Passing stream results into a secondary stream's API path

Connector Development
1

I have three streams.

accounts
|=statement list
|==statements

A field from accounts is used to populate the path for statement list. Two fields from statement list are needed to populate the path for statements.

I have the first two streams working the way I want by defining a class-specific stream slice.

class AccountRelatedStream(ParentClassStream, ABC):    
    
    def stream_slices(
        self, sync_mode: SyncMode, cursor_field: List[str] = None, stream_state: Mapping[str, Any] = None
    ) -> Iterable[Optional[Mapping[str, Any]]]:
        accounts_stream = Accounts(authenticator=self.authenticator)
        for record in accounts_stream.read_records(sync_mode=SyncMode.full_refresh):
            yield {"account_id": record["account"]["account_id"]}

I thought I could do something similar for the last stream, but this isn’t working.

class StatementRelatedStream(ParentClassStream, ABC):    
    
    def stream_slices(
        self, sync_mode: SyncMode, cursor_field: List[str] = None, stream_state: Mapping[str, Any] = None
    ) -> Iterable[Optional[Mapping[str, Any]]]:
        statements_stream = StatementsList(authenticator=self.authenticator)
        for record in statements_stream.read_records(sync_mode=SyncMode.full_refresh):
            yield {"account_id": record["account_id"],"statement_id":record["statement_id"]}

I get an TypeError: 'NoneType' object is not subscriptable error. Any ideas?

2

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3

Hey is this a custom connector? If so can you share the cdk version for it?

4

Hey @harshith – it is a custom connector. I’m on CDK version 0.1.56.

5

Got it. It will be helpful if you can share the repo URL so that we can take a look at the code. Is it possible?

6

Sure thing, here it is. source-canopy is the custom connector.

7

Hey could you also share the screenshot of the error? Or copy the complete error log here

8

Sure, here it is. The relevant code is in the repo in the tandym branch.

{"type": "LOG", "log": {"level": "ERROR", "message": "Encountered an exception while reading stream statements_detail\nTraceback (most recent call last):\n File \"/Users/dra/Code/Tandym Repos/airbyte-tandym/airbyte-integrations/connectors/source-canopy/.venv/lib/python3.9/site-packages/airbyte_cdk/sources/abstract_source.py\", line 113, in read\n yield from self._read_stream(\n File \"/Users/dra/Code/Tandym Repos/airbyte-tandym/airbyte-integrations/connectors/source-canopy/.venv/lib/python3.9/site-packages/airbyte_cdk/sources/abstract_source.py\", line 182, in _read_stream\n for record in record_iterator:\n File \"/Users/dra/Code/Tandym Repos/airbyte-tandym/airbyte-integrations/connectors/source-canopy/.venv/lib/python3.9/site-packages/airbyte_cdk/sources/abstract_source.py\", line 274, in _read_full_refresh\n for _slice in slices:\n File \"/Users/dra/Code/Tandym Repos/airbyte-tandym/airbyte-integrations/connectors/source-canopy/source_canopy/source.py\", line 98, in stream_slices\n for record in statements_stream.read_records(sync_mode=SyncMode.full_refresh):\n File \"/Users/dra/Code/Tandym Repos/airbyte-tandym/airbyte-integrations/connectors/source-canopy/.venv/lib/python3.9/site-packages/airbyte_cdk/sources/streams/http/http.py\", line 410, in read_records\n path=self.path(stream_state=stream_state, stream_slice=stream_slice, next_page_token=next_page_token),\n File \"/Users/dra/Code/Tandym Repos/airbyte-tandym/airbyte-integrations/connectors/source-canopy/source_canopy/source.py\", line 83, in path\n account_id = stream_slice[\"account_id\"]\nTypeError: 'NoneType' object is not subscriptable"}}

9

Got it. Do you mind printing stream_slice and check what data does that variable have?

10

Got this one figured out … the trick was to use a read_slices_from_records function to pass both variables I needed from stream-to-stream. This worked whereas the standard slice function did not … I’m guessing because the “source” stream was nested (for lack of a better word).

    def read_slices_from_records(self, stream_class: Type[ParentClassStream], slice_field: str, slice_field_two: str) -> Iterable[Optional[Mapping[str, Any]]]:
        stream = stream_class(authenticator=self.authenticator)
        stream_slices = stream.stream_slices(sync_mode=SyncMode.full_refresh)
        for stream_slice in stream_slices:
            for record in stream.read_records(sync_mode=SyncMode.full_refresh, stream_slice=stream_slice):
                yield {slice_field: record["account_id"], slice_field_two: record["statement_id"]}
11

You’ll need to create records for both parent streams (account and statement list). I strongly recommend to you enable the cache, so you won’t read the streams two times.
More info here: HTTP-API-based Connectors | Airbyte Documentation

class StatementRelatedStream(ParentClassStream, ABC):    
    
    def stream_slices(
        self, sync_mode: SyncMode, cursor_field: List[str] = None, stream_state: Mapping[str, Any] = None
    ) -> Iterable[Optional[Mapping[str, Any]]]:
        statements_stream = StatementsList(authenticator=self.authenticator)
        accounts = Accounts(authenticator=self.authenticator)
        for record in statements_stream.read_records(sync_mode=SyncMode.full_refresh):
            account_id = search_account_id(record['statement_id')
            yield {"account_id": account_id,"statement_id":record["statement_id"]}

Hope this helps you.