Annotate notifications with user-defined documentation

This page describes how you can configure your alerting policy documentation so that notifications provide incident responders with resources and additional information for incident resolution.

Documentation structure

The documentation of an alerting policy consists of a subject, content, and links. You can configure documentation in the Google Cloud console, the Cloud Monitoring API, and the Google Cloud CLI.

Subjects

The subject of your documentation appears in the subject of notifications for incidents related to your alerting policy. Notification recipients can manage and sort their notifications by subject.

Subject lines are limited to 255 characters. If you don't define a subject in your documentation, then Cloud Monitoring determines the subject line. Subject lines support plain text and variables.

Cloud Monitoring API

Configure the notification subject line by using the subject field of the alerting policy documentation.

Google Cloud console

Configure the notification subject line by using the Notification subject line field in the Notifications and name section of the Create alerting policy page.

Content

The content of your documentation appears in the following notification types:

• Email, under the Policy Documentation header
• PagerDuty
• Pub/Sub
• Slack
• Webhooks

We recommend configuring your content so that incident responders can view remediation steps and incident information in notifications related to your alerting policy. For example, you might configure the documentation to include a summary of the incident and information about relevant resources.

Documentation content supports plain text, Markdown, variables, and channel-specific controls.

Cloud Monitoring API

Configure documentation content by using the content field of the alerting policy documentation.

Google Cloud console

Configure documentation content by using the Documentation field in the Notifications and name section of the Create alerting policy page.

Links

You can add links to your documentation so that incident responders can access resources such as playbooks, repositories, and Google Cloud dashboards from a notification.

Cloud Monitoring API

Documentation links configured in the Cloud Monitoring API appear in the following notification types:

• Email, under the Quick Links header
• PagerDuty
• Pub/Sub
• Webhooks

To configure a link, add a Link to the documentation of your alerting policy. Each link is represented by a display_name and a url. You can have up to three links in your documentation.

The following configuration uses links with one URL to create a link to an incident playbook. The URL includes a variable so that notification recipients can access the correct playbook based on the monitored resource where the incident occurred:

"links" [
  {
    "displayName": "Playbook",
    "url": "https://myownpersonaldomain.com/playbook?name=${resource.type}"
  }
]

Google Cloud console

Documentation links configured in the Google Cloud console appear with the rest of your documentation content in the following notification types:

• Email, under the Policy Documentation header
• PagerDuty
• Pub/Sub
• Slack
• Webhooks

You can add links to your documentation content by including them in the Documentation field of your alerting policy. For example, the following documentation lists a URL for a customer playbook:

### Troubleshooting and Debug References

Playbook: https://myownpersonaldomain.com/playbook?name=${resource.type}

Note: The Google Cloud console doesn't support configuring the Links object for alerting policies.

Markdown in documentation content

You can use Markdown to format your documentation content. Documentation content supports the following subset of Markdown tagging:

• Headers, indicated by initial hash characters.
• Unordered lists, indicated by initial plus, minus, or asterisk characters.
• Ordered lists, indicated by an initial number followed by a period.
• Italic text, indicated by single underscores or asterisks around a phrase.
• Bold text, indicated by double underscores or asterisks around a phrase.
• Links, indicated by [link text](url) syntax. However, we recommend using the Link object to configure links for your content.

For more information about this tagging, see any Markdown reference, for example, Markdown guide.

Variables in documentation

To customize the text in your documentation, you can use variables of the form ${varname}. When the documentation is sent with a notification, the string ${varname} is replaced with a value drawn from the corresponding Google Cloud resource, as described in the following table.

Variable	Value
condition.name	The REST resource name of the condition, such as projects/foo/alertPolicies/1234/conditions/5678.
condition.display_name	The display name of a condition, such as CPU usage increasing rapidly.
log.extracted_label.KEY	The value of the label KEY, extracted from a log entry. For log-based alerting policies only; for more information, see Create a log-based alerting policy by using the Monitoring API.
metadata.system_label.KEY	The value of the system-supplied resource metadata label KEY.^1
metadata.user_label.KEY	The value of the user-defined resource metadata label KEY.^1,3
metric.type	The metric type, such as compute.googleapis.com/instance/cpu/utilization.
metric.display_name	The display name for the metric type, such as CPU utilization.
metric.label.KEY	The value of the metric label KEY.^1 To find the labels associated with the metric type, see Metric list. When the value of the variable ${metric.label.KEY} doesn't start with a digit, a letter, a forward slash (/), or an equal sign (=), Monitoring omits the label from notifications. When you migrate a Prometheus alerting rule, the Prometheus alert field templates {{$value}} and {{humanize $value}} appear as ${metric.label.VALUE}, in the alerting policy documentation configuration. In this case, VALUE holds the value of the PromQL query. You can also use ${metric.label.VALUE} when you create PromQL queries in Google Cloud.
metric_or_resource.labels	This variable renders all metric and resource label values as a sorted list of key-value pairs. If a metric label and a resource label have the same name, then only the metric label is rendered. When you migrate a Prometheus alerting rule, the Prometheus alert field templates {{$labels}} and {{humanize $labels}} appear as ${metric_or_resource.labels} in the alerting policy documentation configuration.
metric_or_resource.label.KEY	If KEY is a valid label, then this variable renders in the notification as the value of ${metric.label.KEY}. If KEY is a valid resource, then this variable renders in the notification as the value of ${resource.label.KEY}. If KEY is neither a valid label nor a valid resource, then this variable renders in the notification as an empty string. When you migrate a Prometheus alerting rule, the Prometheus alert field templates {{$labels.KEY}} and {{humanize $labels.KEY}} appear as ${metric_or_resource.labels.KEY} in the alerting policy documentation configuration.
policy.name	The REST resource name of the policy, such as projects/foo/alertPolicies/1234.
policy.display_name	The display name of a policy, such as High CPU rate of change.
policy.user_label.KEY	The value of the user label KEY.^1 Keys must start with a lowercase letter. Keys and values can contain only lowercase letters, digits, underscores, and dashes.
project	The ID of the scoping project of a metrics scope, such as a-gcp-project.
resource.type	The monitored-resource type, such as gce_instance.
resource.project	The project ID of the monitored resource of the alerting policy.
resource.label.KEY	The value of the resource label KEY.^1,2,3 To find the labels associated with the monitored-resource type, see Resource list.

¹ For example, ${resource.label.zone} is replaced with the value of the zone label. The values of these variables are subject to grouping; see null values for more information.
² To retrieve the value of the project_id label on a monitored resource in the alerting policy, use ${resource.project}.
³ You can't access user-defined resource metadata labels by using resource.label.KEY. Use metadata.user_label.KEY instead.

Usage notes

• Only the variables in the table are supported. You can't combine them into more complex expressions, like ${varname1 + varname2}.
• To include the literal string ${ in your documentation, escape the $ symbol with a second $ symbol, and $${ renders as ${ in your documentation.
• These variables are replaced by their values only in notifications sent through notification channels. In the Google Cloud console, when the documentation is shown, you see the variables, not the values. Examples in the console include the descriptions of incidents and the preview of the documentation when creating an alerting policy.
• Ensure that the aggregation settings of the condition don't eliminate the label. If the label is eliminated, then the value of the label in the notification is null. For more information, see Variable for a metric label is null.

Note: Labels that you add to log-based metrics can't be used in template expressions. However, you can display these labels in chart legends and you can filter time series by the label values.

null values

Values for the metric.*, resource.* and metadata.* variables are derived from time series. Their values can be null if no values are returned from the time series query.

• The resource.label.KEY and metric.label.KEY variables can have null values if your alerting policy uses cross-series aggregation (reduction), for example, calculating the SUM across each of the time-series that match a filter. When using cross-series aggregation, any labels not used in grouping are dropped and as a result they render as null when the variable is replaced with its value. All labels are retained when there is no cross-series aggregation. For more information, see Variable for a metric label is null.

• Values for metadata.* variables are available only if the labels are explicitly included in a condition's filter or grouping for cross-series aggregation. That is, you must refer to the metadata label in either filter or grouping for it to have a value for the template.

Variable resolution

Variables in documentation templates are resolved only in the notifications sent by using the following notification channels:

• Email
• Google Chat
• Slack
• Pub/Sub, JSON schema version 1.2
• Webhooks, JSON schema version 1.2
• PagerDuty, JSON schema version 1.2

Note: Variables are not resolved, but appear as strings like ${varname}, in other contexts, in notifications sent by using other notification channels.

Channel controls

The text in the documentation field can also include special characters used by the notification channel itself to control formatting and notifications.

For example, Slack uses @ for mentions. You can use @ to link the notification to a specific user ID. Mentions can't include names. Suppose you include a string like this in the documentation field:

<@backendoncall> Incident created based on policy ${policy.display_name}

When the documentation field is received by the relevant Slack channel as part of the notification, the previous string causes Slack to send an additional message to the user ID backendoncall. The message sent by Slack to the user could contain relevant information from the notification; for example, "Incident created based on policy High CPU rate of change".

These additional options are specific to the channels; for more information on what may be available, consult the documentation provided by the channel vendor.

Example

The following example shows Google Cloud console and Cloud Monitoring API versions of template documentation for a CPU utilization alerting policy. These examples use an email for the notification channel type. The documentation templates include several variables to summarize the incident and to reference the alerting policy and condition REST resources.

Cloud Monitoring API

  "documentation": {
    "content": "### CPU utilization exceeded\n\n### Summary\n\nThe ${metric.display_name} of the ${resource.type} ${resource.label.instance_id} in the project ${resource.project} has exceeded 5% for over 60 seconds.\n\n#### Additional resource information\n\nCondition resource name: ${condition.name}  \nAlerting policy resource name: ${policy.name}",
    "mimeType": "text/markdown",
    "subject": "Alert: ${metric.display_name} exceeded",
    "links": [
      {
        "displayName": "Playbook",
        "url": "https://myownpersonaldomain.com/playbook?name=${resource.type}"
      },
      {
        "displayName": "Repository with debug scripts",
        "url": "https://altostrat.com"
      },
      {
        "displayName": "Google Cloud dashboard",
        "url": "https://example.com"
      }
    ]
  }

The following image shows how this template appears in an email notification:

Google Cloud console

### CPU utilization exceeded

#### Summary

The ${metric.display_name} of the ${resource.type}
${resource.label.instance_id} in the project ${resource.project} has
exceeded 5% for over 60 seconds.

#### Additional resource information

Condition resource name: ${condition.name}  
Alerting policy resource name: ${policy.name}  

#### Troubleshooting and Debug References

Playbook: https://myownpersonaldomain.com/playbook?name=${resource.type}  
Repository with debug scripts: https://altostrat.com  
${resource.type} dashboard: https://example.com

The following image shows how this template appears in an email notification: