Notification message templates

Notification message templates enable you to customize your notification event data before it's sent to your third-party destination. The templates map your custom values to the values used by your third-party destination.

This gives you full control over what data will be sent and where, as well as being able to fully engage with the services you use.

Message template variables

A message template is what you use to convert New Relic event data to data that's consumable by your third-party service. Variables are specific attributes that are mapped to data fields in your third-party service.

Message templates are written in a simple templating language called Handlebars. Variables in the message templates are written as expressions inside double curly braces {{ }}.

A screenshot of an example webhook notification message template.

Use the notification message template to map your New Relic notifications to the fields in your external services.

The New Relic variable names are listed in the message template variables menu. The variables are grouped into subcategories.

In the variables menu, type {{ to select from a list of variables. As you type, variable names appear via autocomplete. The variable type is written on the right-hand side. You can add enriched data to these variables.

A screenshot of the variables menu that. shows the breadth of variable options available.

The variables menu shows the options you have when mapping New Relic notification fields onto the fields in your external service.

Use the Handlebars syntax

When an event generates a notification, the message template uses the Handlebar variables to map the notification data to the fields used by your third-party service.

The Handlebars language provides many features in addition to basic variable replacement, including evaluating nested input objects and functions, such as iterations (loops), conditional statements, and more. In Handlebars, these functions are called helpers.

Helper functions

Our message templates support the Handlebars built-in helpers.

In addition, we've added other helpers that might be useful to you.

The {{json}} helper converts text to a JSON element.

Use this when you're configuring a Webhook’s payload, which uses a JSON syntax, and any other situation you might want to pass JSON formatted data.

For example, with a variable called data.

{
  "data": {
    "tags": ["infra, team-a"]
  }
}

To get the names array as a JSON element, use the {{json}} helper:

{{json data.tags}}

to get:

["infra", "team-a"]

Use the equality {{#eq}} helper to compare variables.

Compares variables a and b, renders 'yes' or 'no':

{{#eq a b}} yes {{else}} no {{/eq}}

Compares string value "a" to variable b, renders 'yes' or 'no':

{{#eq "a" b}} yes {{else}} no {{/eq}}

Renders 'true' or 'false':

{{eq a b}}

Renders 'y' or 'n':

{{eq a b yes='y' no='n'}}

Use the {{#contains}} helper to compare variables.

Asserts that b contains a, renders 'yes' or 'no':

{{#contains a b}} yes {{else}} no {{/contains}}

Asserts that variable b contains string value "a", renders 'yes' or 'no':

{{#contains "a" b}} yes {{else}} no {{/contains}}

Renders 'true' or 'false':

{{contains a b}}

Renders 'y' or 'n':

{{contains a b yes='y' no='n'}}

The replace helper replaces instances of the first parameter in the second parameter with the child block.

Use else clause to specify what happens when no instance of the first parameter is found. If it is omitted an empty string will be generated.

Example #1: replace the word dog with cat in the sentence The dog likes to eat:

{{#replace "dog" "The dog likes to eat"}}cat{{/replace}}

to get:

The cat likes to eat

Example #2: replace the word cat with mouse in the sentence The dog likes to eat:

{{#replace "cat" "The dog likes to eat"}}mouse{{/replace}}

to get an empty string:

Example #3: replace the word cat with mouse in the sentence The dog likes to eat, using the else clause:

{{#replace "cat" "The dog likes to eat"}}mouse{{else}}There is no cat to replace{{/replace}}

to get:

There is no cat to replace

Example #4: replace the word dog with cat in the sentence The DOG likes to eat while ignoring case:

{{#replace "/dog/i" "The DOG likes to eat"}}cat{{/replace}}

to get:

The cat likes to eat

Example #5: replace the variable {{needle}} with the variable {{replacement}} in the variable {{haystack}}:

{{#replace needle haystack }}{{replacement}}{{/replace}}

using this data:

{
  "needle": "/dog/i",
  "haystack": "The DOG likes to eat",
  "replacement": "cat"
}

to get:

The cat likes to eat

Usage examples

The examples are based on a variable called data:

"data": {
    "tags":["infra, team-a"],
    "id":123456789,
    "name": "Alice",
}

The data value has an equivalent, dot-notated format:

"data.tags": ["infra, team-a"]
"data.id": 123456789
"data.name": "Alice"

Validate data

If id equals 123456789, then the output is valid. If not, the output is not valid.

{{eq data.name "Alice" yes='valid' no='not valid'}}

If name equals Alice, then the output is valid.

Return JSON

Get the tags and object’s properties in a JSON form:

{{json data.tags}}

This would return the following JSON:

["infra", "team-a"]

Get values from an array

Get the first tag from the tags array:

{{json data.tags.[0]}}

This would return the first value from the array:

bash

$"infra"

Iterate through an array

Iterate a variable of type array and aggregate the values into a string:

{{#each tags}}{{this}}{{#unless @last}}, {{/unless}}{{/each}}

The result contains the tags, seperated by commas (the trailing comma is omitted):

bash

$infra, team

Similarly, iterate the data variable, aggregate the object’s values, and output a JSON element:

{{#each (json data)}}{{this}}{{/each}}

This would return a JSON such as:

{
  "tags": ["infra, team-a"],
  "name": "Alice",
  "id": "123456789"
}

Iterate the data variable, then aggregate the object’s entries to a string:

{{#each data}}{{@key}}: {{this}}{{#unless @last}}, {{/unless}}{{/each}}

This would return a string such as:

bash

$tags: infra,team-a, name: Alice, id: 123456789

Handle missing attributes

In some cases, an attribute may be missing from the variables menu, or not exist whatsoever.

We can use the #if statement to set a fallback, such as:

{{#if data.type}} {{ json data.type }} {{else}}"N/A"{{/if}}

would return the string "N/A".

Message template variables

The variables menu

Use the Handlebars syntax

Helper functions

JSON

Equality

Contains

Replace

Usage examples

Validate data

Return JSON

Get values from an array

Iterate through an array

Handle missing attributes