Docker image for litewitness

[wolfv]

I think it would be helpful if there was an easy to spinup docker image for litewitness. On the one hand it could make it simpler for people to spin up their own witnesses. On the other, I would love to be able to simply use it for the witness conformance tests (https://github.com/prefix-dev/siglog/tree/main/witness-conformance).

Maybe we could also come up with a CLI interface / environment variables that could work across different witness implementations.

[FiloSottile]

Running a witness is a long-term commitment and it's very very important to persist storage. Ideally operators would also at least skim updates to protect from the witness software author (me). Docker can be made to work for those goals, but IMHO a ready-to-use image encourages deploying with automatic updates and ephemeral storage.

Litewitness has essentially no requirements of its environment, so I don't think this would save much effort either. The Dockerfile would be three lines.

[wolfv]

To clarify: My use case was for testing locally whether the transparency log implementation works fine. For that, I wanted to spin up a log server and local witness with eg docker compose.

I don't think running a witness should have a high barrier. Adding one to the witness network should maybe have a high barrier :)