Declare your application environment variables in a standardised way!

Tired of inconsistent environment variable handling 😮‍💨? Tired of having to use os.LookupEnv and implementing parsing every time you need to extract a value 😩? Are you especially tired of seeing duplicate code blocks when variables are used in more than one place 😤? Enter standardized environment variable parsing!

A stepwise instruction for a better way of life:

1. Define a place where you want your environment variables to be declared. This could be your application's main entrypoint, or a separate env package, whatever your heart desires.
2. Register your environment variables in the chosen place. Determine which are required and their datatypes.
3. Call Parse() and your declared variables are good to go.

package main

import (
  env "github.com/trebent/envparser"
  logging "github.com/trebent/megaapp/log"
)

var (
  logLevel = env.Register(*env.Opts[string]{
    Name:     "LOG_LEVEL",
    Desc:     "The log level of the application.",
    Required: true,
  })
)

func main() {
  // Output the environment parser help text to stdout when --help is executed.
  flag.CommandLine.SetOutput(os.Stdout)
	flag.Usage = func() {
		fmt.Fprintf(flag.CommandLine.Output(), "Usage of %s:\n", os.Args[0])
		fmt.Fprintf(flag.CommandLine.Output(), "\n")
		fmt.Fprintf(flag.CommandLine.Output(), envparser.Help())
	}
	flag.Parse()

  // Exits with exit code 1 in case the registered environment variables could
  // not be parsed according to the rules you set up.
  _ = env.Parse()

  logging.SetLogLevel(logLevel.Value())
  ...
}

See the Golang package. Documentation is provided as part of the code.