Files
dotfiles/.i3/lemonbar/i3_lemonbar_launcher.py
2020-01-24 23:21:56 +01:00

221 lines
7.6 KiB
Python
Executable File

import fcntl, sys, os, time, logging
import queue
import signal, atexit
import subprocess
import contextlib
from threading import Thread
import argparse
import i3_lemonbar_config as config
import i3_lemonbar_common as common
import i3_lemonbar_modules as modules
import i3_lemonbar_parser as lemonparser
def assert_only_instance():
"""
If PID file exists:
Look for process with given PID
If found:
Exit program
If not found:
Delete PID file and continue
Look for fifo file
If exists:
Delete it
"""
try:
pid = None
with open(config.pid_file, 'r') as fp:
pid = int(fp.read())
except IOError:
common.logger.debug('Could not open PID file. Assuming non existent')
except ValueError:
common.logger.debug('''PID file contents broken''')
try:
os.remove(config.pid_file)
common.logger.debug('''Deleted old PID file, continuing as usual''')
except OSError:
common.logger.debug('''Failed deleting old PID file.''')
os._exit(1)
if pid is not None:
try:
common.logger.debug('''Found old PID file. Looking for owner''')
os.kill(pid, 0)
common.logger.debug('''Owner exists''')
common.logger.debug('''Failed, another instance of the launcher is running
(PID {})'''.format(pid))
os._exit(1)
except ProcessLookupError:
common.logger.debug('''Owner does not exist''')
try:
os.remove(config.pid_file)
common.logger.debug('''Deleted old PID file, continuing as usual''')
except OSError:
common.logger.debug('''Failed deleting old PID file.''')
os._exit(1)
with open(config.pid_file, 'w+') as fp:
fp.write('{:d}'.format(os.getpid()))
common.logger.debug('''Created and wrote to PID file''')
common.create_new_fifo(config.fifo_file_status)
def handle_exit(signum, frame):
common.logger.info('Signal handler called with signal {}'.format(signum))
common.logger.info('Calling os._exit(0)')
os._exit(0)
# Terminates process p nicely
def nice_term(p):
if p is not None:
p.terminate()
def nice_delete(f):
with contextlib.suppress(FileNotFoundError):
os.remove(f)
def clean_up():
common.logger.debug('Cleaning up')
nice_delete(config.pid_file)
nice_delete(config.fifo_file_status)
modules.stop_all()
os._exit(0)
def keep_fifo_open():
with open(config.fifo_file_status, 'w', buffering=1) as fifo_write:
while True:
fifo_write.write('HEARTBEAT\n')
time.sleep(30)
class LemonbarWrapper:
def __init__(self, only_instance = True):
assert only_instance, 'Multiple instances not supported' # TODO
assert_only_instance() # Creates pid file and fifo file
self.buffer_in = common.Shelf()
self.all_threads = []
# Start writing and reading threads
# Create readers before writers
self.p_lemonbar = subprocess.Popen(config.lemonbar_args, stdin=subprocess.PIPE
, stdout=subprocess.PIPE, text=True)
self.start_thread(target = self.exec_commands, desc='Execute commands thread')
self.start_thread(target = self.write_parsed, desc='Write parsed status thread')
self.start_thread(target = keep_fifo_open, desc='Keep fifo open thread')
self.start_thread(target = self.put_fifo_in_queue, desc='Put fifo entries in queue thread')
modules.start_all(self)
common.logger.debug('Threads started')
# Helpers to start threads
def start_thread(self, target, desc):
# Wrapper around arbitrary target
def run_thread(target, desc):
target()
common.health_logger.info('"%s" reached end', desc)
thread = Thread(target = run_thread, args=(target, desc))
self.all_threads.append(thread)
common.health_logger.info('"%s" starting', desc)
thread.start()
def join(self):
for thread in self.all_threads:
thread.join()
# Thread targets
def write_parsed(self):
# Write parse entries in queue to lemonbar
while True:
data = self.buffer_in.get() # Blocking read
self.p_lemonbar.stdin.write(data + '\n')
self.p_lemonbar.stdin.flush()
#common.logger.debug('Read: "{0}"'.format(data))
#common.logger.debug('Parsed "{0}"'.format(psd))
def exec_commands(self):
while True:
data = self.p_lemonbar.stdout.readline()
if not data:
common.logger.debug('Lemonbar closed, exiting')
common.health_logger.info('Lemonbar closed, exiting')
clean_up()
break
common.logger.debug('Trying reading: "{0}"'.format(data.strip('\n')))
try:
modules.do_action(data)
except Exception as e:
common.logger.debug('Exception occured executing command\n Line in: {}'.format(data))
common.logger.debug(str(e))
if len(data) == 0:
common.logger.debug("Lemonbar output closed")
break
common.logger.debug('Read: "{0}"'.format(data.strip('\n')))
def put_fifo_in_queue(self):
with open(config.fifo_file_status, 'r', buffering=1) as fifo_read:
# Let parser read from fifo
common.logger.debug("FIFO {} opened for reading".format(config.fifo_file_status))
while True:
try:
data = fifo_read.readline() # Blocking read
if len(data) == 0:
common.logger.debug("Writer closed")
break
data = data.rstrip() # Remove trailing newlines
self.buffer_in.put(lemonparser.parse_line(data))
except BrokenPipeError:
common.logger.debug('Broken pipe in parse status thread, exiting')
common.health_logger.info('Broken pipe in parse status thread, exiting')
clean_up()
except Exception as e:
common.logger.debug('Unknown exception in parse status thread, exiting')
common.health_logger.info('Unknown exception in parse status thread, exiting')
raise
common.logger.debug(str(e))
clean_up()
if __name__ == "__main__":
parser = argparse.ArgumentParser()
parser.add_argument('--debug', action='store_true')
args = parser.parse_args()
if(args.debug):
debuglvl = logging.DEBUG
else:
debuglvl = logging.INFO
# Setup logger to stdout
formatter = logging.Formatter('%(asctime)s %(levelname)s %(message)s')
handler = logging.StreamHandler(sys.stdout)
handler.setFormatter(formatter)
common.logger = logging.getLogger('Normal logger')
common.logger.setLevel(debuglvl)
common.logger.addHandler(handler)
# Setup health logger to file in tmp
formatter = logging.Formatter('%(asctime)s %(message)s')
handler = logging.FileHandler(config.health_file)
handler.setFormatter(formatter)
common.health_logger = logging.getLogger('Health logger')
common.health_logger.addHandler(handler)
# Ensure clean up on exit
atexit.register(clean_up)
signal.signal(signal.SIGTERM, handle_exit)
signal.signal(signal.SIGINT, handle_exit)
# Start the lemonbar wrapper
LemonbarWrapper().join()
common.logger.debug('Reached end')