This repository contains modules to load configuration analogous to the Global gem. Refere to Global's documentation for more details

See main Global documentation for setup instructions.

go get github.com/railsware/go-global/v2/aws

import (
  "os"
  awsConfig "github.com/aws/aws-sdk-go-v2/config"
  globalAWS "github.com/railsware/go-global/v2/aws"
)
type Config struct {
  Database struct {
    PoolSize int `json:"pool_size"`
    URLs []string `json:"urls"`
  } `json:"database"`
}
var config Config
awsConfig, err := awsConfig.LoadDefaultConfig(context.TODO())
if err != nil {
  log.Fatalf("cannot load aws config: %v", err)
}
awsParamPrefix := os.Getenv("AWS_PARAM_PREFIX")
err := globalAWS.LoadConfigFromParameterStore(
  awsConfig,
  globalAWS.LoadConfigOptions{ParamPrefix: awsParamPrefix},
  &config
)
// config.Database.URLs[0] loaded from /param_prefix/database/urls/0
// config.Database.PoolSize loaded from /param_prefix/database/pool_size

• Supported value types: string, int, bool ("carview.php?tsp=true"/"false").

• A []byte can be loaded from Base64 encoded string.

• Complex type should be either a struct, a map or a slice. You can arbitrarily nest them.

• For structs, use global or json tag to set field name.

• For maps, the key name is the map key (maps must use strings as keys.)

• For slices, all subscripts in Parameter Store must be integers.

If you use Global in AWS environments, you can DRY up the code by following a convention:

• Set up param prefix in the AWS_PARAM_PREFIX environment variable.
• Make sure the IAM role has permissions to the params

Then you can simply use:

var config Config
// Will panic if anything goes wrong
globalAWS.MustLoadConfig(&config)

By default, Global assumes that all params from Parameter Store must be mapped to config fields, and returns a warning if some param does not correspond to a config field.

Sometimes, it is expected that the config only contains a subset of the params, and such a warning is unnecessary.

In this case, set options.IgnoreUnmappedParams to true. Note that other mapping issues, like a type mismatch, will still cause an error.