Developer Experience with. Spencer Gibb, Dave Syer, Spring Cloud

Transcription

1 Developer Experience with Spencer Gibb, Dave Syer, 2015 Spring Cloud

2 Authors Spencer Dave

3 Developer Experience Microservices lead to a very open flexible architecture Developer needs to work on isolated codebase No one wants to re deploy the universe for every commit What tools and techniques are available to help?

4 Database/middleware: Docker standard docker images exist for all common middleware perfect for development can be used in production with care

5 Middleware: Discovery and DI How to wire up your application code to required middleware, and make the same code run in all environments? be Cloud Native use autoconfiguration use Service Discovery and Registry patterns use Spring Cloud Connectors (a bit: see blog) use Spring Cloud Stream for messaging

6 Provisioning a system for testing Docker compose (great for repeatability) Locally with VirtualBox Remotely: Lattice AWS, Cloud Foundry, Kubernetes, Terraform, etc. CI systems native support (travis, bamboo, etc.)

7 Debugging and fault finding Your app won t always work first time. How to diagnose the problem? dynamic log levels at runtime actuator endpoints: /env, /trace, /mappings, /autoconfig feature switches remote debugger (see later: Spring Boot Devtools) deploy locally distributed tracing (http and messages) (http proxy with replay)

8 Service discovery background

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10 Routing from remote system to IDE Cloud Foundry Tunnel Service Registry Local Service Remote Client local dev experience use proxy to tunnel back to IDE (e.g. ngrok) Spring Tool Suite and Boot Dashboard

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12 Loadbalancer configuration models flag to enable local route prefer route that looks local flag a request (e.g. header with correlation ID)

13 Customizing Ribbon Ribbon is a client side smart load balancer from Netflix OSS IRule: Load balancing algorithm (round robin, random, etc ) ServerList: Where to get the list of servers to load balance. ServerListFilter: filters list of allows configuration for a named ribbon client.

14 Stubbing High level: Greenfield (dependent services don t exist yet, write stubs) Brownfield (dependent services exist and have published artifacts) Example tools/approaches: publish producer stubs vs. consumer tests "forced stubbing": micro infra from 4finance ad hoc stubbing: accurest, wiremock, stubby4j, Spring MVC embedded stubs vs. remote stubs

15 Stubbing Brownfield Services Create Wiremock stubs using tests or dsl AccuREST uses a groovy dsl to create integration tests and stubs. Spring REST Docs uses tests to generate snippets for documentation and can be used to create stubs. Run Wiremock using generated stubs Run consuming services against Wiremock stubs

16 Stubbing: AccuREST DSL Generates a MockMVC test and a Wiremock stub import io.codearte.accurest.dsl.groovydsl GroovyDsl groovydsl = GroovyDsl.make { request { method 'GET' url '/foo' } response { status 200 headers { header 'Content-Type' : 'application/json;charset=utf-8' } body '''{ "value" : 42 }''' } }

17 Stubbing: Spring REST public void setup() { this.mockmvc = MockMvcBuilders.webAppContextSetup(this.context).apply(documentationConfiguration().snippets().withDefaults(curlRequest(), httprequest(), httpresponse(), new WiremockStubSnippet())).build(); public void foo() { this.mockmvc.perform(get("/foo").accept(mediatype.application_json)).andexpect(status().isok()).anddo(document("foo")); }

18 Stubbing: Wiremock Stub { } "request": { "method": "GET", "url": "/foo" }, "response": { "status": 200, "headers": { "Content-Type": "application/json;charset=utf-8" }, "body": "{\"value\":42}" }

19 Stubbing: 4finance stubrunner Publish stub files to nexus repository (or local maven repo) Describe all services dependencies in application.yml Stubrunner uses list of dependencies Grabs stubs from repository Runs a wiremock server for each dependency using fetched stubs Registers server in service discovery Consuming service can function against stubs

20 Greenfield Stubbing: Spring public class StubFleetLocationServiceApplication { public String home() { return "forward:/stubs/locations.json"; }... Nice side effect: mock MVC and restdocs for tests and docs can be reused to verify real service contract

21 Hot reloading and code swapping Basic IDE features (JVM hotswap and resource reload) Spring Boot devtools app restart and browser plugin STS Spring Loaded (Grails, JHipster) JRebel

22 Devtools locally App monitors its classpath and restarts when changes detected: Browser IDE update Files monitor App

23 Devtools with browser Browser plugin automatically refreshes views: Browser IDE Remote Client App update monitor Files monitor App

24 Hot reloading and debugging Hot reloading of local application code deployed on Cloud Foundry / Lattice Cloud Foundry IDE Remote Client App update monitor Files App Spring Boot support via devtools classloader flushes dirty resources remote debug also possible (but slow)

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26 Links cloud dev experience.html cloud cloud samples cloud dependencies sample

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