Triggers

Triggers are closely tied to the execute resource. Every resource has the ability to trigger an execute resource through the triggers meta-parameter. Just like requires this meta-parameter is available to all resources by default.

When the passive parameter of an execute resource is set to true, the resource only applies when triggered by other resources. By default a resource triggers an execute resource when the following conditions apply:

  • the triggering resource is successfully created
  • the triggering resource is successfully deleted
  • the triggering resource is successfully changed

These conditions can be altered through the when parameter. This enables use cases where some execute resource should only be triggered when a resource is created and another should be triggered when the same resource is deleted.

When the when parameter is omitted, the default behavior above applies.

When multiple resources are configured to trigger the same execute resource, the latter is applied only once, after each of those resources have run to completion.

Since only execute resources can be triggered, the triggers meta-parameter accepts only references to execute resources.

Parameters

For each item in the triggers array (see also Resources) the following parameters are available:

NameTypeDescriptionMandatoryDefault
typestringAt this time the only valid value for this parameter is execute, since this is the only type of resource that can be triggered by others.yes
namestringThe name of the execute resource.yes
whenarrayDetermines the condition on which to trigger the execute resource. Items in this array must be one of created, deleted or changed.no[created, changed, deleted]

Example

<...>

resources:
  - type: execute
    parameters:
	  ensure: present
      name: reload-sshd
	  command:
	    - systemctl
	    - reload
		- sshd.service
	  passive: true

  - type: file
    parameters:
      ensure: present
      path: /etc/ssh/sshd_config
	  owner: root
	  group: root
	  content:
	    value: |
          Port 22
		  Listen 0.0.0.0
		  
		  PermitRootLogin no
		  PasswordAuthentication no
		  PubkeyAuthentication yes
		  AllowTcpForwarding yes
    triggers:
      - type: execute
        name: reload-sshd
        # Reload sshd only when the file is created or changed.
		when:
		  - created
		  - changed

<...>

<...>

resources:
  - type: execute
    parameters:
	  ensure: present
      name: daemon-reload
	  command:
	    - systemctl
	    - daemon-reload
	  passive: true

  - type: file
    parameters:
      ensure: present
      path: /etc/systemd/system/some-unit.service
	  owner: root
	  group: root
	  content:
	    value: |
          ...
    triggers:
      - type: execute
        name: daemon-reload
		# This is the default behavior and the same as if `when` is omitted.
		when:
		  - created
		  - changed
		  - deleted

<...>