Enable jsch logging?

AdamCameron · March 24, 2025, 1:37pm

Hi
We’ve just tried to upgrade to 5.4.7.2, and this has borked our ability to connect to one of our upstream suppliers’ SFTP servers.

We’re getting this:

com.jcraft.jsch.JSchException:
Session.connect: java.io.IOException: End of IO Stream Read

Googling about, it seems there’s likely a mismatch in some encryption handshaking or something like that. This is interesting:

I’d really like to get some debug logging of our attempts to connect to the supplier’s server via <cfftp>, but all the guidance re logging for the flavour of Jsch yer using (Jsch Logging · mwiede/jsch Wiki · GitHub I believe) - is - unsurprisingly - Java-centric. No help to me using Lucee’s FTP wrapper.

Is there anything I can pass to in my JAVA_OPTS or change settings in a config file to enable this logging?

For now we’re having to rollback to 5.4.4.38

Cheers for any insight.

–
Adam

Zackster · March 24, 2025, 2:02pm

try lucee.debug.jsch=true

github.com

lucee/Lucee/blob/5.4/core/src/main/java/lucee/runtime/net/ftp/SFTPClientImpl.java#L51


      
          	private boolean stopOnError;
          	private String fingerprint;
          	private String replyString;
          	private int replyCode;
          	private boolean positiveCompletion;
          	private String sshKey;
          	private String passphrase;
          
          	static {
          		// set system property lucee.debug.jsch=true to enable debug output from JSch
          		if (Caster.toBooleanValue(SystemUtil.getSystemPropOrEnvVar("lucee.debug.jsch", ""), false)) {
          			JSch.setLogger(new com.jcraft.jsch.Logger() {
          				@Override
          				public boolean isEnabled(int i) {
          					return true;
          				}
          
          				@Override
          				public void log(int i, String s) {
          					// System. out.println("JSch: " + s);
          				}