Back up and restore files

By following the steps below you will back up a simple text file to an HTTP file server and then restore it back via a publicly available Eclipse Hono sandbox using Eclipse Kanto. A simple Eclipse Hono northbound business application written in Python is provided to explore the capabilities for remotely backing up and restoring files.

Before you begin

To ensure that all steps in this guide can be executed, you need:

• servefile installed

  This is a small Python HTTP server used in the example to serve the uploads and downloads. It does not have to be running on your edge device, but it has to be accessible from there. You can install it by executing:

  pip3 install servefile
  

• If you don’t have an installed and running Eclipse Kanto on your edge device, follow Install Eclipse Kanto

• If you don’t have a connected Eclipse Kanto to Eclipse Hono sandbox, follow Explore via Eclipse Hono

• The file backup and restore application

  Navigate to the quickstart folder where the resources from the Explore via Eclipse Hono guide are located and execute the following script:

  wget https://github.com/eclipse-kanto/kanto/raw/main/quickstart/hono_commands_fb.py
  

Back up

By default, all directories in /var/tmp/file-backup/ or the directory itself can be backed up. For this example, create a file data.txt which will be later backed up:

sudo mkdir -p /var/tmp/file-backup && sudo echo "This is the first line in the file!" >> /var/tmp/file-backup/data.txt

You can verify that the file was successfully created by executing the following command:

cat /var/tmp/file-backup/data.txt

This should produce This is the first line in the file! as an output.

Choose a directory where the text file will be uploaded, open a new terminal there and run servefile with the flag -u to enable a file upload:

servefile -u .

To explore the file backup, we will use a Python script to request and monitor the operation. The location where the Python application will run does not have to be your edge device as it communicates remotely with Eclipse Hono only.

Now we are ready to request the text file backup from the edge via executing the application that requires the command to execute (backup), Eclipse Hono tenant (-t), the device identifier (-d) and the host where the backup will be uploaded to:

python3 hono_commands_fb.py backup -t demo -d demo:device -h localhost

You can check out that the backup file data.zip is on your HTTP file server by listing the content of the servefile working directory.

Restore

To explore the restore capabilities you will first modify the data.txt file, and then you will restore it to the version before the changes by using the backup, that was created earlier.

You can modify the data.txt file with the following command:

sudo echo "This is the second line in the file!" >> /var/tmp/file-backup/data.txt

You can verify that the file was successfully updated by executing the following command:

cat /var/tmp/file-backup/data.txt

This output should be:

This is the first line in the file!
This is the second line in the file!

Navigate to the terminal where servefile was started and terminate it. Start it again with the flag -l to enable a file download:

servefile -l .

To explore the file restore, we will use a Python script to request and monitor the operation. The location where the Python application will run does not have to be your edge device as it communicates remotely with Eclipse Hono only.

Now we are ready to request the text file restore from the edge via executing the application that requires the command to execute (restore), Eclipse Hono tenant (-t), the device identifier (-d) and the host where the backup file will be downloaded from:

python3 hono_commands_fb.py restore -t demo -d demo:device -h localhost

Verify

You can check out that the original file is restored by executing the following command:

cat /var/tmp/file-backup/data.txt

This should produce This is the first line in the file! as an output.

Clean up

Stop servefile and clean up its working directory. Remove the data.txt file from the /var/tmp/file-backup directory.