Ability to detect health status of indexer

[PaulRBerg]

As discussed in the TG chat group, it's currently not possible to detect the health status of an Envio indexer.

[DZakh]

How do you do this with SubGraph?

[PaulRBerg]

I don't know

[DZakh]

I think to solve this by exposing progressBlockTimestamp, so in UI you can check if it doesn't change eg for 20seconds, you display a notification that there's an issue with the indexer and the data is 20seconds behind. What do you think?

[PaulRBerg]

Yeah that sounds like a good workaround, especially on L2s

[PaulRBerg]

@DZakh does this approach make sense to you?

Use the _meta table to fetch progressBlock:

query GetProgressBlock {
  _meta(where: { chainId: { _eq: 1 }}) {
    progressBlock
  }
}

And check that the returned progressBlock is close to the last block provided by the chain's RPC server. At the time of posting this comment, for Ethereum, the latest block is 23947294:

If the _meta.progressBlock is smaller than the RPC value by, say, 100 blocks, then we can consider Envio to be offline.

[DZakh]

Yes, this is what we use internally to detect that indexer is not progressing 👍

[PaulRBerg]

cool, thx for confirming