README.md

container-report

This is an experimental tool that emits a JSON report of the contents of an image.

It's current intended use is to be passed two images and to have their reports diffed using diff.

Example:

$ go run ./ cgr.dev/chainguard/static -f etc/os-release --fileinfo lib/apk/db/installed

The above command produces this output:

{
  "config": {
    "architecture": "amd64",
    "author": "github.com/chainguard-dev/apko",
    "created": "2023-03-10T00:15:03Z",
    "history": [
      {
        "author": "apko",
        "created": "2023-03-10T00:15:03Z",
        "created_by": "apko",
        "comment": "This is an apko single-layer image"
      }
    ],
    "os": "linux",
    "rootfs": {
      "type": "layers",
      "diff_ids": [
        "sha256:37c70343fbc5f44533f0c42ea7a5ca6ba39082af6a9985ec692be4331f00d592"
      ]
    },
    "config": {
      "Env": [
        "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
        "SSL_CERT_FILE=/etc/ssl/certs/ca-certificates.crt"
      ],
      "User": "65532"
    }
  },
  "layers": [
    {
      "mediaType": "application/vnd.oci.image.layer.v1.tar+gzip",
      "size": 485822,
      "digest": "sha256:195eac9a778e27555a03d931a68d286437f05ad1196ce1202d9bfcd312b9710d"
    }
  ],
  "files": {
    "etc/os-release": {
      "Typeflag": 48,
      "Name": "etc/os-release",
      "Linkname": "",
      "Size": 199,
      "Mode": 420,
      "Uid": 0,
      "Gid": 0,
      "Uname": "root",
      "Gname": "root",
      "ModTime": "2023-03-09T19:15:03-05:00",
      "AccessTime": "0001-01-01T00:00:00Z",
      "ChangeTime": "0001-01-01T00:00:00Z",
      "Devmajor": 0,
      "Devminor": 0,
      "Xattrs": null,
      "PAXRecords": null,
      "Format": 2,
      "Contents": "NAME=\"Alpine Linux\"\nID=alpine\nVERSION_ID=3.18_alpha20230208\nPRETTY_NAME=\"Alpine Linux edge\"\nHOME_URL=\"https://alpinelinux.org/\"\nBUG_REPORT_URL=\"https://gitlab.alpinelinux.org/alpine/aports/-/issues\"\n"
    },
    "lib/apk/db/installed": {
      "Typeflag": 48,
      "Name": "lib/apk/db/installed",
      "Linkname": "",
      "Size": 44275,
      "Mode": 420,
      "Uid": 0,
      "Gid": 0,
      "Uname": "root",
      "Gname": "root",
      "ModTime": "2023-03-09T19:15:03-05:00",
      "AccessTime": "0001-01-01T00:00:00Z",
      "ChangeTime": "0001-01-01T00:00:00Z",
      "Devmajor": 0,
      "Devminor": 0,
      "Xattrs": null,
      "PAXRecords": null,
      "Format": 2,
      "Contents": ""
    }
  }
}

You can also inspect a file in a tar file, like you get from apko build or docker save:

crane pull cgr.dev/chainguard/static saved.tar
go run ./ file://saved.tar ...

Or an image in Docker storage:

docker pull cgr.dev/chainguard/static
go run ./ docker://cgr.dev/chainguard/static

go.mod

module github.com/chainguard-dev/container-report

go 1.20

require (
	github.com/google/go-containerregistry v0.13.0
	github.com/spf13/cobra v1.6.0
	golang.org/x/exp v0.0.0-20230310171629-522b1b587ee0
)

require (
	github.com/Microsoft/go-winio v0.6.0 // indirect
	github.com/containerd/stargz-snapshotter/estargz v0.12.1 // indirect
	github.com/docker/cli v20.10.20+incompatible // indirect
	github.com/docker/distribution v2.8.1+incompatible // indirect
	github.com/docker/docker v20.10.20+incompatible // indirect
	github.com/docker/docker-credential-helpers v0.7.0 // indirect
	github.com/docker/go-connections v0.4.0 // indirect
	github.com/docker/go-units v0.5.0 // indirect
	github.com/gogo/protobuf v1.3.2 // indirect
	github.com/inconshreveable/mousetrap v1.0.1 // indirect
	github.com/klauspost/compress v1.15.11 // indirect
	github.com/mitchellh/go-homedir v1.1.0 // indirect
	github.com/opencontainers/go-digest v1.0.0 // indirect
	github.com/opencontainers/image-spec v1.1.0-rc2 // indirect
	github.com/pkg/errors v0.9.1 // indirect
	github.com/sirupsen/logrus v1.9.0 // indirect
	github.com/spf13/pflag v1.0.5 // indirect
	github.com/vbatts/tar-split v0.11.2 // indirect
	golang.org/x/mod v0.6.0 // indirect
	golang.org/x/net v0.1.0 // indirect
	golang.org/x/sync v0.1.0 // indirect
	golang.org/x/sys v0.1.0 // indirect
	golang.org/x/tools v0.2.0 // indirect
)

go.sum

github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
github.com/Microsoft/go-winio v0.6.0 h1:slsWYD/zyx7lCXoZVlvQrj0hPTM1HI4+v1sIda2yDvg=
github.com/Microsoft/go-winio v0.6.0/go.mod h1:cTAf44im0RAYeL23bpB+fzCyDH2MJiz2BO69KH/soAE=
github.com/containerd/stargz-snapshotter/estargz v0.12.1 h1:+7nYmHJb0tEkcRaAW+MHqoKaJYZmkikupxCqVtmPuY0=
github.com/containerd/stargz-snapshotter/estargz v0.12.1/go.mod h1:12VUuCq3qPq4y8yUW+l5w3+oXV3cx2Po3KSe/SmPGqw=
github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
github.com/cpuguy83/go-md2man/v2 v2.0.2/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/docker/cli v20.10.20+incompatible h1:lWQbHSHUFs7KraSN2jOJK7zbMS2jNCHI4mt4xUFUVQ4=
github.com/docker/cli v20.10.20+incompatible/go.mod h1:JLrzqnKDaYBop7H2jaqPtU4hHvMKP+vjCwu2uszcLI8=
github.com/docker/distribution v2.8.1+incompatible h1:Q50tZOPR6T/hjNsyc9g8/syEs6bk8XXApsHjKukMl68=
github.com/docker/distribution v2.8.1+incompatible/go.mod h1:J2gT2udsDAN96Uj4KfcMRqY0/ypR+oyYUYmja8H+y+w=
github.com/docker/docker v20.10.20+incompatible h1:kH9tx6XO+359d+iAkumyKDc5Q1kOwPuAUaeri48nD6E=
github.com/docker/docker v20.10.20+incompatible/go.mod h1:eEKB0N0r5NX/I1kEveEz05bcu8tLC/8azJZsviup8Sk=
github.com/docker/docker-credential-helpers v0.7.0 h1:xtCHsjxogADNZcdv1pKUHXryefjlVRqWqIhk/uXJp0A=
github.com/docker/docker-credential-helpers v0.7.0/go.mod h1:rETQfLdHNT3foU5kuNkFR1R1V12OJRRO5lzt2D1b5X0=
github.com/docker/go-connections v0.4.0 h1:El9xVISelRB7BuFusrZozjnkIM5YnzCViNKohAFqRJQ=
github.com/docker/go-connections v0.4.0/go.mod h1:Gbd7IOopHjR8Iph03tsViu4nIes5XhDvyHbTtUxmeec=
github.com/docker/go-units v0.5.0 h1:69rxXcBk27SvSaaxTtLh/8llcHD8vYHT7WSdRZ/jvr4=
github.com/docker/go-units v0.5.0/go.mod h1:fgPhTUdO+D/Jk86RDLlptpiXQzgHJF7gydDDbaIK4Dk=
github.com/gogo/protobuf v1.3.2 h1:Ov1cvc58UF3b5XjBnZv7+opcTcQFZebYjWzi34vdm4Q=
github.com/gogo/protobuf v1.3.2/go.mod h1:P1XiOD3dCwIKUDQYPy72D8LYyHL2YPYrpS2s69NZV8Q=
github.com/google/go-containerregistry v0.13.0 h1:y1C7Z3e149OJbOPDBxLYR8ITPz8dTKqQwjErKVHJC8k=
github.com/google/go-containerregistry v0.13.0/go.mod h1:J9FQ+eSS4a1aC2GNZxvNpbWhgp0487v+cgiilB4FqDo=
github.com/inconshreveable/mousetrap v1.0.1 h1:U3uMjPSQEBMNp1lFxmllqCPM6P5u/Xq7Pgzkat/bFNc=
github.com/inconshreveable/mousetrap v1.0.1/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
github.com/kisielk/errcheck v1.5.0/go.mod h1:pFxgyoBC7bSaBwPgfKdkLd5X25qrDl4LWUI2bnpBCr8=
github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
github.com/klauspost/compress v1.15.11 h1:Lcadnb3RKGin4FYM/orgq0qde+nc15E5Cbqg4B9Sx9c=
github.com/klauspost/compress v1.15.11/go.mod h1:QPwzmACJjUTFsnSHH934V6woptycfrDDJnH7hvFVbGM=
github.com/mitchellh/go-homedir v1.1.0 h1:lukF9ziXFxDFPkA1vsr5zpc1XuPDn/wFntq5mG+4E0Y=
github.com/mitchellh/go-homedir v1.1.0/go.mod h1:SfyaCUpYCn1Vlf4IUYiD9fPX4A5wJrkLzIz1N1q0pr0=
github.com/opencontainers/go-digest v1.0.0 h1:apOUWs51W5PlhuyGyz9FCeeBIOUDA/6nW8Oi/yOhh5U=
github.com/opencontainers/go-digest v1.0.0/go.mod h1:0JzlMkj0TRzQZfJkVvzbP0HBR3IKzErnv2BNG4W4MAM=
github.com/opencontainers/image-spec v1.1.0-rc2 h1:2zx/Stx4Wc5pIPDvIxHXvXtQFW/7XWJGmnM7r3wg034=
github.com/opencontainers/image-spec v1.1.0-rc2/go.mod h1:3OVijpioIKYWTqjiG0zfF6wvoJ4fAXGbjdZuI2NgsRQ=
github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/russross/blackfriday/v2 v2.0.1/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
github.com/shurcooL/sanitized_anchor_name v1.0.0/go.mod h1:1NzhyTcUVG4SuEtjjoZeVRXNmyL/1OwPU0+IJeTBvfc=
github.com/sirupsen/logrus v1.7.0/go.mod h1:yWOB1SBYBC5VeMP7gHvWumXLIWorT60ONWic61uBYv0=
github.com/sirupsen/logrus v1.9.0 h1:trlNQbNUG3OdDrDil03MCb1H2o9nJ1x4/5LYw7byDE0=
github.com/sirupsen/logrus v1.9.0/go.mod h1:naHLuLoDiP4jHNo9R0sCBMtWGeIprob74mVsIT4qYEQ=
github.com/spf13/cobra v1.6.0 h1:42a0n6jwCot1pUmomAp4T7DeMD+20LFv4Q54pxLf2LI=
github.com/spf13/cobra v1.6.0/go.mod h1:IOw/AERYS7UzyrGinqmz6HLUo219MORXGxhbaJUqzrY=
github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
github.com/urfave/cli v1.22.4/go.mod h1:Gos4lmkARVdJ6EkW0WaNv/tZAAMe9V7XWyB60NtXRu0=
github.com/vbatts/tar-split v0.11.2 h1:Via6XqJr0hceW4wff3QRzD5gAk/tatMw/4ZA7cTlIME=
github.com/vbatts/tar-split v0.11.2/go.mod h1:vV3ZuO2yWSVsz+pfFzDG/upWH1JhjOiEaWq6kXyQ3VI=
github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
golang.org/x/exp v0.0.0-20230310171629-522b1b587ee0 h1:LGJsf5LRplCck6jUCH3dBL2dmycNruWNF5xugkSlfXw=
golang.org/x/exp v0.0.0-20230310171629-522b1b587ee0/go.mod h1:CxIveKay+FTh1D0yPZemJVgC/95VzuuOLq5Qi4xnoYc=
golang.org/x/mod v0.2.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
golang.org/x/mod v0.3.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
golang.org/x/mod v0.6.0 h1:b9gGHsz9/HhJ3HF5DHQytPpuwocVTChQJK3AvoLRD5I=
golang.org/x/mod v0.6.0/go.mod h1:4mET923SAdbXp2ki8ey+zGs1SLqsuM2Y0uvdZR/fUNI=
golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
golang.org/x/net v0.0.0-20200226121028-0de0cce0169b/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
golang.org/x/net v0.0.0-20201021035429-f5854403a974/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
golang.org/x/net v0.1.0 h1:hZ/3BUoy5aId7sCpA/Tc5lt8DkFgdVS2onTpJsZ/fl0=
golang.org/x/net v0.1.0/go.mod h1:Cx3nUiGt4eDBEyega/BKRp+/AlGL8hYe7U9odMt2Cco=
golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
golang.org/x/sync v0.0.0-20201020160332-67f06af15bc9/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
golang.org/x/sync v0.0.0-20201207232520-09787c993a3a/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
golang.org/x/sync v0.1.0 h1:wsuoTGHzEhffawBOhz5CYhcrV4IdKZbEyZjBMuTp12o=
golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/sys v0.0.0-20191026070338-33540a1f6037/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.1.0 h1:kunALQeHf1/185U1i0GOB/fy1IPRDDpuoOOqRReG57U=
golang.org/x/sys v0.1.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
golang.org/x/tools v0.0.0-20200619180055-7c47624df98f/go.mod h1:EkVYQZoAsY45+roYkvgYkIh4xh/qjgUK9TdY2XT94GE=
golang.org/x/tools v0.0.0-20210106214847-113979e3529a/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
golang.org/x/tools v0.2.0 h1:G6AHpWxTMGY1KyEYoAQ5WTtIekUUvDNjan3ugu60JvE=
golang.org/x/tools v0.2.0/go.mod h1:y4OqIKeOV/fWJetJ8bXPU1sEVniLMIyDAZWeHdV+NTA=
golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

main.go

package main

import (
	"archive/tar"
	"bytes"
	"context"
	"encoding/json"
	"flag"
	"fmt"
	"io"
	"log"
	"os"
	"os/signal"
	"path/filepath"
	"runtime"
	"strings"

	"github.com/google/go-containerregistry/pkg/authn"
	"github.com/google/go-containerregistry/pkg/name"
	v1 "github.com/google/go-containerregistry/pkg/v1"
	"github.com/google/go-containerregistry/pkg/v1/daemon"
	"github.com/google/go-containerregistry/pkg/v1/mutate"
	"github.com/google/go-containerregistry/pkg/v1/remote"
	"github.com/google/go-containerregistry/pkg/v1/tarball"
	"github.com/spf13/cobra"
	"golang.org/x/exp/slices"
)

var (
	platform = flag.String("platform", "linxu/amd64", "platform of image to get")
	// TODO: report files in all layers, incl whether they're shadowed by higher layers.
)

type report struct {
	Config v1.ConfigFile   `json:"config"`
	Layers []v1.Descriptor `json:"layers"`
	Files  map[string]file `json:"files,omitempty"`
}

type file struct {
	tar.Header
	Contents string
}

func main() {
	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
	defer cancel()

	if err := cmd().ExecuteContext(ctx); err != nil {
		os.Exit(1)
	}
}

func cmd() *cobra.Command {
	var platform string
	var files, fileinfos []string
	var limit int64
	var cfg, layers bool

	cmd := &cobra.Command{
		Args: cobra.ExactArgs(1),
		RunE: func(cmd *cobra.Command, args []string) error {
			ctx := cmd.Context()

			var img v1.Image
			if strings.HasPrefix(args[0], "file://") {
				img = must(tarball.ImageFromPath(strings.TrimPrefix(args[0], "file://"), nil))
			} else if strings.HasPrefix(args[0], "docker://") {
				img = must(daemon.Image(must(name.ParseReference(strings.TrimPrefix(args[0], "docker://")))))
			} else {
				img = must(remote.Image(must(name.ParseReference(args[0])),
					remote.WithContext(ctx),
					remote.WithPlatform(*must(v1.ParsePlatform(platform))),
					remote.WithAuthFromKeychain(authn.DefaultKeychain)))
			}

			report := report{
				Files: map[string]file{},
			}

			if layers {
				report.Layers = must(img.Manifest()).Layers
			}
			if cfg {
				report.Config = *must(img.ConfigFile())
			}

			rc := mutate.Extract(img)
			defer rc.Close()
			tr := tar.NewReader(rc)
			for {
				th, err := tr.Next()
				if err == io.EOF {
					break
				}
				if err != nil {
					log.Fatal(err)
				}

				if slices.Equal(files, []string{"all"}) ||
					slices.Contains(files, th.Name) ||
					slices.Contains(fileinfos, th.Name) {
					report.Files[th.Name] = file{
						Header: *th,
					}
				}

				if slices.Equal(files, []string{"all"}) || slices.Contains(files, th.Name) {
					var buf bytes.Buffer
					n, err := io.Copy(&buf, io.LimitReader(tr, limit))
					if err != nil {
						return err
					}
					c := buf.String()
					if n == limit {
						c += "[[[TRUNCATED]]]"
					}
					f := report.Files[th.Name]
					f.Contents = c
					report.Files[th.Name] = f
				}
			}

			enc := json.NewEncoder(os.Stdout)
			enc.SetIndent("", "  ")
			return enc.Encode(report)
		},
	}

	cmd.Flags().StringVar(&platform, "platform", "linux/amd64", "platform of the image to get")
	cmd.Flags().StringSliceVar(&fileinfos, "fileinfo", nil, "files to report metadata")
	cmd.Flags().StringSliceVarP(&files, "file", "f", nil, "files to fully read and report (or 'all')")
	cmd.Flags().Int64Var(&limit, "limit", 10000, "limit size of file bytes to report (or 'all')")
	cmd.Flags().BoolVar(&cfg, "config", true, "if true, report image config metadata")
	cmd.Flags().BoolVar(&layers, "layers", true, "if true, report layer metadata")
	return cmd
}

func must[T any](t T, err error) T {
	if err != nil {
		_, file, line, ok := runtime.Caller(1)
		prefix := "unknown line"
		if ok {
			prefix = fmt.Sprintf("%s:%d", filepath.Base(file), line)
		}
		log.Fatalf("%s: %v", prefix, err)
	}
	return t
}