triggerbindings.md

TriggerBindings

As per the name, TriggerBindings bind against events/triggers. TriggerBindings enable you to capture fields from an event and store them as parameters. The separation of TriggerBindings from TriggerTemplates was deliberate to encourage reuse between them.

apiVersion: tekton.dev/v1alpha1
kind: TriggerBinding
metadata:
  name: pipeline-binding
spec:
  params:
  - name: gitrevision
    value: $(body.head_commit.id)
  - name: gitrepositoryurl
    value: $(body.repository.url)
  - name: contenttype
    value: $(header.Content-Type)

TriggerBindings are connected to TriggerTemplates within an EventListener, which is where the pod is actually instantiated that "listens" for the respective events.

Parameters

TriggerBindings can provide params which are passed to a TriggerTemplate. Each parameter has a name and a value.

Event Variable Interpolation

In order to parse generic events as efficiently as possible, GJSON is used internally. As a result, the binding path syntax differs slightly from standard JSON. As of now, the following patterns are supported within TriggerBinding parameter value interpolation: - \$\(body(\.[[:alnum:]/_\-\.\\]+|\.#\([[:alnum:]=<>%!"\*_-]+\)#??)*\) - \$\(header(\.[[:alnum:]_\-]+)?\)

Body

HTTP Post request body data can be referenced using variable interpolation. Text in the form of $(body.X.Y.Z) is replaced by the body data at JSON path X.Y.Z.

$(body) is replaced by the entire body.

The following are some example variable interpolation replacements:

-> "{\"key1\": \"value1\", \"key2\": {\"key3\": \"value3\"}, \"key4\":
[\"value4\", \"value5\"]}"

$(body.key1) -> "value1"

$(body.key2) -> "{\"key3\": \"value3\"}"

$(body.key2.key3) -> "value3"

$(body.key4.0) -> "value4"

Header

HTTP Post request header data can be referenced using variable interpolation. Text in the form of $(header.X) is replaced by the event's header named X.

$(header) is replaced by all of the headers from the event.

The following are some example variable interpolation replacements:

$(header) -> "{\"One\":[\"one\"], \"Two\":[\"one\",\"two\",\"three\"]}"

$(header.One) -> "one"

$(header.Two) -> "one two three"

$(header.Two.1) -> "two"

Multiple Bindings

In an EventListener, you may specify multiple bindings as part of your trigger. This allows you to create reusable bindings that can be mixed and matched with various triggers. For example, a trigger with one binding that extracts event information, and another bind that provides deploy environment information:

apiVersion: tekton.dev/v1alpha1
kind: TriggerBinding
metadata:
  name: event-binding
spec:
  params:
  - name: gitrevision
    value: $(body.head_commit.id)
  - name: gitrepositoryurl
    value: $(body.repository.url)
---
apiVersion: tekton.dev/v1alpha1
kind: TriggerBinding
metadata:
  name: prod-env
spec:
  params:
  - name: environment
    value: prod
---
apiVersion: tekton.dev/v1alpha1
kind: TriggerBinding
metadata:
  name: staging-env
spec:
  params:
  - name: environment
    value: staging
---
apiVersion: tekton.dev/v1alpha1
kind: EventListener
metadata:
  name: listener
spec:
  triggers:
    - name: prod-trigger
      bindings:
        - name: event-binding
        - name: prod-env
      template:
        name: pipeline-template
    - name: staging-trigger
      bindings:
        - name: event-binding
        - name: staging-env
      template:
        name: pipeline-template