Prysm: Slasher health check via rpc

[stefa2k]

🚀 Feature Request

Description

To monitor the services the beacon-chain already supplies a number of json-rpc but slasher doesn't have any kind of health check endpoints yet.

Describe the solution you'd like

Similar to beacon-chain implementing a simple json-rpc should do the trick, stating the slasher's connectivity to a beacon chain and availability for validators' submits. This can be as simple as https://api.prylabs.net/#/Node/GetSyncStatus

Describe alternatives you've considered

The working alternative right now is to just check if the service ports of slasher are open for requests. But this has some obvious downsides:

• another service could listen to this port
• no information on service's status

[prestonvanloon]

All binaries support a /healthz endpoint served on the monitoring port. The "healthz" endpoint returns a 200 when the node is healthy and a 500 when not healthy. It also prints out the statuses of current services. If this endpoint returns 200, then it is OK to serve requests.

• Beacon-chain http://localhost:8080/healthz
• Validator http://localhost:8081/healthz
• Slasher http://localhost:8082/healthz

[shayzluf]

Closing this issue. Please reopen if you think this issue have to be addressed further

[nisdas]

I think what @stefa2k is getting at is that currently the health check in the slasher doesn't tell us when its ready to serve data to external clients. I had a look at all the Status methods and they weren't checking for when the slasher is ready, just basic grpc errors. Reopening this until that is addressed.

[prestonvanloon]

@shayzluf Any update on this issue?

[shayzluf]

Will add those capabilities to healthz endpoint tomorrow @prestonvanloon