Chapter 55. Predicate Filter Action Filter based on a JsonPath Expression 55.1. Configuration Options The following table summarizes the configuration options available for the predicate-filter-action Kamelet: Property Name Description Type Default Example expression * Expression The JsonPath Expression to evaluate, without the external parenthesis. Since this is a filter, the expression will be a negation, this means that if the foo field of the example is equals to John, the message will go ahead, otherwise it will be filtered out. string "@.foo =~ /.*John/" Note Fields marked with an asterisk (*) are mandatory. 55.2. Dependencies At runtime, the predicate-filter-action Kamelet relies upon the presence of the following dependencies: camel:core camel:kamelet camel:jsonpath 55.3. Usage This section describes how you can use the predicate-filter-action . 55.3.1. Knative Action You can use the predicate-filter-action Kamelet as an intermediate step in a Knative binding. predicate-filter-action-binding.yaml apiVersion: camel.apache.org/v1alpha1 kind: KameletBinding metadata: name: predicate-filter-action-binding spec: source: ref: kind: Kamelet apiVersion: camel.apache.org/v1alpha1 name: timer-source properties: message: "Hello" steps: - ref: kind: Kamelet apiVersion: camel.apache.org/v1alpha1 name: predicate-filter-action properties: expression: "@.foo =~ /.*John/" sink: ref: kind: Channel apiVersion: messaging.knative.dev/v1 name: mychannel 55.3.1.1. Prerequisite Make sure you have "Red Hat Integration - Camel K" installed into the OpenShift cluster you're connected to. 55.3.1.2. Procedure for using the cluster CLI Save the predicate-filter-action-binding.yaml file to your local drive, and then edit it as needed for your configuration. Run the action by using the following command: oc apply -f predicate-filter-action-binding.yaml 55.3.1.3. Procedure for using the Kamel CLI Configure and run the action by using the following command: kamel bind timer-source?message=Hello --step predicate-filter-action -p "step-0.expression=@.foo =~ /.*John/" channel:mychannel This command creates the KameletBinding in the current namespace on the cluster. 55.3.2. Kafka Action You can use the predicate-filter-action Kamelet as an intermediate step in a Kafka binding. predicate-filter-action-binding.yaml apiVersion: camel.apache.org/v1alpha1 kind: KameletBinding metadata: name: predicate-filter-action-binding spec: source: ref: kind: Kamelet apiVersion: camel.apache.org/v1alpha1 name: timer-source properties: message: "Hello" steps: - ref: kind: Kamelet apiVersion: camel.apache.org/v1alpha1 name: predicate-filter-action properties: expression: "@.foo =~ /.*John/" sink: ref: kind: KafkaTopic apiVersion: kafka.strimzi.io/v1beta1 name: my-topic 55.3.2.1. Prerequisites Ensure that you've installed the AMQ Streams operator in your OpenShift cluster and created a topic named my-topic in the current namespace. Make also sure you have "Red Hat Integration - Camel K" installed into the OpenShift cluster you're connected to. 55.3.2.2. Procedure for using the cluster CLI Save the predicate-filter-action-binding.yaml file to your local drive, and then edit it as needed for your configuration. Run the action by using the following command: oc apply -f predicate-filter-action-binding.yaml 55.3.2.3. Procedure for using the Kamel CLI Configure and run the action by using the following command: kamel bind timer-source?message=Hello --step predicate-filter-action -p "step-0.expression=@.foo =~ /.*John/" kafka.strimzi.io/v1beta1:KafkaTopic:my-topic This command creates the KameletBinding in the current namespace on the cluster. 55.4. Kamelet source file https://github.com/openshift-integration/kamelet-catalog/predicate-filter-action.kamelet.yaml

Commands:
apiVersion: camel.apache.org/v1alpha1 kind: KameletBinding metadata: name: predicate-filter-action-binding spec: source: ref: kind: Kamelet apiVersion: camel.apache.org/v1alpha1 name: timer-source properties: message: "Hello" steps: - ref: kind: Kamelet apiVersion: camel.apache.org/v1alpha1 name: predicate-filter-action properties: expression: "@.foo =~ /.*John/" sink: ref: kind: Channel apiVersion: messaging.knative.dev/v1 name: mychannel
apply -f predicate-filter-action-binding.yaml
kamel bind timer-source?message=Hello --step predicate-filter-action -p "step-0.expression=@.foo =~ /.*John/" channel:mychannel
apiVersion: camel.apache.org/v1alpha1 kind: KameletBinding metadata: name: predicate-filter-action-binding spec: source: ref: kind: Kamelet apiVersion: camel.apache.org/v1alpha1 name: timer-source properties: message: "Hello" steps: - ref: kind: Kamelet apiVersion: camel.apache.org/v1alpha1 name: predicate-filter-action properties: expression: "@.foo =~ /.*John/" sink: ref: kind: KafkaTopic apiVersion: kafka.strimzi.io/v1beta1 name: my-topic
apply -f predicate-filter-action-binding.yaml
kamel bind timer-source?message=Hello --step predicate-filter-action -p "step-0.expression=@.foo =~ /.*John/" kafka.strimzi.io/v1beta1:KafkaTopic:my-topic