kubegen

kubegen stands for kubernetes file generator

Shall be a very lightweight approach to handle templating.

Project website: https://github.com/de-jcup/kubegen

How to use

Define a template structure

Structure:

projects
   myproject1
     templates
        01_initial
           01_config_maps.yaml
       02_resources
           01_pods.yaml
           02_services.yaml
           03_deployment.yaml
        03_scripts
            something.sh
        99_end.yaml
       ...
     values
        values.properties
        values_dev.properties
        values_prod.properties
  myproject2
      templates
         01_do_it.yaml
  values
     values.properties
     values_int.properties

Call and generate

java -jar kubegen-all.jar <command> <options> <systemproperties>

There are following options:

Usage: kubegen [options] [command] [command options]
  Options:
    --help
      Shows this help
    --imageVersion
      Shows imageVersion of kubegen
    --verbose
      Shows verbose output
      Default: false
  Commands:
    build      Build environment specific kubernetes files and create 
            install.sh script for execution
      Usage: build [options]
        Options:
          -c, --contextKey
            Key containing Kubernetes context to use. Generated scripts will 
            make use of this. If none defined KUBEGEN_CONTEXT_NAME will be 
            used 
            Default: KUBEGEN_CONTEXT_NAME
        * -e, --environment
            Environment, e.g. dev|int|prod
        * -i, --imageVersion
            Docker image imageVersion. Will be accessible as variable 
            `KUBEGEN_IMAGE_VERSION` 
          -k, --kubeconfigKey
            Key containing Kubernetes config file to use. Generated scripts 
            will make use of this. If none defined KUBEGEN_KUBECONFIG_FILE 
            will be used
            Default: KUBEGEN_KUBECONFIG_FILE
          -n, --namespaceKey
            Key containing Kubernetes namespace to use. Generated scripts will 
            use this as target namespace. If none defined 
            KUBEGEN_NAMESPACE_NAME will be used
            Default: KUBEGEN_NAMESPACE_NAME
        * -p, --project
            Project name
          -s, --sourceFolder
            Base source folder to search for projects. If not defined current 
            dir will be used
            Default: /home/albert/develop/projects/jcup/kubegen/.
          -t, --targetFolder
            Target output folder. If not defined, $projectFolder/buildCommand 
            will be used

    scaffold      Creates a scaffolding for a new project in current directory
      Usage: scaffold [options]
        Options:
        * -e, --environments
            Environments, e.g. dev|int|prod
        * -p, --project
            Project name

Shell script generation

install.sh will be generated and contains ready to go install scripts with automated context change etc. dependening on the used CLI options.

Environments

Environments are automatically resolved by inspected value_$xxx.properties. Folder values - if existing - in project parent folder is provided to any project. So there can be a shared setup provided. If project has no own values folder only parent folder environments are used. Otherwise data will be merged but project does override.

System property override

When you call the jar with a system property starting with kubegen.you can set custom values from command line and also override fix defined values.

For example setting -Dkubegen.TEST_VALUE1=mypropvalue you will have {{ .TEST_VALUE1 }} available in templates

System environment entry override

Same as for system property override: KUBEGEN_TEST_VALUE1 will be mapped in template to {{ .TEST_VALUE1 }}. But system properties are superior to environment entries!

Example

For example myproject1 has also environment int available because defined in parent.

When calling

java -jar kubegen-all.jar build -p myproject -e=prod -i=1.0.0 -n=KEY_TO_DEFINE_NAMESPACE

we got

myproject
     ...
        01_initial
           01_config_maps.yaml
        02_resources
           01_pods.yaml
           02_services.yaml
           03_deployment.yaml
        03_scripts
           something.sh
        99_end.yaml
        install.sh

All keys defined in templates (GO template style) e.g. {{ .MY_VALUE }} will be replaced by corresponding values.

value.properties will be overriden by environment specific one.

For more details call

java -jar kubegen-all.jar --help

sven-dmlr / kubegen