python:3.6-alpine "unsupported manifest media type and no default available"

[groodt]

I'm having some issues pulling down the python:3.6-alpine image.

❯ docker manifest inspect index.docker.io/python:3.6-alpine
unsupported manifest media type and no default available: application/vnd.docker.distribution.manifest.v1+prettyjws

Other versions of python and alpine are working. As does python:3.6-stretch.

❯ docker manifest inspect index.docker.io/python:3.5-alpine
WORKS

❯ docker manifest inspect index.docker.io/python:3.6-alpine
FAILS

❯ docker manifest inspect index.docker.io/python:3.6-stretch
WORKS

❯ docker manifest inspect index.docker.io/python:3.7-alpine
WORKS

Any ideas? It feels like the image needs to be republished, but I'm not sure.

[wglambert]

Looks like an issue with the docker manifest inspect experimental feature

$ docker run --rm weshigbee/manifest-tool inspect index.docker.io/python:3.6-alpine
Name:   index.docker.io/python:3.6-alpine (Type: application/vnd.docker.distribution.manifest.list.v2+json)
Digest: sha256:c3b0a0317d0759a0c0b8cf2b2c60ea09729bc9b7faf464ee67434f45de2bb3d1
 * Contains 7 manifest references:
1    Mfst Type: application/vnd.docker.distribution.manifest.v2+json
1       Digest: sha256:39832cd8530d791f512f81d43cc83d9e07e14617d89d33b5d779e5454db7bead
1  Mfst Length: 1368
1     Platform:
1           -      OS: linux
1           -    Arch: amd64
1           - Variant: 
1           - Feature: 
1     # Layers: 5
         layer 1: digest = sha256:8e402f1a9c577ded051c1ef10e9fe4492890459522089959988a4852dee8ab2c
         layer 2: digest = sha256:cda9ba2397ef5f09cf0e723c11a145dbb42779e78fe441904085928399386f10
         layer 3: digest = sha256:7a817918d4d52ca5e7c3c57d904971a321843ba919e35bab135452b2f4f23b66
         layer 4: digest = sha256:e64fbda5eefbb4602ea8e96be3ab4c05b9a77e5a8a42341650b10e0d5a3f7b09
         layer 5: digest = sha256:6d027cc21c420fc1c60ebd5920f41a43971e0644d2e288fa3e8cc5fcc2004685

2    Mfst Type: application/vnd.docker.distribution.manifest.v2+json
2       Digest: sha256:d6282ec9a8ee0a93fdd3ef688ca4e693dbf02e4634d412fa535a8deec901c84b
2  Mfst Length: 1368
. . .

$ docker run --rm weshigbee/manifest-tool inspect index.docker.io/python:3.5-alpine
Name:   index.docker.io/python:3.5-alpine (Type: application/vnd.docker.distribution.manifest.list.v2+json)
Digest: sha256:6926e850135e6bcf419b00ed5be411094ce8f9c0deb9ae896238567882022e10
 * Contains 7 manifest references:
1    Mfst Type: application/vnd.docker.distribution.manifest.v2+json
1       Digest: sha256:c9e3d7c1768946bda737919a0e70ceccc6d16500a94861a0b7393055a7bd7fae
1  Mfst Length: 1368
1     Platform:
1           -      OS: linux
1           -    Arch: amd64
1           - Variant: 
1           - Feature: 
1     # Layers: 5
. . .

[groodt]

Maybe, but if I push a version of the https://github.com/docker-library/python/blob/master/3.6/alpine3.9/Dockerfile
which I build myself and push to AWS ECR, it is working 🤷‍♂️

[tianon]

I'm not sure where this index.docker.io/... stuff is coming from, but I did some tests and I also can't reproduce any failure on python:3.6-alpine here. :confused:

[groodt]

@tianon Random question, but Linux or Mac?

❯ docker version
Client: Docker Engine - Community
 Version:           18.09.2
 API version:       1.39
 Go version:        go1.10.8
 Git commit:        6247962
 Built:             Sun Feb 10 04:12:39 2019
 OS/Arch:           darwin/amd64
 Experimental:      true

Server: Docker Engine - Community
 Engine:
  Version:          18.09.2
  API version:      1.39 (minimum version 1.12)
  Go version:       go1.10.6
  Git commit:       6247962
  Built:            Sun Feb 10 04:13:06 2019
  OS/Arch:          linux/amd64
  Experimental:     false

[tianon]

Hitting the registry API directly (via curl), not using any particular client, and this is the manifest list object I get back on python:3.6-alpine (with a digest of sha256:c3b0a0317d0759a0c0b8cf2b2c60ea09729bc9b7faf464ee67434f45de2bb3d1):

{
   "schemaVersion": 2,
   "mediaType": "application/vnd.docker.distribution.manifest.list.v2+json",
   "manifests": [
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 1368,
         "digest": "sha256:39832cd8530d791f512f81d43cc83d9e07e14617d89d33b5d779e5454db7bead",
         "platform": {
            "architecture": "amd64",
            "os": "linux"
         }
      },
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 1368,
         "digest": "sha256:d6282ec9a8ee0a93fdd3ef688ca4e693dbf02e4634d412fa535a8deec901c84b",
         "platform": {
            "architecture": "arm",
            "os": "linux",
            "variant": "v6"
         }
      },
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 1368,
         "digest": "sha256:9f5fc9bc1cdec38adce2ea4ed8e944e4f887edb3ee96d470a023c2f847db2b9c",
         "platform": {
            "architecture": "arm",
            "os": "linux",
            "variant": "v7"
         }
      },
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 1368,
         "digest": "sha256:625cc2937a84e498b32acc473e4ebbfc6547020491044ac8bf0bd42887759150",
         "platform": {
            "architecture": "arm64",
            "os": "linux",
            "variant": "v8"
         }
      },
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v1+json",
         "size": 10173,
         "digest": "sha256:0cf8ddbe9102f47fcdeb85fb84c66b179ba10a0eba75686fbe455b54f4ef4155",
         "platform": {
            "architecture": "386",
            "os": "linux"
         }
      },
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 1368,
         "digest": "sha256:ca9d2e15059ec4462bfeef37b4f8177f144edaca32fec207b63684450ae1e2df",
         "platform": {
            "architecture": "ppc64le",
            "os": "linux"
         }
      },
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "size": 1368,
         "digest": "sha256:efc0e3f0860f416ca7c0bdd405e2b8fee0a7db7df4c0d6627ca4dcc2345e1cb2",
         "platform": {
            "architecture": "s390x",
            "os": "linux"
         }
      }
   ]
}

[groodt]

If I use the docker image above, it works fine.
docker run --rm weshigbee/manifest-tool inspect index.docker.io/python:3.6-alpine

It only fails if I run it direct on my Mac.
docker manifest inspect index.docker.io/python:3.6-alpine

[groodt]

Could the issue be this rogue v1 for linux?

      {
         "mediaType": "application/vnd.docker.distribution.manifest.v1+json",
         "size": 10173,
         "digest": "sha256:0cf8ddbe9102f47fcdeb85fb84c66b179ba10a0eba75686fbe455b54f4ef4155",
         "platform": {
            "architecture": "386",
            "os": "linux"
         }
      },

[groodt]

If I look at the output of this docker run --rm weshigbee/manifest-tool inspect index.docker.io/python:3.5-alpine on my Mac, all the manifests are the same version. "application/vnd.docker.distribution.manifest.v2+json"

The output of this shows one manifest that has a different version.
docker run --rm weshigbee/manifest-tool inspect index.docker.io/python:3.6-alpine

5    Mfst Type: application/vnd.docker.distribution.manifest.v1+json
5       Digest: sha256:0cf8ddbe9102f47fcdeb85fb84c66b179ba10a0eba75686fbe455b54f4ef4155
5  Mfst Length: 10173
5     Platform:
5           -      OS: linux
5           -    Arch: 386
5           - Variant:
5           - Feature:
5     # Layers: 0

[yosifkit]

This is the same as docker-library/golang#269. In other words, this was a quirk the Docker Hub had when we were pushing images and we can't control whether it is pushed as manifest V2 schema 1 or manifest V2 schema 2.

[groodt]

This is the same as docker-library/golang#269. In other words, this was a quirk the Docker Hub had when we were pushing images and we can't control whether it is pushed as manifest V2 schema 1 or manifest V2 schema 2.

Thanks. That sucks. So are you saying that pushing images is non-deterministic or was it just a blip and republishing should fix it?

[yosifkit]

Well, re-push would probably fix it, but a no-op docker push is so slow on the Docker Hub that our automation uses timestamp comparison to skip already pushed images.

https://github.com/docker-library/official-images/blob/14e4cff4459c224c371670d777db89f4ab60f03b/bashbrew/go/src/bashbrew/cmd-push.go#L47-L52
https://github.com/docker-library/official-images/blob/14e4cff4459c224c371670d777db89f4ab60f03b/bashbrew/go/src/bashbrew/hub.go#L34

[tianon]

It was a blip in the Hub:
https://github.com/docker-library/golang/issues/269#issuecomment-473599728

[groodt]

Anybody know who would be responsible for re-pushing the images? I feel like Python3.6 isn't old enough to simply neglect.

[tianon]

python:3.6-alpine is fixed :+1: