网站建设与制作,wordpress通过tag获取文章,个人网站免费空间,钢筋网片规格型号逻辑图解 上图来自Dapr官网教程#xff0c;其中Checkout是一个服务#xff0c;负责生成订单号#xff0c; Order Processor是另一个服务#xff0c;负责处理订单。Checkout服务需要调用Order Processor的API#xff0c; 让Order Processor获取到其生成的订单号并进行处理。…逻辑图解 上图来自Dapr官网教程其中Checkout是一个服务负责生成订单号 Order Processor是另一个服务负责处理订单。Checkout服务需要调用Order Processor的API 让Order Processor获取到其生成的订单号并进行处理。
本地测试(Self-Hosted)
按照官网教程进行实验的过程中用python的代码测试发现Order Processor没有任何的输出信息。 改用golang的代码测试 发现Order Processor依然没有任何的输出 但是checkout服务出现以下错误 APP Order passed: {errorCode:ERR_DIRECT_INVOKE,message:fail to invoke, id: order-processor, err: timeout waiting for address for app id order-processor}表明没有解析到请求的app id(oder-processor). 教程中并没有其他说明但是观察上图Service Invokation的图解告诉我们 dapr进行服务调用时 需要Name resolution component, 本地模式中 dapr默认会使用mDNS进行域名解析, 这个错误表明mDNS解析失败。
查阅域名解析相关文档, 替代方案可以是在本地部署consul 作为域名解析的组件。在dapr的配置文件~/.dapr/config.yaml中添加consul组件以下代码中的最后4行
apiVersion: dapr.io/v1alpha1
kind: Configuration
metadata:name: daprConfig
spec:tracing:samplingRate: 1zipkin:endpointAddress: http://localhost:9411/api/v2/spansnameResolution:component: consulconfiguration:selfRegister: true重新安装dapr环境
dapr uninstall
dapr init 注意此处只是将consul注册为dapr的一个组件但consul的示例还需要我们自己创建 此时我们还没有创建consul的实例 如果此时运行checkout的代码则会报错
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code0x2 addr0x20 pc0x10536808c]goroutine 119 [running]:
github.com/dapr/dapr/pkg/messaging.(*directMessaging).getRemoteApp(0x14000ada600, {0x140003d78e0?, 0x0?})/Users/runner/work/dapr/dapr/pkg/messaging/direct_messaging.go:309 0x7c
github.com/dapr/dapr/pkg/messaging.(*directMessaging).Invoke(0x14000ada600, {0x10700d988, 0x1400034b800}, {0x140003d78e0?, 0x14000c41538?}, 0x102354dc0?)/Users/runner/work/dapr/dapr/pkg/messaging/direct_messaging.go:126 0x3c
github.com/dapr/dapr/pkg/http.(*api).onDirectMessage.func1({0x10700d988?, 0x1400034b800?})/Users/runner/work/dapr/dapr/pkg/http/api.go:1390 0x88
github.com/dapr/dapr/pkg/resiliency.(*NoOp).EndpointPolicy.func1(0x1053e137c?)/Users/runner/work/dapr/dapr/pkg/resiliency/noop.go:36 0x30
github.com/dapr/dapr/pkg/http.(*api).onDirectMessage(0x1400053a300, 0x1400034b800)/Users/runner/work/dapr/dapr/pkg/http/api.go:1389 0x598
github.com/fasthttp/router.(*Router).Handler(0x14000b4f5e0, 0x1400034b800)/Users/runner/go/pkg/mod/github.com/fasthttp/routerv1.4.12/router.go:427 0x7f0
github.com/dapr/dapr/pkg/diagnostics.(*httpMetrics).FastHTTPMiddleware.func1(0x1400034b800)/Users/runner/work/dapr/dapr/pkg/diagnostics/http_monitoring.go:227 0x104
github.com/dapr/dapr/pkg/diagnostics.HTTPTraceMiddleware.func1(0x1400034b800)
apiVersion: dapr.io/v1alpha1/Users/runner/work/dapr/dapr/pkg/diagnostics/http_tracing.go:56 0x138
github.com/valyala/fasthttp.(*Server).serveConn(0x14000e7e900, {0x1070211f0?, 0x140005a31f0})/Users/runner/go/pkg/mod/github.com/valyala/fasthttpv1.40.0/server.go:2311 0xde4
github.com/valyala/fasthttp.(*workerPool).workerFunc(0x140005d15e0, 0x140004ea320)/Users/runner/go/pkg/mod/github.com/valyala/fasthttpv1.40.0/workerpool.go:224 0x70
github.com/valyala/fasthttp.(*workerPool).getCh.func1()/Users/runner/go/pkg/mod/github.com/valyala/fasthttpv1.40.0/workerpool.go:196 0x38
created by github.com/valyala/fasthttp.(*workerPool).getCh/Users/runner/go/pkg/mod/github.com/valyala/fasthttpv1.40.0/workerpool.go:195 0x220
❌ The daprd process exited with error code: exit status 2
ℹ️
terminated signal received: shutting down
❌ Error exiting Dapr: exit status 2
✅ Exited App successfully如上 即使我们运行的是python版本的测试代码 报错仍然是golang的panic 这是因为这个异常是dapr抛出的而不是app的代码抛出的 原因是连接不上dapr注册的nameResolution组件。
用下面的命令启动一个consul容器
docker run -d --namedev-consul -e CONSUL_BIND_INTERFACEeth0 consul再运行教程中的代码则可以得到正确的结果了。
k8s中的名字解析
上面一节解释了在本地测试时 dapr是如何通过app id找到相应的应用。在k8s集群中 dapr默认会使用k8s集群的DNS进行域名解析。那么在k8s中 dapr具体是怎么使用DNS的呢
在官网教程中, 创建了两个应用分别是nodeapp和pythonapp, 他们的yaml文件中分别定义了各自的dapr.io/app-id, 分别是nodeapp和pythonapp, 在部署了这两个应用后我们会发现多了两个k8s service: nodeapp-dapr和pythonapp-dapr
➜ checkout git:(master) ✗ kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.0.0.1 none 443/TCP 3d14h
nodeapp LoadBalancer 10.0.253.82 52.188.179.178 80:30807/TCP 75m
nodeapp-dapr ClusterIP None none 80/TCP,50001/TCP,50002/TCP,9090/TCP 75m
pythonapp-dapr ClusterIP None none 80/TCP,50001/TCP,50002/TCP,9090/TCP 8m40s
redis-headless ClusterIP None none 6379/TCP 86m
redis-master ClusterIP 10.0.244.122 none 6379/TCP 86m
redis-replicas ClusterIP 10.0.141.54 none 6379/TCP 86m由此可知, k8s会识别dapr.io/app-id 并根据其值x, 创建一个名为x-dapr的service则可以以解析service域名同样的方式对dapr的app id进行解析了。
