New tt CLI module - cluster

[TarantoolBot]

Product: tt CLI
Since: with Tarantool 3.0
Audience/target: all
Root document: https://www.tarantool.io/en/doc/latest/reference/commands/
SME: @ psergee @ oleg-jukovec

Details

The patch introduces a new module cluster. The module has two
commands:

• show - to show a configuration for a cluster or an instance.
• publish - to publish a cluster or an instance configuration.

The target could be a cluster or an instance configuration. It could
be a fully-merged (from all sources) configuration for an application
or just a remote configuration part in case of etcd.

Usage:

• tt cluster show (<APP_NAME> | <APP_NAME:INSTANCE_NAME> | <URI>) [--validate]
  • The optional --validate flag enables validation for a showed
    configuration.
• tt cluster publish (<APP_NAME> | <APP_NAME:INSTANCE_NAME> | <URI>) file [--force]
  • The optional --force flag skips validation of uploaded
    configuration.

The APP_NAME is a name of an application.

The INSTANCE_NAME is a name of an instance in the application.

The URI specifies a etcd connection settings in the following format:

http(s)://[username:password@]host:port[/prefix][?arguments]

• prefix - a base path to Tarantool configuration in etcd.

Possible arguments:

• name - a name of an instance in the cluster configuration.
• timeout - a request timeout in seconds (default 3.0).
• ssl_key_file - a path to a private SSL key file.
• ssl_cert_file - a path to an SSL certificate file.
• ssl_ca_file - a path to a trusted certificate authorities (CA)
  file.
• ssl_ca_path - a path to a trusted certificate authorities (CA)
  directory.
• verify_host - set off (default true) verification of the
  certificate’s name against the host.
• verify_peer - set off (default true) verification of the peer’s
  SSL certificate.

See also: Working with tt cluster.

Part of #506
Requested by @oleg-jukovec in tarantool/tt@be252da.