feature: store sync start timestamp

[bonustrack]

We should store a timestamp of when the instance started to sync, and potentially when it got fully sync, this would give us some data on how long it take to sync.

[bonustrack]

Actually this is something we should be able to get using process.uptime() on the server, (without changing Checkpoint).

[Sekhmet]

What we want to do with this startup time? Expose it on the API level? Like with /status route?

[bonustrack]

@Sekhmet It's for the console to better understand if a server is stuck, so ideally it should be exposed somewhere, either a REST endpoint or the GraphQL API. Maybe we can use the same approach for https://github.com/snapshot-labs/workflow/issues/641 too

[bonustrack]

Related: https://github.com/snapshot-labs/workflow/issues/640

[Sekhmet]

I think the best would be to expose /status endpoint like this:

{
  "startupTime": 12345,
  "indexers": {
    "sep": {
      "startBlock": 1500,
      "currentBlock": 1500,
      "latestBlock": 5000,
    }
  }
}

It can't really be integrated in Checkpoint as Checkpoint is HTTP agnostic (it exposes Express middleware by default, but you can use it with non-express.js servers as well, like with Apollo.

So maybe it could be a method Checkpoint.getStatus() that can then just be hooked up on the consumer side where needed.

[bonustrack]

What if it's part of the GraphQL API? This way it will be exposed by default to any Checkpoint instance

[Sekhmet]

We could make it part of GraphQL API, but it makes querying it harder (in status checks etc.).

[bonustrack]

Another approach is fine too for me