apenwarr-redo/redo/cmd_log.py
Avery Pennarun 61f3e4672e Workaround for completely broken file locking on Windows 10 WSL.
WSL (Windows Services for Linux) provides a Linux-kernel-compatible ABI
for userspace processes, but the current version doesn't not implement
fcntl() locks at all; it just always returns success.  See
https://github.com/Microsoft/WSL/issues/1927.

This causes us three kinds of problem:
  1. sqlite3 in WAL mode gives "OperationalError: locking protocol".
     1b. Other sqlite3 journal modes also don't work when used by
         multiple processes.
  2. redo parallelism doesn't work, because we can't prevent the same
     target from being build several times simultaneously.
  3. "redo-log -f" doesn't work, since it can't tell whether the log
     file it's tailing is "done" or not.

To fix #1, we switch the sqlite3 journal back to PERSIST instead of
WAL.  We originally changed to WAL in commit 5156feae9d to reduce
deadlocks on MacOS.  That was never adequately explained, but PERSIST
still acts weird on MacOS, so we'll only switch to PERSIST when we
detect that locking is definitely broken.  Sigh.

To (mostly) fix #2, we disable any -j value > 1 when locking is broken.
This prevents basic forms of parallelism, but doesn't stop you from
re-entrantly starting other instances of redo.  To fix that properly,
we need to switch to a different locking mechanism entirely, which is
tough in python.  flock() locks probably work, for example, but
python's locks lie and just use fcntl locks for those.

To fix #3, we always force --no-log mode when we find that locking is
broken.
2019-01-02 14:49:33 -05:00

265 lines
9 KiB
Python

"""redo-log: print past build logs. """
import errno, fcntl, os, re, struct, sys, time
import termios
from .atoi import atoi
from . import env, logs, options, state
optspec = """
redo-log [options...] [targets...]
--
r,recursive show build logs for dependencies too
u,unchanged show lines for dependencies not needing to be rebuilt
f,follow keep watching for more lines to be appended (like tail -f)
no-details only show 'redo' recursion trace, not build output
no-status don't display build summary line in --follow
no-pretty don't pretty-print logs, show raw @@REDO output instead
no-color disable ANSI color; --color to force enable (default: auto)
debug-locks print messages about file locking (useful for debugging)
debug-pids print process ids in log messages (useful for debugging)
ack-fd= (internal use only) print REDO-OK to this fd upon starting
"""
o = options.Options(optspec)
(opt, flags, extra) = o.parse(sys.argv[1:])
targets = extra
topdir = os.getcwd()
already = set()
depth = []
total_lines = 0
status = None
start_time = time.time()
# regexp for matching "redo" lines in the log, which we use for recursion.
# format:
# redo path/to/target which might have spaces
# redo [unchanged] path/to/target which might have spaces
# redo path/to/target which might have spaces (comment)
REDO_LINE_RE = re.compile(r'^@@REDO:([^@]+)@@ (.*)\n$')
def _tty_width():
s = struct.pack("HHHH", 0, 0, 0, 0)
try:
s = fcntl.ioctl(sys.stderr.fileno(), termios.TIOCGWINSZ, s)
except (IOError, ImportError):
return atoi(os.environ.get('WIDTH')) or 70
(ysize, xsize, ypix, xpix) = struct.unpack('HHHH', s)
return xsize or 70
def is_locked(fid):
return (fid is not None) and not state.Lock(fid=fid).trylock()
def _fix_depth():
env.v.DEPTH = len(depth) * ' '
def _rel(top, mydir, path):
return os.path.relpath(os.path.join(top, mydir, path), topdir)
def catlog(t):
"""Copy the given log content to our current log output device.
Note: this function's behaviour depends on global command-line options.
"""
global total_lines, status
if t in already:
return
if t != '-':
depth.append(t)
_fix_depth()
already.add(t)
mydir = os.path.dirname(t)
if t == '-':
f = sys.stdin
fid = None
loglock = None
logname = None
else:
try:
sf = state.File(name=t, allow_add=False)
except KeyError:
sys.stderr.write('redo-log: [%s] %r: not known to redo.\n'
% (os.getcwd(), t,))
sys.exit(24)
fid = sf.id
del sf
state.rollback()
logname = state.logname(fid)
loglock = state.Lock(fid + state.LOG_LOCK_MAGIC)
loglock.waitlock(shared=True)
f = None
delay = 0.01
was_locked = is_locked(fid)
line_head = ''
width = _tty_width()
while 1:
if not f:
try:
f = open(logname)
except IOError, e:
if e.errno == errno.ENOENT:
# ignore files without logs
pass
else:
raise
if f:
# Note: normally includes trailing \n.
# In 'follow' mode, might get a line with no trailing \n
# (eg. when ./configure is halfway through a test), which we
# deal with below.
line = f.readline()
else:
line = None
if not line and (not opt.follow or not was_locked):
# file not locked, and no new lines: done
break
if not line:
was_locked = is_locked(fid)
if opt.follow:
# Don't display status line for extremely short-lived runs
if opt.status and time.time() - start_time > 1.0:
width = _tty_width()
head = 'redo %s ' % ('{:,}'.format(total_lines))
tail = ''
for n in reversed(depth):
remain = width - len(head) - len(tail)
# always leave room for a final '... ' prefix
if remain < len(n) + 4 + 1 or remain <= 4:
if len(n) < 6 or remain < 6 + 1 + 4:
tail = '... %s' % tail
else:
start = len(n) - (remain - 3 - 1)
tail = '...%s %s' % (n[start:], tail)
break
elif n != '-':
tail = n + ' ' + tail
status = head + tail
if len(status) > width:
sys.stderr.write(
'\nOVERSIZE STATUS (%d):\n%r\n'
% (len(status), status))
assert len(status) <= width
sys.stdout.flush()
sys.stderr.write('\r%-*.*s\r' % (width, width, status))
time.sleep(min(delay, 1.0))
delay += 0.01
continue
total_lines += 1
delay = 0.01
if not line.endswith('\n'):
line_head += line
continue
if line_head:
line = line_head + line
line_head = ''
if status:
sys.stdout.flush()
sys.stderr.write('\r%-*.*s\r' % (width, width, ''))
status = None
g = re.match(REDO_LINE_RE, line)
if g:
# FIXME: print prefix if @@REDO is not at start of line.
# logs.PrettyLog does it, but only if we actually call .write().
words, text = g.groups()
kind, pid, when = words.split(':')[0:3]
pid = atoi(pid)
relname = _rel(topdir, mydir, text)
fixname = os.path.normpath(os.path.join(mydir, text))
if kind == 'unchanged':
if opt.unchanged:
if opt.debug_locks:
logs.meta(kind, relname, pid=pid)
elif fixname not in already:
logs.meta('do', relname, pid=pid)
if opt.recursive:
if loglock:
loglock.unlock()
catlog(os.path.join(mydir, text))
if loglock:
loglock.waitlock(shared=True)
already.add(fixname)
elif kind in ('do', 'waiting', 'locked', 'unlocked'):
if opt.debug_locks:
logs.meta(kind, relname, pid=pid)
logs.write(line.rstrip())
elif fixname not in already:
logs.meta('do', relname, pid=pid)
if opt.recursive:
assert text
if loglock:
loglock.unlock()
catlog(os.path.join(mydir, text))
if loglock:
loglock.waitlock(shared=True)
already.add(fixname)
elif kind == 'done':
rv, name = text.split(' ', 1)
logs.meta(kind, rv + ' ' + _rel(topdir, mydir, name))
else:
logs.write(line.rstrip())
else:
if opt.details:
logs.write(line.rstrip())
if loglock:
loglock.unlock()
if status:
sys.stdout.flush()
sys.stderr.write('\r%-*.*s\r' % (width, width, ''))
status = None
if line_head:
# partial line never got terminated
print line_head
if t != '-':
assert depth[-1] == t
depth.pop(-1)
_fix_depth()
def main():
queue = []
try:
if not targets:
sys.stderr.write(
'redo-log: give at least one target; ' +
'maybe "all"?\n')
sys.exit(1)
state.init(targets)
if opt.status < 2 and not os.isatty(2):
opt.status = False
logs.setup(
tty=sys.stdout, parent_logs=False,
pretty=opt.pretty, color=opt.color)
if opt.debug_locks:
env.v.DEBUG_LOCKS = 1
if opt.debug_pids:
env.v.DEBUG_PIDS = 1
if opt.ack_fd:
# Write back to owner, to let them know we started up okay and
# will be able to see their error output, so it's okay to close
# their old stderr.
ack_fd = int(opt.ack_fd)
assert ack_fd > 2
if os.write(ack_fd, 'REDO-OK\n') != 8:
raise Exception('write to ack_fd returned wrong length')
os.close(ack_fd)
queue += targets
while queue:
t = queue.pop(0)
if t != '-':
logs.meta('do', _rel(topdir, '.', t), pid=0)
catlog(t)
except KeyboardInterrupt:
sys.exit(200)
except IOError, e:
if e.errno == errno.EPIPE:
pass
else:
raise
if __name__ == '__main__':
main()