rtail.py

#!/usr/bin/env python

"""
Usage:

  ./rtail.py user@host:path/foo.log bar.log host2:/path/baz.log
"""

import optparse
import os
import re
import select
import subprocess
import sys
import time


def main():
    op = optparse.OptionParser()
    options, args = op.parse_args()
    streams = list()
    for arg in args:
        if re.match(r"^(.+@)?[a-zA-Z0-9.-]+:.+", arg):
            # this is a remote location
            hostname, path = arg.split(":", 1)
            s = subprocess.Popen(["ssh", hostname, "tail -f " + path], stdout=subprocess.PIPE)
            s.name = arg
            streams.append(s)
        else:
            s = subprocess.Popen(["tail", "-f", arg], stdout=subprocess.PIPE)
            s.name = arg
            streams.append(s)

    lastName = None
    while True:
        r, _, _ = select.select(
            [stream.stdout.fileno() for stream in streams], [], [])
        for fileno in r:
            for stream in streams:
                if stream.stdout.fileno() != fileno:
                    continue
                data = os.read(fileno, 4096)
                if not data:
                    streams.remove(stream)
                    break
                if stream.name != lastName:
                    print "%s:" % stream.name
                    lastName = stream.name
                sys.stdout.write(data)
                break

if __name__ == "__main__":
    main()