switch to envconfig for configuration

[arschles]

the ./pkg/config/env package has lots and lots of envy.Get (and friends) calls, with defaults, type conversions, etc...

let's remove all that duplicated code and use envconfig

[marwan-at-work]

@arschles Should we have a config struct with all of our expected environment variables?

[ghost]

I think so @marwan-at-work. What do you think about using an init to first load the config, then the subsequent calls can return needed variables?

[michalpristas]

👍 for a configuration file. keep dev defaults there. we can inject/replace the file with test/prod env easily on deploy

[marwan-at-work]

What about having a json or toml representation of that config struct and so instead of populating env variables and keeping track of them, we just have one file where all this stuff lives.
Something like this

type Config struct {
  GoBinPath string
  OlympusGlobalURL string
  DebugLevel string
  ...
}

And then we can have several json representations for different environments:

config.local.json

{
  "GoBinPath": "go",
  "OlympusGlobalURL": "http://localhost:3001",
  "DebugLevel": "debug"
}

and then config.prod.json

{
  "GoBinPath": "go",
  "OlympusGlobalURL": "https://www.olympus.com",
  "DebugLevel": "warning"
}

This way we don't need envconfig, or we can use it for overrides in the config if we really want to. Which is cool w/ me.

We can also use https://github.com/go-playground/validator to validate that some Config fields are required as such

type Config struct {
  GoBinPath string `validate:"required"` 
  OlympusGlobalURL string `env:"OLYMPUS_GLOBAL_URL"`
  DebugLevel string
  ...
}

[rohancme]

I'll work on this!