Template Processor Plugin

The template processor applies a Go template to metrics to generate a new tag. The primary use case of this plugin is to create a tag that can be used for dynamic routing to multiple output plugins or using an output specific routing option.

The template has access to each metric's measurement name, tags, fields, and timestamp using the interface in /template_metric.go.

Read the full Go Template Documentation.

Global configuration options

In addition to the plugin-specific configuration settings, plugins support additional global and plugin configuration settings. These settings are used to modify metrics, tags, and field or create aliases and configure ordering, etc. See the CONFIGURATION.md for more details.

Configuration

# Uses a Go template to create a new tag
[[processors.template]]
  ## Go template used to create the tag name of the output. In order to
  ## ease TOML escaping requirements, you should use single quotes around
  ## the template string.
  tag = "topic"

  ## Go template used to create the tag value of the output. In order to
  ## ease TOML escaping requirements, you should use single quotes around
  ## the template string.
  template = '{{ .Tag "hostname" }}.{{ .Tag "level" }}'

Examples

Combine multiple tags to create a single tag

[[processors.template]]
  tag = "topic"
  template = '{{ .Tag "hostname" }}.{{ .Tag "level" }}'

- cpu,level=debug,hostname=localhost time_idle=42
+ cpu,level=debug,hostname=localhost,topic=localhost.debug time_idle=42

Use a field value as tag name

[[processors.template]]
  tag = '{{ .Field "type" }}'
  template = '{{ .Name }}'

- cpu,level=debug,hostname=localhost time_idle=42,type=sensor
+ cpu,level=debug,hostname=localhost,sensor=cpu time_idle=42,type=sensor

Add measurement name as a tag

[[processors.template]]
  tag = "measurement"
  template = '{{ .Name }}'

- cpu,hostname=localhost time_idle=42
+ cpu,hostname=localhost,measurement=cpu time_idle=42

Add the year as a tag, similar to the date processor

[[processors.template]]
  tag = "year"
  template = '{{.Time.UTC.Year}}'

Add all fields as a tag

Sometimes it is useful to pass all fields with their values into a single message for sending it to a monitoring system (e.g. Syslog, GroundWork), then you can use .Fields or .Tags:

[[processors.template]]
  tag = "message"
  template = 'Message about {{.Name}} fields: {{.Fields}}'

- cpu,hostname=localhost time_idle=42
+ cpu,hostname=localhost,message=Message\ about\ cpu\ fields:\ map[time_idle:42] time_idle=42

More advanced example, which might make more sense:

[[processors.template]]
  tag = "message"
  template = '''Message about {{.Name}} fields:
{{ range $field, $value := .Fields -}}
{{$field}}:{{$value}}
{{ end }}'''

- cpu,hostname=localhost time_idle=42
+ cpu,hostname=localhost,message=Message\ about\ cpu\ fields:\ntime_idle:42\n time_idle=42

Just add the current metric as a tag

[[processors.template]]
  tag = "metric"
  template = '{{.}}'

- cpu,hostname=localhost time_idle=42
+ cpu,hostname=localhost,metric=cpu\ map[hostname:localhost]\ map[time_idle:42]\ 1257894000000000000 time_idle=42

# README