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Device Aliases

Plugin devices each have an ID associated with them, which is generated by the SDK deterministically. These IDs are computed hashes and are not a human-friendly means to identify or reference a device manually.

To make this easier, the Synse SDK allows devices to have an alias associated with it. A device alias is just a string which should be human readable and provides a meaningful way to reference the device, as an alternative to the device ID. In order to ensure that a device alias only references a single device, the aliases must also be unique. While there are some safeguards/checks built into the SDK, it is the responsibility of the plugin configurer to ensure that there are no alias collisions.

A device alias can be used in place of a device ID for all Synse operations. Device aliases are defined in the device configuration. There are two ways that an alias can be specified: explicitly, or via template.

Explict Alias

An explicit alias is just a string which is not processed any further. For example:

version: 3
- type: example-device
  - info: example device instance 1
      name: device-1

This example configuration defines device-1 as the device's explicit alias.

Templated Alias

The device alias may also be defined with a Go template string.

version: 3
- type: example-device
  - info: example device instance 1
      partNumber: abc123
      template: 'device-{{ .Device.Type }}-{{ ctx "partNumber" }}-1'

In the above example, the alias would render out to "device-example-device-abc123-1".

An AliasContext provides the context for the template. From it, the device information and plugin information can be referenced.

Alias Context

Key Description
.Meta.Name The name of the plugin.
.Meta.Maintainer The plugin maintainer.
.Meta.Description The description of the plugin.
.Meta.VCS The VCS string for the plugin.
.Device.Type The type of the device.
.Device.Info The device's configured human-readable info string.
.Device.Handler The name of the device's device handler.
.Device.SortIndex The optional custom sort index for the device.
.Device.WriteTimeout The duration string for the device write timeout.
.Device.Output The name of the optionally configured device output.

Additionally, the SDK provides some simple template functions:

Function Description Example
env Get a value from the environment. {{ env "PLUGIN_HOSTNAME" }}
ctx Get a value from the device's configured context. {{ ctx "manufacturer" }}