Listen to a folder

On this workshop we will learn how to listen to changes in a folder using Apache Camel.

We will be using Kaoto version 1.0.0.

The suggested way of following this workshop is to read the goals of each exercise and try to do it without looking at the solution. After finishing the exercise, you can check if the solution reached is the same as the solution suggested.

If you are having difficulties with an exercise, you can try to take a look at the Hints. If that’s not enough, you can check on the Solution section how to do it.

Note that there may be more than one way of finishing the exercise.

1.- Log changes

The goals for this exercise are:

• Start the flow with a file-watch step which watches a local folder like /tmp/tutorial and configure parameter recursive as false
• Then log the detected change with an output like Detected ${header.CamelFileEventType} on file ${header.CamelFileName} at ${header.CamelFileLastModified}

Make sure your folder (/tmp/tutorial) exists before running this integration.

Hints

• To add new steps to the canvas, take a look at the User Guide .
• To configure a step and fill the configuration properties, click on the step icon of the canvas.
• The first step you want to add is called file-watch. Don’t confuse it with file
• The second step is a log. There may be more than one log option, choose the one without the camel logo for simplicity.

Solution

The following video showcases the solution.

At this point, the text editor should show the following code:

- from:
    uri: file-watch:/tmp/tutorial
    parameters:
      recursive: false
    steps:
    - log:
        message: Detected  ${header.CamelFileEventType} on file ${header.CamelFileName}
          at ${header.CamelFileLastModified}

If it doesn’t look like that but you want to go to the following exercise, you can copy and paste that code on the text editor and click on the green tick button to synchronize.

2.- Add a filter

Now we want to add a filter between the file-watch and the file that copies the file in another folder everytime a file gets created.

This will require adding two steps:

• A step filter that will open a branch of steps that will be executed only when ${header.CamelFileEventType} equals ‘CREATE’`
• A step file to create the new file in /tmp/backup or whatever folder you choose (different from the previous one)

Make sure your folder (/tmp/backup) exists before running this integration.

Hints

• To create a new file, you have to use the step file
• Configure the directory name of the file step as /tmp/backup (or whatever folder you are using)
• The condition of the filter is configured in the simple text field as ${header.CamelFileEventType} == 'CREATE'

Solution

The following video showcases the solution.

At this point, the text editor should show the following code:

- from:
    uri: file-watch:/tmp/tutorial
    parameters:
      recursive: false
    steps:
    - filter:
        simple: ${header.CamelFileEventType} == 'CREATE'
        steps:
        - to:
            uri: file:/tmp/backup
    - log:
        message: Detected  ${header.CamelFileEventType} on file ${header.CamelFileName}
          at ${header.CamelFileLastModified}

If it doesn’t look like that but you want to go to the following exercise, you can copy and paste that code on the text editor and click on the green tick button to synchronize.

More information

More information about Apache Camel routes can be found on the Apache Camel website