Reload alerts via Slack

What’s this?

Butler can send two kinds of alert messages via Slack:

• When a scheduled, or started from the QMC reload task fails.
• When a scheduled, or started from the QMC reload task is somehow stopped.

See the Concepts section for additional details.

A complete reference to the config file format is found here.

Basic vs formatted Slack alerts

Slack alerts come in two forms:

• Customizable formatting using a template concept. A standard template that will fit most use cases is included with Butler. Using this option the last part of the script log can be included in the message, allowing you to tell from the Slack message what caused the reload to fail.
• A fixed, more basic format that is built into Butler. No template file needed.

Which option to go for depends on whether you want just a notification that something went wrong, or if you want as much detail as possible in the Slack message.

Sample message with custom formatting

A “reload task failed” Slack message using the custom formatting option could look like this:

Here’s how to set this up:

1. Create an incoming webhook in Slack, take note of its URL (you will need it in step 2 below).

2. Edit the Slack section of the config file i.e. the settings in Butler.slackNotification.reloadTaskFailure and/or Butler.slackNotification.reloadTaskAborted sections of the confi file.

   The messageType property should be set to formatted.
   The basicMsgTemplate property is not used with formatted messages and can thus be left empty,

3. Edit the template file(s) as needed, these are specified by Butler.slackNotification.reloadTaskFailure.templateFile and Butler.slackNotification.reloadTaskAborted.templateFile. They are using the Handlebars templating engine, to which Butler provides template fields with actual values.

   The available template fields are described here.

   Sample template files are available in the GitHub repository’s src/config/slack_templates directory.

4. Restart Butler if it’s already running.

Sample message with basic formatting

A “reload task failed” Slack message with basic formatting could look like this:

To set it up:

1. Create an incoming webhook in Slack if you don’t already have one, take note of its URL (you will need it in step 2 below).

2. Edit the Slack section of the config file i.e. the settings in Butler.slackNotification.reloadTaskFailure and/or Butler.slackNotification.reloadTaskAborted sections of the confi file.

   The messageType property should be set to basic.
   The basicMsgTemplate property is the message that will be sent via Slack. Template fields can be used.

3. Restart Butler if it’s already running.

Customizing Slack messages

When using the formatted Slack alerts you have full freedom to create the alert you need.
Behind the scenes Slack messages are constructed from blocks defined in a JSON object. Each block can then contain either plain text, Markdown, images, buttons etc.

The Slack documentation is the best place for learning how to customize messages.

When it comes to Butler, it uses the Handlebars templating engine to render the template files into Slack JSON objects that are then sent to Slack via their APIs.

A few things to keep in mind when creating custom Slack messages:

• The handlebars syntax itself must be correct. If incorrect no Slack JSON object will be created. And no Slack messages sent.
• The handlebars template must result in a JSON object that adheres to Slack’s API specifications.
  If the JSON syntax is somehow invaid the Slack API will return errors and no messages sent. JSON can be pretty sensitive to details, there should for example not be any trailing commas in properly formatted JSON objects.

Some useful links to Slacks’s documentation:

• Creating rich message layouts: General info on how messages are structured and created..
• Formatting text for app surfaces: How to use markdown, formatting of links, escaping text etc..
• Reference: Layout blocks: The official docs for creating Slack messages.
• Block Kit Builder: Great sandbox wtih readily available examples of different message layouts, syntax and more. Note: You must be logged into your Slack account to use this tool.

How it works

The concept is the same for all alert types.

Settings in config file

---
Butler:
  ...
  ...
  # Settings for notifications and messages sent to Slack
  slackNotification:
    enable: false
    restMessage:                      
      webhookURL: <web hook URL from Slack>   # Webhook to use when sending basic Slack messages via Butler's REST API 
    reloadTaskFailure:
      enable: false
      webhookURL: <web hook URL from Slack>
      channel: sense-task-failure     # Slack channel to which task failure notifications are sent
      messageType: formatted          # formatted / basic. Formatted means that template file below will be used to create the message.
      basicMsgTemplate: 'Qlik Sense reload failed: "{{taskName}}"'      # Only needed if message type = basic
      rateLimit: 300                  # Min seconds between emails for a given taskID. Defaults to 5 minutes.
      headScriptLogLines: 10
      tailScriptLogLines: 10
      templateFile: /path/to/slack/template/directory/failed-reload.handlebars
      fromUser: Qlik Sense
      iconEmoji: ':ghost:'
    reloadTaskAborted:
      enable: false
      webhookURL: <web hook URL from Slack>
      channel: sense-task-aborted     # Slack channel to which task stopped notifications are sent
      messageType: formatted          # formatted / basic. Formatted means that template file below will be used to create the message.
      basicMsgTemplate: 'Qlik Sense reload aborted: "{{taskName}}"'       # Only needed if message type = basic
      rateLimit: 300                  # Min seconds between emails for a given taskID. Defaults to 5 minutes.
      headScriptLogLines: 10
      tailScriptLogLines: 10
      templateFile: /path/to/slack/template/directory/aborted-reload.handlebars
      fromUser: Qlik Sense
      iconEmoji: ':ghost:'

  ...
  ...
  udpServerConfig:
    enable: false                                     # Should the UDP server responsible for receving task failure and session events be started? true/false
    serverHost: <FQDN or IP (or localhost) of server where Butler is running>
    portTaskFailure: 9998
  ...
  ...