How to append write to google cloud storage file from app engine?

Question

This deprecated API supports appending content to google cloud storage file:

FileWriteChannel FileService.openWriteChannel(AppEngineFile file,
                       


        

Answer 1

While Google Cloud Storage objects are immutable, there is something that could help you if you need to do limited appends: object compose

This operation basically concatenates the contents of a number of objects in the same bucket under a new name, like cat file1 file2 > newfile but without re-writing data.

So you could create a new object, upload the contents to append to it, close and subsequently compose this new piece at the end of your main file.

There is a caveat: a maximum of 1024 'pieces' per object are allowed, and composing objects that are themselves composed counts as composing the original pieces (so you can't cheat the limit by iterated composing).