Chapter 3. Developing and running Camel K integrations

Procedure

1. Install VS Code on your development platform. For example, on Red Hat Enterprise Linux:

   1. Install the required key and repository:

      $ sudo rpm --import https://packages.microsoft.com/keys/microsoft.asc
      $ sudo sh -c 'echo -e "[code]\nname=Visual Studio Code\nbaseurl=https://packages.microsoft.com/yumrepos/vscode\nenabled=1\ngpgcheck=1\ngpgkey=https://packages.microsoft.com/keys/microsoft.asc" > /etc/yum.repos.d/vscode.repo'

   2. Update the cache and install the VS Code package:

      $ yum check-update
      $ sudo yum install code

      For details on installing on other platforms, see the VS Code installation documentation.

2. Enter the code command to launch the VS Code editor. For more details, see the VS Code command line documentation.

3. Install the VS Code Camel Extension Pack, which includes the extensions required for Camel K. For example, in VS Code:

   1. In the left navigation bar, click Extensions.
   2. In the search box, enter Apache Camel.

   3. Select the Extension Pack for Apache Camel by Red Hat, and click Install.

      

      For more details, see the instructions for the Extension Pack for Apache Camel by Red Hat.

Procedure

1. Enter the camel init command to generate a simple Java integration file. For example:

   $ camel init HelloCamelK.java

2. Open the generated integration file in your IDE and edit as appropriate. For example, the HelloCamelK.java integration automatically includes the Camel timer and log components to help you get started:

   // camel-k: language=java
   
   import org.apache.camel.builder.RouteBuilder;
   
   public class HelloCamelK extends RouteBuilder {
     @Override
     public void configure() throws Exception {
   
         // Write your routes here, for example:
         from("timer:java?period=1s")
           .routeId("java")
           .setBody()
             .simple("Hello Camel K from ${routeId}")
           .to("log:info");
   
     }
   }

Procedure

1. Enter the camel init command to generate a simple YAML integration file. For example:

   $ camel init hello.camelk.yaml

2. Open the generated integration file in your IDE and edit as appropriate. For example, the hello.camelk.yaml integration automatically includes the Camel timer and log components to help you get started:

   # Write your routes here, for example:
   - from:
       uri: "timer:yaml"
       parameters:
         period: "1s"
       steps:
         - set-body:
             constant: "Hello Camel K from yaml"
         - to: "log:info"

Procedure

1. Log into your OpenShift cluster using the oc client tool, for example:

   $ oc login --token=my-token --server=https://my-cluster.example.com:6443

2. Ensure that the Camel K Operator is running, for example:

   $ oc get pod
   NAME                               READY   STATUS    RESTARTS   AGE
   camel-k-operator-86b8d94b4-pk7d6   1/1     Running   0          6m28s

3. Enter the kamel run command to run your integration in the cloud on OpenShift. For example:

   Java example

   $ kamel run HelloCamelK.java
   integration "hello-camel-k" created

   YAML example

   $ kamel run hello.camelk.yaml
   integration "hello" created

4. Enter the kamel get command to check the status of the integration:

   $ kamel get
   NAME       PHASE           KIT
   hello      Building Kit    myproject/kit-bq666mjej725sk8sn12g

   When the integration runs for the first time, Camel K builds the integration kit for the container image, which downloads all the required Camel modules and adds them to the image classpath.

5. Enter kamel get again to verify that the integration is running:

   $ kamel get
   NAME       PHASE   KIT
   hello      Running myproject/kit-bq666mjej725sk8sn12g

6. Enter the kamel log command to print the log to stdout:

   $ kamel log hello
   [1] 2021-08-11 17:58:40,573 INFO  [org.apa.cam.k.Runtime] (main) Apache Camel K Runtime 1.7.1.fuse-800025-redhat-00001
   [1] 2021-08-11 17:58:40,653 INFO  [org.apa.cam.qua.cor.CamelBootstrapRecorder] (main) bootstrap runtime: org.apache.camel.quarkus.main.CamelMainRuntime
   [1] 2021-08-11 17:58:40,844 INFO  [org.apa.cam.k.lis.SourcesConfigurer] (main) Loading routes from: SourceDefinition{name='camel-k-embedded-flow', language='yaml', location='file:/etc/camel/sources/camel-k-embedded-flow.yaml', }
   [1] 2021-08-11 17:58:41,216 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (main) Routes startup summary (total:1 started:1)
   [1] 2021-08-11 17:58:41,217 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (main)     Started route1 (timer://yaml)
   [1] 2021-08-11 17:58:41,217 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (main) Apache Camel 3.10.0.fuse-800010-redhat-00001 (camel-1) started in 136ms (build:0ms init:100ms start:36ms)
   [1] 2021-08-11 17:58:41,268 INFO  [io.quarkus] (main) camel-k-integration 1.6.6 on JVM (powered by Quarkus 1.11.7.Final-redhat-00009) started in 2.064s.
   [1] 2021-08-11 17:58:41,269 INFO  [io.quarkus] (main) Profile prod activated.
   [1] 2021-08-11 17:58:41,269 INFO  [io.quarkus] (main) Installed features: [camel-bean, camel-core, camel-k-core, camel-k-runtime, camel-log, camel-support-common, camel-timer, camel-yaml-dsl, cdi]
   [1] 2021-08-11 17:58:42,423 INFO  [info] (Camel (camel-1) thread #0 - timer://yaml) Exchange[ExchangePattern: InOnly, BodyType: String, Body: Hello Camel K from yaml]
   ...

7. Press Ctrl-C to terminate logging in the terminal.

Procedure

1. Log into your OpenShift cluster using the oc client tool, for example:

   $ oc login --token=my-token --server=https://my-cluster.example.com:6443

2. Ensure that the Camel K Operator is running, for example:

   $ oc get pod
   NAME                               READY   STATUS    RESTARTS   AGE
   camel-k-operator-86b8d94b4-pk7d6   1/1     Running   0          6m28s

3. Enter the kamel run command with --dev to run your integration in development mode on OpenShift in the cloud. The following shows a simple Java example:

   $ kamel run HelloCamelK.java --dev
   Condition "IntegrationPlatformAvailable" is "True" for Integration hello-camel-k: test/camel-k
   Integration hello-camel-k in phase "Initialization"
   Integration hello-camel-k in phase "Building Kit"
   Condition "IntegrationKitAvailable" is "True" for Integration hello-camel-k: kit-c49sqn4apkb4qgn55ak0
   Integration hello-camel-k in phase "Deploying"
   Progress: integration "hello-camel-k" in phase Initialization
   Progress: integration "hello-camel-k" in phase Building Kit
   Progress: integration "hello-camel-k" in phase Deploying
   Integration hello-camel-k in phase "Running"
   Condition "DeploymentAvailable" is "True" for Integration hello-camel-k: deployment name is hello-camel-k
   Progress: integration "hello-camel-k" in phase Running
   Condition "CronJobAvailable" is "False" for Integration hello-camel-k: different controller strategy used (deployment)
   Condition "KnativeServiceAvailable" is "False" for Integration hello-camel-k: different controller strategy used (deployment)
   Condition "Ready" is "False" for Integration hello-camel-k
   Condition "Ready" is "True" for Integration hello-camel-k
   [1] Monitoring pod hello-camel-k-7f85df47b8-js7cb
   ...
   ...
   [1] 2021-08-11 18:34:44,069 INFO  [org.apa.cam.k.Runtime] (main) Apache Camel K Runtime 1.7.1.fuse-800025-redhat-00001
   [1] 2021-08-11 18:34:44,167 INFO  [org.apa.cam.qua.cor.CamelBootstrapRecorder] (main) bootstrap runtime: org.apache.camel.quarkus.main.CamelMainRuntime
   [1] 2021-08-11 18:34:44,362 INFO  [org.apa.cam.k.lis.SourcesConfigurer] (main) Loading routes from: SourceDefinition{name='HelloCamelK', language='java', location='file:/etc/camel/sources/HelloCamelK.java', }
   [1] 2021-08-11 18:34:46,180 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (main) Routes startup summary (total:1 started:1)
   [1] 2021-08-11 18:34:46,180 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (main)     Started java (timer://java)
   [1] 2021-08-11 18:34:46,180 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (main) Apache Camel 3.10.0.fuse-800010-redhat-00001 (camel-1) started in 243ms (build:0ms init:213ms start:30ms)
   [1] 2021-08-11 18:34:46,190 INFO  [io.quarkus] (main) camel-k-integration 1.6.6 on JVM (powered by Quarkus 1.11.7.Final-redhat-00009) started in 3.457s.
   [1] 2021-08-11 18:34:46,190 INFO  [io.quarkus] (main) Profile prod activated.
   [1] 2021-08-11 18:34:46,191 INFO  [io.quarkus] (main) Installed features: [camel-bean, camel-core, camel-java-joor-dsl, camel-k-core, camel-k-runtime, camel-log, camel-support-common, camel-timer, cdi]
   [1] 2021-08-11 18:34:47,200 INFO  [info] (Camel (camel-1) thread #0 - timer://java) Exchange[ExchangePattern: InOnly, BodyType: String, Body: Hello Camel K from java]
   [1] 2021-08-11 18:34:48,180 INFO  [info] (Camel (camel-1) thread #0 - timer://java) Exchange[ExchangePattern: InOnly, BodyType: String, Body: Hello Camel K from java]
   [1] 2021-08-11 18:34:49,180 INFO  [info] (Camel (camel-1) thread #0 - timer://java) Exchange[ExchangePattern: InOnly, BodyType: String, Body: Hello Camel K from java]
   ...

4. Edit the content of your integration DSL file, save your changes, and see the changes displayed instantly in the terminal. For example:

   ...
   integration "hello-camel-k" updated
   ...
   [2] 2021-08-11 18:40:54,173 INFO  [org.apa.cam.k.Runtime] (main) Apache Camel K Runtime 1.7.1.fuse-800025-redhat-00001
   [2] 2021-08-11 18:40:54,209 INFO  [org.apa.cam.qua.cor.CamelBootstrapRecorder] (main) bootstrap runtime: org.apache.camel.quarkus.main.CamelMainRuntime
   [2] 2021-08-11 18:40:54,301 INFO  [org.apa.cam.k.lis.SourcesConfigurer] (main) Loading routes from: SourceDefinition{name='HelloCamelK', language='java', location='file:/etc/camel/sources/HelloCamelK.java', }
   [2] 2021-08-11 18:40:55,796 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (main) Routes startup summary (total:1 started:1)
   [2] 2021-08-11 18:40:55,796 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (main)     Started java (timer://java)
   [2] 2021-08-11 18:40:55,797 INFO  [org.apa.cam.imp.eng.AbstractCamelContext] (main) Apache Camel 3.10.0.fuse-800010-redhat-00001 (camel-1) started in 174ms (build:0ms init:147ms start:27ms)
   [2] 2021-08-11 18:40:55,803 INFO  [io.quarkus] (main) camel-k-integration 1.6.6 on JVM (powered by Quarkus 1.11.7.Final-redhat-00009) started in 3.025s.
   [2] 2021-08-11 18:40:55,808 INFO  [io.quarkus] (main) Profile prod activated.
   [2] 2021-08-11 18:40:55,809 INFO  [io.quarkus] (main) Installed features: [camel-bean, camel-core, camel-java-joor-dsl, camel-k-core, camel-k-runtime, camel-log, camel-support-common, camel-timer, cdi]
   [2] 2021-08-11 18:40:56,810 INFO  [info] (Camel (camel-1) thread #0 - timer://java) Exchange[ExchangePattern: InOnly, BodyType: String, Body: Hello Camel K from java]
   [2] 2021-08-11 18:40:57,793 INFO  [info] (Camel (camel-1) thread #0 - timer://java) Exchange[ExchangePattern: InOnly, BodyType: String, Body: Hello Camel K from java]
   ...

5. Press Ctrl-C to terminate logging in the terminal.

Procedure

1. Add a Camel K modeline entry to your integration file. For example:

   ThreeScaleRest.java

   // camel-k: trait=3scale.enabled=true trait=container.limit-memory=256Mi 1
   import org.apache.camel.builder.RouteBuilder;
   
   public class ThreeScaleRest extends RouteBuilder {
   
     @Override
     public void configure() throws Exception {
         rest().get("/")
           .to("direct:x");
   
         from("direct:x")
           .setBody().constant("Hello");
     }
   }

   Enables both the container and 3scale traits, to expose the route through 3scale and to limit the container memory.

2. Run the integration, for example:

   kamel run ThreeScaleRest.java

   The kamel run command outputs any modeline options specified in the integration, for example:

   Modeline options have been loaded from source files
   Full command: kamel run ThreeScaleRest.java --trait=3scale.enabled=true --trait=container.limit-memory=256Mi

Code example

1. Following is a simple integration that uses a Configmap to expose some message on an HTTP endpoint. You can start creating such an integration and testing in a namespace called development.

   kubectl create configmap my-cm --from-literal=greeting="hello, I am development!" -n development

   PromoteServer.java

   import org.apache.camel.builder.RouteBuilder;
   
   public class PromoteServer extends RouteBuilder {
     @Override
     public void configure() throws Exception {
       from("platform-http:/hello?httpMethodRestrict=GET").setBody(simple("resource:classpath:greeting"));
     }
   }

2. Now run it.

   kamel run --dev -n development PromoteServer.java --config configmap:my-cm [-t service.node-port=true]

3. You must tweak the service trait, depending on the Kubernetes platform and the level of exposure you want to provide. After that you can test it.

   curl http://192.168.49.2:32116/hello
   hello, I am development!

4. After testing of your integration, you can move it to a production environment. You must have the destination environment (a Openshift namespace) ready with an operator (sharing the same operator source container registry) and any configuration, such as the configmap you have used here. For that scope, create one on the destination namespace.

   kubectl create configmap my-cm --from-literal=greeting="hello, I am production!" -n production

   Note

   For security reasons, there is a check to ensure that the expected resources such as Configmaps, Secrets and Kamelets are present on the destination. If any of these resources are missing, the integration does not move.

5. You can now promote your integration.

   kamel promote promote-server -n development --to production
   kamel logs promote-server -n production

6. Test the promoted integration.

   curl http://192.168.49.2:30764/hello
   hello, I am production!

   Since the Integration is reusing the same container image, the new application is executed immediately. Also, the immutability of the Integration is assured as the container used is exactly the same as the one tested in development (changes are just the configurations).

   Note

   The integration running in the test is not altered in any way and keeps running until you stop it.