cmd/tailscale/cli: stabilise the output of `tailscale lock log --json`

This patch changes the behaviour of `tailscale lock log --json` to make
it more useful for users. It also introduces versioning of our JSON output.

## Changes to `tailscale lock log --json`

Previously this command would print the hash and base64-encoded bytes of
each AUM, and users would need their own CBOR decoder to interpret it in
a useful way:

```json
[
  {
    "Hash": [
      80,
      136,
      151,
      …
    ],
    "Change": "checkpoint",
    "Raw": "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"
  }
]
```

Now we print the AUM in an expanded form that can be easily read by scripts,
although we include the raw bytes for verification and auditing.

```json
{
  "SchemaVersion": "1",
  "Messages": [
    {
      "Hash": "KCEJPRKNSXJG2TPH3EHQRLJNLIIK2DV53FUNPADWA7BZJWBDRXZQ",
      "AUM": {
        "MessageKind": "checkpoint",
        "PrevAUMHash": null,
        "Key": null,
        "KeyID": null,
        "State": {
          …
        },
        "Votes": null,
        "Meta": null,
        "Signatures": [
          {
            "KeyID": "tlpub:e44874d1ea48ecf3d6dac8ca09cfe70dc958ad83b656393432016c3ed229c8d6",
            "Signature": "8yAKKHPpuOWsuTwfzgeAAPRXZIuCiavS5fjxeiCR2JTlYaU23NxNChezg7tVlEXdH+z151u9na/PQknxsSBwBQ=="
          }
        ]
      },
      "Raw": "pAEFAvYFpQH2AopYIAkPN-8V3cJpkoC5ZY2-RI2Bcg2q5G7tRAQQd67W3YpnWCDPOo4KGeQBd8hdGsjoEQpSXyiPdlm-NXAlJ5dS1qEbFlggylNJDQM5ZQ2ULNsXxg2ZBFkPl_D93I1M56_rowU-UIlYIPZ_SxT9EA2Idy9kaCbsFzjX_s3Ms7584wWGbWd_f_QAWCBHYZzYiAPpQ-NXN-1Wn2fopQYk4yl7kNQcMXUKNAdt1lggcfjcuVACOH0J9pRNvYZQFOkbiBmLOW1hPKJsbC1D1GdYIKrJ38XMgpVMuTuBxM4YwoLmrK_RgXQw1uVEL3cywl3QWCA0FilVVv8uys8BNhS62cfNvCew1Pw5wIgSe3Prv8d8pFggQrwIt6ldYtyFPQcC5V18qrCnt7VpThACaz5RYzpx7RNYIKskOA7UoNiVtMkOrV2QoXv6EvDpbO26a01lVeh8UCeEA4KjAQECAQNYIORIdNHqSOzz1trIygnP5w3JWK2DtlY5NDIBbD7SKcjWowEBAgEDWCD27LpxiZNiA19k0QZhOWmJRvBdK2mz-dHu7rf0iGTPFwQb69Gt42fKNn0FGwRUiav_k6dDF4GiAVgg5Eh00epI7PPW2sjKCc_nDclYrYO2Vjk0MgFsPtIpyNYCWEDzIAooc-m45ay5PB_OB4AA9Fdki4KJq9Ll-PF6IJHYlOVhpTbc3E0KF7ODu1WURd0f7PXnW72dr89CSfGxIHAF"
    }
  ]
}
```

This output was previously marked as unstable, and it wasn't very useful,
so changing it should be fine.

## Versioning our JSON output

This patch introduces a way to version our JSON output on the CLI, so we
can make backwards-incompatible changes in future without breaking existing
scripts or integrations.

You can run this command in two ways:

```
tailscale lock log --json
tailscale lock log --json=1
```

Passing an explicit version number allows you to pick a specific JSON schema.
If we ever want to change the schema, we increment the version number and
users must opt-in to the new output.

A bare `--json` flag will always return schema version 1, for compatibility
with existing scripts.

Updates https://github.com/tailscale/tailscale/issues/17613
Updates https://github.com/tailscale/corp/issues/23258

Signed-off-by: Alex Chan <alexc@tailscale.com>

Change-Id: I897f78521cc1a81651f5476228c0882d7b723606

0 files changed, 0 insertions, 0 deletions