+00:00",
         "LastUpdatedTime":"2022-02-03 15:00:33.301000+00:00",
         "PublishedVersionNumber":4,
         "LastPublishedTime":"2022-02-01 18:51:13.217000+00:00"
      },
      {
         "Arn":"arn:aws:quicksight:eu-west-1:xxxxxx:dashboard/xxxxx",
         "DashboardId":"xxxx",
         "Name":"xxxx",
         "CreatedTime":"2022-02-02 13:33:32.003000+00:00",
         "LastUpdatedTime":"2022-02-02 13:41:15.952000+00:00",
         "PublishedVersionNumber":2,
         "LastPublishedTime":"2022-02-02 13:33:32.003000+00:00"
      },
      {
         "Arn":"arn:aws:quicksight:eu-west-1:xxxxx:dashboard/xxxxx",
         "DashboardId":"xxxxx",
         "Name":"xxxxxxx",
         "CreatedTime":"2021-04-20 15:30:05.956000+00:00",
         "LastUpdatedTime":"2021-04-20 16:08:14.600000+00:00",
         "PublishedVersionNumber":2,
         "LastPublishedTime":"2021-04-20 15:30:05.956000+00:00"
      }
   ],
   "RequestId":"b9474cf1-f20a-4e2e-8381-7c910c0405c5"
}

from aws_lambda_powertools import Logger
from aws_lambda_powertools.logging import correlation_paths
from aws_lambda_powertools.event_handler.api_gateway import ApiGatewayResolver, CORSConfig

from quicksight import list_dashboards, get_dashboard_embed_url

logger = Logger()
cors_config = CORSConfig(allow_origin="*", max_age=600, allow_credentials=True)
app = ApiGatewayResolver(cors=cors_config)


@logger.inject_lambda_context(correlation_id_path=correlation_paths.API_GATEWAY_REST)
def lambda_handler(event, context):
    logger.info(event)
    return app.resolve(event, context)


@app.get("/test-bug")
def get_list_dashboard():
    res = list_dashboards() 
    logger.info(res) # <----- Object just before
    return res

Environment

• Powertools version used: 1.25.5
• Packaging format (Layers, PyPi):
• AWS Lambda function runtime: 3.9 (Arm)
• Debugging logs

How to enable debug mode**

# paste logs here

[michaelbrewer]

@filol you could pass in your custom serializer to the api gateway resolver.

ie:

import json

from aws_lambda_powertools import Logger
from aws_lambda_powertools.logging import correlation_paths
from aws_lambda_powertools.event_handler.api_gateway import ApiGatewayResolver, CORSConfig

from quicksight import list_dashboards, get_dashboard_embed_url

def json_serial(obj):
    if isinstance(obj, (datetime, date)):
        return obj.isoformat()
    raise TypeError ("Type %s not serializable" % type(obj))


def custom_serializer(obj) -> str:
    return json.dumps(obj, default=json_serial)


logger = Logger()
cors_config = CORSConfig(allow_origin="*", max_age=600, allow_credentials=True)
app = APIGatewayRestResolver(serializer=custom_serializer, cors=cors_config)


@logger.inject_lambda_context(correlation_id_path=correlation_paths.API_GATEWAY_REST)
def lambda_handler(event, context):
    logger.info(event)
    return app.resolve(event, context)


@app.get("/test-bug")
def get_list_dashboard():
    res = list_dashboards() 
    ...

There is no end for all of the data types json.dumps should / could support.But the default formatting is not always clear.

[heitorlessa]

Hi @filol - Thank you for opening an issue with us. @michaelbrewer is correct - this is a type serialization issue that only you would be best positioned to addressed it (e.g., should it be as string, as ISO string, etc.).

This is also similar to any non-JSON serializable values. We document them here on how you can bring your own serializer, like Michael suggested above.

Closing.

Thank you!