plugin/ready/readiness.go

package ready

// The Readiness interface needs to be implemented by each plugin willing to provide a readiness check.
type Readiness interface {
	// Ready is called by ready to see whether the plugin is ready.
	Ready() bool
}
Add ready plugin (#2616) Add a ready plugin that allows plugin to signal when they are ready. Once a plugin is ready it is not queried again. This uses same mechanism as the health plugin: each plugin needs to implement an interface. Implement readines for the erratic plugin to aid in testing. Add README.md and tests moduled after the health plugin; which will be relegated to just providing process health. In similar vein to health this is a process wide setting. With this Corefile: ~~~ . { erratic whoami ready } bla { erratic whoami } ~~~ ready will lead to: ~~~ sh % curl localhost:8181/ready % dig @localhost -p 1053 mx example.org % curl localhost:8181/ready OK% ~~~ Meanwhile CoreDNS logs: ~~~ .:1053 bla.:1053 2019-02-26T20:59:07.137Z [INFO] CoreDNS-1.3.1 2019-02-26T20:59:07.137Z [INFO] linux/amd64, go1.11.4, CoreDNS-1.3.1 linux/amd64, go1.11.4, 2019-02-26T20:59:11.415Z [INFO] plugin/ready: Still waiting on: "erratic" 2019-02-26T20:59:13.510Z [INFO] plugin/ready: Still waiting on: "erratic" ~~~ ready can be used in multiple server blocks and will do the right thing; query all those plugins from all server blocks for readiness. This does a similar thing to the prometheus plugin. Signed-off-by: Miek Gieben <miek@miek.nl> 2019-03-07 20:35:16 +00:00			`package ready`

			`// The Readiness interface needs to be implemented by each plugin willing to provide a readiness check.`
			`type Readiness interface {`
			`// Ready is called by ready to see whether the plugin is ready.`
			`Ready() bool`
			`}`