tests/dumbhttp.py

manifest: repurpose flagsdiff() into (node-and-flag)diff()

The manifestdict class already has a method for diff flags between two
manifests (presumably because there is no full access to the private
_flags field). The only caller is merge.manifestmerge(), which also
wants a diff of files between the same manifests. Let's combine the
code for diffing files and flags into a single method on
manifestdict. This puts all the manifest diffing in one place and will
allow for further simplification. It might also be useful for it to be
encapsulated in manifestdict if we later decide to to shard
manifests. The docstring is intentionally unclear about missing
entries for now.

#!/usr/bin/env python

"""
Small and dumb HTTP server for use in tests.
"""

from optparse import OptionParser
import BaseHTTPServer, SimpleHTTPServer, os, signal, subprocess, sys


def run(server_class=BaseHTTPServer.HTTPServer,
        handler_class=SimpleHTTPServer.SimpleHTTPRequestHandler,
        server_address=('localhost', 8000)):
    httpd = server_class(server_address, handler_class)
    httpd.serve_forever()


if __name__ == '__main__':
    parser = OptionParser()
    parser.add_option('-p', '--port', dest='port', type='int', default=8000,
        help='TCP port to listen on', metavar='PORT')
    parser.add_option('-H', '--host', dest='host', default='localhost',
        help='hostname or IP to listen on', metavar='HOST')
    parser.add_option('--pid', dest='pid',
        help='file name where the PID of the server is stored')
    parser.add_option('-f', '--foreground', dest='foreground',
        action='store_true',
        help='do not start the HTTP server in the background')

    (options, args) = parser.parse_args()

    signal.signal(signal.SIGTERM, lambda x, y: sys.exit(0))

    if options.foreground and options.pid:
        parser.error("options --pid and --foreground are mutually exclusive")

    if options.foreground:
        run(server_address=(options.host, options.port))
    else:
        # This doesn't attempt to cleanly detach the process, as it's not
        # meant to be a long-lived, independent process. As a consequence,
        # it's still part of the same process group, and keeps any file
        # descriptors it might have inherited besided stdin/stdout/stderr.
        # Trying to do things cleanly is more complicated, requires
        # OS-dependent code, and is not worth the effort.
        proc = subprocess.Popen([sys.executable, __file__, '-f',
            '-H', options.host, '-p', str(options.port)],
            stdin=open(os.devnull, 'r'),
            stdout=open(os.devnull, 'w'),
            stderr=subprocess.STDOUT)
        if options.pid:
            fp = file(options.pid, 'wb')
            fp.write(str(proc.pid) + '\n')
            fp.close()