Add the cert.create event

[espadolini]

This adds an event that's emitted whenever an auth server issues a certificate (or a set of certificates, like the SSH+TLS pair that is issued to users). The event is only emitted on user cert generation for now.

Sample events:

Local login

{
  "ei": 0,
  "event": "cert.create",
  "uid": "f41a1615-5147-4a1f-8a29-4f62ab0285d3",
  "code": "TC000I",
  "time": "2022-01-21T15:41:59.299Z",
  "cluster_name": "localtele.example.com",
  "cert_type": "user",
  "identity": {
    "user": "espadolini",
    "roles": [
      "access",
      "auditor",
      "editor"
    ],
    "logins": [
      "espadolini"
    ],
    "expires": "2022-01-22T03:41:59.298282Z",
    "route_to_cluster": "localtele.example.com",
    "traits": {
      "logins": [
        "espadolini"
      ]
    },
    "teleport_cluster": "localtele.example.com"
  }
}

OIDC login

{
  "ei": 0,
  "event": "cert.create",
  "uid": "8aa10300-4130-41ba-823f-508af9098688",
  "code": "TC000I",
  "time": "2022-01-21T15:32:43.448Z",
  "cluster_name": "localtele.example.com",
  "cert_type": "user",
  "identity": {
    "user": "edoardo.spadolini.2@teleportinfra.dev",
    "roles": [
      "access"
    ],
    "logins": [
      "-teleport-nologin-c5f6c25c-cb65-456c-bcca-d38c3f6b2cfa"
    ],
    "expires": "2022-01-22T21:32:43.439044Z",
    "route_to_cluster": "localtele.example.com",
    "traits": {
      "at_hash": [
        "uO_uGk7zRUoNWDZUnWi3gg"
      ],
      "aud": [
        "289270662827-193i30qgssofegigee0bad0gv6mr26pl.apps.googleusercontent.com"
      ],
      "azp": [
        "289270662827-193i30qgssofegigee0bad0gv6mr26pl.apps.googleusercontent.com"
      ],
      "email": [
        "edoardo.spadolini.2@teleportinfra.dev"
      ],
      "groups": [
        "this-gets-access-role@teleportinfra.dev",
        "this-gets-no-roles@teleportinfra.dev"
      ],
      "hd": [
        "teleportinfra.dev"
      ],
      "iss": [
        "https://accounts.google.com"
      ],
      "picture": [
        "https://lh3.googleusercontent.com/a/default-user=s96-c"
      ],
      "sub": [
        "101835025516069956467"
      ]
    },
    "teleport_cluster": "localtele.example.com"
  }
}

OIDC login after assuming a role through an access request

{
  "ei": 0,
  "event": "cert.create",
  "uid": "5867c39c-cbd9-4216-9c74-1e66f2800cf7",
  "code": "TC000I",
  "time": "2022-01-21T15:38:06.838Z",
  "cluster_name": "localtele.example.com",
  "cert_type": "user",
  "identity": {
    "user": "edoardo.spadolini.2@teleportinfra.dev",
    "roles": [
      "access",
      "auditor"
    ],
    "logins": [
      "-teleport-nologin-ecdf1efb-59c4-4abf-934f-3e1e085a53b9"
    ],
    "expires": "2022-01-22T21:37:32.018833Z",
    "route_to_cluster": "localtele.example.com",
    "traits": {
      "at_hash": [
        "JuNmTsSRPXl14Jj5Qt7M2A"
      ],
      "aud": [
        "289270662827-193i30qgssofegigee0bad0gv6mr26pl.apps.googleusercontent.com"
      ],
      "azp": [
        "289270662827-193i30qgssofegigee0bad0gv6mr26pl.apps.googleusercontent.com"
      ],
      "email": [
        "edoardo.spadolini.2@teleportinfra.dev"
      ],
      "groups": [
        "this-gets-access-role@teleportinfra.dev",
        "this-gets-no-roles@teleportinfra.dev"
      ],
      "hd": [
        "teleportinfra.dev"
      ],
      "iss": [
        "https://accounts.google.com"
      ],
      "picture": [
        "https://lh3.googleusercontent.com/a/default-user=s96-c"
      ],
      "sub": [
        "101835025516069956467"
      ]
    },
    "teleport_cluster": "localtele.example.com",
    "access_requests": [
      "44aa82d6-d8d3-4b11-85e8-6f548058b86d"
    ]
  }
}

Fixes half of TEL-Q321-7.

Closes #9591.

[russjones]

@espadolini Can you provide an example of what the event looks like, in particular the subject field?

[espadolini]

@espadolini Can you provide an example of what the event looks like, in particular the subject field?

Updated the PR description.

[russjones]

@espadolini I think we should break up the Subject into fields on the event. Users have to parse it right now and it's going to just get harder as we add support for Windows. Plus, even if we say something like it's comma separated, that will be what users expect forever and we'll be stuck with it even if it doesn't work for us in the future.

Also, what do you think about making it cert.create and having a field with the type of certificate. That way it's easier to extend this in the future to support host certs.

[espadolini]

@espadolini I think we should break up the Subject into fields on the event. Users have to parse it right now and it's going to just get harder as we add support for Windows. Plus, even if we say something like it's comma separated, that will be what users expect forever and we'll be stuck with it even if it doesn't work for us in the future.

I did it this way because I intended it to be more for security audit/postmortem situations rather than general event consumption. Should we replicate every field that goes into a tlsca.Identity instead? We'd have to keep the event in sync with every future addition to the Identity type.

Also, what do you think about making it cert.create and having a field with the type of certificate. That way it's easier to extend this in the future to support host certs.

Yeah, that's probably better.

[russjones]

@espadolini Let's change cert_type to be user or host, other than that looks good to me.

[codingllama]

@espadolini, please push changes after reviews to new commits, so it's easier to what changed in relation to the last round.

[espadolini]

@espadolini, please push changes after reviews to new commits, so it's easier to what changed in relation to the last round.

Sorry about that, I tend to just amend commits if they're almost completely rewritten - I'll be more mindful about it in the future.

[codingllama]

Sorry about that, I tend to just amend commits if they're almost completely rewritten - I'll be more mindful about it in the future.

No worries. In an ideal world GitHub would be more helpful in showing diffs. Or maybe I'm just bad at GitHub? 🤷

[russjones]

@espadolini Looks good to me, but make sure you make the webapps changes so this event shows up in the UI.

Feel free to merge this into master, but don't backport until you have the webapps changes for release branches.