pixiu 0.6.0 虽然艰辛，但在社区小伙伴的努力下发布了。这个版本不止有常规社区功能，还有很多功能特性是来源于ASoC-2022 Alibaba Summer of Code，OSPP（中科院软件所[开源软件供应链点亮计划]） , GSoC（Google Summer of Code) 提案内容。

New Features In v0.6.0

nacos config

背景：pixiu 的配置，启动配置项（conf.yaml），日志配置（log.yml）均是从本地文件加载，没有接入动态配置中心的能力，而日常生产环境中，配置通过配置中心集中下发管理是更为灵活和安全的方式之一。

动态配置下发的场景还有很多扩展，接入的组件也因公司的选型有所不同，当前我们主要考虑接入 nacos 配置中心。

注：在设计上可以考虑，如何在二次开发场景下更为“标准、安全、简单”的接入其他配置中心。

Pixiu 启动时从配置中心Nacos 拉取配置 conf.yaml 数据

pixiu.conf的配置不用配置static_resources，需要配置config-center和nacos：

config-center:
  type: nacos
  enable: true
nacos:
  server-configs:
    - ip_addr: "127.0.0.1"
      port: 8848
  client-config:
    username: nacos
    password: nacos

原来我们熟悉pixiu.conf配置内容放到了nacos中：

static_resources:
  listeners:
    - name: "net/http"
      protocol_type: "HTTP"
      address:
        socket_address:
          address: "0.0.0.0"
          port: 8881
      filter_chains:
          filters:
            - name: dgp.filter.httpconnectionmanager
              config:
                route_config:
                  routes:
                    - match:
                        prefix: "*"
                http_filters:
                  - name: dgp.filter.http.dubboproxy
                    config:
                      dubboProxyConfig:
                        auto_resolve: true
                        registries:
                          "zookeeper":
                            protocol: "zookeeper"
                            timeout: "3s"
                            address: "127.0.0.1:2181"
                            username: ""
                            password: ""
                        timeout_config:
                          connect_timeout: 5s
                          request_timeout: 5s

                server_name: "test_http_dubbo"
                generate_request_id: false
      config:
        idle_timeout: 5s
        read_timeout: 5s
        write_timeout: 5s
  shutdown_config:
    timeout: "60s"
    step_timeout: "10s"
    reject_policy: "immediacy"

更详细的配置参考samples： https://github.com/apache/dubbo-go-pixiu-samples/tree/main/dubbogo/simple/farconfnacos

nacos配置支持还需要进一步完善的功能：

• 动态托管/下发用户自定义配置
• 动态下发Pixiu配置

OSPP: Traffic Distribution

流量分发提供两种策略，基于 Request Header 和服务权重的流量切分。

canary-by-header

canary-by-header是要匹配的 Request Header 的值，当 Request Header 设置此值时，它将被路由到相应的cluster（cluster中绑定canary-by-header键值）。当请求不包含这一 Request Header 或 Header 值不匹配时，请求不会被发送到Canary版本，该策略适用于蓝绿发布以及A/B测试

canary-weight

这种策略适用于金丝雀部署，权重范围 0 - 100 按百分比将请求路由到指定的服务。权重为 0 意味着该金丝雀规则不会向 Canary 服务发送任何请求；权重为 100 意味着所有请求都将被发送到 Canary。

Add Graceful Shutdown

通过graceful shutdown 能力，在进程获得系统型号：SIGINT， SIGKILL, SIGTERM信号时执行graceful shutdown过程：拒绝新的请求；等待处理中请求完成直到timeout.

static_resources:
	.......
	.......
  shutdown_config:
    timeout: "60s"
    step_timeout: "10s"
    reject_policy: "immediacy"

配置方式参考： https://github.com/apache/dubbo-go-pixiu-samples/tree/main/shutdown

WASM Plugin for Pixiu

Pixiu 支持 WASM 插件机制，实现http fitler。

PIxiu与WASM扩展代码交互采取 Proxy-Wasm 规范，该规范是开源社区针对「网络代理场景」设计的一套 ABI 规范，采用该规范能让PIxiu复用社区既有的WASM扩展。

WASM原则上应该支持多种语言，这里以Go语言为例，最终通过tinygo编译成wasm文件。如果要实现我们的扩展WASM程序，需要按以下模版进行编码实现：

package main

import (
    "github.com/tetratelabs/proxy-wasm-go-sdk/proxywasm"
    "github.com/tetratelabs/proxy-wasm-go-sdk/proxywasm/types"
)

func main() {
    proxywasm.SetNewHttpContext(newHttpContext)
}

type myHttpContext struct {
    // you must embed the default context so that you need not to re-implement all the methods by yourself
    proxywasm.DefaultHttpContext
    contextID uint32
}

func newHttpContext(rootContextID, contextID uint32) proxywasm.HttpContext {
    return &myHttpContext{contextID: contextID}
}

// override
func (ctx *myHttpContext) OnHttpRequestHeaders(numHeaders int, endOfStream bool) types.Action {

    return types.ActionContinue
}

deploy pixiu as dubbo service ingress gateway in k8s istio

当dubbo部署istio + k8s环境中，pixiu可以作为dubbo provider的ingress gateway，接收dubbo/triple/http的流量，并将请求转发到dubbo provider中。

samples: https://github.com/apache/dubbo-go-pixiu-samples/tree/main/xds/dubbo-go-istio

ASoC 2022: Pixiu Metrics Implementation

Pixiu Metrics提供四个prometheus运行指标：

var reqCnt = &Metric{
	ID:          "reqCnt",
	Name:        "requests_total",
	Description: "How many HTTP requests processed, partitioned by status code and HTTP method.",
	Type:        "counter_vec",
	Args:        []string{"code", "method", "host", "url"},
}

var reqDur = &Metric{
	ID:          "reqDur",
	Name:        "request_duration_seconds",
	Description: "The HTTP request latencies in seconds.",
	Args:        []string{"code", "method", "url"},
	Type:        "histogram_vec",
	Buckets:     reqDurBuckets,
}

var resSz = &Metric{
	ID:          "resSz",
	Name:        "response_size_bytes",
	Description: "The HTTP response sizes in bytes.",
	Args:        []string{"code", "method", "url"},
	Type:        "histogram_vec",
	Buckets:     resSzBuckets,
}

var reqSz = &Metric{
	ID:          "reqSz",
	Name:        "request_size_bytes",
	Description: "The HTTP request sizes in bytes.",
	Args:        []string{"code", "method", "url"},
	Type:        "histogram_vec",
	Buckets:     reqSzBuckets,
}

var standardMetrics = []*Metric{
	reqCnt,
	reqDur,
	resSz,
	reqSz,
}

config配置http_filters: dgp.filter.http.prometheusmetric：

static_resources:
  listeners:
    - name: "net/http"
      protocol_type: "HTTP"
      address:
        socket_address:
          address: "0.0.0.0"
          port: 8888
      filter_chains:
        filters:
          - name: dgp.filter.httpconnectionmanager
            config:
              route_config:
                routes:
                  - match:
                      prefix: /health
                    route:
                      cluster: user
                      cluster_not_found_response_code: 505
                  - match:
                      prefix: /user
                    route:
                      cluster: user
                      cluster_not_found_response_code: 505
                  - match:
                      prefix: /prefix
                    route:
                      cluster: user
                      cluster_not_found_response_code: 505
              http_filters:
                - name: dgp.filter.http.prometheusmetric
                  metric_collect_rules:
                    metric_path: "/metrics"
                    push_gateway_url: "http://127.0.0.1:9091"
                    counter_push: true
                    push_interval_threshold: 3
                    push_job_name: "prometheus"
                - name: dgp.filter.http.httpproxy                    
      config:
        idle_timeout: 5s
        read_timeout: 5s
        write_timeout: 5s
  clusters:
    - name: "user"
      lb_policy: "lb"
      endpoints:
        - id: 1
          socket_address:
            address: 127.0.0.1
            port: 1314
      health_checks:
        - protocol: "tcp"
          timeout: 1s
          interval: 2s
          healthy_threshold: 4
          unhealthy_threshold: 4
  shutdown_config:
    timeout: "60s"
    step_timeout: "10s"
    reject_policy: "immediacy"

sample参考： https://github.com/apache/dubbo-go-pixiu-samples/tree/main/dubbogo/simple/prometheus

feat:consistent hashing

为cluster 提供基于一致性hash的请求负载算法;

clusters:
  - name: "test_dubbo"
    lb_policy: "ConsistentHashing"
    registries:
      "zookeeper":
        timeout: "3s"
        address: "127.0.0.1:2181"
        username: ""
        password: ""

Enhancement in v0.6.0

Remove "Types" on Http to dubbo proxy

在通过http调用dubbo服务的场景中，v0.6.0以前版本需要再请求中包含"types": ...., 来描述dubbo parameters的结构描述，示例 ：{"types":"string"....

func TestPost1(t *testing.T) {
    url := "http://localhost:8883/UserService/com.dubbogo.pixiu.UserService/GetUserByName"
    data := "{"types":"string","values":"tc"}"
    client := &http.Client{Timeout: 5 * time.Second}
    req, err := http.NewRequest("POST", url, strings.NewReader(data))
    req.Header.Set("x-dubbo-http1.1-dubbo-version", "1.0.0")
    req.Header.Set("x-dubbo-service-protocol", "dubbo")
    req.Header.Set("x-dubbo-service-version", "1.0.0")
    req.Header.Set("x-dubbo-service-group", "test")
    assert.NoError(t, err)
    req.Header.Add("Content-Type", "application/json")
    resp, err := client.Do(req)
    assert.NoError(t, err)
    assert.NotNil(t, resp)
    assert.Equal(t, 200, resp.StatusCode)
    s, _ := ioutil.ReadAll(resp.Body)
    assert.True(t, strings.Contains(string(s), "0001"))
}

改进之后data中不需要types数据。

sample 代码： https://github.com/apache/dubbo-go-pixiu-samples/blob/main/dubbogo/simple/direct/test/pixiu_test.go

ASoC 2002: Optimization of Pixiu timeout feature

dgp.filter.http.dubboproxy 支持超时配置：

..........
.........
- name: dgp.filter.http.dubboproxy
  config:
    dubboProxyConfig:
      registries:
        "zookeeper":
          protocol: "zookeeper"
          timeout: "3s"
          address: "127.0.0.1:2181"
          username: ""
          password: ""
      timeout_config:
        connect_timeout: 5s
        request_timeout: 5s

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