freman/config

12 factor configuration as a typesafe struct in as little as two function calls

Config

Manage your application config as a typesafe struct in as little as two function calls.

type MyConfig struct {
	DatabaseUrl string
	Port int
	FeatureFlag bool
	...
}

var c MyConfig
config.FromEnv().To(&c)

How It Works

Its just simple, pure stdlib.

• The type of a field determines what strconv function is called.
• All string conversion rules are as defined in the strconv package
• If chaining multiple data sources, data sets are merged. Later values override previous values.
  • e.g. From("dev.config").FromEnv().To(&c)
• Unset values remain as their native zero value

Why you should use this

• Its the cloud-native way to manage config. See 12 Factor Apps
• Simple:
  • only 2 lines to configure.
• Composeable:
  • Merge local files and environment variables for effortless local development.
• small:
  • only stdlib
  • < 160 LoC

Design Philosophy.

Opinionated and narrow in scope. This library is only meant to do config binding. Feel free to use it on its own, or alongside other libraries.

• Only structs at the entry point. This keeps the API surface small.

• Slices are space delimited. This matches how environment variables and commandline args are handled by the go cmd.

• No slices of structs. The extra complexity isn't warranted for such a niche usecase.

• No maps. The only feature of maps not handled by structs for this usecase is dynamic keys.

  • TODO

• No pointer members. If you really need one, just take the address of parts of your struct.