sets3lock

Distributed locking using Amazon S3.

sets3lock provides a distributed locking mechanism backed by Amazon S3. It allows you to implement mutual exclusion across multiple processes or servers easily and cost-effectively using only S3, without the need to manage additional infrastructure like Redis or ZooKeeper.

INSTALL

# use sets3lock via CLI.
go get github.com/shogo82148/cmd/sets3lock

# use sets3lock as a library.
go install github.com/shogo82148/sets3lock@latest

USAGE

$ sets3lock [-nNxX] s3://bucket/key program [args...]
-n: No delay. If fn is locked by another process, sets3lock gives up.
-N: (Default.) Delay. If fn is locked by another process, sets3lock waits until it can obtain a new lock.
-x: If lock object creation/update fails or the lock cannot be obtained, sets3lock exits zero.
-X: (Default.) If lock object creation/update fails or the lock cannot be obtained, sets3lock prints an error message and exits nonzero.
-version: show version
-expire-grace-period: set expire grace period duration after TTL expiration

import "github.com/shogo82148/sets3lock"

func main() {
  ctx := context.Background()
  l, err := sets3lock.New(ctx, "s3://bucket/key")
  if err != nil {
    panic(err)
  }
  if _, err := l.LockWithErr(ctx); err != nil {
    panic(err)
  }
  defer func() {
    if err := l.UnlockWithErr(ctx); err != nil {
      panic(err)
    }
  }()

  // do something that requires mutual exclusion.
}

You need to allow s3:GetObject, s3:PutObject, s3:DeleteObject actions by your IAM policy.

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": ["s3:GetObject", "s3:PutObject", "s3:DeleteObject"],
      "Resource": "arn:aws:s3:::bucket/key"
    }
  ]
}

RELATED WORKS

• The setlock program (an utility of daemontools)
• moznion/go-setlock
• fujiwara/go-redis-setlock
• mashiike/setddblock