httplib.BadStatusLine exception occurred once in 10000 "tahoe put"s to the same SDMF writecap

[zancas]

Traceback (most recent call last):
  File "/home/arc/tahoe-lafs/support/bin/tahoe", line 9, in <module>
    load_entry_point(\'allmydata-tahoe==1.9.0.post132\', \'console_scripts\', \'tahoe\')()
  File "/home/arc/tahoe-lafs/src/allmydata/scripts/runner.py", line 116, in run
    rc = runner(sys.argv[1:], install_node_control=install_node_control)
  File "/home/arc/tahoe-lafs/src/allmydata/scripts/runner.py", line 102, in runner
    rc = cli.dispatch[command](so)
  File "/home/arc/tahoe-lafs/src/allmydata/scripts/cli.py", line 541, in put
    rc = tahoe_put.put(options)
  File "/home/arc/tahoe-lafs/src/allmydata/scripts/tahoe_put.py", line 85, in put
    resp = do_http("PUT", url, infileobj)
  File "/home/arc/tahoe-lafs/src/allmydata/scripts/common_http.py", line 68, in do_http
    return c.getresponse()
  File "/usr/lib/python2.7/httplib.py", line 1027, in getresponse
    response.begin()
  File "/usr/lib/python2.7/httplib.py", line 407, in begin
    version, status, reason = self._read_status()
  File "/usr/lib/python2.7/httplib.py", line 371, in _read_status
    raise BadStatusLine(line)
httplib.BadStatusLine: \'\'

[davidsarah]

It looks as though either the gateway failed to output a valid first line in its HTTP response, or the CLI failed to read that line correctly.

[davidsarah]

The first thing to do here is to see if we can reproduce it with, say, 100000 CLI requests. We don't currently know whether this occurs only for the specific operation in the description (tahoe put on a writecap), or it is something that can happen with low probability on any connection to the gateway.

[davidsarah]

A httplib.BadStatusLine exception also occurred in #1824 when the gateway was killed during a CLI operation. We should probably just catch it and report a friendlier error.