Fix START_CMD implementation

[tombeynon]

Adjusts the START_CMD implementation so that:

• Docker command takes precedence if set
• Next is START_CMD arg/env variable if set
• Otherwise cosmovisor run start if COSMOVISOR_ENABLED
• Otherwise $PROJECT_BIN start
• snapshot.sh script is always used if SNAPSHOT_PATH is set, with the command it runs set by the above logic

Also documents Cosmovisor support in the README, and adds a bit more logging so it's clear what's happening.

I considered adding a SNAPSHOT_ENABLED env instead of implicitly enabling with SNAPSHOT_PATH, but decided not to change that yet.

[PikachuEXE]

Tested on a testnet node with snapshot enabled
Seems working

[orenl-lava]

• Docker command takes precedence if set
• Next is START_CMD arg/env variable if set
• Otherwise cosmovisor run start if COSMOVISOR_ENABLED
• Otherwise $PROJECT_BIN start
  snapshot.sh script is always used if SNAPSHOT_PATH is set, with the command it runs set by the above logic

I'd prefer to treat cosmovisor like snapshot, i.e.
"cosmovisor is always used if COSMOVISOR_ENABLED is set, with the command set by the above logic."

Also, the separation between args ($@ case) and $START_CMD case is intentional, because the latter breaks when one of the args has includes a space.

[orenl-lava]

This would break if docker command has an arg that includes a (white)space, e.g. docker run .... arg1 arg2 "third arg" ... - the exec statements at lines 364/367 will not preserve the quotes. That s why the previous version kept the two cases - docker args and START_CMD - separately.

[tombeynon]

This might need tweaking a bit further then, but should be an easy enough change

[tombeynon]

I can take a look over the next few days unless you want to submit a PR, but could you raise an issue to explain it if not?

[tombeynon]

I'd prefer to treat cosmovisor like snapshot

The problem with that is cosmovisor can only run commands directed to the node binary, so you'd need to disable cosmovisor support if you want to run any other command, e.g. a simple ls. Snapshot can technically run any command just wrapped by the snapshot script. It feels too restrictive, especially since if you want to use cosmovisor with a custom command you can just pass the cosmovisor run prefix yourself.