dfresh

dfresh helps maintain the freshness of Docker image references.

Installing

You can download dfresh binaries from our Releases page.

Alternatively, use the Docker image, via this handy alias:

alias dfresh="docker run -ti --rm -v ~/.docker:/root/.docker -v `pwd`:/cwd realestate/dfresh"

Get Docker repository tags

Use the tags subcommand to list available tags for a repository.

$ dfresh tags nginx | head
1-alpine-perl
1-alpine
1-perl
1.10-alpine
1.10.0-alpine
1.10.0
1.10.1-alpine
1.10.1
1.10.2-alpine
1.10.2

Resolve Docker image references

The resolve subcommand "locks" a reference by adding a digest.

$ dfresh resolve ruby:2.3
ruby:2.3@sha256:08868d719684cf9cafacbaa1786ad01111332b4c1e65abd67833db603d8dab7f

Check for outdated image references

dfresh check [flags] FILE...

check searches the named input FILEs for fully-specified (IMAGE:TAG@DIGEST) references. Where a newer image is available for the IMAGE:TAG, it prints old and new digests, returning exit-status 1 if any references are out-of-date.

Examples

$ dfresh check Dockerfile docker-compose.yml
Dockerfile:1: fluent/fluentd:latest
  old sha256:f4e780c4e121bd409a204b7dd74ca4570e185b7386f9853f7b221ef3a2d6ca94
  new sha256:69a5ae45f4b99dfa8f9eadd7b6b8103bef8073bbffc101c10cf063c358d5b1d1
docker-compose.yml:46: nginx
  old sha256:0fe6413f3e30fcc5920bc8fa769280975b10b1c26721de956e1428b9e2f29d04
  new sha256:41ad9967ea448d7c2b203c699b429abe1ed5af331cd92533900c6d77490e0268

$ echo $?
1

Update image references

dfresh update [flags] [FILE...]

update is like check, except that it updates references in the named input FILEs, in place.

If no files are specified, update processes STDIN and writes the updated content to STDOUT.

Examples

Update references in a file:

$ head -1 Dockerfile
FROM ruby:2.3@sha256:a5ebd3bc0bf3881258975f8afa1c6d24429dfd4d7dd53a299559a3e927b77fd7

$ dfresh update Dockerfile
Dockerfile:1: ruby:2.3
  old sha256:a5ebd3bc0bf3881258975f8afa1c6d24429dfd4d7dd53a299559a3e927b77fd7
  new sha256:08868d719684cf9cafacbaa1786ad01111332b4c1e65abd67833db603d8dab7f

$ head -1 Dockerfile
FROM ruby:2.3@sha256:08868d719684cf9cafacbaa1786ad01111332b4c1e65abd67833db603d8dab7f

Update references in a pipeline:

$ echo "FROM ruby:2.3@sha256:a5ebd3bc0bf3881258975f8afa1c6d24429dfd4d7dd53a299559a3e927b77fd7" |
  dfresh update
FROM ruby:2.3@sha256:08868d719684cf9cafacbaa1786ad01111332b4c1e65abd67833db603d8dab7f

Getting started

To "bootstrap" use of dfresh update, you can specify a dummy digest, consisting of one or more question-marks, e.g.

$ head -1 Dockerfile
FROM ruby:2.3@?

$ dfresh update Dockerfile
Dockerfile:1: ruby:2.3
  old ?
  new sha256:08868d719684cf9cafacbaa1786ad01111332b4c1e65abd67833db603d8dab7f

Releasing

Creating the binaries and pushing to both github.com and hub.docker.com is all wrapped up niceling into a script.

$ auto/release-docker-image

After that has completed, you can head to the releases page and create a new release. Upload the binaries from that will have been created in the target/ folder after running the release script above.