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Build Template Intro

When building an image, we support template to give maintainers full control of generated ClusterFile. For example:

service:
  name: {{ .serviceName }}
  port:
    {{- if typeIs "string" .servicePort }}
    name: {{ .servicePort }}
    {{- else if or (typeIs "int" .servicePort) (typeIs "float64" .servicePort) }}
    number: {{ .servicePort | int }}
    {{- end }}

Goto Golang's text/template for base intro and more details.

Enhance template function​

Futhermore, we support templateFunc to enhance template function. For example:

shim: /var/run/image-cri-shim.sock
cri: /run/containerd/containerd.sock
address: http://{{ .registryDomain }}:{{ .registryPort }}
force: true
debug: false
image: /var/lib/image-cri-shim
{{ if and (ne .SEALOS_SYS_KUBE_VERSION "") (semverCompare "^1.26.0" .SEALOS_SYS_KUBE_VERSION) }}version: v1{{ else }}version: v1alpha2{{ end }}
timeout: 15m
auth: {{ .registryUsername }}:{{ .registryPassword }}

Here we use semverCompare to check users are running at k8s version above v1.26.0 or not, if true, generate version: v1, else false to generate version: v1alpha2.
With this support, we can easily manage multi-version kubernetes support with one cluster image file.

Some most frequently used template functions​

  • semverCompare compare Semantic Versioning, not string compare.
  • default default can give a default value if the value is empty or not defined.
  • toYaml display current value(object,map,array) to yaml format string.

For full supported function list: lick here