Will check etags when writing a file to avoid writing files that don't need to be overwritten (etags are MD5 sums of file contents)

For more information about afero see the github page.

package foo

import (
    "github.com/goamz/goamz/aws"
    "github.com/ryansb/af3ro"
    "github.com/spf13/afero"
)


var s3fs afero.Fs = af3ro.NewS3Fs(af3ro.Bucket("some.bucket.name"), af3ro.Region(aws.USEast), af3ro.EnvAuth())

Don't use this for big files for these reasons:

• Files are stored in memory until being written to S3 so you can OOM your program.
• Multipart uploads aren't supported, full file contents are uploaded in one PUT request.
• Etags for multipart files aren't supported and will fail, causing files uploaded initially as multipart to always be re-uploaded.

Data is only written to S3 when a file is closed so be aware that failing to close a file means it won't be written.

Permissions are translated from os.FileMode to AWS S3 ACLs, which are less expressive and don't completely map to FileModes, so double-check that the correct permissions are set in S3

Basically, this is for small files where you (for some reason) aren't able to use the goamz/s3 library directly and have to present a local-like filesystem interface.