Managing external event sources

Create and manage external event sources for a spoke or a scoped application that listen to events occurring in an application outside ServiceNow. Then, you can create external trigger definitions and associate them with the external event sources. When the event that you specify in the external trigger definition occurs, it starts one or more flows on your ServiceNow instance.

Before you begin

Role required: trigger_designer (Can create, read, update, or delete external event sources) and trigger_designer_read (can perform read-only operations on the external event sources that the trigger_designer role creates.)

Confirm that you have installed the External Trigger Builder plugin on your instance. External Trigger Builder v1.0.3 is the latest available version.

About this task

An external event source is an end point on your ServiceNow instance which listens to a system or application outside of ServiceNow. After the application outside ServiceNow sends an event to the external event source, it enables a trigger definition to start one or more flows. For example, you define an external event source for an issue-tracking software that communicates with an external trigger definition that you have defined. The external trigger definition listens to the event source and starts a flow when a new issue is created in the issue-tracking software. Both the external event source and the trigger definitions are defined on your ServiceNow instance. An external trigger definition gives a set of conditions that tells your ServiceNow instance when to start a flow.

Create an external event source

Create an external event source for a spoke or scoped application that listens to events occurring in an application or system outside ServiceNow. Based on the external event source, you can create an external trigger definition that receives communication from the external event source and starts a flow on your ServiceNow instance.

Before you begin

Role required: trigger_designer (Can create, read, update, or delete external event sources) and trigger_designer_read (can perform read-only operations on the external event sources that the trigger_designer role creates.)

Confirm that you have installed the External Trigger Builder plugin on your instance.

Procedure

1. Navigate to All > Process Automation > Workflow Studio.
2. Click the Integrations tab.
3. Click the spoke.
   The Spokes tab is selected by default. If it isn’t selected already, confirm that you have selected it.

   

4. On the left panel, click Event sources.
   
5. Click Create event source.
6. In the Event Source name field, provide a unique name to the external event source.
7. Optional: In the Description field, enter a description of the external event source.
   
8. Click Create event source.
   The external event source is created in the draft state.
9. Optional: View the external event source in the draft state.
   1. Select the spoke tab.
      
   2. Select the Drafts tab.
      The external event source that you created, appears.

      Tip:

      If the external event source doesn't appear, refresh the page, and then select the Drafts tab.
10. Under the Authentication heading, select the method to authenticate the webhook that the external application sends to your ServiceNow instance.
    The following authentication methods are available.

    • Basic
    • OAuth
    • Hash
    • Token

    If you choose the Hash or Token authentication method, then you must specify the information given in the table.

    Table 1. Authentication specifications

    Authentication method	Field	Description
    Basic		Option to specify that user names and passwords that the external application sends will be authenticated.
    OAuth		Option to specify that OAuth mechanism will be used to authenticate the webhooks from the external application.
    Hash	Authentication Location	Option to specify the location where the external application or system includes the hash when sending the message. The available locations are: Query parameters Header
    	Parameter Name	Option to specify the name of the field where you can find the hash.
    	Hash algorithm	Option to specify the algorithm using which the hash is calculated. The available algorithms are: HmacSHA256 HmacSHA384 HmacSHA512
    	Prefix	Option to specify a value that may come before the hash.
    	HMAC Util Script	Option to specify the script that generates or validates the hash. To know more about HMAC, see Configure HMAC - Token-based authentication.
    Token	Authentication Location	Option to specify the location where the external system includes the token when sending the message. The available locations are: Query parameters Header
    	Parameter Name	Option to specify the name of the field where you can find the token.
    	Prefix	Option to specify a value that may come before the token.

11. Click Publish.
    The external event source is available for you to associate with an external trigger definition.

    

12. Optional: View the published external event source.
    1. Select the spoke tab.
       
    2. Select the Published tab.
    The external event source that you published, appears.

    Tip:

    If the external event source doesn't appear, refresh the page and select the Drafts tab.

What to do next

Create a saved external trigger and associate it with the external event source that you created.

Update an external event source

Update an external event source that is in the draft or published state.

Before you begin

Role required: trigger_designer (Can create, read, update, or delete external event sources) and trigger_designer_read (can perform read-only operations on the external event sources that the trigger_designer role creates.)

Confirm that you have installed the External Trigger Builder plugin on your instance.

About this task

You can update all information of an external event source in the draft state but only its name and description in the published state.

Procedure

1. Navigate to All > Process Automation > Workflow Studio.
2. Click the Integrations tab.
3. Click the spoke that has the external event source defined.
   The Spokes tab is selected by default. If it isn’t selected, confirm that you have selected it.

   

4. On the left panel, click Event sources.
   
5. To update an event source in the draft state, do the steps.
   1. Click the Drafts tab.
   2. Click the external event source that you want to update.
   3. Click the ellipsis button () and then click Properties.
   4. In the Event source properties form, update the information.
   5. Click Update.
      The external event source is updated.
6. To update an event source in the published state, do the steps.
   1. Click the Published tab.
   2. Click the external event source that you want to update.
   3. Click the ellipsis button () and then click Properties.
   4. In the Event source properties form, update the information in the following fields.
      • Event source name
      • Description
   5. Click Update.
      The external event source is updated.

Delete an external event source

Delete an external event source in the draft or published state that is not associated with an external trigger definition.

Before you begin

Role required: trigger_designer (Can create, read, update, or delete external event sources) and trigger_designer_read (can perform read-only operations on the external event sources that the trigger_designer role creates.)

Confirm that you have installed the External Trigger Builder plugin on your instance.

Procedure

1. Navigate to All > Process Automation > Workflow Studio.
2. Click the Integrations tab.
3. Click the spoke that has the external event source defined.
   The Spokes tab is selected by default. If it isn’t selected, confirm that you have selected it.

   

4. On the left panel, click Event sources.
   
5. Click the Published or Drafts tab.
6. Click the external event source that you want to delete.
7. Click the ellipsis button () and then select Properties.
8. Click Delete.
9. On the Delete event source dialog, click Delete.
   The external event source is deleted.

   Note:

   You can't delete an external event source that has one or more external triggers associated.