Triggering on Pub/Sub Messages

In order to programatically trigger pipelines, you can configure Spinnaker to subscribe and listen to a pub/sub topic and push messages to the configured topic. This can be used to trigger pipelines during CI jobs, from the command line, or from a third-party system. The message payload will be available in the Pipeline’s execution.

Note: It’s possible to configure multiple pipelines to trigger off of a single pub/sub message.

Only Google Pub/Sub is supported. See the instructions here to set up Google Pub/Sub.

Adding a pub/sub trigger to a pipeline

Assuming you have created a pipeline, under Configuration, select Add Trigger and make its type selector Pub/Sub.

To select a pub/sub subscription to trigger from, select values for Pub/Sub System Type and Subscription Name.

Note: The subscription must be configured before it is available to select in the UI.

Payload constraints

If you want to ensure that a pub/sub trigger only fires when a certain message payload arrives, you can provide Payload Constraints in the trigger. These are key/value pairs where the key must be found in the incoming message payload and the value must match using regex.

For example, if we had configured:

For clarity, the constraints are foo = bar and bing = b.*p.

The following message payload would be accepted:

  "foo": "bar",
  "bing": "boooop",
  "x": ["1", "2", "3"]

But this message payload would be rejected (pipeline would not trigger):

  "foo": "bar",
  "x": ["1", "2", "3"]

Passing parameters

Say your pipeline accepted some parameters (e.g. the desired stack to deploy to), you can make this explicit by adding a pipeline parameter on the same configuration screen as the pub/sub trigger:

For more information on how to use pipeline parameters, see the pipeline expressions guide.

Warning: there are several reserved parameter keys (names) that cause unexpected behavior and failures if overwritten by a pipeline parameter definition. See the list of reserved parameter and evaluate variable key names.

If you were to manually execute this pipeline, you would be prompted with the following dialogue:

If instead you were to trigger this pipeline with a Pub/Sub Trigger, you could supply each parameter a value inside a key/value map called parameters in the message body. Take the following message payload for example:

  "parameters": {
    "stack": "prod"

Note: If you selected the Required checkbox for a parameter without providing a default, the pipeline will not trigger if a parameter is not present. The difference between this and the preconditions covered earlier is that when a precondition isn’t met, Spinnaker will not even try to run the pipeline. However, when a required parameter doesn’t exist, Spinnaker will try and fail to run a pipeline, surfacing a “Failed Execution” in the UI.

Passing artifacts

If your pipeline requires artifacts (for example, a Kubernetes manifest file stored in GCS), you can make this explicit by defining an Expected Artifact and assigning it to the Pub/Sub Trigger as shown below:

In order for this to work, you need to supply the required artifact in the pub/sub message payload, and configure Spinnaker so that it can translate the pub/sub payload into a Spinnaker artifact.

If you’re using GCR, you can use the --message-format flag and Spinnaker will translate the payload automatically:

hal config pubsub google subscription edit my-gcr-subscription \
  --message-format GCR

Otherwise, you need to supply a translation template so that Spinnaker can translate the pub/sub payload into a Spinnaker artifact. To do this, create a Jinja template.

Note: The output of the Jinja transform must be a JSON list of Spinnaker artifacts. The translation template itself can be any valid Jinja transform.

Use the following hal command to tell Spinnaker how to find the template:

hal config pubsub google subscription edit my-gcs-subscription \
  --template-path /path/to/jinja/template


Let’s say you have a message payload containing the following structure:

  "location": "gs://jtk54-artifacts/manifest.yml"

You can use the following Jinja template to translate the above into the Spinnaker artifact format:

    "type": "gcs/object", # static type.
    "reference": "{{ location }}", # 'location' in the pub/sub payload.