I am trying to create a Data Factory that once a week copies and process large blob files (The Source) to a SQL database (The Sink) in python - by reading the input data set line by line, extracting an ID - using that ID to do a lookup on CosmosDB to get an additional piece of data recomposing the output dataset and writing to the sink. I have a python script that does this once off (ie reads the entire blob every time) without ADF but am now wanting use the scheduling features on ADF to automate this.
Is there a way of creating a custom copy activity in Python that I can inject my current code logic into. Azure currently only documents .Net custom activities (https://learn.microsoft.com/en-us/azure/data-factory/transform-data-using-dotnet-custom-activity) which does not fit into my stack.
The python azure SDK doesn't currently have any documentation on creating custom activity.