Expressions

Playbook event filters use Common Expression Language (CEL).

The Common Expression Language (CEL) is a non-Turing complete language designed for simplicity, speed, safety, and portability. CEL's C-like syntax is similar to expressions in C++, Go, Java, and TypeScript.

Examples:

notify-with-filter.yaml
---
apiVersion: mission-control.flanksource.com/v1
kind: Playbook
metadata:
  name: notify-with-filter
spec:
  on:
    config:
      - event: created
  configs:
    - type: Kubernetes::Pod
  actions:
    - name: Send notification
      exec:
        script: notify-send "{{.config.name}} was created"
    - name: Bad script to create a failing action
      exec:
        script: non-existing-command
    - 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 config was created"

Conditionally running actions

Playbook actions can be conditionally executed using CEL expressions. These expressions must return a bool value (return false to skip the action).

Expressions support the following functions in addition to the standard CEL functions.

Function	Description
always()	Execute regardless of playbook state (cancelled/failed)
failure()	Execute if any previous actions failed
skip()	Skip execution of this action
success()	Execute only if all previous actions succeeded (default)
timeout()	Execute only if any previous actions timed out

Examples

• if: config.deleted_at ? true: false
• if: always()

Context

Expressions have access to the following variables and functions:

Field	Description	Schema
config	Configuration object passed to the playbook	ConfigItem
component	Component object passed to the playbook	Component
check	Canary Check object passed to the playbook	Check
params	User-provided parameters for the playbook	map[string]string
user.id	Unique identifier of the user who triggered the action	string
user.name	Full name of the user who triggered the action	string
user.email	Email address of the user who triggered the action	string
action.name	Name of the current action	string
action.status	Current status of the action (scheduled, running, succeeded, failed, skipped, or cancelled)	string
action.scheduled_time	Timestamp when the action was scheduled	string
action.start_time	Timestamp when the action execution began	string

For playbooks triggered via webhooks, the following additional fields are available:

Field	Description	Scheme
request.content	Content sent on the webhook request	string
request.headers	Headers sent on the webhook request	map[string]string
request.json	JSON content if the webhook content is JSON	map[string]any
request.params	Query parameters sent on the webhook request	map[string]string
request.url	Endpoint of the webhook. Example /playbook/webhook/test-webhook	string