Clarify usage of Maven configuration

[jmesnil]

I find the usage of the Maven configuration ambiguous:

./prospero install --help
Install a new application server instance.

      --channel=<channel>   Channel file URL.
      --channel-repo=<channelRepositories>
                            URL of a remote Maven repository that contains artifacts required to build an application container.

-> I find the name channel-repo confusing. aiui, this parameter allows to configure any Maven repositories to fetch the application server bits. Could it be renamed to remote-repositories ?
-> The help message should be updated to something like: `URLs of remote Maven repositories that contains the artifacts required to install the application server ( multiple URLs are separated by comma).

      --local-repo=<localRepo>
                            Path to a local Maven repository.

-> should be path to the local Maven repository (there is always a single local maven repo).
-> could it default to $HOME/.m2/repository?

      --offline             Perform installation from local Maven repository only. Offline installation requires --local-repo to be configured.

-> if we provide a default value for local-repo, offline installation would not required it to be configured. wdyt?

If I want to perform an offline installation, ideally, I should be able to run

 ./prospero install --fpl=eap-8.0 --dir=eap8 --channel-repo=file:///Users/jmesnil/tmp/jboss-eap-8.0.0.Beta-maven-repository/maven-repository/ --offline

[jmesnil]

prospero/prospero-cli/src/main/java/org/wildfly/prospero/cli/commands/InstallCommand.java

Lines 116 to 117 in 8b3aab3

	.setChannelRepo(channelRepositories == null || channelRepositories.isEmpty() ?
	null : channelRepositories.get(0).toString())

Only the first URL from channel-repo is used, is that correct?

[spyrkob]

Only the first URL from channel-repo is used, is that correct?

That seems to be a mistake from when we moved to Picocli. I'll fix that

[spyrkob]

if we provide a default value for local-repo, offline installation would not required it to be configured. wdyt?

At the moment the default is to use a temporary folder for the local repository as there were some concerns about disk usage.
But we can make it so that if --local-repo is present without value it defaults to ~/.m2/repository, and if value is present it uses the specified folder?
Or maybe using ~/.m2/repository should be default, --local-repo allows to change this location and a new flag (eg --no-local-repo) would use the temp?

[jmesnil]

Or maybe using ~/.m2/repository should be default, --local-repo allows to change this location and a new flag (eg --no-local-repo) would use the temp?

That sounds a good approach. --no-local-repo could be renamed to --no-resolve-local-cache or something similar?

[spyrkob]

cc @marekkopecky