[config] Flatten config store & provide generic show/set

[christopheranderson]

Problem

Plugins currently have no way of hooking into config. Our config is relatively complex which creates the need for a schema/etc.

Desired solution

Flatten the config store (so it's just dict<string, string>) and provide config:show:index and config:set:index that add key/value

Specification

API changes

• bf config:show:index [--key/-k]
  • Behaviors:
    1. IF a key is specified AND the key exists, it shows that particular key's value
    2. IF a key is specified AND the key does NOT exist, it prints "undefined" [1]
    3. ELSE, when no key is specified, it shows all config (in json)
• bf config:set:index --key/-k --value/-v
  • Behaviors:
    1. IF key and/or value are not specified, return an error. Suggested text: "You must specify both --key and --value".
    2. ELSE key is set to value, regardless of whether the key existed previously. [2]

Storage changes

• The store SHOULD be flat
  • (i.e we'll move from [key: string]: any to [key: string]: string.)
• For plugin specific settings (i.e. qnamaker, chatdown, etc.), the pattern SHOULD be <plugin>__<key>[3].
  • This avoids conflicts with similar setting names (i.e. id, applicationKey, etc.)
• Existing CLI commands for qnamaker and telemetry SHOULD use this flat format

Notes

• [1]: This is based on the behavior of npm config get asdfasdfasdfasdf. git config --get asdfasdfasdf throws an error. My opinion is that this is the equivalent of a dictionary and many libraries return undefined/null/None when a key doesn't exist, so opting for npm behavior.
• [2]: This is different from our behavior with other "lossy" things like file overwrites, but it's consistent with npm/git CLI behaviors.
• [3]: This is borrowed from the ASP.NET IConfiguration environment variable parser. I've used it in a few other places (outside of .NET) and really enjoyed it. It avoids the problem of needing to concat names together. (i.e I can do QNAMAKER__IS_RANDOM_SETTING_SET and not QNAMAKER__ISRANDOMSETTINGSET which is more readable and I can still programatically distinguish namespace from just "space" underscores. This will allow us to pull config from env and config file, which will be useful once we start caring more about CI.

Scoping

We probably also need a delete command at a certain point, but we'll scope that out of this change since we want to squeeze it in to 4.6.

[munozemilio]

Config is already flatten. Only new commands are pending