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MustacheTemplate

Build Status Dependabot Status GitHub

MustacheTemplate is the next step of complexity when working with Razee. With MustacheTemplate we can inject cluster specific environment variables into resources before applying them to a cluster. We even use this injection method as the mechanism for version control of our resources.

The basic operation of MustacheTemplate is to collect all values defined in .spec.envFrom and .spec.env, then use those values to process all yaml defined in the .spec.templates, and finally apply the processed yaml to the cluster.

Install

kubectl apply -f "https://github.com/razee-io/MustacheTemplate/releases/latest/download/resource.yaml"

Resource Definition

Sample

apiVersion: deploy.razee.io/v1alpha2
kind: MustacheTemplate
metadata:
  name: <mustache_template_name>
  namespace: <namespace>
spec:
  envFrom:
  - genericMapRef:
      apiVersion: deploy.razee.io/v1alpha2
      kind: FeatureFlagSetLD
      name: myLDProject
      namespace: default
  env:
    - name: app-label
      value: "deployment 1"
    - name: desired-replicas
      valueFrom:
        configMapKeyRef:
          name: nginx-config
          key: replicas
          type: number
  templates:
  - apiVersion: v1
    kind: ConfigMap
    metadata:
      name: test-config
    data:
      sample: "{{ desired-replicas }}"
  strTemplates:
  - |
      apiVersion: apps/v1
      kind: Deployment
      metadata:
        name: nginx-deployment
        labels:
          app: nginx
          deployment: {{ app-label }}
      spec:
        replicas: {{ desired-replicas }}
        selector:
          matchLabels:
            app: nginx
        template:
          metadata:
            labels:
              app: nginx
          spec:
            containers:
            - name: nginx
              image: nginx:1.7.9
              ports:
              - containerPort: 80

Spec

Path: .spec

Description: spec is required and must include at least one [envFrom , env] and at least one [templates, strTemplates].

Schema:

spec:
  type: object
  allOf:
    - anyOf:
        - required: [templates]
        - required: [strTemplates]
    - anyOf:
        - required: [envFrom]
        - required: [env]
  properties:
    custom-tags:
      type: array
      ...
    envFrom:
      type: array
      ...
    env:
      type: array
      ...
    templates:
      type: array
      ...
    strTemplates:
      type: array
      ...

Templating Engine

Path: .spec.templateEngine

Description: Specifying which templating engine to use, the available options are mustache and handlebars

Schema:

properties:
  templateEngine:
    type: string
    pattern: "^mustache$|^handlebars$"

Default: 'mustache'

Custom Tags

Path: .spec.custom-tags

Description: Specifying custom tags will override the default mustache tags. This can be useful when you need to reserve {{ }} for some other processing.

Schema:

custom-tags:
  type: array
  maxItems: 2
  minItems: 2
  items:
    type: string
    maxLength: 3
    minLength: 2

Default: ['{{', '}}']

EnvFrom

Path: .spec.envFrom

Description: Allows you to pull in all values from a resource's .data section to be used in template processing. ie. ConfigMaps would use the configMapRef key and CRDs with a high level .data section can be pulled in by using the genericMapRef key. The keys pulled from the resource are what you would use to match values into your templates.

Note:: values are loaded in from .spec.envFrom before .spec.env, and top down. Any values with the same key/name will be overwritten, last in wins.

Schema:

envFrom:
  type: array
  items:
    type: object
    oneOf:
      - required: [configMapRef]
      - required: [secretMapRef]
      - required: [genericMapRef]
    properties:
      optional:
        type: boolean
      configMapRef:
        type: object
        required: [name]
        properties:
          name:
            type: string
          namespace:
            type: string
      secretMapRef:
        type: object
        required: [name]
        properties:
          name:
            type: string
          namespace:
            type: string
      genericMapRef:
        type: object
        required: [apiVersion, kind, name]
        properties:
          apiVersion:
            type: string
          kind:
            type: string
          name:
            type: string
          namespace:
            type: string

EnvFrom Optional

Path: .spec.envFrom[].optional

Description: If fetching env/envFrom resource fails, MustacheTemplate will stop execution and report error to .status. You can allow execution to continue by marking a reference as optional.

Schema:

optional:
  type: boolean

Default: false

Env

Path: .spec.env

Description: Allows you to pull in a single value from a resource's .data section to be used in template processing. ie. ConfigMaps would use the configMapKeyRef key and CRDs with a high level .data section can be pulled from by using the genericKeyRef key. .spec.env.name is what you would use to match values into your templates. You can also specify a type that we will convert your fetched string into, before injecting into your template (one of [number, boolean, json, jsonString, base64]).

Note: values are loaded in from .spec.envFrom before .spec.env, and top down. Any values with the same key/name will be overwritten, last in wins.

Schema:

env:
  type: array
  items:
    type: object
    allOf:
      - required: [name]
      - # all array items should be oneOf ['value', 'valueFrom']
        oneOf:
          - required: [value]
            # if 'value', neither 'optional' nor 'default' may be used
            not:
              anyOf:
                - required: [default]
                - required: [optional]
          - required: [valueFrom]
            # if 'valueFrom', you must define oneOf:
            oneOf:
              - # neither 'optional' nor 'default' is used
                not:
                  anyOf:
                    - required: [default]
                    - required: [optional]
              - # 'optional' is used by itself
                required: [optional]
                not:
                  required: [default]
              - # 'optional' and 'default' are used together IFF optional == true
                required: [optional, default]
                properties:
                  optional:
                    enum: [true]
    properties:
      optional:
        type: boolean
      default:
        x-kubernetes-int-or-string: true
      name:
        type: string
      value:
        x-kubernetes-int-or-string: true
      valueFrom:
        type: object
        oneOf:
          - required: [configMapKeyRef]
          - required: [secretKeyRef]
          - required: [genericKeyRef]
        properties:
          configMapKeyRef:
            type: object
            required: [name, key]
            properties:
              name:
                type: string
              key:
                type: string
              namespace:
                type: string
              type:
                type: string
                enum: [number, boolean, json, jsonString, base64]
          secretKeyRef:
            type: object
            required: [name, key]
            properties:
              name:
                type: string
              key:
                type: string
              namespace:
                type: string
              type:
                type: string
                enum: [number, boolean, json, jsonString, base64]
          genericKeyRef:
            type: object
            required: [apiVersion, kind, name, key]
            properties:
              apiVersion:
                type: string
              kind:
                type: string
              name:
                type: string
              key:
                type: string
              namespace:
                type: string
              type:
                type: string
                enum: [number, boolean, json, jsonString, base64]

Env Optional

Path: .spec.env[].optional

Description: If fetching env/envFrom resource fails, MustacheTemplate will stop execution and report error to .status. You can allow execution to continue by marking a reference as optional: true.

Schema:

optional:
  type: boolean

Default: false

Env Default

Path: .spec.env[].default

Description: If fetching env/envFrom resource fails, but .spec.env[].optional is true and .spec.env[].default is defined, the default value will be used.

Schema:

default:
  x-kubernetes-int-or-string: true

Managed Resource Labels

Reconcile

.spec.templates.metadata.labels[deploy.razee.io/Reconcile]

  • DEFAULT: true
    • A razeedeploy resource (parent) will clean up a resources it applies (child) when either the child is no longer in the parent resource definition or the parent is deleted.
  • false
    • This behavior can be overridden when a child's resource definition has the label deploy.razee.io/Reconcile=false.

Resource Update Mode

.spec.templates.metadata.labels[deploy.razee.io/mode]

Razeedeploy resources default to merge patching children. This behavior can be overridden when a child's resource definition has the label deploy.razee.io/mode=<mode>

Mode options:

  • DEFAULT: MergePatch
    • A simple merge, that will merge objects and replace arrays. Items previously defined, then removed from the definition, will be removed from the live resource.
    • "As defined in RFC7386, a Merge Patch is essentially a partial representation of the resource. The submitted JSON is "merged" with the current resource to create a new one, then the new one is saved. For more details on how to use Merge Patch, see the RFC." Reference
  • StrategicMergePatch
    • A more complicated merge, the kubernetes apiServer has defined keys to be able to intelligently merge arrays it knows about.
    • "Strategic Merge Patch is a custom implementation of Merge Patch. For a detailed explanation of how it works and why it needed to be introduced, see StrategicMergePatch." Reference
    • Kubectl Apply Semantics
  • EnsureExists
    • Will ensure the resource is created and is replaced if deleted. Will not enforce a definition.

Debug Individual Resource

.spec.resources.metadata.labels[deploy.razee.io/debug]

Treats the live resource as EnsureExist. If any Kapitan component is enforcing the resource, and the label deploy.razee.io/debug: true exists on the live resource, it will treat the resource as ensure exist and not override any changes. This is useful for when you need to debug a live resource and dont want Kapitan overriding your changes. Note: this will only work when you add it to live resources. If you want to have the EnsureExist behavior, see Resource Update Mode.

  • ie: kubectl label mtp <your-mtp> deploy.razee.io/debug=true

Lock Cluster Updates

Prevents the controller from updating resources on the cluster. If this is the first time creating the razeedeploy-config ConfigMap, you must delete the running controller pods so the deployment can mount the ConfigMap as a volume. If the razeedeploy-config ConfigMap already exists, just add the pair lock-cluster: true.

  1. export CONTROLLER_NAME=mustachetemplate-controller && export CONTROLLER_NAMESPACE=razee
  2. kubectl create cm razeedeploy-config -n $CONTROLLER_NAMESPACE --from-literal=lock-cluster=true
  3. kubectl delete pods -n $CONTROLLER_NAMESPACE $(kubectl get pods -n $CONTROLLER_NAMESPACE | grep $CONTROLLER_NAME | awk '{print $1}' | paste -s -d ',' -)