private ConfigResponse resolveConfig(HttpConfigRequest request, RequestHandler requestHandler) {
        log.log(Level.FINE, () -> "nocache=" + request.noCache());
        ConfigResponse config = requestHandler.resolveConfig(request.getApplicationId(), request, Optional.empty());
        if (config == null) HttpConfigRequest.throwModelNotReady();
        if (request.requiredGeneration().isPresent() && request.requiredGeneration().get() != config.getGeneration())
            HttpConfigRequest.throwPreconditionFailed(request.requiredGeneration().get());
        return config;
    }
HTTP handler for a getConfig operation

@author Ulf Lilleengen
configserver/src/main/java/com/yahoo/vespa/config/server/http/v2/HttpGetConfigHandler.java