Cobra: Runtime flags

[joernott]

I want to write a software which provides the contents of properties files (key=value), environment variables and command line flags as a unified map to the underlying template engine.

Is it possible in cobra to have flags which are "invented" by the user when invoking the command, e.g.

eb --myvar=myval

so that I will have a map { "myvar": "myval" } somewhere?

[bogem]

No, it's not possible.
Create flags by yourself for every config key as everyone does.

[dnephin]

If you're able to read the properties file before executing Command you can create the Command hierarchy and add flags before calling Execute().

But if you want to receive a map, it might be easier to just have a single flag -o with a https://godoc.org/github.com/spf13/pflag#StringSlice and specify it multiple times.

-o myvar=myval -o other=myval2 ...

You can also create your own custom flag type that builds a map: http://godoc.org/github.com/docker/cli/opts#MapOpts

A third option is to use a -- before your custom flags, like: ./bin -- --myvar=myval. That way you receive the flags as args, and you can parse them yourself into a map.

[joernott]

Thanks for your help, @dnephin this looks like a feasible way. The point is, that I have no idea which flags the user will specify unless I would do a very costly analysis of the templates to render (which I don't know before I don't have the command line parsed), so using a -o flag multiple times for these user defined parameters is a brilliant idea.

@bogem: At coding toime I don't know what the user will feed to the application. If I would be able to read their minds in advance, I would not need to get command line flags, I would take the needed information from my crystal ball.

[bogem]

@joernott sorry for my dumb and angry answer.
@dnephin offered the best solution how cobra can solve your problem.

[joernott]

@bogem Sorry for snapping at you. I really like cobra and want to use it for my project and I couldn't see the simple solution right in front of my eyes.

[bogem]

@joernott You're always welcome in our community!