Chapter 3. Getting started with Camel K
This chapter explains how to set up your development environment and how to develop and deploy simple Camel K integrations written in Java, XML, and YAML. It also shows how to use the kamel
command line to manage Camel K integrations at runtime. For example, this includes running, describing, logging, and deleting integrations,
- Section 3.1, “Setting up your Camel K development environment”
- Section 3.2, “Developing Camel K integrations in Java”
- Section 3.3, “Developing Camel K integrations in XML”
- Section 3.4, “Developing Camel K integrations in YAML”
- Section 3.5, “Running Camel K integrations”
- Section 3.6, “Running Camel K integrations in development mode”
- Section 3.7, “Running Camel K integrations using modeline”
3.1. Setting up your Camel K development environment Copy linkLink copied to clipboard!
You must set up your environment with the recommended development tooling before you can automatically deploy the Camel K quick start tutorials. This section explains how to install the recommended Visual Studio (VS) Code IDE and the extensions that it provides for Camel K.
- VS Code is recommended for ease of use and the best developer experience of Camel K. This includes automatic completion of Camel DSL code and Camel K traits, and automatic execution of tutorial commands. However, you can manually enter your code and tutorial commands using your chosen IDE instead of VS Code.
- The VS Code Camel Extension Pack is a community offering.
Prerequisites
You must have access to an OpenShift cluster on which the Camel K Operator and OpenShift Serverless Operator are installed:
- Section 2.3, “Installing the Camel K and OpenShift command line tools”
Procedure
Install VS Code on your development platform. For example, on Red Hat Enterprise Linux:
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'
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'
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Update the cache and install the VS Code package:
yum check-update sudo yum install code
yum check-update sudo yum install code
Copy to Clipboard Copied! Toggle word wrap Toggle overflow For details on installing on other platforms, see the VS Code installation documentation.
-
Enter the
code
command to launch the VS Code editor. For more details, see the VS Code command line documentation. Install the VS Code Camel Extension Pack, which includes the extensions required for Camel K. For example, in VS Code:
- In the left navigation bar, click Extensions.
- In the search box, enter Apache Camel.
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.
3.2. Developing Camel K integrations in Java Copy linkLink copied to clipboard!
This section shows how to develop a simple Camel K integration in Java DSL. Writing an integration in Java to be deployed using Camel K is the same as defining your routing rules in Camel. However, you do not need to build and package the integration as a JAR when using Camel K.
You can use any Camel component directly in your integration routes. Camel K automatically handles the dependency management and imports all the required libraries from the Camel catalog using code inspection.
Procedure
Enter the
kamel init
command to generate a simple Java integration file. For example:kamel init HelloCamelK.java
kamel init HelloCamelK.java
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Open the generated integration file in your IDE and edit as appropriate. For example, the
HelloCamelK.java
integration automatically includes the Cameltimer
andlog
components to help you get started:Copy to Clipboard Copied! Toggle word wrap Toggle overflow
Next steps
3.3. Developing Camel K integrations in XML Copy linkLink copied to clipboard!
This section explains how to develop a simple Camel K integration in classic XML DSL. Writing an integration in XML to be deployed using Camel K is the same as defining your routing rules in Camel.
You can use any Camel component directly in your integration routes. Camel K automatically handles the dependency management and imports all the required libraries from the Camel catalog using code inspection.
Procedure
Enter the
kamel init
command to generate a simple XML integration file. For example:kamel init hello-camel-k.xml
kamel init hello-camel-k.xml
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Open the generated integration file in your IDE and edit as appropriate. For example, the
hello-camel-k.xml
integration automatically includes the Cameltimer
andlog
components to help you get started:Copy to Clipboard Copied! Toggle word wrap Toggle overflow
Next steps
3.4. Developing Camel K integrations in YAML Copy linkLink copied to clipboard!
This section explains how to develop a simple Camel K integration in YAML DSL. Writing an integration in YAML to be deployed using Camel K is the same as defining your routing rules in Camel.
You can use any Camel component directly in your integration routes. Camel K automatically handles the dependency management and imports all the required libraries from the Camel catalog using code inspection.
Procedure
Enter the
kamel init
command to generate a simple XML integration file. For example:kamel init hello.camelk.yaml
kamel init hello.camelk.yaml
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Open the generated integration file in your IDE and edit as appropriate. For example, the
hello.camelk.yaml
integration automatically includes the Cameltimer
andlog
components to help you get started:Copy to Clipboard Copied! Toggle word wrap Toggle overflow ImportantIntegrations written in YAML must have a file name with the pattern
*.camelk.yaml
or a first line of# camel-k: language=yaml
.
Additional resources
3.5. Running Camel K integrations Copy linkLink copied to clipboard!
You can run Camel K integrations in the cloud on your OpenShift cluster from the command line using the kamel run
command.
Prerequisites
- Section 3.1, “Setting up your Camel K development environment”.
- You must already have a Camel integration written in Java, XML, or YAML DSL.
Procedure
Log into your OpenShift cluster using the
oc
client tool, for example:oc login --token=my-token --server=https://my-cluster.example.com:6443`
oc login --token=my-token --server=https://my-cluster.example.com:6443`
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Open a project in which the Camel K operator is installed, for example:
oc project my-camel-k-project
oc project my-camel-k-project
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Ensure that the Camel K Operator is running, for example:
oc get pod
oc get pod
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Returns output similar to the following:
NAME READY STATUS RESTARTS AGE camel-k-operator-86b8d94b4-pk7d6 1/1 Running 0 6m28s
NAME READY STATUS RESTARTS AGE camel-k-operator-86b8d94b4-pk7d6 1/1 Running 0 6m28s
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Type the
kamel run
command to run your integration in the cloud on OpenShift. For example:Java example
kamel run HelloCamelK.java
kamel run HelloCamelK.java
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Returns:
integration "hello-camel-k" created
integration "hello-camel-k" created
Copy to Clipboard Copied! Toggle word wrap Toggle overflow XML example
kamel run hello-camel-k.xml
kamel run hello-camel-k.xml
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Returns:
integration "hello-camel-k" created
integration "hello-camel-k" created
Copy to Clipboard Copied! Toggle word wrap Toggle overflow YAML example
kamel run hello.camelk.yaml
kamel run hello.camelk.yaml
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Returns:
integration "hello" created
integration "hello" created
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Type
kamel get
to check the status of the integration.NAME PHASE KIT hello Building Kit kit-bq666mjej725sk8sn12g
NAME PHASE KIT hello Building Kit kit-bq666mjej725sk8sn12g
Copy to Clipboard Copied! Toggle word wrap Toggle overflow 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.
Type
kamel get
again to verify that the integration is running:NAME PHASE KIT hello Running kit-bq666mjej725sk8sn12g
NAME PHASE KIT hello Running kit-bq666mjej725sk8sn12g
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Type the
kamel log
command to print the log tostdout
.For example:
kamel log hello
kamel log hello
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Returns output similar to the following:
Copy to Clipboard Copied! Toggle word wrap Toggle overflow -
Press
Ctrl-C
to terminate logging in the terminal.
Additional resources
-
For more details on the
kamel run
command, enterkamel run --help
- For faster deployment turnaround times, see Section 3.6, “Running Camel K integrations in development mode”
- For details of development tools to run integrations, see VS Code Tooling for Apache Camel K by Red Hat
- See also Section 5.1, “Managing Camel K integrations”
3.6. Running Camel K integrations in development mode Copy linkLink copied to clipboard!
You can run Camel K integrations in development mode on your OpenShift cluster from the command line. Using development mode, you can iterate quickly on integrations in development and get fast feedback on your code.
When you specify the kamel run
command with the --dev
option, this deploys the integration in the cloud immediately and shows the integration logs in the terminal. You can then change the code and see the changes automatically applied instantly to the remote integration Pod on OpenShift. The terminal automatically displays all redeployments of the remote integration in the cloud.
The artifacts generated by Camel K in development mode are identical to those that you run in production. The purpose of development mode is faster development.
Prerequisites
- Section 3.1, “Setting up your Camel K development environment”.
- You must already have a Camel integration written in Java, XML, or YAML DSL.
Procedure
Log into your OpenShift cluster using the
oc
client tool, for example:oc login --token=my-token --server=https://my-cluster.example.com:6443
oc login --token=my-token --server=https://my-cluster.example.com:6443
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Ensure that the Camel K Operator is running, for example:
oc get pod
oc get pod
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Returns:
NAME READY STATUS RESTARTS AGE camel-k-operator-86b8d94b4-pk7d6 1/1 Running 0 6m28s
NAME READY STATUS RESTARTS AGE camel-k-operator-86b8d94b4-pk7d6 1/1 Running 0 6m28s
Copy to Clipboard Copied! Toggle word wrap Toggle overflow 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
kamel run HelloCamelK.java --dev
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Returns:
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Edit the content of your integration DSL file, save your changes, and see the changes displayed instantly in the terminal. For example:
Copy to Clipboard Copied! Toggle word wrap Toggle overflow -
Press
Ctrl-C
to terminate logging in the terminal.
Additional resources
-
For more details on the
kamel run
command, enterkamel run --help
- For details of development tools to run integrations, see VS Code Tooling for Apache Camel K by Red Hat
- Section 5.1, “Managing Camel K integrations”
- Section 7.6, “Configuring Camel K integration dependencies”
3.7. Running Camel K integrations using modeline Copy linkLink copied to clipboard!
You can use the Camel K modeline to specify multiple configuration options in a Camel K integration source file, which are executed at runtime. This creates efficiencies by saving you the time of re-entering multiple command line options and helps to prevent input errors.
The following example shows a modeline entry from a Java integration file that configures traits for Prometheus monitoring and 3scale API Management, and includes a dependency on an external Maven library:
// camel-k: language=java trait=prometheus.enabled=true trait=3scale.enabled=true dependency=mvn:org.my/app:1.0
// camel-k: language=java trait=prometheus.enabled=true trait=3scale.enabled=true dependency=mvn:org.my/app:1.0
Prerequisites
- Section 3.1, “Setting up your Camel K development environment”.
- You must already have a Camel integration written in Java, XML, or YAML DSL.
Procedure
Add a Camel K modeline entry to your integration file. For example:
Hello.java
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Enter the following command to run the integration:
kamel run Hello.java
kamel run Hello.java
Copy to Clipboard Copied! Toggle word wrap Toggle overflow Returns:
Modeline options have been loaded from source files Full command: kamel run Hello.java --trait=prometheus.enabled=true --dependency mvn:org.my/application:1.0
Modeline options have been loaded from source files Full command: kamel run Hello.java --trait=prometheus.enabled=true --dependency mvn:org.my/application:1.0
Copy to Clipboard Copied! Toggle word wrap Toggle overflow The
kamel run
command outputs any modeline options specified in the integration.
Additional resources
- Section 9.2, “Camel K modeline options”
- For details of development tools to run modeline integrations, see Introducing IDE support for Apache Camel K Modeline.