# Meta Data

Request metadata fields from the server by adding add-meta = true setting to the widget configuration.

Use these fields for several common use cases:

• Embed extended entity or metric information in series legend labels.
• Calculate derived metrics based on entity tags.
• Set [threshold] value or treemap sizes based on entity tags.

# Metadata Object

If add-meta is set to true, the response contains metadata for the requested metric and entity.

Sample metadata object:

{
  "metric": {
    "name": "docker.cpu.avg.usage.total.percent",
    "enabled": true,
    "dataType": "FLOAT",
    "label": "Docker Cpu Avg Usage Total %",
    "persistent": true,
    "tags": {
      "table": "Docker Container Summary"
    },
    "retentionDays": 0,
    "seriesRetentionDays": 0,
    "invalidAction": "NONE",
    "versioned": false,
    "interpolate": "LINEAR"
  },
  "entity": {
    "name": "dfab04daa838e9795f6246c5ba9f37412213ca897bfe056baf3b71a11d456370",
    "enabled": true,
    "label": "db-test-mysql-5.7",
    "tags": {
      "env.mysql_version": "5.7.18-1debian8",
      "image-name": "mysql",
    }
  }
}

The loaded object can be subsequently accessed in label settings and value expressions.

# Label Settings

The metric and entity metadata object properties can be accessed in the following settings:

• label-format
• column-label-format
• marker-format

label-format = meta.entity.tags.app

Available placeholders:

• meta.metric.field_name
  Metric fields such as label, dataType.
• meta.entity.field_name
  Entity fields such as label, timeZone.
• meta.metric.tags.tag_name
  Metric tag with name tag_name.
• meta.entity.tags.tag_name
  Entity tag with name tag_name.

If the tag name contains special characters, use meta.entity.tags['tag_name'] syntax, for example meta.entity.tags['image-name'].

# Metadata Functions

Function	Description
meta('alias')	Returns meta object for series with the specified alias.
meta()	Returns meta object for the current series.
entityTag('alias', 'tag_name')	Returns entity tag value for series with the specified alias.
entityTag('tag_name')	Returns entity tag value for the current series.
metricTag('alias', 'tag_name')	Returns metric tag value for series with the specified alias.
metricTag('tag_name')	Returns metric tag value for the current series.

The functions can be invoked within the following settings:

• value
• series-value
• display
• enabled
• alert-expression
• size
• color
• node-value (graph widget)
• link-value (graph widget)
• link-alert-expression (graph widget)
• node-alert-expression (graph widget)

The metadata object can be accessed by specifying the path to the property.

meta().metric.label        -> Docker Cpu Avg Usage Total %
meta().metric.tags.table   -> Docker Container Summary
meta().entity.label        -> db-test-mysql-5.7

If the tag name contains special characters, such as 'image-name', enquote the tag name and use brackets to access its value.

meta().entity.tags['image-name']    -> mysql

# Function Examples

alert-expression = value >= meta().metric.maxValue

series-value= meta().entity.tags.stream

alert-expression = (1 - (meta().entity.tags.elevation_ft - value)/meta().entity.tags.elevation_ft) > 0.97

color = ((1 - (meta().entity.tags.elevation_ft - value)/meta().entity.tags.elevation_ft)*100 >= 100) ? 'black': (((1 - (meta().entity.tags.elevation_ft - value)/meta().entity.tags.elevation_ft)*100 >= 95))?'orange':'steelblue'

series-value = meta().entity.tags.crest_elevation_ft  - value

display = +meta().entity.tags["storage_capacity_ac-ft"] > 1000000

alert-expression = value >= meta().metric.maxValue

[series]
    entity = nurswgvml007
    metric = cpu_busy
    alert-style = fill: red
    alert-expression = value > metricTag('threshold_value')

[series]
    label = nomalized 502
    value = value('502') / entityTag('502', 'cpu_count')

# Debugging

To print out the metadata object in the developer console, using the console.log() function.

enabled = console.log(meta()); return true;