Templating

You can use templating to access data from your configs, health checks, and components. Templates allow you to create reusable playbooks by

• Get the namespace of a Kubernetes deployment.
• Get the name of a config.
• Get the status of a health check.

To use templating in your playbooks, you can use the following syntax:

{{.context.property}}

Where:

• context is the context of the template, such as config, check, or component.
• property is the property of the context that you want to access.

For example, to get the namespace of a Kubernetes deployment, you would use the following template:

{{.config.tags.namespace}}

Example

The following playbook scales a Kubernetes deployment to a specified number of replicas.

scale-deployment.yaml
apiVersion: mission-control.flanksource.com/v1
kind: Playbook
metadata:
  name: scale-deployment
spec:
  description: Scale deployment
  configs:
    - type: Kubernetes::Deployment
  parameters:
    - name: replicas
      label: The new desired number of replicas.
  actions:
    - name: 'scale deployment'
      exec:
        script: kubectl scale \
         --replicas={{.params.replicas}} \
         --namespace={{.config.tags.namespace}} \
          deployment {{.config.name}}

This playbook:

• defines a parameter called replicas that a user will supply when running
• gets the deployment's name ({{.config.name}}) and namespace ({{.config.tags.namespace}})
• create a kubectl scale command from these values
• runs the command and prints the results

Context

CEL Expressions

The following variables can be used within the CEL expressions of filter, if, delays and parameters.default:

Field	Description	Schema
config	Config passed to the playbook	ConfigItem
component	Component passed to the playbook	Component
check	Canary Check passed to the playbook	Check
playbook	Playbook passed to the playbook	Playbook
run	Current run	Run
params	User provided parameters to the playbook	map[string]any
request	Webhook request	Webhook Request
env	Environment variables defined on the playbook	map[string]any
user.name	Name of the user who invoked the action	string
user.email	Email of the user who invoked the action	string
agent.id	ID of the agent the resource belongs to.	string
agent.name	Name of the agent the resource belongs to.	string

Conditionally Running Actions

Playbook actions can be selectively executed based on CEL expressions. These expressions must either return

• a boolean value (true indicating run the action & skip the action otherwise)
• or a special function among the ones listed below

Function	Description
always()	run no matter what; even if the playbook is cancelled/fails
failure()	run if any of the previous actions failed
skip()	skip running this action
success()	run only if all previous actions succeeded (default)
timeout()	run only if any of the previous actions timed out

delete-kubernetes-pod.yaml
---
apiVersion: mission-control.flanksource.com/v1
kind: Playbook
metadata:
  name: notify-send-with-filter
spec:
  parameters:
    - name: message
      label: The message for notification
      default: '{{.config.name}}'
  configs:
    - types: 
        - Kubernetes::Pod
  actions:
    - name: Send notification
      exec:
        script: notify-send "{{.config.name}} was created"
    - name: Bad script
      exec:
        script: deltaforce
    - name: Send all success notification
      if: success() # this filter practically skips this action as the second action above always fails
      exec:
        script: notify-send "Everything went successfully"
    - name: Send notification regardless
      if: always()
      exec:
        script: notify-send "a Pod config was created"

Defaulting Parameters

delete-kubernetes-pod.yaml
apiVersion:
  mission-control.flanksource.com/v1
  kind: Playbook
  metadata:
    name: edit
  spec:
    title: 'Edit Kustomize Resource'
    icon: flux
    parameters:
    - default: 'chore: update $(.config.type)/$(.config.name)'
      name: commit_message

Go Templating

When templating actions with Go Templates, the context variables are available as fields of the template's context object . eg .config, .user.email

Templating Actions

delete-kubernetes-pod.yaml
apiVersion: mission-control.flanksource.com/v1
kind: Playbook
metadata:
  name: scale-deployment
spec:
  description: Scale Deployment
  configs:
    - types:
        - Kubernetes::Deployment
  parameters:
    - name: replicas
      label: The new desired number of replicas.
  actions:
    - name: kubectl scale
      exec:
        script: |
          kubectl scale --replicas={{.params.replicas}} \
            --namespace={{.config.tags.namespace}} \
            deployment {{.config.name}}

Functions

Function	Description	Return
getLastAction()	Returns the result of the action that just run	Action Specific
getAction({action})	Return the result of a specific action	Action Specific

Reusing Action Results

action-results.yaml
apiVersion: mission-control.flanksource.com/v1
kind: Playbook
metadata:
  name: use-previous-action-result
spec:
  description: Creates a file with the content of the config
  configs:
    - types:
        - Kubernetes::Pod
  actions:
    - name: Fetch all changes
      sql:
        query: SELECT id FROM config_changes WHERE config_id = '{{.config.id}}'
        driver: postgres
        connection: connection://postgres/local
    - name: Send notification
      if: 'last_result().count > 0'
      notification:
        title: 'Changes summary for {{.config.name}}'
        connection: connection://slack/flanksource
        message: |
          {{$rows:=index last_result "count"}}
          Found {{$rows}} changes