CLI: 'env' command moved to 'env dump' subcommand

[pda]

Move the buildkite-agent env command (which dumps environment to stdout) to buildkite-agent env dump, making buildkite-agent env just a container for this and any future subcommands relating to environment.

As suggested by @sj26 in October: #1803 (comment)

More recently the idea of a buildkite-agent env set <key> <value> command came up in Re: 💡 Agent sockets - Pipelines Dispatch ⚙️

It's relatively safe to assume that the only usage of the existing buildkite-agent env command is by the agent itself, making it essentially a private/internal API which we can safely change.

[triarius]

Suggested change

	{
	Name: "env",
	Usage: "Something something environment variables",
	Subcommands: []cli.Command{
	clicommand.EnvDumpCommand,
	},
	},
	{
	Name: "env",
	Usage: "Something something environment variables",
	Subcommands: []cli.Command{
	clicommand.EnvDumpCommand,
	},
	Action: clicommand.EnvDumpAction,
	},

I think something like this (with appropriate changes in clicommand/env_dump.go) should work to allow buildkite-agent env and buildkite-agent env dump to be synonymous.

Not only does it preserve backward compatibility (up to the flag changes you made), but I actually think this is desirable behaviour in the long term.

[pda]

but I actually think this is desirable behaviour in the long term

I wonder. I don't think dumping the process' current env is very useful outside the one weird use-case we have internally, which we hope to eliminate via control sockets. I can't imagine a user actually wanting to use buildkite-agent env to see their environment as JSON. I'd rather it show the usage and list of subcommands.

[DrJosh9000]

If we're making what is technically a breaking change, you'd appreciate if it went out as soon as possible (in the next release)?

[pda]

Yeah I guess the sooner the better, but not urgent if we feel it needs more discussion.

[pda]

agent.Expect("env") -> agent.Expect("env", "dump")

Thanks — I was just looking into that, and now I don't have to finish doing that :)

[DrJosh9000]

It feels strange to be able to do that 😅