Create Flow Webhook Task
You can send webhook messages to third-party applications based on the results of job executions in your flow.
A webhook task is a callback message between Designer Cloud and another application. They are typically delivered using JSON over HTTP and can be interpreted by the receiving application to take action.
Note
Your receiving application may require that you whitelist the host and port number or IP address of the platform. Please refer to the documentation for your application.
A webhook task is defined at the flow level, although an individual webhook task can be restricted to specific outputs. It is shared between ad-hoc and scheduled executions.
For more information on how to orchestrate execution of your flows, see Overview of Operationalization.
Limitations
Custom security certificates cannot be used.
HTTP-based requests have a 30-second timeout limit.
Webhook tasks are not included when a flow is copied. They are available to collaborators for review, editing, and execution, when a flow is shared.
Tip
You can export and import the flow, which includes the webhook task definition.
You can create a maximum of 50 webhooks per flow.
Prerequisites
Requirements for receiving application
To send webhooks to a target application, the application must be configured to receive the webhook:
Incoming webhooks must be enabled.
Note
Your receiving application may require that you whitelist the host and port number or IP address of the platform. Please refer to the documentation for your application.
You must acquire the URL of the endpoint to which to send the webhook request.
You must acquire any HTTP headers that must be inserted with each webhook request.
If the request must be signed, additional configuration is required. Details are below.
Steps
Open your flow in Flow View. From the flow context menu, select Webhooks.
In the right panel, select Create webhook task.
Set the following parameters:
Parameter
Description
Name
User-visible name of the task.
Url
URL where the webhook message is received by the other application.
Trigger event
Select the event that triggers the message.
Trigger object
Select the object or objects that can trigger the message:
Any job executed in this flow
- Any scheduled or ad-hoc job triggers the messageOnly specific objects
- Select the output or outputs whose success or failure triggers the messageHeaders
Insert HTTP content headers as key-value pairs. For example, if your body is in JSON format, you should include the following header:
key: Content-Type value: application/json
Note
You may be required to submit an authentication token as the value for the
Authorization
key.Please refer to the documentation for your receiving application about the required headers.
Body
(
POST
,PUT
, orPATCH
methods only) The body of the request submitted to the receiving application. In the body, you can use the following references:jobId
- the internal identifier for the jobGroup that was executed.jobStatus
- the status for the job after execution. For more information, see Job History Page. You can apply metadata references to the flow in the Body text. See below for examples.Method
Select the HTTP method to use to deliver the message. The appropriate method depends on the receiving application. Most use cases require the
POST
method.Secret key
(Optional) A secret key can be used to verify the webhook payload. This secret value must be inserted in this location, and it must be included as part of the code used to process the requests in the receiving application. Insert the secret value here as a string without quotes.
For more information on how this secret key is used to generate a signature, see Verify Webhook Signatures below.
Validate SSL certificate
When set to
true
, HTTPS (SSL) communications are verified to be using a valid certificate before transmission.Note
If you must send a request to an endpoint that has an expired/invalid certificate, you must disable SSL verification.
Retry on failure
If the returned status code is outside of the 200-299 range, then the webhook is considered to have failed. When this option is enabled, the request is retried.
To test the connection, click Test. A success message is displayed.
To add the webhook task to the flow, click Create.
When the job is executed:
Depending on the outcome, the webhook task is executed through the other application.
The webhook is listed in the Job Details page.
Flow metadata references in body
In the body of your webhook, you can use the following references:
Reference | Description |
---|---|
$jobId | Internal identifier to the job in the platform. |
$jobStatus | The current status of the webhook job. For more information on job status messages, see Job History Page. |
Examples
Run another job
You can create a webhook task to run another job on the successful execution of this one.
Tip
Use this method to create conditional sequences of job executions.
Prerequisites
You must acquire the recipe identifier for the next job to execute.
Open the flow containing the next recipe.
In Flow View, click the recipe whose outputs you wish to generate.
Review the URL for the recipe object. In the example below, the recipe Id value is
4
:http://www.example.com:3005/flows/1?recipe=4&tab=recipe
Retain this value for below.
Define the flow webhook task
Parameter | Description |
---|---|
Name | This name appears in the Cloud Portal only. |
Url | Specify the URL as follows, replacing the example values with your own: http://www.example.com:3005/v4/jobGroups/ |
Trigger event | Select |
Trigger object | Select the |
Headers | Insert the following two headers: key: Content-Type value: application/json key: Authorization value: Bearer <paste your access token here> Note The token value must be preceded by the string: |
Body | In the body, insert the recipe Id for the value for { "wrangledDataset": { "id": 4 } } |
Method | Select the |
Verify
Run the job for which the webhook was created.
When the job successfully completes, open the flow containing the other job to execute.
When you select the target recipe, a new job should be queued, in-progress, or completed.
Slack channel message
You can create a webhook task to deliver a text message to a Slack channel of your choice.
Prerequisites
Set up your Slack installation to receive webhook messages:
If needed, create a Slack channel to receive your messages.
Create an app.
Activate incoming webhook messages for your app.
Specify the channel to receive your incoming webhook messages.
Copy the URL for the incoming webhook from the cURL statement.
Define the flow webhook task
Parameter | Description |
---|---|
Name | This name appears in the Cloud Portal only. |
Url | Paste the URL that you copied from Slack. |
Headers | Copy the content headers from the Slack cURL command: key: Content-Type value: application/json |
Body | {"text":"Job $jobId has completed. Status: $jobStatus."} |
Method | Select the |
Verify
Click Test to validate that this webhook task will work.
Run a job:
Check the Slack channel for a message.
Check the Webhook tab in the Job Details page.
Verify Webhook Signatures
Warning
Depending on the target application, implementing Webhook signature verification may require developer skills.
Optionally, you can configure the platform to sign the Webhook requests sent for a flow. Signed requests guarantee that the requests are sent from the platform, instead of a third party.
Below, you can review how the signature is created, so that you can configure the receiving application to properly process the signature and its related request.
Webhook Signature Header
Webhook requests are signed by inserting the X-Webhook-Signature
header in the request. These signatures are in the following form:
X-Webhook-Signature: t=<timestamp>,sha256=<signature>
where:
<timestamp>
- Timestamp when the signature was sent. Value is in UNIX time.<signature>
- SHA256 signature. The platform generates this signature using a hash-based message authentication code (HMAC) with SHA-256.
More information on these values is available below.
Example:
X-Webhook-Signature: t=1568818215724,sha256=55fa71b2e391cd3ccba8413fb51ad16984a38edb3cccfe81f381c4b8197ee07a
Check Application Tools
Depending on the application, you may need to complete one of the following sets of tasks to verify the Webhook signatures:
Note
You may need to whitelist the platform in your application. See the application's documentation for details.
You may be required to create some custom coding for your application. Below, you can review details on how to do so, including a JavaScript example.
Process Signed Requests
Timestamp
The timestamp value (t=<timestamp>
) appears at the beginning of the header value to prevent replay attacks, where an attacker could intercept a valid payload and its signature and re-transmit them.
To avoid such attacks, a timestamp is included in the signature header and is also embedded as part of the signed payload.
Since the timestamp is part of the signed payload, an attacker cannot change the timestamp value without invalidating the signature.
If the signature is valid but the timestamp is too old, you can then choose to reject the request.
For example, if you receive a request with a timestamp that corresponds to a date from one hour ago, you should probably reject the request.
For more information on replay attacks, see https://en.wikipedia.org/wiki/Replay_attack.
Signature
The Webhook signature includes as part of its hashed value:
The secret key (entered above)
The timestamp value
Request data:
(POST/PUT/PATCH) - the body of the request
(GET/DELETE) - URL of the request
Step 1 - Extract the timestamp and signatures
Split the X-Webhook-Signature
header:
Split values using the , character as a separator.
Split each of the parts using the = character.
Extract the values for the timestamp and signature. From the above example:
timestamp:
1568818215724
signature:
55fa71b2e391cd3ccba8413fb51ad16984a38edb3cccfe81f381c4b8197ee07a
Step 2 - Create the expected signature
In the receiving application, you can recompute the signature to verify that the request was sent from the platform.
Concatenate the timestamp, the dot character . and the request body (POST/PUT/PATCH methods) or the url (GET/DELETE methods).
Suppose the above example is the signature for a
POST
request, and the request body istest
. The concatenated value is the following:1568818215724.test
You can now compute the HMAC authentication code in your receiving application. In the following JavaScript example, the secret key value is
mySecret
:const crypto = require('crypto'); const message = '1568818215724.test'; // as defined above const hmac = crypto.createHmac('sha256', 'mySecret'); hmac.update(message) const expectedSignature = hmac.digest('hex');
Step 3 - Compare the signatures
The value returned by your code and the value included as the signature in the X-Webhook-Signature
header should be compared:
If the values do not match, reject the request.
If the values do match, compute the difference between the current timestamp and the timestamp in the header. If the difference is outside of your permitted limit, reject the request.
Otherwise, process the request normally in your application.