# ask-community

Martim Passos

09/30/2021, 12:59 PM
Is there a Dagster-onic way of achieving something like this? My case is the following: I have a dataframe with image metadata. For each image, I want to download the file from S3 and break it up into tiles (solid A), write a json manifest (solid B) and upload everything back to S3 (solid C). The way we normally use solids that deal with multiple files is passing a list of paths between them, but in this case I specifically want to process one at a time so S3 always has the latest processed files (the whole thing is gonna take days, I don’t want to wait for it to finish to have the files on S3, and I don’t have enough storage on Render to keep everything there until it finishes)


09/30/2021, 3:59 PM
hi @Martim Passos! this pattern seems pretty aligned with our dynamic mapping functionality. In this case, the first solid would yield a dynamic output for each row in the dataframe.
👍 2

Martim Passos

09/30/2021, 6:31 PM
I knew I had seen something like it somewhere! Thanks for the pointer @owen