dockry

Docker Registry V2 command-line client
(compatible with any registry implementing Docker Registry HTTP API V2, (Docker Hub, GitLab Container Registry, etc); public or private).

In short, it allows you to:

• List Docker image tags.
  e.g. dockry ls alpine, dockry ls gitlab.example.com:4567/group/project --limit=10

(see also dockry ll in Usage)

• Inspect Docker image(s) without docker pulling.
  e.g. dockry inspect node:latest

TIP: Use --format=<go-template> to customize output.
For example, to get a digest of an image:
dockry inspect node:latest --format='{{.name}}@{{.digest}}'
(or simply dockry digest --fq node:latest)

• Delete Docker image(s).
  e.g. dockry rm gitlab.example.com:4567/group/project@sha256:661a5a8...

Installation

macOS

curl -sSL https://github.com/shyiko/dockry/releases/download/0.2.0/dockry-0.2.0-darwin-amd64 \
  -o dockry && chmod a+x dockry && sudo mv dockry /usr/local/bin/  

Verify PGP signature (optional but recommended):

curl -sSL https://github.com/shyiko/dockry/releases/download/0.2.0/dockry-0.2.0-darwin-amd64.asc \
   -o dockry.asc
curl -sS https://keybase.io/shyiko/pgp_keys.asc | gpg --import
gpg --verify dockry.asc /usr/local/bin/dockry

gpg can be installed with brew install gnupg

Linux

curl -sSL https://github.com/shyiko/dockry/releases/download/0.2.0/dockry-0.2.0-linux-amd64 \
  -o dockry && chmod a+x dockry && sudo mv dockry /usr/local/bin/  

Verify PGP signature (optional but recommended):

curl -sSL https://github.com/shyiko/dockry/releases/download/0.2.0/dockry-0.2.0-linux-amd64.asc \
  -o dockry.asc
curl -sS https://keybase.io/shyiko/pgp_keys.asc | gpg --import
gpg --verify dockry.asc /usr/local/bin/dockry

Windows

Download executable from the Releases page.

Usage

Depending on weather you are trying to access public or private registry/repo you may need either to docker login (e.g. docker login gitlab.example.com:4567 if dockry ls gitlab.example.com:4567/group/project fails with 401 UNAUTHORIZED) or use dockry --user=username:password_or_token ....

# list all alpine:* tags
$ dockry ls alpine
latest
edge
3.7
3.6
3.5
3.4
3.3
3.2
3.1
2.7
2.6

# list last 2 mysql images 
# (output fully-qualified names (ready to copy&paste to `docker pull ...`)) 
$ dockry ls mysql --fq --limit=2
mysql:latest
mysql:8

# pretty print 
$ dockry ll node:latest 

latest   linux/amd64    270 MB  3 days ago
latest   linux/arm,v7   240 MB  5 days ago
latest   linux/arm64,v8 245 MB  4 days ago
latest   linux/386      273 MB  6 days ago
latest   linux/ppc64le  256 MB  5 days ago
latest   linux/s390x    252 MB  5 days ago

# pretty print (filter by platform)
$ dockry ll node -p linux/amd64 --limit=5

wheezy   linux/amd64    202 MB  5 days ago
stretch  linux/amd64    343 MB  5 days ago
slim     linux/amd64    92 MB   3 days ago
onbuild  linux/amd64    270 MB  3 days ago
latest   linux/amd64    270 MB  3 days ago

# same as above 
# (-x is an alias for -p linux/amd64) 
$ dockry ll node -x --limit=5

# inspect image without `docker pull`ing
$ dockry inspect node:6.9.1
[
  {
    "name": "node",
    "tag": "6.9.1",
    "digest": "sha256:661a5a830a072c550ad8ad089d212867d0312c28f2992c01989f6c2789925f10",
    "downloadSize": 256247325,
    "os": "linux",
    "arch": "amd64",
    "timestamp": "2016-11-23T19:20:07.81981642Z",
    "config": {
      "cmd": [
        "node"
      ],
      "env": {
        "NODE_VERSION": "6.9.1",
        "NPM_CONFIG_LOGLEVEL": "info",
        "PATH": "/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
      }
    }
  }
]

# customize inspect output 
$ dockry inspect $(dockry ls alpine --fq --limit=3) \
    -p linux/amd64 --format=$'{{.name}}:{{.digest}} {{.tag}}'

alpine@sha256:8c03bb07a531c53ad7d0f6e7041b64d81f99c6e493cb39abba56d956b40eacbc latest 
alpine@sha256:6fa3225360ea1a48aaee4ca87de66e8e12b9a4f749f37acc7b4b5b9cc3d91b13 edge 
alpine@sha256:8c03bb07a531c53ad7d0f6e7041b64d81f99c6e493cb39abba56d956b40eacbc 3.7

# same as above
$ for image in $(dockry ls alpine --fq --limit=3); do
  dockry inspect $image \
    -p linux/amd64 --format=$'{{.name}}:{{.digest}} {{.tag}}' 
  done
    
# output fully-qualified (i.e. with name as a prefix) digest of an image
$ dockry digest --fq shyiko/openvpn:2.4.0_easyrsa-3.0.3
shyiko/openvpn@sha256:5ff43da1e85f8f5fe43aa7d609946d9ceb8ca0a7665cf4bbedc82d840428a8ff

# same as above
$ dockry inspect shyiko/openvpn:2.4.0_easyrsa-3.0.3 --format='{{.name}}@{{.digest}}'

# image(s) can only be deleted using a digest 
# (there is no such thing as "to remove a tag" in Docker Registry V2)
# no tag->digest auto-resolution is taking place so that implications of rm operation would be clear
$ dockry rm $(dockry digest --fq gitlab.example.com:4567/group/project:experimental)

dockry inspect output

(fields marked with * are never empty and thus never omitted)

[
  {
    "name": string*,
    "tag": string,
    "digest": string*,
    "downloadSize": number*,
    "os": string*,
    "osVersion": string,
    "osFeature": []string,
    "arch": string*,
    "cpuVariant": string,
    "cpuFeature": []string,
    "timestamp": string_containing_date_in_iso8601*,
    "config": { 
      // Dockerfile instructions
      "cmd": []string,
      "entrypoint": []string,
      "env": map[string]string,
      "expose": []string,
      "label": map[string]string,
      "onbuild": []string,
      "shell": []string,
      "user": string,
      "volume": []string,
      "workdir": string
    }*
  },
  ...
]

(for more information see dockry --help)

<kbd>Tab</kbd> completion

# bash
source <(dockry completion bash)

# zsh
source <(dockry completion zsh)

Development

PREREQUISITE: go1.9+.

git clone https://github.com/shyiko/dockry $GOPATH/src/github.com/shyiko/dockry 
cd $GOPATH/src/github.com/shyiko/dockry
make fetch

go run *.go

Legal

All code, unless specified otherwise, is licensed under the MIT license.
Copyright (c) 2018 Stanley Shyiko.