in app/com/gu/floodgate/contentsource/ContentSourceApi.scala [183:188]
def cancelReindex(id: String, environment: String) = Action.async { implicit request =>
reindexService.cancelReindex(id, environment: String) map {
case Right(_) => Ok
case Left(error) => BadRequest(Json.toJson(ErrorResponse(error.message)))
}
}