OpenWhisk Feeds, Triggers, and Rules

In the previous sections, we learned how to invoke actions either with the wsk CLI or with HTTP requests using web actions. In this section, we are going to learn how to automate action invocation with OpenWhisk feeds, triggers, and rules. The following diagram illustrates how actions are invoked with events from external event sources using feeds, triggers, and rules:

Figure 8.53: OpenWhisk Feeds, triggers, and rules

Triggers are different types of events sent from event sources. These triggers can be fired either manually with the wsk CLI or automatically from events occurring in external event sources. Some examples of an event source are a Git repository, an email account, or a Slack channel. As illustrated in the preceding diagram, feeds are used to connect the triggers to external event sources. Examples for feeds are as follows:

• A commit is made to a Git repository.
• Incoming email messages to a particular...