业务网关-分流插件

这里所指的分流插件非常类似于nginx的流量转发功能,或者叫反向代理。

背景

尽管nginx的流量转发功能也很强大,但业务上的一些变化有可能出现会让nginx的配置繁多,疲于应付,比如:某款APP随业务发展演化出众多业务线:酒店业务线,机票业务线,餐饮业务线,本地出行业务线。这些业务线的背后往往是不同的部门,不同的技术团队组成,因此会提供不同的服务供APP对接,如果每增加一个新服务都需要去nginx做配置,nginx的配置会随着业务的发展时间的推移变得沉重难以维护。因此我们可以将nginx定义为流量性的网关,与具体的业务无关,只负责基于域名的请求转发,而后端业务线的不同服务的不同由业务网关负责。

另外就是对服务进行逻辑分组的需求,比如将一些重要的请求划分到一组服务器,这组服务器是高性能的;其它边缘业务的请求划分的另外一组服务器,这组服务器配置相对低。再比如我们的灰度环境,均需要基本一定的规则来分配流量。

方案

捕获WebFlux的流量,然后后台将请求转发到相应服务,最后将响应的结果返回给客户端。

实现

捕获流量

实现自定义的WebHandler,

@Override
public Mono<Void> handle(final ServerWebExchange exchange) {

    return new DefaultDiabloPluginChain(plugins).execute(exchange);
}

实现一个插件职责链,调用不同的插件最终返回响应结果。


private static class DefaultDiabloPluginChain implements DiabloPluginChain {

        private int index;

        private final List<DiabloPlugin> plugins;

        DefaultDiabloPluginChain(final List<DiabloPlugin> plugins) {
            this.plugins = plugins;
        }

        @Override
        public Mono<Void> execute(final ServerWebExchange exchange) {

            if (this.index < plugins.size()) {
                DiabloPlugin plugin = plugins.get(this.index++);
                try {
                    return plugin.execute(exchange, this);
                } catch (Exception ex) {
                    log.error("DefaultDiabloPluginChain.execute, traceId: {}, uri: {}, error:{}", exchange.getAttribute(Constants.CLIENT_RESPONSE_TRACE_ID), exchange.getRequest().getURI().getPath(), Throwables.getStackTraceAsString(ex));

                    throw ex;
                }
            } else {
                return Mono.empty(); // complete
            }
        }
    }


分流插件实现


public class DividePlugin extends AbstractDiabloPlugin {

    private final UpstreamCacheManager upstreamCacheManager;

    private final WebClient webClient;

    public DividePlugin(final LocalCacheManager localCacheManager, final UpstreamCacheManager upstreamCacheManager, final WebClient webClient) {
        super(localCacheManager);
        this.upstreamCacheManager = upstreamCacheManager;
        this.webClient = webClient;
    }

    @Override
    protected Mono<Void> doExecute(final ServerWebExchange exchange, final DiabloPluginChain chain, final SelectorData selector, final RuleData rule) {
        final RequestDTO requestDTO = exchange.getAttribute(Constants.REQUESTDTO);
        final String traceId = exchange.getAttribute(Constants.CLIENT_RESPONSE_TRACE_ID);
        final DivideRuleHandle ruleHandle = GsonUtils.getInstance().fromJson(rule.getHandle(), DivideRuleHandle.class);

        String ruleId = rule.getId();
        final List<DivideUpstream> upstreamList = upstreamCacheManager.findUpstreamListByRuleId(ruleId);
        if (CollectionUtils.isEmpty(upstreamList)) {

            log.warn("DividePlugin.doExecute upstreamList is empty, traceId: {}, uri: {}, ruleName:{}", traceId, exchange.getRequest().getURI().getPath(), rule.getName());
            exchange.getResponse().setStatusCode(HttpStatus.SERVICE_UNAVAILABLE);
            return chain.execute(exchange);
        }

        final String ip = Objects.requireNonNull(exchange.getRequest().getRemoteAddress()).getAddress().getHostAddress();

        DivideUpstream divideUpstream =
                LoadBalanceUtils.selector(upstreamList, ruleHandle.getLoadBalance(), ip);

        if (Objects.isNull(divideUpstream)) {

            log.warn("DividePlugin.doExecute divideUpstream is empty, traceId: {}, uri: {}, loadBalance:{}, ruleName:{}, upstreamSize: {}", traceId, exchange.getRequest().getURI().getPath(), ruleHandle.getLoadBalance(), rule.getName(), upstreamList.size());
            exchange.getResponse().setStatusCode(HttpStatus.SERVICE_UNAVAILABLE);
            return chain.execute(exchange);
        }

        if (exchange.getAttributeOrDefault(Constants.GATEWAY_ALREADY_ROUTED_ATTR, false)) {
            log.warn("DividePlugin.doExecute alread routed, traceId: {}, uri: {}, ruleName:{}", traceId, exchange.getRequest().getURI().getPath(), rule.getName());

            exchange.getResponse().setStatusCode(HttpStatus.FORBIDDEN);
            return chain.execute(exchange);
        }
        exchange.getAttributes().put(Constants.GATEWAY_ALREADY_ROUTED_ATTR, true);

        exchange.getAttributes().put(Constants.GATEWAY_CONTEXT_UPSTREAM_HOST, divideUpstream.getUpstreamHost());
        exchange.getAttributes().put(Constants.GATEWAY_CONTEXT_RULE_ID, ruleId);

        HttpCommand command = new HttpCommand(exchange, chain,
                requestDTO, divideUpstream, webClient, ruleHandle.getTimeout());
        return command.doHttpInvoke();
    }

    public SelectorData filterSelector(final List<SelectorData> selectors, final ServerWebExchange exchange) {
        return selectors.stream()
                        .filter(selector -> selector.getEnabled() && filterCustomSelector(selector, exchange))
                        .findFirst().orElse(null);
    }

    private Boolean filterCustomSelector(final SelectorData selector, final ServerWebExchange exchange) {
        if (selector.getType() == SelectorTypeEnum.CUSTOM_FLOW.getCode()) {

            List<ConditionData> conditionList = selector.getConditionList();
            if (CollectionUtils.isEmpty(conditionList)) {
                return false;
            }

            // 后台初始定义为host且表达式为 =
            if (MatchModeEnum.AND.getCode() == selector.getMatchMode()) {
                ConditionData conditionData = conditionList.get(0);
                return Objects.equals(exchange.getRequest().getHeaders().getFirst("Host"), conditionData.getParamValue().trim());
            } else {
                return conditionList.stream().anyMatch(c -> Objects.equals(exchange.getRequest().getHeaders().getFirst("Host"), c.getParamValue().trim()));
            }

        }
        return true;
    }

    @Override
    public String named() {
        return PluginEnum.DIVIDE.getName();
    }

    @Override
    public Boolean skip(final ServerWebExchange exchange) {
        final RequestDTO body = exchange.getAttribute(Constants.REQUESTDTO);
        return !Objects.equals(Objects.requireNonNull(body).getRpcType(), RpcTypeEnum.HTTP.getName());
    }

    @Override
    public PluginTypeEnum pluginType() {
        return PluginTypeEnum.FUNCTION;
    }

    @Override
    public int getOrder() {
        return PluginEnum.DIVIDE.getCode();
    }

}

WebClient

将http请求转发出去,主要依赖WebClient,它提供了响应式接口。具体的操作封装在HttpCommand工具类中,核心代码如下:

public Mono<Void> doHttpInvoke() {

        URI uri = buildRealURL(divideUpstream, exchange);
        traceId = exchange.getAttribute(Constants.CLIENT_RESPONSE_TRACE_ID);
        if (uri == null) {
            log.warn("HttpCommand.doNext real url is null, traceId: {}, uri: {}", traceId, exchange.getRequest().getURI().getPath());
            exchange.getResponse().setStatusCode(HttpStatus.SERVICE_UNAVAILABLE);
            return chain.execute(exchange).then(Mono.defer(() -> Mono.empty()));
        }
        // 后续有时间再加 todo 没有清除掉
        // IssRpcContext.commitParams(IssRpcContextParamKey.TRACE_ID, traceId);

        if (requestDTO.getHttpMethod().equals(HttpMethodEnum.GET.getName())) {

            return webClient.get().uri(f -> uri)
                            .headers(httpHeaders -> {
                                httpHeaders.add(Constants.TRACE_ID, traceId);
                                httpHeaders.addAll(exchange.getRequest().getHeaders());
                            })
                            .exchange()
                            // 默认doOnError异常会传递
                            .doOnError(e -> log.error("HttpCommand.doHttpInvoke Failed to webClient get execute, traceId: {}, uri: {}, cause:{}", traceId, uri, Throwables.getStackTraceAsString(e)))
                            .timeout(Duration.ofMillis(timeout))
                            .flatMap(this::doNext);
        } else if (requestDTO.getHttpMethod().equals(HttpMethodEnum.POST.getName())) {

            return webClient.post().uri(f -> uri)
                            .headers(httpHeaders -> {
                                httpHeaders.add(Constants.TRACE_ID, traceId);
                                httpHeaders.addAll(exchange.getRequest().getHeaders());
                            })
                            .contentType(buildMediaType())
                            .body(BodyInserters.fromDataBuffers(exchange.getRequest().getBody()))
                            .exchange()
                            .doOnError(e -> log.error("HttpCommand.doHttpInvoke Failed to webClient post execute, traceId: {}, uri: {}, cause:{}", traceId, uri, Throwables.getStackTraceAsString(e)))
                            .timeout(Duration.ofMillis(timeout))
                            .flatMap(this::doNext);
        } else if (requestDTO.getHttpMethod().equals(HttpMethodEnum.OPTIONS.getName())) {
            return webClient.options().uri(f -> uri)
                            .headers(httpHeaders -> {
                                httpHeaders.add(Constants.TRACE_ID, traceId);
                                httpHeaders.addAll(exchange.getRequest().getHeaders());
                            })
                            .exchange()
                            .doOnError(e -> log.error("HttpCommand.doHttpInvoke Failed to webClient options execute, traceId: {}, uri: {}, cause:{}", traceId, uri, Throwables.getStackTraceAsString(e)))
                            .timeout(Duration.ofMillis(timeout))
                            .flatMap(this::doNext);
        } else if (requestDTO.getHttpMethod().equals(HttpMethodEnum.HEAD.getName())) {
            return webClient.head().uri(f -> uri)
                            .headers(httpHeaders -> {
                                httpHeaders.add(Constants.TRACE_ID, traceId);
                                httpHeaders.addAll(exchange.getRequest().getHeaders());
                            })
                            .exchange()
                            .doOnError(e -> log.error("HttpCommand.doHttpInvoke Failed to webClient head execute, traceId: {}, uri: {}, cause:{}", traceId, uri, Throwables.getStackTraceAsString(e)))
                            .timeout(Duration.ofMillis(timeout))
                            .flatMap(this::doNext);
        } else if (requestDTO.getHttpMethod().equals(HttpMethodEnum.PUT.getName())) {

            return webClient.put().uri(f -> uri)
                            .headers(httpHeaders -> {
                                httpHeaders.add(Constants.TRACE_ID, traceId);
                                httpHeaders.addAll(exchange.getRequest().getHeaders());
                            })
                            .contentType(buildMediaType())
                            .body(BodyInserters.fromDataBuffers(exchange.getRequest().getBody()))
                            .exchange()
                            .doOnError(e -> log.error("HttpCommand.doHttpInvoke Failed to webClient put execute, traceId: {}, uri: {}, cause:{}", traceId, uri, Throwables.getStackTraceAsString(e)))
                            .timeout(Duration.ofMillis(timeout))
                            .flatMap(this::doNext);

        } else if (requestDTO.getHttpMethod().equals(HttpMethodEnum.DELETE.getName())) {

            return webClient.delete().uri(f -> uri)
                            .headers(httpHeaders -> {
                                httpHeaders.add(Constants.TRACE_ID, traceId);
                                httpHeaders.addAll(exchange.getRequest().getHeaders());
                            })
                            .exchange()
                            .doOnError(e -> log.error("HttpCommand.doHttpInvoke Failed to webClient delete execute, traceId: {}, uri: {}, cause:{}", traceId, uri, Throwables.getStackTraceAsString(e)))
                            .timeout(Duration.ofMillis(timeout))
                            .flatMap(this::doNext);

        } else if (requestDTO.getHttpMethod().equals(HttpMethodEnum.PATCH.getName())) {
            return webClient.patch().uri(f -> uri)
                            .headers(httpHeaders -> {
                                httpHeaders.add(Constants.TRACE_ID, traceId);
                                httpHeaders.addAll(exchange.getRequest().getHeaders());
                            })
                            .contentType(buildMediaType())
                            .body(BodyInserters.fromDataBuffers(exchange.getRequest().getBody()))
                            .exchange()
                            .doOnError(e -> log.error("HttpCommand.doHttpInvoke Failed to webClient patch execute, traceId: {}, uri: {}, cause:{}", traceId, uri, Throwables.getStackTraceAsString(e)))
                            .timeout(Duration.ofMillis(timeout))
                            .flatMap(this::doNext);
        }

        log.warn("HttpCommand doHttpInvoke Waring no match doHttpInvoke end, traceId: {}, httpMethod: {}, uri: {}", traceId, requestDTO.getHttpMethod(), uri.getPath());

        return Mono.empty();
    }

网关项目开源

以上内容基于业务网关的一个小模块,详细请看这里:diablo在这里

posted on 2020-08-16 22:38  min.jiang  阅读(816)  评论(0编辑  收藏  举报