Automating Image Processing with Java and SFTP

Published {$created} by Viggo

Yesterday was a scramble. Our image processing pipeline was failing intermittently, choking on large batches of data from our edge devices. The core issue wasn't the processing itself, but the unreliable transfer of those images to our internal servers for review. We needed a robust, automated solution – and quickly.

Our initial approach involved scripting transfers using scp, but the lack of resilience and difficulty in incorporating error handling made it unsuitable. That’s when we shifted gears and explored using Java and SFTP. I wanted something I could integrate with our existing build process.

The first hurdle was authentication. While password authentication is possible, it’s a significant security risk. Instead, we opted for SSH key-based authentication. Following the guide at https://ftpgrid.com/tutorials/create-ssh-keys-for-sftp-scp-authentication/, we generated an SSH key pair and added the public key to the SFTP account we created on edgeN.ftpgrid.com. The tutorials/advanced-ssh-key-authentication-for-sftp article was extremely helpful in verifying the setup.

Next, the Java code itself. We leveraged the JSch library for SFTP operations. A simple ChannelSftp object handled the connection, uploads, and basic error checking. The quick-storage-api-java-sftp-ftp article (https://ftpgrid.com/tutorials/quick-storage-api-java-sftp-ftp/) provided a solid foundation for the code.

// Simplified example using JSch
ChannelSftp sftp = session.openChannel(Channel.SFTP);
sftp.connect();
try {
    sftp.put(localFile, remoteFile);
} catch (SftpException e) {
    // Handle error – retry, log, etc.
    System.err.println("SFTP upload failed: " + e.getMessage());
} finally {
    sftp.disconnect();
}

The biggest improvement came from using Quota Management. Our previous system was vulnerable to denial of service if a device flooded the system with images. Setting limits on bandwidth and storage space via the dashboard (https://ftpgrid.com/features/) significantly mitigated this risk.

For testing, we used a small subset of images. For production, we’re planning to integrate the SFTP upload into our existing image processing pipeline. We’ve also configured audit logging to monitor file transfers and identify any potential issues early on. A key benefit is the clarity offered by the activity timeline (https://ftpgrid.com/features/).

While our free tier (https://ftpgrid.com/tutorials/ftpgrid-free-tier-launch/) was sufficient for initial testing, we're likely to upgrade to a paid plan as image volume increases. The pricing information is available at https://ftpgrid.com/pricing/.

Key Takeaways

• SFTP for Robustness: SFTP provides a secure and reliable alternative to older protocols like SCP.
• SSH Key Authentication: Prioritize SSH key-based authentication for enhanced security.
• Quota Management for Security: Implement storage and bandwidth limits to protect your infrastructure.
• Java and JSch: Leverage Java's rich ecosystem for automating SFTP tasks.

Next Steps

We will now be implementing a more robust error handling mechanism and implementing automated retries.