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Device Tags

Tags are ways to identify groups of devices, making it easier to perform operations on multiple devices at once, such as getting readings.

For more detailed information on device tags and their structure, see the Tags page in the Synse Server documentation.

When specifying tags in a device configuration, the tag may contain a Go template string to allow templated values to be passed in at runtime if you don't know them at config time. A good example of this is when running a plugin on Kubernetes as a DaemonSet and the plugin is specific to the node it is running on (e.g. the server has sensors on it). In such a case, you may want to be able to filter by rack location, so you can specify a template to capture that info:

tags:
- rack/id:{{ env "NODE_NAME" }}

Currently, tag templates only support the env function, which allows you to get a value from environment. Note that these templates are not parsed on config load. Instead, they are parsed a little later on device build. This allows the SDK to first unify multiple potential sources of configuration (e.g. from file, environment, or command line).

The SDK auto-generates some tags, such an an ID tag and a Type tag. Additional tags can be specified for a device in its configuration. A simple example of configuring device tags is below:

version: 3
devices:
- type: example
  tags:
  - tag1
  - vapor/example:tag
  instances:
  - info: an example device instance
    tags:
    - vapor/another:tag