Improve debugging output

Being able to see in the logs when a request has been made to an
unimplemented handler is important.

Furthermore, being able to access the deep SSH debug messaging is
important when trying to diagnose subtle issues related to SFTP / SSH
protocol.

src/classes/SftpSessionHandler.ts

@@ -167,7 +167,7 @@ export class SftpSessionHandler {
    */
   // eslint-disable-next-line class-methods-use-this
   public writeHandler = (): void => {
-    logger.verbose('Request: SFTP write file (SSH_FXP_WRITE)');
+    logger.error('UNIMPLEMENTED Request: SFTP write file (SSH_FXP_WRITE)');
   };
 
   /**
@@ -195,7 +195,7 @@ export class SftpSessionHandler {
    */
   // eslint-disable-next-line class-methods-use-this
   public fsetStatHandler = (): void => {
-    logger.verbose('Request: SFTP write open file statistics (SSH_FXP_FSETSTAT)');
+    logger.error('UNIMPLEMENTED Request: SFTP write open file statistics (SSH_FXP_FSETSTAT)');
   };
 
   /**
@@ -328,7 +328,7 @@ export class SftpSessionHandler {
    */
   // eslint-disable-next-line class-methods-use-this
   public removeHandler = (): void => {
-    logger.verbose('Request: SFTP remove file (SSH_FXP_REMOVE)');
+    logger.error('UNIMPLEMENTED Request: SFTP remove file (SSH_FXP_REMOVE)');
   };
 
   /**
@@ -339,7 +339,7 @@ export class SftpSessionHandler {
    */
   // eslint-disable-next-line class-methods-use-this
   public rmDirHandler = (): void => {
-    logger.verbose('Request: SFTP remove directory (SSH_FXP_RMDIR)');
+    logger.error('UNIMPLEMENTED Request: SFTP remove directory (SSH_FXP_RMDIR)');
   };
 
   /**
@@ -387,7 +387,7 @@ export class SftpSessionHandler {
    */
   // eslint-disable-next-line class-methods-use-this
   public readLinkHandler = (): void => {
-    logger.verbose('Request: SFTP read link (SSH_FXP_READLINK)');
+    logger.error('UNIMPLEMENTED Request: SFTP read link (SSH_FXP_READLINK)');
   };
 
   /**
@@ -398,7 +398,7 @@ export class SftpSessionHandler {
    */
   // eslint-disable-next-line class-methods-use-this
   public setStatHandler = (): void => {
-    logger.verbose('Request: SFTP set file attributes (SSH_FXP_SETSTAT)');
+    logger.error('UNIMPLEMENTED Request: SFTP set file attributes (SSH_FXP_SETSTAT)');
   };
 
   /**
@@ -409,7 +409,7 @@ export class SftpSessionHandler {
    */
   // eslint-disable-next-line class-methods-use-this
   public mkDirHandler = (): void => {
-    logger.verbose('Request: SFTP create directory (SSH_FXP_MKDIR)');
+    logger.error('UNIMPLEMENTED Request: SFTP create directory (SSH_FXP_MKDIR)');
   };
 
   /**
@@ -420,7 +420,7 @@ export class SftpSessionHandler {
    */
   // eslint-disable-next-line class-methods-use-this
   public renameHandler = (): void => {
-    logger.verbose('Request: SFTP file rename (SSH_FXP_RENAME)');
+    logger.error('UNIMPLEMENTED Request: SFTP file rename (SSH_FXP_RENAME)');
   };
 
   /**
@@ -431,7 +431,7 @@ export class SftpSessionHandler {
    */
   // eslint-disable-next-line class-methods-use-this
   public symLinkHandler = (): void => {
-    logger.verbose('Request: SFTP create symlink (SSH_FXP_SYMLINK)');
+    logger.error('UNIMPLEMENTED Request: SFTP create symlink (SSH_FXP_SYMLINK)');
   };
 
   private readonly genericStatHandler = (reqId: number, itemPath: Buffer): void => {

src/server.ts

@@ -14,6 +14,7 @@ if (typeof process.env.SSH_HOST_KEY_PATH === 'string') {
 
 const serverConfig: ServerConfig = {
   hostKeys,
+  debug: (message) => logger.silly(message),
 };
 
 const connectionListener = (client: Connection): void => {