Add port command

[LarsKumbier]

Adds the port command, closes #51

[AlexZeitler]

@LarsKumbier Thanks for your contribution. It's published on npm as 0.15.0

[stefanmeschke]

Thanks for this feature.
I think it would be very nice, if the port command returns only the port and not the whole address. And it is missing in the docs. :)

Do you agree? Should I raise a PR?

[AlexZeitler]

@stefanmeschke Makes sense to me.

@LarsKumbier Would this break something for you aside from only getting the port?
@Steveb-p Any thoughts?

[Steveb-p]

@AlexZeitler usually I believe we do not "enhance" original docker-compose responses. In this case, reading the port from the output is rather trivial, so introducing a special case might not be worth it.

After all, all you need to do to read the port from the output would then be as simple as

const output = "0.0.0.0:2181"
const pos = output.indexOf(":")
const port = output.slice(pos + 1)

[LarsKumbier]

yeah, but it get's more complicated with ipv6, error-messages of docker-compose, docker not reachable for whatever reason... string-parsing is just one of the things that is bound to break somewhen.

I think it would be a good addition to get a more structured output in this package to any of the commands, because everyone using this will currently write the same code to do the same things.

For this specific command, an output like this would be more appropriate:

{
    "address": "0.0.0.0",
    "originalPort": "33165"
}

So yeah, I'd like to see a generally changed output format like this:

{
  "raw": "<output>",
  "result": { "address": "0.0.0.0", "originalPort": "33165" }
}

[AlexZeitler]

@LarsKumbier That's exactly what I had in mind after reading the response from @Steveb-p. I think we should embrace this for each command/result.

We should use interfaces for result which would allow users of the lib to use TypeScripts declaration merging if a property on result is missing due to newer docker-compose(the underlying tool) version.

I think it would be a good addition to get a more structured output in this package to any of the commands, because everyone using this will currently write the same code to do the same things.

For this specific command, an output like this would be more appropriate:

{
    "address": "0.0.0.0",
    "originalPort": "33165"
}

So yeah, I'd like to see a generally changed output format like this:

{
  "raw": "<output>",
  "result": { "address": "0.0.0.0", "originalPort": "33165" }
}

[stefanmeschke]

I really like the idea of

{
  "raw": "<output>",
  "result": { "address": "0.0.0.0", "originalPort": "33165" }
}

To be backward compatible it could be something like this:

export interface IDockerComposeResult<T> {
  exitCode: number | null;
  out: string;
  err: string;
  result: T;
}

[AlexZeitler]

Yes. @stefanmeschke Please create a new issue and copy your suggestion and your last answer from here as a starting point to it.

Also please refer to this PR so we have everything tracked.

We should also define what result is in case of err.

[Steveb-p]

@stefanmeschke when output was not an address & port, what did you receive?

@AlexZeitler @stefanmeschke democratically I'm outvoted I guess :) and I do see the merit of what you want to do.

Can we open a new issue so we can check each and every call to docker-compose and decide when we're going with additional processing for them?