allow specification of source/target under a different name

[janl]

At the moment, the -u parameter specifics both the CouchDB instance that the _replicat[e|or] endpoint is used as well as the full URL for the source and target database you want to migrate.

I have a scenario where I want to run couch-continuum on a CouchDB instance that isn’t available to the public, and I also don’t want to install c-c on the machine that runs CouchDB. So I’m setting up an ssh tunnel, and try to target that, e.g. couch-continuum -N db_name -u http://127.0.0.1:11000.

This will make c-c fail because it will create a replication from http://127.0.0.1:1100/npm to http://127.0.0.1:1100/npm_temp_copy which won’t work because 127.0.0.1:11000 is only valid on the machine that initiated the ssh tunnel.

I tried using couch-continuum -N https://private-cluster-domain/db_name -u http://127.0.0.1:11000 but that then fails because that private-cluster-domain isn’t available to the machine that c-c runs on, so it can’t do its utility checks.

I’m not sure if this is our of scope for c-c, but I wanted to leave this here.