This checks the request against the `read` permission for
`sys/events/subscribe/{eventType}` on the initial subscribe.
Future work includes moving this to its own verb (`subscribe`)
and periodically rechecking the request.
Tested locally by minting a token with the wrong permissions
and verifying that they are rejected as expected, and that
they work if the policy is adjusted to `sys/event/subscribe/*`
(or the specific topic name) with `read` permissions.
I had to change the `core.checkToken()` to be publicly accessible,
as it seems like the easiest way to check the token on the
`logical.Request` against all relevant policies, but without
going into all of the complex logic further in `handleLogical()`.
Co-authored-by: Tom Proctor <tomhjp@users.noreply.github.com>
Also updates the event receieved to include a timestamp.
Websockets support both JSON and protobuf binary formats.
This can be used by either `wscat` or the new
`vault events subscribe`:
e.g.,
```sh
$ wscat -H "X-Vault-Token: $(vault print token)" --connect ws://127.0.0.1:8200/v1/sys/events/subscribe/abc?json=true
{"event":{"id":"5c5c8c83-bf43-7da5-fe88-fc3cac814b2e", "note":"testing"}, "eventType":"abc", "timestamp":"2023-02-07T18:40:50.598408Z"}
...
```
and
```sh
$ vault events subscribe abc
{"event":{"id":"5c5c8c83-bf43-7da5-fe88-fc3cac814b2e", "note":"testing"}, "eventType":"abc", "timestamp":"2023-02-07T18:40:50.598408Z"}
...
```
Co-authored-by: Tom Proctor <tomhjp@users.noreply.github.com>
