relogger.py

#!/usr/bin/env python
'''Act as a simple relay from a FIFO logging target (or regular file)
   Into another file and the local UNIX syslog service

   Call with the name of a file to write to (new log file) and the name of a FIFO
   or regular file to relay from.
'''

if __name__ == '__main__':
    import sys, time, syslog

    ## https://docs.python.org/2/library/syslog.html                                                                                    ## syslog.openlog('HGS relogger', syslog.LOG_LOCAL7, syslog.LOG_ALERT)
    syslog.openlog('HGS relogger', syslog.LOG_USER)
    log = open(sys.argv[1], 'ab', 0)
    with open(sys.argv[2], 'rb', 0) as f:
        try:
            linebuf = []
            while True:
                time.sleep(0.5)
                line = f.readline()
                if not line.strip():
                    # skip blank lines
                    continue
                # rest of this buffers up indented line to pass them all as one
                # long call to syslog ... but you might want to skip all this
                # and just blindly write each fragment:
                if line[0] in ' \t':
                    linebuf.append(line)
                else:
                    finished_line = ''.join(linebuf)
                    syslog.syslog(syslog.LOG_ALERT, finished_line)
                    ## syslog.syslog(finished_line)
                    log.write(finished_line)
                    linebuf = [line]
        except KeyboardInterrupt:  # Exit cleanly, without stacktrace on SIGINT
            # Remember to flush last (possibly partial) logged line buffer:
            finished_line = ''.join(linebuf)
            syslog.syslog(syslog.LOG_ALERT, finished_line)
            log.write(finished_line)
        # file implicitly by context manager