Printer rotation command (#174)

* Parsing for mod printer

* Implemented mod-printer functionality

* Test and bugfix mod-printer

* Update mod-printer with more modern Python functions

* Change mod-printer to subparsers

* Add list_printers mod-printer base function

* Add list subcommand to mod-printer

* Minor mod-printer doc fix

* Fix mod-printer formatting, general verbosity

staff/lab/mod-printer

@@ -0,0 +1,111 @@
+#!/usr/bin/env python3
+"""Remove or add printers to/from CUPS classes."""
+import argparse
+import re
+import subprocess
+import sys
+
+
+def modify_printer(args):
+    """Perform internal call to CUPS CLI to modify class(es)."""
+    # Determine which CUPS classes are available
+    lpstat_proc = subprocess.run(['lpstat', '-p'], check=True,
+                                 stdout=subprocess.PIPE, stdin=subprocess.PIPE)
+    lpstat_out = lpstat_proc.stdout.decode('utf-8').strip().split('\n')
+
+    # Parse lpstat output for printer class names
+    # Output is of the form: printer <printername> is idle. <etc>
+    cups_classes = [re.search(r'printer (\S*) is', classname).group(1) for classname in lpstat_out]
+
+    if args.verbose:
+        print('Found CUPS classes: %s' % cups_classes)
+
+    # Override with specified classname if provided and valid
+    if args.classname:
+        if args.classname in cups_classes:
+            cups_classes = [args.classname]
+            if args.verbose:
+                print('Overriding CUPS classes with parameter: %s' % args.classname)
+        else:
+            print('ERROR: Specified class %s could not be found in available classes %s'
+                  % (args.classname, cups_classes))
+            return 1
+
+    # Perform pre-call logging and input processing
+    printer = args.printer.lower()
+    if args.verbose:
+        print('Printer to perform action on: %s' % printer)
+    action_flag = '-r' if args.action == 'remove' else '-c'
+    if args.verbose:
+        print('Action to be performed (and flag): %s (%s)' % (args.action, action_flag))
+
+    # Call lpadmin command to perform addition/removal
+    for classname in cups_classes:
+        action_cmd = ['lpadmin', '-p', printer + '-' + classname, action_flag, classname]
+        subprocess.run(action_cmd, check=True)
+        action_out = 'added to' if args.action == 'add' else 'removed from'
+        print('Printer %s was successfully %s %s' % (printer, action_out, classname))
+
+
+def list_printers(args):
+    """Perform internal call to CUPS CLI to list printer status(es) (and potentially jobs)."""
+    # Initialize base lpstat command
+    lpstat_cmd = ['lpstat', '-c']
+
+    # Add on to lpstat command with arguments
+    if args.classname:
+        lpstat_cmd.append(args.classname)
+    if args.jobs:
+        lpstat_cmd.append('-o')
+
+    if args.verbose:
+        print('Calling %s to list printer status' % lpstat_cmd)
+
+    # Call lpstat - prints members of the class and can
+    # be configured to include jobs as well. No way to
+    # check for printers not in classes.
+    lpstat_proc = subprocess.run(lpstat_cmd, check=True, stdout=subprocess.PIPE, stdin=subprocess.PIPE)
+
+    # Parse output to fit printer arg, or send directly to stdout
+    status_msgs = lpstat_proc.stdout.decode('utf-8')
+    if args.printer:
+        for line in status_msgs.split('\n'):
+            if args.printer in line or 'members of class' in line:
+                print(line)
+    else:
+        print(status_msgs, end='')
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument('-v', '--verbose', '--debug',
+                        action='store_true',
+                        help='output more verbose logging to stdout'
+                        )
+    parser.add_argument('-c', '--classname', help='modify/list only a specific class')
+
+    subparsers = parser.add_subparsers(dest='action', help='action to perform', required=True)
+
+    add_parser = subparsers.add_parser('add', help='add a printer')
+    add_parser.add_argument('printer', help='name of printer to add')
+
+    remove_parser = subparsers.add_parser('remove', help='remove a printer')
+    remove_parser.add_argument('printer', help='name of printer to remove')
+
+    list_parser = subparsers.add_parser('list', help='list printer statuses')
+    list_parser.add_argument('-p', '--printer', help='list only this named printer')
+    list_parser.add_argument('-j', '--jobs',
+                             action='store_true', help='include print jobs')
+
+    args = parser.parse_args()
+    if args.action == 'add' or args.action == 'remove':
+        return modify_printer(args)
+    elif args.action == 'list':
+        return list_printers(args)
+    else:
+        print('ERROR: Invalid action passed %s' % args.action)
+        return 1
+
+
+if __name__ == '__main__':
+    sys.exit(main())