Key rotation in Panda

[rtyley]

This is mainly notes for Roberto, feel free to ignore:

pan-domain-authentication/pan-domain-auth-play/src/main/scala/com/gu/pandomainauth/action/Actions.scala

Lines 200 to 218 in 7c182f8

	def readAuthenticatedUser(request: RequestHeader): Option[AuthenticatedUser] = readCookie(request) map { cookie =>
	CookieUtils.parseCookieData(cookie.cookie.value, settings.publicKey)
	}
	def readCookie(request: RequestHeader): Option[PandomainCookie] = {
	request.cookies.get(settings.cookieSettings.cookieName).map { cookie =>
	val forceExpiry = request.cookies.get(FORCE_EXPIRY_KEY).exists(_.value != "0")
	PandomainCookie(cookie, forceExpiry)
	}
	}
	def generateCookie(authedUser: AuthenticatedUser): Cookie =
	Cookie(
	name = settings.cookieSettings.cookieName,
	value = CookieUtils.generateCookieData(authedUser, settings.privateKey),
	domain = Some(domain),
	secure = true,
	httpOnly = true
	)

There can be two PanDomainAuthSettingsRefresher instances in a single project:

https://github.com/guardian/login.gutools/blob/31f80134fb99b020acfa2d3196171ad549365082/app/AppComponents.scala#L14-L31