RPC method to translate dbt CLI strings into RPC tasks

The rpc server provides methods like run, compile, test, etc. These methods accept a params: dictionary that configures the nature of the task. The dbt rpc server should make it possible to translate a CLI string (eg. dbt run --models abc+) into a method query. In this case, that would look like:

{
  "method": "run",
  "params": {
    "models": "abc+"
  }
}

There are broadly two ways we can accomplish this:

1. Add a new method (eg. run_dbt_task) which accepts a CLI-string and proxies the request to the appropriate task (and returns the delegated response).
2. Add a new method which accepts a CLI-string and returns a parsed representation of the command, which can be used to query the appropriate method

Of these, I think the first approach would be preferable (avoid an extra round-trip) if it doesn’t make the RPC server implementation too convoluted. What say you @beckjake?

[beckjake]

I’m not sure yet, but my idea is:

• an RPC-specific argument parser that raises a dbt exception on exit and a mechanism to choose the parser class in parse_args
• some way for RPC tasks to take either the existing dictionaries or a parsed args object
• A new RPC task that takes in a string, builds an argparse.args, and uses the cls attribute of the parsed args to decide which “real” RPC task to delegate to

This way involves the least possible amount of code rewriting, I think.

[beckjake]

I think it’s easier to just take a string, we can feed it directly to argparse and translate the cls value into its RPC equivalent or something.

I do wish we’d had this design from the start, I would have designed it to be easier to support this behavior.