com.gu.management.switchables.scala Maven / Gradle / Ivy
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package com.gu.management
import java.util.concurrent.atomic.AtomicBoolean
/**
* This trait should be used by anything that wants to read
* the state of a switch
*/
trait Switch {
def isSwitchedOn: Boolean
def isSwitchedOff: Boolean = !isSwitchedOn
def opt[T](block: => T): Option[T] = if (isSwitchedOn) Some(block) else None
}
object Switch {
object On {
def unapply(switch: Switch): Boolean = switch.isSwitchedOn
}
object Off {
def unapply(switch: Switch): Boolean = switch.isSwitchedOff
}
}
/**
* This trait should be used by anything that wants to
* mutate the state of a switch
*/
trait Switchable extends Switch {
def switchOn()
def switchOff()
/**
* @return a single url-safe word that can be used to construct urls
* for this switch.
*/
def name: String
/**
* @return a sentence that describes, in websys understandable terms, the
* effect of switching this switch
*/
def description: String
}
/**
* A simple implementation of Switchable that does the right thing in most cases
*/
case class DefaultSwitch(name: String, description: String, initiallyOn: Boolean = true) extends Switchable with Loggable {
private val isOn = new AtomicBoolean(initiallyOn)
def isSwitchedOn = isOn.get
def switchOn() {
logger.info("Switching on " + name)
isOn set true
}
def switchOff() {
logger.info("Switching off " + name)
isOn set false
}
}
class Switchboard(val applicationName: String, switches: Seq[Switchable]) extends HtmlManagementPage with Postable {
val title = "Switchboard"
val path = "/management/switchboard"
override val needsAuth = true
def body(r: HttpRequest) = {
val switchToShow = r getParameter "switch"
def shouldShow(s: Switchable) = switchToShow.map(s.name ==).getOrElse(true)
}
private def renderSwitch(s: Switchable) =
{ renderButtons(s) }
private def renderButtons(s: Switchable) =
if (s.isSwitchedOn)
ON
else
OFF
def post(r: HttpRequest) {
for (switch <- switches) {
r.getParameter(switch.name) match {
case Some("ON") => switch.switchOn()
case Some("OFF") => switch.switchOff()
case Some(other) => sys.error("Expected ON or OFF as value for " + switch.name + " parameter")
case _ => // ignore
}
}
}
}