What is CI CD pipeline?

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a series of steps that must be performed 
in order to deliver a new version of software 
(bulding > testing > deploying)

CI

Continous Integration

helps developers merge and test code more frequently, even on a daily basis. CI requires that all tests are automated.

CD

Continuous Deployment / Conitnous Delivery

the next step in the process where the tested code from continuous integration is automatically deployed in various environments by a manual trigger. In continuous delivery, developers need to push changes to their production environment manually.

Benefits

• Less risk: automated tests reduce the chance of introducing bugs, creating a safety net that increases the developer’s confidence in their code.

• More frequent releases: the automation provided by continuous delivery and continuous deployment allows developers to release and deploy software safely many times per day.

• Improved productivity: freed from the manual labor of building and testing the code, developers can focus on the creative aspects of coding.

• Elevated quality: CI acts as a quality gate, preventing code that is not up to standards from getting released.

• Better design: the iterative nature of continuous integration lets developers work in small increments, allowing a higher degree of experimentation, which leads to more innovative ideas.

• reference : https://www.youtube.com/watch?v=0Emq5FypiMM

Example

• reference : https://crispyblog.kr/development/common/8

• reference : https://velog.io/@haeny01/AWS-Jenkins%EB%A5%BC-%ED%99%9C%EC%9A%A9%ED%95%9C-Docker-x-SpringBoot-CICD-%EA%B5%AC%EC%B6%95

Example) Jenkins

Unit Test (In Java case : Jacoco + JUnit)

jacoco

• a library checking Java code coverage
• 테스트코드를 돌리고 그 커버리지 결과를 눈으로 보기 좋도록 html이나 xml, csv 같은 리포트로 생성합니다.
• 테스트 결과가 내가 설정한 커버리지 기준을 만족하는지 확인하는 기능도 있습니다.
• import to Gradle configuration

• jacocoTestReport

  binary coverage 결과를 사람이 보기 편한 형태의 report로 저장(html, xml, csv…)

• jacocoTestCoverageVerification

  내가 원하는 coverage 기준을 설정

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jacocoTestReport {
  reports {
    // 원하는 리포트를 켜고 끌 수 있습니다.
    html.enabled true
    xml.enabled false
    csv.enabled false

//  각 리포트 타입 마다 리포트 저장 경로를 설정할 수 있습니다.
//  html.destination file("$buildDir/jacocoHtml")
//  xml.destination file("$buildDir/jacoco.xml")

// dependsOn으로 실행 순서 지정 가능
  dependsOn (`:test`,
            `:jacocoTestReport`,
            `:jacocoTestCoverageVerification`)
  }
}

jacocoTestCoverageVerification {
  violationRules {
    rule {
      element = 'CLASS'

      limit {
        counter = 'BRANCH'
        value = 'COVEREDRATIO'
        minimum = 0.90
      }
    }
  }
}

// default
test {
  jacoco {
    enabled = true
    destinationFile = file("$buildDir/jacoco/$.exec")
    includes = []
    excludes = []
    excludeClassLoaders = []
    includeNoLocationClasses = false
    sessionId = "<auto-generated value>"
    dumpOnExit = true
    classDumpDir = null
    output = JacocoTaskExtension.Output.FILE
    address = "localhost"
    port = 6300
    jmx = false
  }
}

• reference : «https://techblog.woowahan.com/2661/>

JUnit

• a simple Java unit testing framework
• Annotations
  • @Test
  • @BeforeEach
  • @AfterEach
  • @DisplayName
• Assert…
  • assertEquals
  • asssertThat().isEqualsTo()
  • assertAll

** vs org.springframework.util.Assert - not for test code - often used to parameter verification

build.gradle

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test {
  useJUnitPlatform()
}

Test.java

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import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.Assertions;

public class CaluratorTest {                                            @Test 
  public void testSum() {
    // ... 
    Assertions.assertEquals(...);
  }}

• reference :

https://phoenixnap.com/kb/what-is-jenkins

https://epthffh.tistory.com/entry/Junit%EC%9D%84-%EC%9D%B4%EC%9A%A9%ED%95%9C-%EB%8B%A8%EC%9C%84%ED%85%8C%EC%8A%A4%ED%8A%B8

Example) Gitlab CI/CD

Use .gitlab-ci.yml for automation

• how to make [.gitlab-ci.yml]

https://buildkite.com/ci-cd

Example) BuildKite

https://buildkite.com/ci-cd

Interview Questions

• reference : https://semaphoreci.com/blog/common-cicd-interview-questions