Cli: docker images --digest image does not display digest

[ctaggart]

Description

The image digest is <none> if you specify the image.

Steps to reproduce the issue:

C:\Users\camer\tmp> docker images --digests
REPOSITORY          TAG                 DIGEST                                                                    IMAGE ID            CREATED             SIZE
mono                latest              sha256:55ce025f24578afe68cdf579dd3a42b9af7e4c729eadefa1f0a236d6387a8eb2   61351f52f2f9        3 weeks ago         531MB
mono                slim                sha256:9cb9c6131656a1ea0413e22fa5854a38672d792e63be3fd51c4da214b43113ae   ac8dc438b799        3 weeks ago         170MB
C:\Users\camer\tmp> docker images --digests mono:slim
REPOSITORY          TAG                 DIGEST              IMAGE ID            CREATED             SIZE
mono                slim                <none>              ac8dc438b799        3 weeks ago         170MB

Describe the results you received:

Describe the results you expected:
I want the digest displayed.

Additional information you deem important (e.g. issue happens only occasionally):

Output of docker version:

C:\Users\camer\tmp> docker --version
Docker version 17.09.0-ce, build afdb6d4

Output of docker info:

C:\Users\camer\tmp> docker info
Containers: 0
 Running: 0
 Paused: 0
 Stopped: 0
Images: 2
Server Version: 17.09.0-ce
Storage Driver: overlay2
 Backing Filesystem: extfs
 Supports d_type: true
 Native Overlay Diff: true
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins:
 Volume: local
 Network: bridge host ipvlan macvlan null overlay
 Log: awslogs fluentd gcplogs gelf journald json-file logentries splunk syslog
Swarm: inactive
Runtimes: runc
Default Runtime: runc
Init Binary: docker-init
containerd version: 06b9cb35161009dcb7123345749fef02f7cea8e0
runc version: 3f2f8b84a77f73d38244dd690525642a72156c64
init version: 949e6fa
Security Options:
 seccomp
  Profile: default
Kernel Version: 4.9.49-moby
Operating System: Alpine Linux v3.5
OSType: linux
Architecture: x86_64
CPUs: 2
Total Memory: 1.934GiB
Name: moby
ID: XEH3:K2GT:SI6C:LDQH:CCLI:46Y2:IISU:RXUS:56QI:GLQJ:25TP:DCXF
Docker Root Dir: /var/lib/docker
Debug Mode (client): false
Debug Mode (server): true
 File Descriptors: 16
 Goroutines: 26
 System Time: 2017-12-04T22:02:36.4444744Z
 EventsListeners: 0
Registry: https://index.docker.io/v1/
Experimental: true
Insecure Registries:
 127.0.0.0/8
Live Restore Enabled: false

Additional environment details (AWS, VirtualBox, physical, etc.):

Looks related to https://github.com/docker/cli/pull/439

[boaz0]

yep, I can reproduce it.
It looks like if the tag is added to timage name, then the digests is not displayed.

I will investigate this a little bit more.

Thanks a lot @ctaggart

EDIT

It looks like this is not really related to #439.
digests isn't shown because the response from the backed doesn't include digests.

I am trying to figure out why this happens.

EDIT 2

When passing reference with tag, the daemon detects that this is a named-tag reference and doesn't append its digests to RepoDigests.

It doesn't relate to the client side at all.

[boaz0]

@thaJeztah I remember someone complained about missing digests when using Moby API. Do I remember correctly?

Thanks.

[northtyphoon]

I encountered the same issue. RepoDigests returned from the daemon was empty. Is there any workaround?

FYI @shhsu

EDIT

I found the daemon wouldn't return digest for local build images until I pushed the images.

[panuhorsmalahti]

I see this also when using --filter by image and tag. If I filter just by the image name but not the tag the digest is displayed correctly.

[karol-brejna-i]

Same here:

$ docker images --digests | grep alpine | grep 3.6
alpine                             3.6                 sha256:f006ecbb824d87947d0b51ab8488634bf69fe4094959d935c0c103f4820a417d   76da55c8019d        12 months ago       3.97 MB

vs

$ docker images --digests alpine:3.6
REPOSITORY          TAG                 DIGEST              IMAGE ID            CREATED             SIZE
alpine              3.6                 <none>              76da55c8019d        12 months ago       3.97 MB

[vikas027]

This is another way to do it

$ docker image inspect <image_name_or_id> -f '{{.RepoDigests}}'

[karol-brejna-i]

@vikas027 It doesn't work either, right?

[jimmidyson]

@vikas027 That works for me - thanks!

[jimmidyson]

Hmm it actually doesn't work consistently.

[jimmidyson]

Ah the image has to be pushed before digest is calculated - see https://github.com/moby/moby/issues/32016

[vikas027]

Yeah, because digest is dependent on the registry provider.

[jharveysmith]

Has there been any progress here? @vikas027 are you saying that pushing to different registries will result in different digests?

[vikas027]

yes @jharveysmith . sha256 (or Id) changes when you have different registries. If you want to check the integrity of the image, use RepoDigests

[speller]

It looks like no one wants to fix the "show digest" command to actually show digests!

[vikas027]

It looks like no one wants to fix the "show digest" command to actually show digests!

Does this help you?