This example demonstrates how to get started with Camel K and an SQL database via JDBC drivers. We will show how to quickly set up an integration producing data into a Postgres database (you can use any relational database of your choice). We will show also how to read data from the same database.
The quickstart is based on the Apache Camel K upstream database examples.
This example can be run on any OpenShift 4.3+ cluster or a local development instance (such as CRC). Ensure that you have a cluster available and login to it using the OpenShift oc command line tool.
You need to create a new project named camel-k-jdbc for running this example. This can be done directly from the OpenShift web console or by executing the command oc new-project camel-k-jdbc on a terminal window.
oc new-project camel-k-jdbc
You need to install the Camel K operator in the camel-k-jdbc project. To do so, go to the OpenShift 4.x web console, login with a cluster admin account and use the OperatorHub menu item on the left to find and install "Red Hat Integration - Camel K". You will be given the option to install it globally on the cluster or on a specific namespace.
If using a specific namespace, make sure you select the camel-k-jdbc project from the dropdown list.
This completes the installation of the Camel K operator (it may take a couple of minutes).
When the operator is installed, from the OpenShift Help menu ("?") at the top of the WebConsole, you can access the "Command Line Tools" page, where you can download the "kamel" CLI, that is required for running this example. The CLI must be installed in your system path.
Refer to the "Red Hat Integration - Camel K" documentation for a more detailed explanation of the installation steps for the operator and the CLI.
You can use the following section to check if your environment is configured properly.
OpenShift CLI ("oc")
The OpenShift CLI tool ("oc") will be used to interact with the OpenShift cluster.
Connection to an OpenShift cluster
In order to execute this demo, you will need to have an OpenShift cluster with the correct access level, the ability to create projects and install operators as well as the Apache Camel K CLI installed on your local system.
Apache Camel K CLI ("kamel")
Apart from the support provided by the VS Code extension, you also need the Apache Camel K CLI ("kamel") in order to access all Camel K features.
The following requirements are optional. They don't prevent the execution of the demo, but may make it easier to follow.
VS Code Extension Pack for Apache Camel
The VS Code Extension Pack for Apache Camel by Red Hat provides a collection of useful tools for Apache Camel K developers, such as code completion and integrated lifecycle management. They are recommended for the tutorial, but they are not required.
You can install it from the VS Code Extensions marketplace.
We'll connect to the camel-k-jdbc project and check the installation status. To change project, open a terminal tab and type the following command:
oc project camel-k-jdbc
We should now check that the operator is installed. To do so, execute the following command on a terminal:
oc get csv
When Camel K is installed, you should find an entry related to red-hat-camel-k-operator in phase Succeeded.
You can now proceed to the next section.
We assume you already have a database up and running. If it's not the case, you can easily create a new instance on Openshift Online or create your own Postgres sample database. You can also deploy any other database instance through a wizard using the +Add button on your Openshift Console.
For this tutorial, we're using a Postgres database service named postgresql deployed in the same camel-k-jdbc project. In order to configure the JDBC you will need to get the following settings: the JDBC url, driver, username and password. You may require assistance from your database administrator if you are not managing directly the database instance.
To set up the database tables and some test data you can use the sample postgres database available at the Apache Camel K upstream database examples
If you are using the Postgres instance mentioned above, you will set up the credentials as part of the deployment process.
NOTE: make sure your Openshift cluster have connectivity with your database if it's deployed outside the cluster.
You should set a Kubernetes Secret in order to avoid exposing sensitive information. You can bundle the configuration expected by the application in a secret. For convenience we have put them into a file named datasource.properties, however, they can be provided in the cluster differently. Please, notice that these values have to correspond to the ones expected by your instance, so, you can replace the values provided in our examples with yours.
oc create secret generic my-datasource --from-file=datasource.properties
At this stage, run a producer integration. This one will insert a row in a test table, every 10 seconds.
kamel run JDBCInsert.java --dev --config secret:my-datasource
Please, notice that we must specify certain dependencies that will be needed at runtime. In particular, we will have to provide the JDBC driver that is expected by the database. In our example, we're using the Postgresql drivers: make sure you pick up the proper driver according to your database instance.
The producer will create a new message and push into the database and log some information.
...
[2] 2021-06-18 13:39:22,590 INFO [info] (Camel (camel-1) thread #0 - timer://sql-insert) Exchange[ExchangePattern: InOnly, BodyType: String, Body: INSERT INTO test (data) VALUES ('message #3')]
[2] 2021-06-18 13:39:32,574 INFO [info] (Camel (camel-1) thread #0 - timer://sql-insert) Exchange[ExchangePattern: InOnly, BodyType: String, Body: INSERT INTO test (data) VALUES ('message #4')]
...
Now we can run a consumer integration. This one will read 5 rows from a test table, every 10 seconds.
kamel run JDBCSelect.java --dev --config secret:my-datasource
Also, here we had to specify certain dependencies that may change if you use a different database. A consumer will start logging the events found in the table:
...
[1] 2021-06-18 13:40:05,609 INFO [info] (Camel (camel-1) thread #0 - timer://foo) Exchange[ExchangePattern: InOnly, BodyType: java.util.ArrayList, Body: [{data=message #1}, {data=message #2}, {data=message #3}, {data=message #4}]]
...
NOTE: You may have run the consumer and producer as separate routes in the same integration.
Your integrations are running in the background terminal processes.
To exit dev mode and terminate the execution, hit ctrl+c on the terminal window.
To clean up everything, execute the following command:
oc delete project camel-k-jdbc