[#entities]
= Entities

An entity is something that exists - a "thing", like a VM, or a Container is an entity. OliveTin allows you to then dynamically generate actions based around these entities.

This is really useful if you want to generate wake on lan or poweroff actions for `server` entities, for example.

A very popular use case that entities were designed for was for `container` entities - in a similar way you could generate `start`, `stop`, and `restart` container actions.

Entities are just loaded from files on disk, OliveTin will also watch these files for updates while OliveTin is running, and update entities.

Entity data files can contain any fields you need. Those values are available in action templates as `{{ .CurrentEntity.field }}` — for example, `{{ .CurrentEntity.status }}` or `{{ .CurrentEntity.hostname }}`.

Entity field values are **not** sanitized for shell safety. If you substitute them into `shell` or `shellAfterCompleted`, OliveTin assumes the entity files are server-controlled and that you accept responsibility for that data. See xref:action_execution/shellvsexec.adoc#shell-entity-env-trust[Entity and .Env values are not shell-sanitized].

To control which fields appear in the Entities page table and entity details view, configure `properties` on the entity definition in `config.yaml`. See xref:entities/properties.adoc[Entity properties] for details.

To restrict which users may see an entity type (list, details, search, and related UI), list `acls` on the entity definition. See xref:security/acl.adoc#acls[Access Control Lists] (Entities section). Entity types with no `acls` stay unrestricted.

[source,yaml]
----
entities:
  - file: /etc/OliveTin/containers.json
    name: container

  - file: /etc/OliveTin/servers.yaml
    name: server
    icon: ssh
    acls:
      - ops
    properties:
      - name: hostname
        title: Hostname
      - name: ip
        title: IP
----

Entity Actions can only be used on xref:dashboards/intro.adoc[Dashboards].

== What's Next?

Now that you understand entities, here's how to use them effectively:

* xref:entities/properties.adoc[Configure entity properties] - Choose which fields appear in the UI and API
* xref:entities/icons.adoc[Configure entity icons] - Set an icon for each entity type
* xref:entities/yaml.adoc[Create YAML entity files] - Learn the YAML format for entity files
* xref:entities/json.adoc[Create JSON entity files] - Learn the JSON format for entity files
* xref:entities/examples.adoc[View entity examples] - See complete examples of entity configurations
* xref:dashboards/intro.adoc[Use entities in dashboards] - Combine entities with dashboards for dynamic action generation
* xref:solutions/container-control-panel/index.adoc[Container control panel solution] - See a complete example using container entities
* xref:solutions/systemd-control-panel/index.adoc[Systemd control panel solution] - See a complete example using systemd entities
