Fake S3

Fake S3 is a gem designed to run a small server on localhost that will correctly handle AWS/S3 GETs and PUTs (among others) while using the local filesystem as the storage backend. This has a number of benefits for anyone working on an application with AWS integration.

Probably the biggest benefit is offline development. There’s also a lower configuration burden as there’s no longer special bucket names or keys the manage, the development environment just expects localhost to work. Finally, there’s a very real cost savings. Originally, we paid for two buckets per developer just to support the sample data for dev and test. Now we need none.

Install

$ gem install fakes3

Run

$ fakes3 -r /mnt/s3 -p 4567

Configure

For example:

development:
  bucket_name: development

  # doesn't matter
  access_key_id:     123
  secret_access_key: abc

  # does matter
  server: localhost
  port:   4567

Assuming you’ve got some rake tasks which load up S3 with sample data, just go ahead and run them, you’ll find files created directly under /mnt/s3/development and the requests your local instance makes will just return that data.

All with no cloud-access needed.

Init script

In case you didn’t notice, the fakes3 command is a bit verbose, which may be OK, but if you’re like me and just want to run this as a background service, the following (naive) init script should do the job:

#!/bin/bash

if [[ ! -d /mnt/s3 ]]; then
  mkdir /mnt/s3 || return 1
  chown -R vagrant:vagrant /mnt/s3 # make it user-writable
fi

case $1 in
  start)
    fakes3 -r /mnt/s3 -p 4567 &>/dev/null &
    echo $! > /var/run/fakes3.pid
    ;;
  stop)
    kill -9 `cat /var/run/fakes3.pid`
    ;;
  restart)
    $0 stop
    sleep 3
    $0 start
    ;;
esac