Mergefs

A tiny go package which combines together fs.FS filesystems.

mergefs.FS looks through a slice of fs.FS filesytems in order to find a given file. It returns the first match, or os.ErrNotExist.

Related work

mergefs could be used to overlay multiple fs.FS filesystems on top of each other.

• marshalfs for backing a fileystem with your objects.
• Standard Library:
  • dirfs contains os.DirFS - this 'default' implementation is backed by an actual filesystem.
  • testfs contains a memory-map implementation and a testing tool. The standard library contains a few other fs.FS implementations (like 'zip')
  • embedfs provides access to files embedded in the running Go program.
• An earlier work, afero is a filesystem abstraction for Go, which has been the standard for filesystem abstractions up until go1.15. It's read-write, and it's a mature project. The interfaces look very different (big with lots of methods), so it's not really compatible.
• s3fs is a fs.FS backed by the AWS S3 client
• hashfs appends SHA256 hashes to filenames to allow for aggressive HTTP caching.