HDDS-11878. Use CommandSpec to find top-level command

[adoroszlai]

What changes were proposed in this pull request?

Problem

GenericParentCommand provides a way to access GenericCli methods from sub-subcommands. However, its usage is tedious and comes with boilerplate code that needs to:

• implement GenericParentCommand
• define methods manually
• define member variable for @ParentCommand (injected by picocli)

Adding new methods to GenericParentCommand becomes harder the more implementations we have. The interface needs to be implemented on all sub-command levels.
Currently only very few implementations exists. Some subcommands access top-level command via similar parent chain, but without implementing GenericParentCommand.

Solution

Picocli keeps track of the command hierarchy and allows accessing the top-level command directly via CommandSpec.

Changes in this PR:

• Introduce new AbstractSubcommand/AbstractMixin base classes. Subcommands/mixins that want to access the top-level command can do so easily by extending it.
• Remove boilerplate implementation of GenericParentCommand.
• Remove parent chains where it is only used to access the top-level command.

Accessing the top-level command directly makes it easier to reorganize subcommands, add them to different parents, or even multiple parents at different levels.

https://issues.apache.org/jira/browse/HDDS-11878

How was this patch tested?

Tested some of the commands changed, that they still reflect the --verbose flag:

$ ozone sh --verbose volume info /vol1
Volume Name : vol1
VOLUME_NOT_FOUND org.apache.hadoop.ozone.om.exceptions.OMException: Volume vol1 is not found
	at org.apache.hadoop.ozone.om.protocolPB.OzoneManagerProtocolClientSideTranslatorPB.handleError(OzoneManagerProtocolClientSideTranslatorPB.java:763)
	at org.apache.hadoop.ozone.om.protocolPB.OzoneManagerProtocolClientSideTranslatorPB.getVolumeInfo(OzoneManagerProtocolClientSideTranslatorPB.java:462)
	at org.apache.hadoop.ozone.client.rpc.RpcClient.getVolumeDetails(RpcClient.java:498)

$ ozone admin container info 1
Container id: 1
Pipeline id: 9dc28c7f-4e45-4a3b-8d87-ce8b1d788e86
...

$ ozone admin --verbose container info 1
Container id: 1
Pipeline Info: Pipeline[ Id: 9dc28c7f-4e45-4a3b-8d87-ce8b1d788e86, Nodes: 5b43e396-c1e8-4ab0-907a-1988d8ae3ff7(ozone-datanode-1.ozone_default/172.17.0.8) ReplicaIndex: 0f40dd8b8-bf0d-4e71-b3b7-6f99cedbf786(ozone-datanode-3.ozone_default/172.17.0.9) ReplicaIndex: 0d930ec97-4ffd-4d49-8177-96430fc508ae(ozone-datanode-2.ozone_default/172.17.0.2) ReplicaIndex: 0, ReplicationConfig: RATIS/THREE, State:OPEN, leaderId:5b43e396-c1e8-4ab0-907a-1988d8ae3ff7, CreationTimestamp2024-12-13T21:28:06.443Z[UTC]]
...

CI:
https://github.com/adoroszlai/ozone/actions/runs/12428823594

[adoroszlai]

@nandakumar131 please review. This is based on your comment about removing GenericParentCommand.

[nandakumar131]

Thanks @adoroszlai for working on this.
At high level the change looks good to me, I will take a closer look at this tomorrow.

[nandakumar131]

Not related to this change:
While reviewing the code I realised that there are two ways in which we are handling MissingSubCommand.

throw new MissingSubcommandException(
        this.shell.getCmd().getSubcommands().get("xxx"));

and

GenericCli.missingSubcommand(spec);

Can we unify this as well? I can take it up.

[nandakumar131]

LGTM.

[nandakumar131]

This can be made private and only expose getOzoneConf to avoid creating multiple OzoneConfiguration. We can do this in a follow-up jira.

[adoroszlai]

Created HDDS-11992 for this, please feel free to pick up, if you have time, otherwise I can work on it.

[nandakumar131]

Thanks @adoroszlai for the contribution!

[adoroszlai]

Thanks @nandakumar131 for reviewing and merging this.

Not related to this change: While reviewing the code I realised that there are two ways in which we are handling MissingSubCommand.
...
Can we unify this as well? I can take it up.

Good point, but actually neither of these are necessary with the current version of picocli. This will be cleaned up in HDDS-11880.