Add initial rffmpeg

rffmpeg.py

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+#!/usr/bin/env python3
+
+# rffmpeg.py - Remote FFMPEG transcoding for Jellyfin
+#
+#    Copyright (C) 2019  Joshua M. Boniface <joshua@boniface.me>
+#
+#    This program is free software: you can redistribute it and/or modify
+#    it under the terms of the GNU General Public License as published by
+#    the Free Software Foundation, either version 3 of the License, or
+#    (at your option) any later version.
+#
+#    This program is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU General Public License for more details.
+#
+#    You should have received a copy of the GNU General Public License
+#    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+#
+###############################################################################
+#
+# rffmpeg works as a drop-in replacement to an existing ffmpeg binary. It is
+# used to launch ffmpeg commands on a remote machine via SSH, while passing
+# in any stdin from the calling environment. Its primary usecase is to enable
+# a program such as Jellyfin to distribute its ffmpeg calls to remote machines
+# that might be better suited to transcoding or processing ffmpeg.
+#
+# rffmpeg uses a configuration file, by default at `/etc/rffmpeg/rffmpeg.yml`,
+# to specify a number of settings that the processes will use. This includes
+# the remote system(s) to connect to, temporary directories, SSH configuration,
+# and other settings.
+#
+###############################################################################
+
+###############################################################################
+# Imports and helper functions
+###############################################################################
+
+import os, sys, time, io
+import yaml
+import subprocess
+
+def debug(msg):
+    sys.stderr.write(str(msg) + '\n')
+
+###############################################################################
+# Configuration parsing
+###############################################################################
+
+# Load config file
+default_config_file = '/etc/rffmpeg/rffmpeg.yml'
+
+# Get alternative configuration file from environment
+try:
+    config_file = os.environ['RFFMPEG_CONFIG']
+except:
+    config_file = default_config_file
+
+# Parse the configuration
+debug('Loading configuration from file "{}"'.format(config_file))
+with open(config_file, 'r') as cfgfile:
+    try:
+        o_config = yaml.load(cfgfile)
+    except Exception as e:
+        debug('ERROR: Failed ot parse configuration file: {}'.format(e))
+        exit(1)
+try:
+    config = {
+        'state_tempdir':  o_config['rffmpeg']['state']['tempdir'],
+        'state_filename': o_config['rffmpeg']['state']['filename'],
+        'state_contents': o_config['rffmpeg']['state']['contents'],
+        'remote_hosts':   o_config['rffmpeg']['remote']['hosts'],
+        'remote_user':    o_config['rffmpeg']['remote']['user'],
+        'remote_args':    o_config['rffmpeg']['remote']['args'],
+        'pre_commands':   o_config['rffmpeg']['commands']['pre'],
+        'ffmpeg_command': o_config['rffmpeg']['commands']['ffmpeg']
+    }
+except Exception as e:
+    debug('ERROR: Failed to load configuration: {}'.format(e))
+    exit(1)
+
+# Parse CLI args (ffmpeg command line)
+all_args = sys.argv
+cli_ffmpeg_args = all_args[1:]
+
+###############################################################################
+# State parsing and target determination
+###############################################################################
+
+# Ensure the state directory exists or create it
+if not os.path.exists(config['state_tempdir']):
+    os.makedirs(config['state_tempdir'])
+
+# Check for existing state files
+state_files = os.listdir(config['state_tempdir'])
+
+# Read each statefile to determine which hosts are in use
+active_hosts = list()
+for state_file in state_files:
+    with open(config['state_tempdir'] + '/' + state_file, 'r') as statefile:
+        contents = statefile.readlines()
+        active_hosts.append(contents[0])
+
+# Find out which active hosts are in use
+host_counts = dict()
+for host in config['remote_hosts']:
+    count = 0
+    for ahost in active_hosts:
+        if host == ahost:
+            count += 1
+    host_counts[host] = count
+
+# Select the host with the lowest count (first host is parsed last)
+lowest_count = 999
+target_host = None
+for host in config['remote_hosts']:
+    if host_counts[host] < lowest_count:
+        lowest_count = host_counts[host]
+        target_host = host
+
+if not target_host:
+    debug('ERROR: Failed to find a valid target host')
+    exit(1)
+
+# Set up our state file
+our_statefile = config['state_tempdir'] + '/' + config['state_filename'].format(pid=os.getpid())
+with open(our_statefile, 'w') as statefile:
+    statefile.write(config['state_contents'].format(host=target_host))
+
+###############################################################################
+# Set up our remote command
+###############################################################################
+
+rffmpeg_command = list()
+
+# Add SSH component
+rffmpeg_command.append('ssh')
+rffmpeg_command.append('-tt')
+rffmpeg_command.append('-q')
+for arg in config['remote_args']:
+    if arg:
+        rffmpeg_command.append(arg)
+
+# Add user+host string
+rffmpeg_command.append('{}@{}'.format(config['remote_user'], target_host))
+debug("Running rffmpeg against {}@{}".format(config['remote_user'], target_host))
+
+# Add any pre command
+for cmd in config['pre_commands']:
+    if cmd:
+        rffmpeg_command.append(cmd)
+
+# Add ffmpeg component
+rffmpeg_command.append(config['ffmpeg_command'])
+
+# Parse and re-quote the arguments
+for arg in cli_ffmpeg_args:
+    if arg[0] != '-':
+        rffmpeg_command.append('"{}"'.format(arg))
+    else:
+        rffmpeg_command.append('{}'.format(arg))
+
+rffmpeg_cli = ' '.join(rffmpeg_command)
+debug("rffmpeg command line: {}".format(rffmpeg_cli))
+
+###############################################################################
+# Execute the remote command
+###############################################################################
+p = subprocess.run(rffmpeg_command,
+                     shell=False,
+                     bufsize=0,
+                     universal_newlines=True,
+                     stdin=sys.stdin,
+                     stderr=sys.stderr,
+                     stdout=sys.stdout)
+
+###############################################################################
+# Cleanup
+###############################################################################
+os.remove(our_statefile)
+exit(p.returncode)

rffmpeg.yml.sample

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+---
+# Example configuration file for rffmpeg
+# Copy this sample to `/etc/rffmpeg/rffmpeg.yml and replace the various attributes
+# with the values for your environment. For more details please see the README.
+
+rffmpeg:
+    state:
+        # Temporary directory to store state
+        tempdir: "/run/shm/rffmpeg"
+
+        # Filename format for state instance files, usually instance_[pid].pid
+        filename: "instance_{pid}.pid"
+
+        # Contents of the state instance file; usually just the active host
+        contents: "{host}"
+
+    remote:
+        # A YAML list of remote hosts to connect to
+        hosts:
+            - gpu1
+#            - gpu2
+#            - gpu3
+
+        # The remote SSH user to connect as
+        user: ffmpeg
+
+        # A YAML list of additional SSH arguments (e.g. private keys)
+        args: 
+            - ""
+
+    commands:
+        # A YAML list of prefixes to the ffmpeg command (e.g. sudo, nice, etc.)
+        pre:
+            - ""
+
+        # ffmpeg command binary
+        ffmpeg: "/usr/lib/jellyfin-ffmpeg/ffmpeg"