Add crane flatten #1104

jonjohnsonjr · 2021-08-12T00:02:24Z

This is adapted from #735 but changes the UX a bit to match what we've come to expect from crane.

Add pkg/crane.Upload as well, for uploading a layer.

$ crane manifest gcr.io/kaniko-project/executor | jq .

{
  "schemaVersion": 2,
  "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
  "config": {
    "mediaType": "application/vnd.docker.container.image.v1+json",
    "size": 3707,
    "digest": "sha256:1c812ffa8ec16797474d59cdb7667439e6bc26eb6054f7257b9016bdbc452d11"
  },
  "layers": [
    {
      "mediaType": "application/vnd.docker.image.rootfs.diff.tar.gzip",
      "size": 14219823,
      "digest": "sha256:94ed89128ee0d8b28f7cf724c516e51c041424c4bd5bb125fecfeeb76307eb9c"
    },
    {
      "mediaType": "application/vnd.docker.image.rootfs.diff.tar.gzip",
      "size": 4523491,
      "digest": "sha256:a804545c4b2ee9188580e438a3b56db29aad1af748ec2ec0c3d1d5e5fc55b538"
    },
    {
      "mediaType": "application/vnd.docker.image.rootfs.diff.tar.gzip",
      "size": 2964519,
      "digest": "sha256:0f9a0bccd2dc597ec892a7f3e255b14c7c1fd0800cd173f2126a2dda3e519f91"
    },
    {
      "mediaType": "application/vnd.docker.image.rootfs.diff.tar.gzip",
      "size": 6563884,
      "digest": "sha256:5d7f42cbc20d9b6bcf306b4402940b4aabc0e655273ee6832814fcc99c3ebfee"
    },
    {
      "mediaType": "application/vnd.docker.image.rootfs.diff.tar.gzip",
      "size": 357642,
      "digest": "sha256:16f9858f396996c895a2ad07bdca08f3ec724e5485688e3cda31f8c3fca014c5"
    },
    {
      "mediaType": "application/vnd.docker.image.rootfs.diff.tar.gzip",
      "size": 153,
      "digest": "sha256:f5f0d1ae165026c9094a1fca5f5f9f488cd19fffb6d0d7a7bc94e8c486fab7ad"
    },
    {
      "mediaType": "application/vnd.docker.image.rootfs.diff.tar.gzip",
      "size": 540,
      "digest": "sha256:cc48692dd99f82f2708b30beed23974456ff65c9b3c1b5394e17df7fd39460ac"
    },
    {
      "mediaType": "application/vnd.docker.image.rootfs.diff.tar.gzip",
      "size": 132,
      "digest": "sha256:b9a35a76a8f42260e1a25d274acc94dedac2b8d85b117d428e8491b5ea526184"
    },
    {
      "mediaType": "application/vnd.docker.image.rootfs.diff.tar.gzip",
      "size": 339,
      "digest": "sha256:f68c2840c45f74cc7e3fedc214f88ac76252fd1f5e6e16008fa01d74c08d8f85"
    }
  ]
}

$ crane flatten gcr.io/kaniko-project/executor -t gcr.io/jonjohnson-test/kaniko:flattened
2021/08/11 17:03:23 pushed blob: sha256:90a1ce29e3c1e97127cbd84238973006c669f79c4608974e4d23dd96dfaa246a
2021/08/11 17:03:25 pushed blob: sha256:748697bc98d140e2fef5aaac09361e65ee9ec230d0dd3860d42b991150d47e06
2021/08/11 17:03:26 gcr.io/jonjohnson-test/kaniko:flattened: digest: sha256:e55cacb041826deefc92f2740d3bc4742c8b9597e587efa43fa4b7fe89127f64 size: 429
gcr.io/jonjohnson-test/kaniko@sha256:e55cacb041826deefc92f2740d3bc4742c8b9597e587efa43fa4b7fe89127f64

$ crane manifest gcr.io/jonjohnson-test/kaniko:flattened | jq .

{
  "schemaVersion": 2,
  "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
  "config": {
    "mediaType": "application/vnd.docker.container.image.v1+json",
    "size": 3419,
    "digest": "sha256:748697bc98d140e2fef5aaac09361e65ee9ec230d0dd3860d42b991150d47e06"
  },
  "layers": [
    {
      "mediaType": "application/vnd.docker.image.rootfs.diff.tar.gzip",
      "size": 28533261,
      "digest": "sha256:90a1ce29e3c1e97127cbd84238973006c669f79c4608974e4d23dd96dfaa246a"
    }
  ]
}

Note that we preserve the original history in comment and what was flattened in the created_by comment. I'm not sure if we actually want to include the original image ref, or if we should just include the original image digest here to make this more reproducible.

$ crane config gcr.io/jonjohnson-test/kaniko:flattened | jq .

{
  "architecture": "amd64",
  "created": "2021-05-19T20:00:47.261095682Z",
  "history": [
    {
      "created": "0001-01-01T00:00:00Z",
      "created_by": "crane flatten sha256:6ecc43ae139ad8cfa11604b592aaedddcabff8cef469eda303f1fb5afe5e3034",
      "comment": "[{\"created\":\"2021-05-19T20:00:46.895205234Z\",\"created_by\":\"COPY /go/src/github.com/GoogleContainerTools/kaniko/out/executor /kaniko/executor # buildkit\",\"comment\":\"buildkit.dockerfile.v0\"},{\"created\":\"2021-05-19T20:00:46.929792602Z\",\"created_by\":\"COPY /usr/local/bin/docker-credential-gcr /kaniko/docker-credential-gcr # buildkit\",\"comment\":\"buildkit.dockerfile.v0\"},{\"created\":\"2021-05-19T20:00:46.958575143Z\",\"created_by\":\"COPY /go/src/github.com/awslabs/amazon-ecr-credential-helper/bin/local/docker-credential-ecr-login /kaniko/docker-credential-ecr-login # buildkit\",\"comment\":\"buildkit.dockerfile.v0\"},{\"created\":\"2021-05-19T20:00:46.994104887Z\",\"created_by\":\"COPY /go/src/github.com/chrismellard/docker-credential-acr-env/build/docker-credential-acr-env /kaniko/docker-credential-acr # buildkit\",\"comment\":\"buildkit.dockerfile.v0\"},{\"created\":\"2021-05-19T20:00:47.010924888Z\",\"created_by\":\"COPY /ca-certificates.crt /kaniko/ssl/certs/ # buildkit\",\"comment\":\"buildkit.dockerfile.v0\"},{\"created\":\"2021-05-19T20:00:47.026599082Z\",\"created_by\":\"COPY /kaniko/.docker /kaniko/.docker # buildkit\",\"comment\":\"buildkit.dockerfile.v0\"},{\"created\":\"2021-05-19T20:00:47.03965574Z\",\"created_by\":\"COPY files/nsswitch.conf /etc/nsswitch.conf # buildkit\",\"comment\":\"buildkit.dockerfile.v0\"},{\"created\":\"2021-05-19T20:00:47.051870289Z\",\"created_by\":\"ENV HOME=/root\",\"comment\":\"buildkit.dockerfile.v0\",\"empty_layer\":true},{\"created\":\"2021-05-19T20:00:47.051870289Z\",\"created_by\":\"ENV USER=root\",\"comment\":\"buildkit.dockerfile.v0\",\"empty_layer\":true},{\"created\":\"2021-05-19T20:00:47.051870289Z\",\"created_by\":\"ENV PATH=/usr/local/bin:/kaniko\",\"comment\":\"buildkit.dockerfile.v0\",\"empty_layer\":true},{\"created\":\"2021-05-19T20:00:47.051870289Z\",\"created_by\":\"ENV SSL_CERT_DIR=/kaniko/ssl/certs\",\"comment\":\"buildkit.dockerfile.v0\",\"empty_layer\":true},{\"created\":\"2021-05-19T20:00:47.051870289Z\",\"created_by\":\"ENV DOCKER_CONFIG=/kaniko/.docker/\",\"comment\":\"buildkit.dockerfile.v0\",\"empty_layer\":true},{\"created\":\"2021-05-19T20:00:47.051870289Z\",\"created_by\":\"ENV DOCKER_CREDENTIAL_GCR_CONFIG=/kaniko/.config/gcloud/docker_credential_gcr_config.json\",\"comment\":\"buildkit.dockerfile.v0\",\"empty_layer\":true},{\"created\":\"2021-05-19T20:00:47.051870289Z\",\"created_by\":\"WORKDIR /workspace\",\"comment\":\"buildkit.dockerfile.v0\"},{\"created\":\"2021-05-19T20:00:47.261095682Z\",\"created_by\":\"RUN docker-credential-gcr config --token-source=env # buildkit\",\"comment\":\"buildkit.dockerfile.v0\"},{\"created\":\"2021-05-19T20:00:47.261095682Z\",\"created_by\":\"ENTRYPOINT [\\\"/kaniko/executor\\\"]\",\"comment\":\"buildkit.dockerfile.v0\",\"empty_layer\":true}]"
    }
  ],
  "os": "linux",
  "rootfs": {
    "type": "layers",
    "diff_ids": [
      "sha256:67bf165867562b1841e1255e879e60340484743d8a3bceddb93c488c0379e0d1"
    ]
  },
  "config": {
    "Entrypoint": [
      "/kaniko/executor"
    ],
    "Env": [
      "PATH=/usr/local/bin:/kaniko",
      "HOME=/root",
      "USER=root",
      "SSL_CERT_DIR=/kaniko/ssl/certs",
      "DOCKER_CONFIG=/kaniko/.docker/",
      "DOCKER_CREDENTIAL_GCR_CONFIG=/kaniko/.config/gcloud/docker_credential_gcr_config.json"
    ],
    "WorkingDir": "/workspace"
  }
}

This is adapted from google#735 but changes the UX a bit to match what we've come to expect from crane. Add pkg/crane.Upload as well, for uploading a layer.

codecov-commenter · 2021-08-12T00:03:45Z

Codecov Report

Merging #1104 (fb4d2f0) into main (bcbf8d3) will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #1104      +/-   ##
==========================================
+ Coverage   75.41%   75.44%   +0.02%     
==========================================
  Files         108      108              
  Lines        7685     7692       +7     
==========================================
+ Hits         5796     5803       +7     
  Misses       1334     1334              
  Partials      555      555

Impacted Files	Coverage Δ
pkg/crane/push.go	`100.00% <100.00%> (ø)`

Continue to review full report at Codecov.

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jonjohnsonjr · 2021-08-12T00:11:19Z

Re: reproducibility... a stupid idea:

If the original image ref is by digest, we could include only the digest in the created_by string. If it's by tag, we could include everything (repo:tag@digest).

It's a weak heuristic, but I think pretty okay. The only issue is if someone is flattening by digest and wants the original image ref, we'd exclude it.

cmd/crane/cmd/flatten.go

imjasonh · 2021-08-12T00:49:21Z

cmd/crane/cmd/flatten.go

+			// If the new ref isn't provided, write over the original image.
+			// If that ref was provided by digest (e.g., output from
+			// another crane command), then strip that and push the
+			// mutated image by digest instead.


In #960 if you rebase by digest we'll push to :rebased unless you tell us what to push to. I don't love it, but I especially don't love it if it's going to disagree with the UX of crane flatten <img-by-digest>.

I don't love that either, can do the same thing in #960 that we do here?

imjasonh · 2021-08-12T00:54:40Z

cmd/crane/cmd/flatten.go

+				log.Fatalf("parsing %s: %v", newRef, err)
+			}
+			if _, ok := r.(name.Digest); ok {
+				// If we're pushing by digest, we need to upload the layer first.


This is because the stream.Layer's digest won't be known until it's uploaded, right? Does pushing to some fallback tag instead help here?

I'd rather not push to a fallback tag because that might overwrite an existing tag or pollute the registry.

imjasonh · 2021-08-12T16:42:40Z

Can/should we detect and unset base image annotations from the flattened image?

jonjohnsonjr · 2021-08-12T18:21:24Z

Can/should we detect and unset base image annotations from the flattened image?

I'd lean towards no. The base image is still the same, because in theory this is an equivalent but flattened image. If you wanted to rebuild based on the base changing, you could do rebuild && flatten. You could argue that the original image is the base image, but I'm not sure if we want to assume that.

imjasonh · 2021-08-12T18:48:01Z

cmd/crane/cmd/flatten.go

+			// Stupid hack to support insecure flag.
+			nameOpt := []name.Option{}
+			if ok, err := cmd.Parent().PersistentFlags().GetBool("insecure"); err != nil {
+				log.Fatalf("flag problems: %v", err)
+			} else if ok {
+				nameOpt = append(nameOpt, name.Insecure)
+			}
+			r, err := name.ParseReference(newRef, nameOpt...)
+			if err != nil {
+				log.Fatalf("parsing %s: %v", newRef, err)
+			}
+
+			desc, err := crane.Head(ref, *options...)
+			if err != nil {
+				log.Fatalf("checking %s: %v", ref, err)
+			}
+			if !cmd.Parent().PersistentFlags().Changed("platform") && desc.MediaType.IsIndex() {
+				log.Fatalf("flattening an index is not yet supported")
+			}
+


brb stealing these 😄

jonjohnsonjr added 2 commits August 11, 2021 16:58

Add crane flatten

2a01001

This is adapted from google#735 but changes the UX a bit to match what we've come to expect from crane. Add pkg/crane.Upload as well, for uploading a layer.

./hack/update-codegen.sh

96c6e6c

jonjohnsonjr assigned imjasonh Aug 12, 2021

imjasonh reviewed Aug 12, 2021

View reviewed changes

Support --insecure in flatten

aeb09e6

jonjohnsonjr added 2 commits August 12, 2021 11:38

Make --platform work

e56253f

Make flatten location-independent

fb4d2f0

imjasonh approved these changes Aug 12, 2021

View reviewed changes

jonjohnsonjr merged commit bea59b9 into google:main Aug 12, 2021

jonjohnsonjr deleted the flatten branch August 12, 2021 18:49

imjasonh mentioned this pull request Aug 12, 2021

Implement annotation-based rebase hints #960

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Add crane flatten #1104

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Add crane flatten #1104

Add crane flatten #1104

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