tuna and Mattermost
In addition to Mattermost App, it is possible to create Outgoing Webhooks - URLs to which messages will be sent if a keyword is mentioned in the specified channel.
Step 1. Download the client
Инструкция доступна на странице.
Step 2. Start a server to handle events from Mattermost
Information about the structure of incoming requests can be found in the official documentation.
Step 3. Run tuna
Specify your server port in the startup arguments:
tuna http 8080
Or with a static address:
tuna http 8080 --subdomain=mattermost-webhook
Step 4. Create a new Webhook
Go to the Integrations section, then "Outgoing Webhooks" and click the "Add Outgoing Webhook" button. Fill out the form that appears, and for the "Callback URL" value, specify the address received from tuna (for example, https://mattermost-webhook.ru.tuna.am) and the path to your server method for handling events (for example, /event).