Configuring printing from Yandex Cloud Desktop to a local printer in Linux

Install the necessary tools:

• The inotify-tools utility.
• CUPS print server.
• The printer-driver-cups-pdf package for virtual PDF print checks. To configure a physical printer, install that printer’s driver.
• The [Samba]https://en.wikipedia.org/wiki/Samba_(software) package.

Do it by running these commands:

sudo apt update
sudo apt install inotify-tools cups printer-driver-cups-pdf samba

Create a shared folder at /srv/printdrop and set up access permissions for it:

sudo mkdir -p /srv/printdrop
sudo chown lp:lp /srv/printdrop
sudo chmod 0770 /srv/printdrop

This folder will be used for file exchange between the desktop and the local machine.

Set up Samba:

1. Open /etc/samba/smb.conf:

   sudo nano /etc/samba/smb.conf
   

2. Add this code at the end of the file:

   [printdrop]
     path = /srv/printdrop
     browseable = yes
     writable = yes
     guest ok = yes
     force user = lp
     force group = lp
     create mask = 0660
     directory mask = 0770
   

Configure CUPS:

1. Open /etc/cups/cups-pdf.conf:

   sudo nano /etc/cups/cups-pdf.conf
   

2. Find the Out ${HOME}/PDF or #Out ${HOME}/PDF line and replace it with the following:

   Out /tmp/cups-pdf-output
   

Create a folder at /tmp/cups-pdf-output and set up access to it:

sudo mkdir -p /tmp/cups-pdf-output
sudo chown lp:lp /tmp/cups-pdf-output
sudo chmod 755 /tmp/cups-pdf-output

This folder will store files sent for printing.

Configure the service to watch the shared folder:

1. Create a file named print-watcher.sh:

   sudo nano /usr/local/bin/print-watcher.sh
   

2. Paste this code into the print-watcher.sh file:

   #!/bin/bash
   WATCH_DIR="/srv/printdrop"
     PRINTER="PDF" # locally installed printer
     USER="lp" # user the print is initiated for
     inotifywait -m -e close_write,moved_to --format '%w%f' "$WATCH_DIR" | while read FILE; do
       if [[ "${FILE,,}" == *.pdf ]]; then
         lp -U "$USER" -d "$PRINTER" "$FILE" && rm -f "$FILE"
       fi
     done
   

   Note

   For a physical printer, in the PRINTER="PDF" parameter, replace PDF with the physical printer (queue) name.

3. Make the file executable:

   sudo chmod +x /usr/local/bin/print-watcher.sh
   

4. Create a service file named print-watcher.service:

   sudo nano /etc/systemd/system/print-watcher.service
   

5. Paste this code into the print-watcher.service file:

   [Unit]
     Description=Watch printdrop and print files
     
     [Service]
     ExecStart=/usr/local/bin/print-watcher.sh
     Restart=always
     User=lp
     Group=lp
     
     [Install]
     WantedBy=multi-user.target
   

Activate the service and restart the printing and file exchange services:

sudo systemctl daemon-reload
sudo systemctl restart cups
sudo systemctl restart smbd
sudo systemctl enable --now print-watcher.service

Result:

Created symlink /etc/systemd/system/multi-user.target.wants/print-watcher.service → /etc/systemd/system/print-watcher.service.

Run this command to test the service:

systemctl status print-watcher.service

Result:

● print-watcher.service - Watch printdrop and print files
    Loaded: loaded (/etc/systemd/system/print-watcher.service; enabled; preset: enabled)
    Active: active (running) since ...
    ...

Save the public IPv4 address of your local machine. One way to learn it is by using Yandex Internetometer. You will need this address to mount the shared folder on your desktop.

Connect to the desktop.

Install the CUPS server and the cifs-utils package:

sudo apt update
sudo apt install cups
sudo apt-get install cifs-utils

Configure the backend for the virtual printer:

1. Create a file named /usr/lib/cups/backend/printdrop:

   sudo nano /usr/lib/cups/backend/printdrop
   

2. Paste this code into the file:

   #!/bin/bash
   export PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
   if test "$#" = "0"; then
     echo 'file printdrop:/printdrop "PrintDrop" "/printdrop"'
     exit 0
   fi
   
   DROP_DIR="/home/<desktop_user_name>/printdrop"
   mkdir -p /tmp/cups-shared
   
   JOBFILE="$6"  # if CUPS provides the file as an argument
   TS=$(date +%s)-$RANDOM
   OUT="$DROP_DIR/job-$TS.pdf"
   SHARED_OUT="/tmp/cups-shared/job-$TS.pdf"
   
   if [ -n "$JOBFILE" ] && [ -f "$JOBFILE" ]; then
     cp "$JOBFILE" "$SHARED_OUT"
     chmod -R 777 /tmp/cups-shared
     sudo -u <desktop_user_name> /usr/local/bin/copy-as-user.sh "$SHARED_OUT" "$OUT"
   else
     cat - > "$SHARED_OUT"
     sudo -u <desktop_user_name> /usr/local/bin/copy-as-user.sh "$SHARED_OUT" "$OUT"
   fi
   

   Specify the name of the desktop user you will use to send files for printing.

3. Set up access to the file:

   sudo chmod 755 /usr/lib/cups/backend/printdrop
   sudo chown root:root /usr/lib/cups/backend/printdrop
   

Set up access to the shared folder:

1. Create a file named /usr/local/bin/copy-as-user.sh:

   sudo nano /usr/local/bin/copy-as-user.sh
   

2. Paste the helper script code:

   #!/bin/bash
   mv "$1" "$2.tmp"
   mv "$2.tmp" "$2"
   

3. Set up access to the file:

   sudo chmod +x /usr/local/bin/copy-as-user.sh
   sudo chown root:root /usr/local/bin/copy-as-user.sh
   

4. Set up permissions:

   sudo visudo
   

5. At the end of the file that opens, paste this line:

   lp ALL=(<desktop_user_name>) NOPASSWD: /usr/local/bin/copy-as-user.sh
   

   Specify the name of the desktop user you will use to send files for printing.

Create a virtual printer and activate it:

sudo lpadmin -p DropPrinter -E -v printdrop:/printdrop
sudo cupsenable DropPrinter
sudo cupsaccept DropPrinter

You will now see a message that a new printer was added.

Create a folder for shared folder mounting:

sudo mkdir -p ~/printdrop

Mount the shared folder:

sudo mount -t cifs //<local_machine_IP_address>/printdrop ~/printdrop -o guest,uid=$(id -u),gid=$(id -g)

Specify the IPv4 address you saved earlier.

On your desktop, create or download any PDF file.

On your desktop, send the PDF file for printing by selecting the new virtual printer.

You will now see a message that the file was added to the printing queue.

On your local machine, check the printing queue of the virtual PDF printer.