Can we export the buildkit LLB generated by envd?

[Xiaoaier-Z-L]

i can export LLB by buildkit's example, it's easy to generate dot layout, but i cann't make a visual dag graph by the LLB op, just as tensorboard's tensor graph, i think it's efficient to debug your LLB performant.

for example, i generate dot layout by buildkit's example and i want to make a further compare with the 0 and 1 example's llb.

buildkit0 llb

{
  "Op": {
    "Op": {
      "source": {
        "identifier": "docker-image://docker.io/library/alpine:latest"
      }
    },
    "platform": {
      "Architecture": "amd64",
      "OS": "linux"
    },
    "constraints": {}
  },
  "Digest": "sha256:665ba8b2cdc0cb0200e2a42a6b3c0f8f684089f4cd1b81494fbb9805879120f7",
  "OpMetadata": {
    "caps": {
      "source.image": true
    }
  }
}
{
  "Op": {
    "Op": {
      "source": {
        "identifier": "docker-image://docker.io/library/golang:1.19-alpine"
      }
    },
    "platform": {
      "Architecture": "amd64",
      "OS": "linux"
    },
    "constraints": {}
  },
  "Digest": "sha256:6d747b1fc73f23b8bd82f8430eeba451cfd0704594a8456867dc5425ace82ad9",
  "OpMetadata": {
    "caps": {
      "source.image": true
    }
  }
}
{
  "Op": {
    "inputs": [
      {
        "digest": "sha256:6d747b1fc73f23b8bd82f8430eeba451cfd0704594a8456867dc5425ace82ad9",
        "index": 0
      }
    ],
    "Op": {
      "exec": {
        "meta": {
          "args": [
            "apk",
            "add",
            "--no-cache",
            "g++",
            "linux-headers"
          ],
          "env": [
            "PATH=/usr/local/go/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
            "GOPATH=/go"
          ],
          "cwd": "/"
        },
        "mounts": [
          {
            "input": 0,
            "dest": "/",
            "output": 0
          }
        ]
      }
    },
    "platform": {
      "Architecture": "amd64",
      "OS": "linux"
    },
    "constraints": {}
  },
  "Digest": "sha256:ec8cb8bab7719e6f1b83bf76cfe3bbae2c885f0af14c016b730f50a2a2b6964c",
  "OpMetadata": {
    "caps": {
      "exec.meta.base": true,
      "exec.mount.bind": true
    }
  }
}
...

buildkit1 llb

{
  "Op": {
    "Op": {
      "source": {
        "identifier": "docker-image://docker.io/library/alpine:latest"
      }
    },
    "platform": {
      "Architecture": "amd64",
      "OS": "linux"
    },
    "constraints": {}
  },
  "Digest": "sha256:665ba8b2cdc0cb0200e2a42a6b3c0f8f684089f4cd1b81494fbb9805879120f7",
  "OpMetadata": {
    "caps": {
      "source.image": true
    }
  }
}
{
  "Op": {
    "inputs": [
      {
        "digest": "sha256:665ba8b2cdc0cb0200e2a42a6b3c0f8f684089f4cd1b81494fbb9805879120f7",
        "index": 0
      }
    ],
    "Op": {
      "exec": {
        "meta": {
          "args": [
            "apk",
            "add",
            "--no-cache",
            "git"
          ],
          "cwd": "/"
        },
        "mounts": [
          {
            "input": 0,
            "dest": "/",
            "output": 0
          }
        ]
      }
    },
    "platform": {
      "Architecture": "amd64",
      "OS": "linux"
    },
    "constraints": {}
  },
  "Digest": "sha256:66ebad2e1d306c811fa194515cbbec337b2783b9eb9a903e10127e707332ecbb",
  "OpMetadata": {
    "caps": {
      "exec.meta.base": true,
      "exec.mount.bind": true
    }
  }
}
{
  "Op": {
    "inputs": [
      {
        "digest": "sha256:66ebad2e1d306c811fa194515cbbec337b2783b9eb9a903e10127e707332ecbb",
        "index": 0
      }
    ],
    "Op": {
      "exec": {
        "meta": {
          "args": [
            "git",
            "clone",
            "https://github.com/moby/buildkit.git",
            "/go/src/github.com/moby/buildkit"
          ],
          "cwd": "/"
        },
        "mounts": [
          {
            "input": 0,
            "dest": "/",
            "output": 0
          }
        ]
      }
    },
    "platform": {
      "Architecture": "amd64",
      "OS": "linux"
    },
    "constraints": {}
  },
  "Digest": "sha256:0abdb41f3e324aca3959091ffefc21a14913923f411901bb2394a39942489281",
  "OpMetadata": {
    "caps": {
      "exec.meta.base": true,
      "exec.mount.bind": true
    }
  }
}
...

i think it's a cool feature, and can be great convenience to analysis envd's image build performance!

[kemingy]

ref to #1124

[Xiaoaier-Z-L]

i got it, thanks!