Mattermost

If your organization uses the Mattermost team communications platform, you can configure Horizon to send notices to any Mattermost channel via an incoming webhook. You must configure an incoming webhook in your Mattermost team and do a bit of manual configuration to your Horizon instance.

First, add the following bit of XML to the notificationCommands.xml configuration file (no customization should be needed):

<command binary="false">
  <name>mattermost</name>
  <execute>org.opennms.netmgt.notifd.MattermostNotificationStrategy</execute>
  <comment>class for sending messages to a Mattermost team channel for notifications</comment>
  <argument streamed="false">
    <switch>-subject</switch>
  </argument>
  <argument streamed="false">
    <switch>-tm</switch>
  </argument>
</command>

Then create a new file called mattermost.properties in the opennms.properties.d directory with the following contents (customizing values as appropriate):

org.opennms.netmgt.notifd.mattermost.webhookURL=https://mattermost.example.com/hooks/bf980352b5f7232efe721dbf0626bee1

Restart OpenNMS so that the mattermost.properties file will be loaded. Your new mattermost notification command is now available for use in a destination path.

Additional options

The following table lists optional properties that you may use in mattermost.properties to customize your Mattermost notifications.

To improve the layout, the property names have been shortened to their final component; you must prepend org.opennms.netmgt.notifd.mattermost. when using them.

Table 1. Additional optional parameters for the Mattermost notification strategy
Parameter	Description	Default	Example
channel	Specify a channel or private group other than the one targeted by the webhook.	Webhook default	NetOps
username	The username to associate with the notification posts.	None	OpenNMS_Bot
iconEmoji	An emoji sequence to use as the icon for the notification posts.	No icon	:metal:
iconURL	The URL of an image to use as the icon for the notification posts.	No icon	https://example.org/assets/icon.png
useSystemProxy	Should the system-wide proxy settings be used? Configure the system proxy settings via system properties.	true	true

Some of the optional configuration parameters are incompatible with some versions of Mattermost. For instance, the channel option is known not to work with Mattermost 3.7.0.

For more information on incoming webhooks in Mattermost, see Mattermost Integration Guide.