Gocd is good, but talk about Jenkins

Preface

In recent years Docker、 Kubernetes、 Helm、 Yunyuan is in full swing ,Jenkins With the contributions of the open source community and similar CloudBees Blessings of the team . Keep up with technology trends , The output is integrated into Docker、 Kubernetes、 Helm、AWS And so on , also Jenkins X, The original configuration page Manage Nodes also " Quietly " Turned into Manage Nodes and Clouds. On the other hand , Enterprises with good self-study ability , Also based on Jenkins API Develop a set of Devops CICD platform , to Jenkins that " old man " Put on a young coat , The effect is also very ideal .

Jenkins Open source features , There are also a sea of plug-ins , Low learning threshold, etc , Make it a good choice . At least with limited resources , In view of the need to build a few assembly lines in the project ,Jenkins perfect .

Even as a lover of new technology , When you use other new CI Tool time , You might as well look back at this “ old man ”, Some of the general rules contained in it 、 Ideas will let you know how to build an easy-to-use for a project 、 Easy to expand 、 Easy to maintain assembly line .

To improve code reusability Shared Library

If you work for more than one project Code Repo Write more than one jenkinsfile, You will probably encounter a lot of duplicate code in multiple different pipelines , Especially in the projects that serve many micro Services . Most of the time, in order to make things easier, we copy and paste similar logic codes to different jenkinsfile In the middle , But if one day you need to change a little order , Then you'll suffer a little .

and Shared Library Is one of the ways to solve code duplication , Just according to the reasonable division of pipeline sections , Abstract and encapsulate the repeated or common parts of pipeline logic , The code under these shared libraries can be simply referenced in all pipelines , And can greatly shorten jenkinsfile The number of lines of code in , It also makes it easier to read 、 Easy maintenance .

And in the later show Azure Pipelines, Github Actions Seems to know the benefits of reusing function , And the common Tasks/Actions Placed in the public Marketplace in . Developers can use it directly , You can also develop your own software and upload it to Marketplace For more people to use . Users are also exempt from maintaining a separate similar to Jenkins Shared Libray Code warehouse for , Fully staffed . in addition , Cloud native tools Tekton, Among them Task There are similar practices .

Shared libraries are getting bigger , When the calling relationship becomes more and more complex , Have to consider the problem of code quality . Then you need to test the code to ensure quality , How to Shared Library To test ？ Of course you can write Jenkinsfile Put it in Jenkins Created in Job To run , You will know if there is a problem with the code when you run . But there is no doubt that this method is not very elegant , Recommended JenkinsPipelineUnit（ A shared library unit testing framework ）.

Templating JTE

Just like a development framework , The aim is to quickly build a number of standardized projects , The same is true of the functionality provided by the template ： For the same type of pipeline , Most build processes are the same , Even the running commands are the same , Such an assembly line The similarity of configuration files is also very high . that Jenkins Templating Engine It is a very good solution for such scenarios .

for example , In the large-scale project of microservices , Often a system is composed of dozens of small microservices , These dozens of microservices need their own CICD The assembly line , To complete the packaging 、 Deployment process , They are the same development framework , The build environment required 、 Tools 、 Testing process 、 The release strategy and so on are all carved out of the same mold .

" people " As its name , Jenkins Templating Engine It is a tool used to make assembly line templating , abbreviation JTE. from JTE The birth time can be seen on the homepage 2019 year 5 month , Quite young . For different types of projects , such as Maven、 Gradle To make some template regulations , In short, it is used to unify the internal pipeline Stage、Steps Logic in 、 Parameters, etc. .

After completing the above code , And installation JTE plug-in unit 、 Configured correctly Jenkins Under the premise of , Add default file in specific business code pipeline_config.groovy after , When you create a new assembly line, you are specific to build configuration Options to choose Jenkins Templating Engine, The assembly line can be built , Just a simple 2、3 That's ok .

whereas JTE The advantages of , These are the following three points ：

（ originate https://www.jenkins.io/blog/2019/05/09/templating-engine/）

And go to the other CICD Look in the tools , Similar practices can also be seen . for example Gocd Of Pipeline Templates, Azure Pipelines Of templates.

Centralized management Job DSL

If you are going through a microservice project ,Code Repo A large number of , And each Repo All need to pass a Jenkinsfile Define a pipeline . When you face dozens of hundreds Repo, It is a little tedious to manage and maintain them decentrally .Job DSL Plugin Allow to use DSL Create projects programmatically , The operation of job creation is realized through script , Enables you to automate and standardize Jenkins To configure .

This plug-in can not only create various types of Job（Maven jobs、Freestyle jobs、 Assembly line jobs...）, Can also create Folder、 Dashboard View、 List View wait . The vivid effect is shown in the figure below ,“ Bury a seed , Harvest a few big trees ”.

At the catalog level of the code base , First of all, it is suggested to follow Project Divide , For each Project Define the individual Seed Job; The second will Job The definition of, etc. is isolated from the logical implementation , This ensures that xxx.jenkinsfile The independence of the content in , And is adopting Job DSL After the plug-in , For the original jenkinsfile There is no need to make significant changes , Take it and you can use it .

This tool will undoubtedly Pipeline As Code The idea of has evolved a step further , The pipeline creation process is also coded . And then in Jenkins In practice , If you want to pursue more configuration coding , Let's see. Jenkins Configuration as Code, abbreviation JCasC. This tool can completely convert most Jenkins Resources for 、 Configuration coding , Installing a plug-in 、 To configure Github Server、 Management Certificates 、 New tasks can be completed through files , Don't need to UI Do any operation on the interface .

Postscript

The above ideas provide a corresponding implementation in this paper , But it goes far beyond the methods mentioned , Of course, there are more or less similar methods , But we can't change without our ancestors . Even if there are more CICD The emergence of new tools , Maybe we can find another way in some small places , But the general solution can not bypass the existing ideas to solve the problem . For example, in Azure Pipelines in , Templates Can provide similar functions Shared Library and JTE The function of , Only the implementation form is different , The core idea is the same .

Specific use also needs to be combined with project attributes 、 Branching strategy 、 Release strategy 、 Rights management 、 Server environment and other aspects shall be considered comprehensively , There are also many similar to Nightly Build This construction strategy is worthy of our reference .“ All roads lead to Rome ”, How to save time 、 Save effort to achieve our ultimate goal , And how to maintain the assembly line after the completion , It is worth thinking and designing .

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