fabric

Package coreservices/configurator

The configurator is a core microservice of Microbus and it must be included with practically all applications. Microservices that define config properties will not start if they cannot reach the configurator. This is why you’ll see the configurator included first in most self-contained apps, such as in main/main.go:

func main() {
	app := application.New()
	app.Add(
		// Configurator should start first
		configurator.NewService(),
	)
	app.Add(
		// Other microservices...
	)
	err := app.Run()
	if err != nil {
		fmt.Fprintf(os.Stderr, "%+v", err)
		os.Exit(19)
	}
}

The configurator is the owner of the values of the configuration properties. It loads these values from config.yaml and config.local.yaml files located in the current working directory and its ancestor directories. Precedence is given to YAML files in a subdirectory over its ancestor directory. Within a given directory, config.local.yaml takes precedence over config.yaml.

domain:
  PropertyName: PropertyValue

A property value is applicable to a microservice that defines a property with the same name, and whose hostname equals or is a sub-domain of the domain name. The special domain all applies to all microservices. For example, in the following example, the value of Foo is applicable only to the www.example.com microservice, while the value of Moo is applicable to both www.example.com and zzz.example.com. The value of Zoo is applicable only to zzz.example.com.

www.example.com:
  Foo: Bar
example.com:
  Moo: Cow
all:
  Zoo: Keeper

www := connector.New("www.example.com")
www.DefineConfig("Foo")
www.DefineConfig("Moo")

zzz := connector.New("zzz.example.com")
zzz.DefineConfig("Moo")
zzz.DefineConfig("Zoo")

Note that both domain names and case insensitive, while property names are case sensitive.

Every 20 minutes the configurator broadcasts the command https://all:888/config-refresh to instruct all microservices to refresh their config. They respond by calling the configurator’s :888/values endpoint to fetch the current values. This guarantees that microservices do not fall out of sync with their configuration, at least not for long.

The :444/refresh endpoint can be called manually to force a refresh at any time.

This site is open source. Improve this page.