12 factor configuration as a typesafe struct in as little as two function calls
Manage your application config as a typesafe struct in as little as two function calls.
type MyConfig struct {
DatabaseUrl string `config:"DATABASE_URL"`
FeatureFlag bool `config:"FEATURE_FLAG"`
Port int // tags are optional. PORT is assumed
...
}
var c MyConfig
err := config.FromEnv().To(&c)
It's just simple, pure stdlib.
A field's type determines what strconv function is called.
All string conversion rules are as defined in the strconv package
time.Duration
follows the same parsing rules as time.ParseDuration
*net.URL
follows the same parsing rules as url.Parse
*net.URL
fields on the struct must be a pointerIf chaining multiple data sources, data sets are merged. Later values override previous values.
config.From("dev.config").FromEnv().To(&c)
Unset values remain intact or as their native zero value
Nested structs/subconfigs are delimited with double underscore
PARENT__CHILD
Env vars map to struct fields case insensitively
Any errors encountered are aggregated into a single error value
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.
No pointer members. If you really need one, just take the address of parts of your struct.
*url.URL
, which is explicitly a pointer for ease of use, matching the url
package conventions