Watcher Slack Action | Elasticsearch Guide

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Watcher Slack Actionedit

Use the slack action to send messages to a Slack team’s channels or users. To send Slack messages, you need to configure at least one Slack account in elasticsearch.yml.

Configuring Slack actionsedit

You configure Slack actions in the actions array. Action-specific attributes are specified using the slack keyword.

The following snippet shows a simple slack action definition:

"actions" : {
  "notify-slack" : {
    "transform" : { ... },
    "throttle_period" : "5m",
    "slack" : {
      "message" : {
        "to" : [ "#admins", "@chief-admin" ], 
        "text" : "Encountered  {{ctx.payload.hits.total}} errors in the last 5 minutes (facepalm)" 
      }
    }
  }
}

	The channels and users you want to send the message to.
	The content of the message.

Using attachments to format Slack messagesedit

In addition to sending simple text-based messages, you can use the Slack attachment mechanism to send formatted messages. Watcher leverages Slack attachments to enable you to dynamically populate templated messages from the execution context payload.

The following snippet shows a standard message attachment:

"actions" : {
  "notify-slack" : {
    "throttle_period" : "5m",
    "slack" : {
      "account" : "team1",
      "message" : {
        "from" : "watcher",
        "to" : [ "#admins", "@chief-admin" ],
        "text" : "System X Monitoring",
        "attachments" : [
          {
            "title" : "Errors Found",
            "text" : "Encountered  {{ctx.payload.hits.total}} errors in the last 5 minutes (facepalm)",
            "color" : "danger"
          }
        ]
      }
    }
  }
}

To define an attachment template that is dynamically populated from the payload, you specify dynamic_attachments in the watch action. For example, a dynamic attachment could reference histogram buckets in the payload and build an attachment per bucket.

In the following example, the watch input executes a search with a date histogram aggregation and the Slack action:

Transforms the payload to a list where each item in the list holds the month, the user count for that month, and the color that represents the sentiment associated with that count (danger or bad).
Defines an attachment template that references items in the list generated by the transform.

"input" : {
  "search" : {
    "request" : {
      "body" : {
        "aggs" : {
          "users_per_month" : {
            "date_histogram" : {
              "field" : "@timestamp",
              "interval" : "month"
            }
          }
        }
      }
    }
  }
},
...
"actions" : {
  "notify-slack" : {
    "throttle_period" : "5m",
    "transform" : {
      "script" : {
        "source" : "['items': ctx.payload.aggregations.users_per_month.buckets.collect(bucket -> ['count': bucket.doc_count, 'name': bucket.key_as_string, 'color': bucket.doc_count < 100 ? 'danger' : 'good'])]",
        "lang" : "painless"
      }
    },
    "slack" : {
      "account" : "team1",
      "message" : {
        "from" : "watcher",
        "to" : [ "#admins", "@chief-admin" ],
        "text" : "System X Monitoring",
        "dynamic_attachments" : {
          "list_path" : "ctx.payload.items" 
          "attachment_template" : {
            "title" : "{{month}}", 
            "text" : "Users Count: {{count}}",
            "color" : "{{color}}"
          }
        }
      }
    }
  }
}

	The list generated by the action’s transform.
	The parameter placeholders refer to attributes in each item of the list generated by the transform.

Slack action attributesedit

Name	Required	Description
`message.from`	no	The sender name to display in the Slack message. Overrides the incoming webhook’s configured name.
`message.to`	yes	The channels and users you want to send the message to. Channel names must start with `#` and user names must start with `@`. Accepts a string value or an array of string values.
`message.icon`	no	The icon to display in the Slack messages. Overrides the incoming webhook’s configured icon. Accepts a public URL to an image.
`message.text`	yes	The message content.
`message.attachments`	no	Slack message attachments. Message attachments enable you to create more richly-formatted messages. Specified array as defined in the Slack attachments documentation.
`message.dynamic_attachments`	no	Slack message attachments that can be populated dynamically based on the current watch payload. For more information, see Using attachments to format Slack messages.
`proxy.host`	no	The proxy host to use (only in combination with `proxy.port`)
`proxy.port`	no	The proxy port to use (only in combination with `proxy.host`)

Configuring Slack Accountsedit

You configure the accounts Watcher can use to communicate with Slack in the xpack.notification.slack namespace in elasticsearch.yml.

You need a Slack App with the Incoming Webhooks feature to configure a Slack account. Use the generated webhook URL to set up your Slack account in Elasticsearch.

To configure a Slack account, at a minimum you need to specify the account name and webhook URL in the Elasticsearch keystore (see secure settings):

bin/elasticsearch-keystore add xpack.notification.slack.account.monitoring.secure_url

You can no longer configure Slack accounts using elasticsearch.yml settings. Please use Elasticsearch’s secure keystore method instead.

You can specify defaults for the Slack notification attributes:

xpack.notification.slack:
  account:
    monitoring:
      message_defaults:
        from: x-pack
        to: notifications
        icon: http://example.com/images/watcher-icon.jpg
        attachment:
          fallback: "X-Pack Notification"
          color: "#36a64f"
          title: "X-Pack Notification"
          title_link: "https://www.elastic.co/guide/en/x-pack/current/index.html"
          text: "One of your watches generated this notification."
          mrkdwn_in: "pretext, text"

To notify multiple channels, create a webhook URL for each channel in Slack and multiple Slack accounts in Elasticsearch (one for each webhook URL).

If you configure multiple Slack accounts, you either need to configure a default account or specify which account the notification should be sent with in the slack action.

xpack.notification.slack:
  default_account: team1
  account:
    team1:
      ...
    team2:
      ...

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