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Config Template

The config template is defined with CUE language. To describe the config parameter, storage structure and extension features. His rendering works similarly to the Definition.

When you need to custom the template​

  1. Create multiple configs with the same type. Such as the Image Registry and the Helm Repository.
  2. Define certain parameters and check the validity.
  3. Write the config to the Nacos server. Reference
  4. Render and generate the Secret or Other resources by the parameters. Such as the Grafana template.
  5. Need to classify the configs and list them.

How to define a template​

Write a cue template​

There are many Out-of-Box templates you could refer to.

More templates let's find in the addon catalog.

A sample template should include sections:

  • metadata(Required)
metadata: {
    name:        "terraform-alibaba"
    alias:       "Terraform Provider for Alibaba Cloud"
    sensitive:   true
    scope:       "system"
    description: "Terraform Provider for Alibaba Cloud"
}

Define the base info for this template.

  • template.parameter(Required)
template: {
    parameter: {
        //+usage=The name of Terraform Provider for Alibaba Cloud, default is `default`
        name: *"default" | string
        //+usage=Get ALICLOUD_ACCESS_KEY per this guide https://help.aliyun.com/knowledge_detail/38738.html
        ALICLOUD_ACCESS_KEY: string
        //+usage=Get ALICLOUD_SECRET_KEY per this guide https://help.aliyun.com/knowledge_detail/38738.html
        ALICLOUD_SECRET_KEY: string
        //+usage=Get ALICLOUD_REGION by picking one RegionId from Alibaba Cloud region list https://www.alibabacloud.com/help/doc-detail/72379.htm
        ALICLOUD_REGION: string
    }
}
  • template.output
output: {
        apiVersion: "v1"
        kind:       "Secret"
        metadata: {
            name:      context.name
            namespace: context.namespace
        }
        type: "Opaque"
        stringData: credentials: strings.Join([creds1, creds2], "\n")
    }

This section is not required, If you want to specify, it must be a Secret.

  • template.outputs
outputs: {
        "grafana": {
            apiVersion: "o11y.prism.oam.dev/v1alpha1"
            kind:       "Grafana"
            metadata: {
                name: context.name
            }
            spec: {
                endpoint: parameter.endpoint
                if parameter.auth != _|_ {
                    access: {
                        if parameter.auth.username != _|_ && parameter.auth.password != _|_ {
                            username: parameter.auth.username
                            password: parameter.auth.password
                        }
                        if parameter.auth.token != _|_ {
                            token: parameter.auth.token
                        }
                    }
                }
            }
        }
    }

This section defines the output resources other than Secret. They will be created after the config is created and deleted after the config is deleted.

  • template.nacos
nacos: {
        // The endpoint can not references the parameter.
        endpoint: {
            // Users must create a config base the nacos-server template firstly.
            name: "nacos"
        }
        format: parameter.contentType

        // could references the parameter
        metadata: {
            dataId: parameter.dataId
            group:  parameter.group
            if parameter.appName != _|_ {
                appName: parameter.appName
            }
            if parameter.namespaceId != _|_ {
                namespaceId: parameter.namespaceId
            }
            if parameter.tenant != _|_ {
                tenant: parameter.tenant
            }
            if parameter.tag != _|_ {
                tag: parameter.tag
            }
        }
        content: parameter.content
    }

This section is not required if you don't want to create a Nacos config template.

Apply to the hub cluster​

  1. Create or update a template
vela config-template apply -f template.cue
  1. Show the parameters of the template
vela config-template show <Template Name>

How to share the template​

We could copy the cue script to others. But, The addon is a common carrier to share the user-friendly config templates to more community users.

This is an example:

├── config-templates
│   ├── image-registry.cue
│   ├── nacos-config.cue
│   └── nacos-server.cue
├── metadata.yaml
├── parameter.cue
├── readme.md
├── readme_cn.md
├── resources
│   ├── apiserver.cue
│   └── velaux.cue

When installing this addon, the templates will be applied to the hub cluster.