Add quick and hacky prototype of bbb-build-recording backend

cups-backend-build-recording.sh

@@ -0,0 +1,104 @@
+#!/usr/bin/env bash
+
+# Put it into /usr/lib/cups/backend/bbb-build-recording
+
+# Authors:
+# - Mikhail Novosyolov <mikhailnov@dumalogiya.ru>, 2021
+
+# Based on examples at https://community.kde.org/Printing/Developer_Tools
+# Docs:
+# - backend(7) https://www.cups.org/doc/man-backend.html
+###############################################################################
+
+set -efu
+set -o pipefail
+
+# jobtitle=meeting ID (/var/bigbluebutton/recording/raw/$meeting_id),
+# we are not interested in all other variables
+readonly jobtitle=${3}
+
+BBB_DIR_RAW="${BBB_DIR_RAW:-/var/bigbluebutton/recording/raw}"
+
+# Exit codes from /usr/include/cups/backend.h
+CUPS_BACKEND_OK=0                  # Job completed successfully
+CUPS_BACKEND_FAILED=1              # Job failed, use error-policy
+CUPS_BACKEND_AUTH_REQUIRED=2       # Job failed, authentication required
+CUPS_BACKEND_HOLD=3                # Job failed, hold job
+CUPS_BACKEND_STOP=4                # Job failed, stop queue
+CUPS_BACKEND_CANCEL=5              # Job failed, cancel job
+CUPS_BACKEND_RETRY=6               # Job failed, retry this job later
+CUPS_BACKEND_RETRY_CURRENT=7       # Job failed, retry this job immediately
+
+# We use 'set -e', script may fail somewhere,
+# make CUPS restart the job later if the error was unexpected
+_trap_exit(){
+	if [ $? != "$CUPS_BACKEND_OK" ] && [ $? != "$CUPS_BACKEND_FAILED" ]; then
+		exit "$CUPS_BACKEND_RETRY"
+	fi
+}
+trap '_trap_exit' EXIT
+
+input=""
+
+case ${#} in
+	0 )
+		# This is CUPS listing backends
+		# device-class scheme "Unknown" "device-info"
+		echo direct bbb-build-recording \"Unknown\" \"Build recording of BigBlueButton\"
+		exit
+	;;
+	12 )
+		input=/dev/stdin
+	;;
+	13 )
+		# do not remove {} here!
+		input="${13}"
+	;;
+	* )
+		echo CRIT: unsupported number of arguements! 1>&2
+		exit "$CUPS_BACKEND_FAILED"
+	;;
+esac
+
+if [ "$jobtitle" = "(stdin)" ]; then
+	echo CRIT: printing job must be titled! 1>&2
+	exit "$CUPS_BACKEND_FAILED"
+fi
+
+if [ -z "$jobtitle" ]; then
+	echo CRIT: empty title of the printing job! 1>&2
+	exit "$CUPS_BACKEND_FAILED"
+fi
+
+if ! test -d "$BBB_DIR_RAW"/"$jobtitle" ; then
+	echo CRIT: recording ${jobtitle} does not exist! 1>&2
+	exit "$CUPS_BACKEND_FAILED"
+fi
+
+if ! test -f "$BBB_RAW_DIR"/"$jobtitle"/events.xml ; then
+	echo CRIT: recording ${jobtitle} does not have events.xml! 1>&2
+	exit "$CUPS_BACKEND_FAILED"
+fi
+
+# TODO: process it by ourself
+# TODO: watch *.failed and *.done files
+# TODO: use ionotify
+c=0
+while true
+do
+	# 2 hours
+	if [ $c -gt 240 ]; then
+		echo CRIT: timeout waiting for BBB to process recording ${jobtitle} 1>&2
+		exit "$CUPS_BACKEND_RETRY"
+	fi
+	if test -f /var/bigbluebutton/recording/status/processed/${jobtitle}-presentation.fail; then
+		echo CRIT: BBB failed to process recording ${jobtitle} 1>&2
+		exit "$CUPS_BACKEND_FAILED"
+	fi
+	if test -f /var/bigbluebutton/recording/status/processed/${jobtitle}-presentation.done ; then
+		echo INFO: BBB has processed recording ${jobtitle} 1>&2
+		exit "$CUPS_BACKEND_OK"
+	fi
+	sleep 30s
+	c=$((++c))
+done