Add support for container index to inspect endpoint

[pditommaso]

Summary

The goal of this issue is to extend the inspect endpoint so that when it's specified a container reference identified a manifest index, the index content is returned instead of the container using a default platform.

Description

Lets consider the following container image reference docker.io/library/busybox:1.36.1-musl. This identify a multi-platform container having the following index manifest

{
  "manifests" : [ {
    "annotations" : {
      "com.docker.official-images.bashbrew.arch" : "amd64",
      "org.opencontainers.image.base.name" : "scratch",
      "org.opencontainers.image.created" : "2024-09-11T15:32:52Z",
      "org.opencontainers.image.revision" : "5eb4e443534e093c4d8fe2b6761432430827cc95",
      "org.opencontainers.image.source" : "https://github.com/docker-library/busybox.git",
      "org.opencontainers.image.url" : "https://hub.docker.com/_/busybox",
      "org.opencontainers.image.version" : "1.36.1-musl"
    },
    "digest" : "sha256:9a53a254f289b4e9542024676c004f8d4810f785641f8bbbecce03dda576e037",
    "mediaType" : "application/vnd.oci.image.manifest.v1+json",
    "platform" : {
      "architecture" : "amd64",
      "os" : "linux"
    },
    "size" : 608
  }, {
    "annotations" : {
      "com.docker.official-images.bashbrew.arch" : "amd64",
      "vnd.docker.reference.digest" : "sha256:9a53a254f289b4e9542024676c004f8d4810f785641f8bbbecce03dda576e037",
      "vnd.docker.reference.type" : "attestation-manifest"
    },
    "digest" : "sha256:0361177897a7ac91b4ce83791d354ee0f34273b7ca1fcf06324d880591d26805",
    "mediaType" : "application/vnd.oci.image.manifest.v1+json",
    "platform" : {
      "architecture" : "unknown",
      "os" : "unknown"
    },
    "size" : 559
  }, {
    "annotations" : {
      "com.docker.official-images.bashbrew.arch" : "arm32v6",
      "org.opencontainers.image.base.name" : "scratch",
      "org.opencontainers.image.created" : "2024-09-11T15:32:52Z",
      "org.opencontainers.image.revision" : "f952f50fdb990288c88868e2dd4466bfee28bbfc",
      "org.opencontainers.image.source" : "https://github.com/docker-library/busybox.git",
      "org.opencontainers.image.url" : "https://hub.docker.com/_/busybox",
      "org.opencontainers.image.version" : "1.36.1-musl"
    },
    "digest" : "sha256:17934c55824eff3072923db6cd7c3ba00359e57b730e5581e7273c610738f910",
    "mediaType" : "application/vnd.oci.image.manifest.v1+json",
    "platform" : {
      "architecture" : "arm",
      "os" : "linux",
      "variant" : "v6"
    },
    "size" : 608
  }, {
    "annotations" : {
      "com.docker.official-images.bashbrew.arch" : "arm32v7",
      "org.opencontainers.image.base.name" : "scratch",
      "org.opencontainers.image.created" : "2024-09-11T15:32:52Z",
      "org.opencontainers.image.revision" : "9789898767be841976f1e28e0f89212db2de833d",
      "org.opencontainers.image.source" : "https://github.com/docker-library/busybox.git",
      "org.opencontainers.image.url" : "https://hub.docker.com/_/busybox",
      "org.opencontainers.image.version" : "1.36.1-musl"
    },
    "digest" : "sha256:c0d515df4d44c2a984c0aa8553e06b030a52c3800a6621e3ee393f3f42f8e995",
    "mediaType" : "application/vnd.oci.image.manifest.v1+json",
    "platform" : {
      "architecture" : "arm",
      "os" : "linux",
      "variant" : "v7"
    },
    "size" : 608
  }, {
    "annotations" : {
      "com.docker.official-images.bashbrew.arch" : "arm32v7",
      "vnd.docker.reference.digest" : "sha256:c0d515df4d44c2a984c0aa8553e06b030a52c3800a6621e3ee393f3f42f8e995",
      "vnd.docker.reference.type" : "attestation-manifest"
    },
    "digest" : "sha256:9a68437b860b73305b2e024ef5b59549de4854ca797f1ed5999fa8e0cc30d203",
    "mediaType" : "application/vnd.oci.image.manifest.v1+json",
    "platform" : {
      "architecture" : "unknown",
      "os" : "unknown"
    },
    "size" : 559
  }, {
    "annotations" : {
      "com.docker.official-images.bashbrew.arch" : "arm64v8",
      "org.opencontainers.image.base.name" : "scratch",
      "org.opencontainers.image.created" : "2024-09-11T15:32:52Z",
      "org.opencontainers.image.revision" : "9df05e09b53bcc7629ec0fc93242780ad29073b8",
      "org.opencontainers.image.source" : "https://github.com/docker-library/busybox.git",
      "org.opencontainers.image.url" : "https://hub.docker.com/_/busybox",
      "org.opencontainers.image.version" : "1.36.1-musl"
    },
    "digest" : "sha256:c6cdebd45a7b8fb6849484c6e079ed0db781d65bed367ae5804919ad3a4eda67",
    "mediaType" : "application/vnd.oci.image.manifest.v1+json",
    "platform" : {
      "architecture" : "arm64",
      "os" : "linux",
      "variant" : "v8"
    },
    "size" : 608
  }, {
    "annotations" : {
      "com.docker.official-images.bashbrew.arch" : "arm64v8",
      "vnd.docker.reference.digest" : "sha256:c6cdebd45a7b8fb6849484c6e079ed0db781d65bed367ae5804919ad3a4eda67",
      "vnd.docker.reference.type" : "attestation-manifest"
    },
    "digest" : "sha256:9d84b10e7a10cd4d54b3b6c8c94d1da57f7d14e4f7072d9f956c66ada1dbbdcc",
    "mediaType" : "application/vnd.oci.image.manifest.v1+json",
    "platform" : {
      "architecture" : "unknown",
      "os" : "unknown"
    },
    "size" : 559
  }, {
    "annotations" : {
      "com.docker.official-images.bashbrew.arch" : "i386",
      "org.opencontainers.image.base.name" : "scratch",
      "org.opencontainers.image.created" : "2024-09-11T15:32:52Z",
      "org.opencontainers.image.revision" : "cef2f29824bb353e1d13da2b52657f7645afb1ff",
      "org.opencontainers.image.source" : "https://github.com/docker-library/busybox.git",
      "org.opencontainers.image.url" : "https://hub.docker.com/_/busybox",
      "org.opencontainers.image.version" : "1.36.1-musl"
    },
    "digest" : "sha256:75d42d953cfefc2d76e9fad9552842624ced51571d8a549575a7d0bf92b6b030",
    "mediaType" : "application/vnd.oci.image.manifest.v1+json",
    "platform" : {
      "architecture" : "386",
      "os" : "linux"
    },
    "size" : 608
  }, {
    "annotations" : {
      "com.docker.official-images.bashbrew.arch" : "i386",
      "vnd.docker.reference.digest" : "sha256:75d42d953cfefc2d76e9fad9552842624ced51571d8a549575a7d0bf92b6b030",
      "vnd.docker.reference.type" : "attestation-manifest"
    },
    "digest" : "sha256:10191af490b0793ec16e9f37b5eaade84c4523d9fcc622453462defff1f64eac",
    "mediaType" : "application/vnd.oci.image.manifest.v1+json",
    "platform" : {
      "architecture" : "unknown",
      "os" : "unknown"
    },
    "size" : 559
  }, {
    "annotations" : {
      "com.docker.official-images.bashbrew.arch" : "ppc64le",
      "org.opencontainers.image.base.name" : "scratch",
      "org.opencontainers.image.created" : "2024-09-11T15:32:52Z",
      "org.opencontainers.image.revision" : "083d1a17d8cc851d6d29d798ca4b1f3ee4b6b564",
      "org.opencontainers.image.source" : "https://github.com/docker-library/busybox.git",
      "org.opencontainers.image.url" : "https://hub.docker.com/_/busybox",
      "org.opencontainers.image.version" : "1.36.1-musl"
    },
    "digest" : "sha256:1ebc4a9fb266aad32bfc753d9d5c87b6e1f1a6eb7a976784b4af28930af9a167",
    "mediaType" : "application/vnd.oci.image.manifest.v1+json",
    "platform" : {
      "architecture" : "ppc64le",
      "os" : "linux"
    },
    "size" : 608
  }, {
    "annotations" : {
      "com.docker.official-images.bashbrew.arch" : "ppc64le",
      "vnd.docker.reference.digest" : "sha256:1ebc4a9fb266aad32bfc753d9d5c87b6e1f1a6eb7a976784b4af28930af9a167",
      "vnd.docker.reference.type" : "attestation-manifest"
    },
    "digest" : "sha256:45f85288f5b67beffb4fb8ccafdf0b841f1f5b76f103841c5f23ba67385ee15b",
    "mediaType" : "application/vnd.oci.image.manifest.v1+json",
    "platform" : {
      "architecture" : "unknown",
      "os" : "unknown"
    },
    "size" : 559
  }, {
    "annotations" : {
      "com.docker.official-images.bashbrew.arch" : "riscv64",
      "org.opencontainers.image.base.name" : "scratch",
      "org.opencontainers.image.created" : "2024-09-11T15:32:52Z",
      "org.opencontainers.image.revision" : "32ea9383b7ff2b818d8a206ed264d5a721b5a290",
      "org.opencontainers.image.source" : "https://github.com/docker-library/busybox.git",
      "org.opencontainers.image.url" : "https://hub.docker.com/_/busybox",
      "org.opencontainers.image.version" : "1.36.1-musl"
    },
    "digest" : "sha256:2d91f6c14d238a12d20fa53250a1c5c9f5322c8457904103fb04184fad393077",
    "mediaType" : "application/vnd.oci.image.manifest.v1+json",
    "platform" : {
      "architecture" : "riscv64",
      "os" : "linux"
    },
    "size" : 608
  }, {
    "annotations" : {
      "com.docker.official-images.bashbrew.arch" : "riscv64",
      "vnd.docker.reference.digest" : "sha256:2d91f6c14d238a12d20fa53250a1c5c9f5322c8457904103fb04184fad393077",
      "vnd.docker.reference.type" : "attestation-manifest"
    },
    "digest" : "sha256:c7f2cc09e7b0bde204cb01cb04f1da1745a42c2995f76459fbe65d0f200566df",
    "mediaType" : "application/vnd.oci.image.manifest.v1+json",
    "platform" : {
      "architecture" : "unknown",
      "os" : "unknown"
    },
    "size" : 559
  }, {
    "annotations" : {
      "com.docker.official-images.bashbrew.arch" : "s390x",
      "org.opencontainers.image.base.name" : "scratch",
      "org.opencontainers.image.created" : "2024-09-11T15:32:52Z",
      "org.opencontainers.image.revision" : "6789229a68e5c3879f0eab31059f08466884e147",
      "org.opencontainers.image.source" : "https://github.com/docker-library/busybox.git",
      "org.opencontainers.image.url" : "https://hub.docker.com/_/busybox",
      "org.opencontainers.image.version" : "1.36.1-musl"
    },
    "digest" : "sha256:88a9b9e39c4f9b715a14b5cebe89bcbe16af930490b8aeb5632a003300568a09",
    "mediaType" : "application/vnd.oci.image.manifest.v1+json",
    "platform" : {
      "architecture" : "s390x",
      "os" : "linux"
    },
    "size" : 608
  }, {
    "annotations" : {
      "com.docker.official-images.bashbrew.arch" : "s390x",
      "vnd.docker.reference.digest" : "sha256:88a9b9e39c4f9b715a14b5cebe89bcbe16af930490b8aeb5632a003300568a09",
      "vnd.docker.reference.type" : "attestation-manifest"
    },
    "digest" : "sha256:bb77b53bfddda83eae274a1d304711c3cb820043ce5e67132ef77953f810d601",
    "mediaType" : "application/vnd.oci.image.manifest.v1+json",
    "platform" : {
      "architecture" : "unknown",
      "os" : "unknown"
    },
    "size" : 559
  } ],
  "mediaType" : "application/vnd.oci.image.index.v1+json",
  "schemaVersion" : 2
}

The access to a specific container requires providing a specific platform (ie. arch) e.g. linux/amd64.

The goal of this issues is to extend the inspect endpoint so that it returns the content of the index is the a specific platform is not specified