ElectrumX should accept local incoming connections even if it has not fully caught up with the bitcoin daemon

Steps to reproduce:

1. Setup ElectrumX.
2. Setup electrum with oneserver connecting one's own ElectrumX server that was just set up and is not fully blockchain synced yet.

Expected result:

ElectrumX accepts local incoming connection.

Actual result:

ElectrumX does not accept local incoming3 connection.

Issue

Quote https://electrumx-spesmilo.readthedocs.io/en/latest/environment.html

ElectrumX will not serve any incoming connections until it has fully caught up with your bitcoin daemon.

I am arguing that this shouldn't be the case. Should be changed. This seems to be a bug at least in context of using electrum with one's own self-hosted, local ElectrumX server.

ElectrumX should be supporting a local rcp connection when not synced to the tip of the blockchain, at least if some option (environment variable) is configured.

Why is that an issue?

Unexpected and very difficult to figure out what's wrong.

It is highly unusual to open/close a server/service (local) port depending on some internal state (progress of blockchain synchronization). This is the first server application which I've ever seen which is doing this. For example, if nginx is configured but there is an issue with PHP, nginx will show an error message. It won't just close the server listening port.

Suggested Solution

Could you please add an environment variable TRUSTEDSERVER (or better name)? If enabled, always allow local incoming connections.

Related

electrum unwanted disconnect from own ElectrumX server

Start with the readiness behavior described in the ElectrumX environment documentation and the related Electrum issue, then trace how incoming connections are gated while the bitcoin daemon is syncing and how environment settings are handled. Done means a configured local connection is accepted before synchronization completes, while the existing behavior remains unchanged when that setting is not enabled.