Tag a specific drive when capturing usage of all drives on Windows (Telegraf)

If you've got multiple drives mounted in Windows and are monitoring usage with Telegraf, you might find you want to add a specific tag to just one drive for consumption by something in a later workflow.

For example, you might want to alert on root partitions across all servers (i.e. not just Windows boxes) so might want to add a tag to just the C: drive to mark it as a root partition

The [win_perf_counters](https://github.com/influxdata/telegraf/tree/master/plugins/inputs/win_perf_counters) input plugin supports using a Wildcard, so you can easily capture all disks, but it doesn't directly allow you to tag just a single disk within that

This snippet details how to use the Template Processor plugin to conditionally apply a tag based on the value of another tag using a Golang string template

Details

• Language: Telegraf

Snippet

# Capture usage for our disks
[[inputs.win_perf_counters.object]]
  # Disk times and queues
  ObjectName = "LogicalDisk"
  Instances = ["*"]
  Counters = ["% Idle Time", "% Disk Time","% Disk Read Time", "% Disk Write Time", "% User Time", "% free space", "free megabytes"]
  Measurement = "win_disk"

[[processors.template]]
    # The name of the tag we'll add
    tag = "PartitionType"

    # The string template
    #
    # win_perf_counters includes the drive name in tag "instance"
    # so if that equals C: add our tag
    #
    # If the condition isn't true, an empty value will be added and the
    # tag won't be included
    template = '{{if eq (.Tag "instance") "C:"}}RootPartition{{end}}'