@@ -1,6 +1,9 @@
import logging
import signal
import subprocess
+import fcntl
+import errno
+import select
logger = logging.getLogger('BitBake.Process')
@@ -70,18 +73,40 @@ def _logged_communicate(pipe, log, input):
bufsize = 512
outdata, errdata = [], []
+ rin = []
+
+ if pipe.stdout is not None:
+ fd = pipe.stdout.fileno()
+ fl = fcntl.fcntl(fd, fcntl.F_GETFL)
+ fcntl.fcntl(fd, fcntl.F_SETFL, fl | os.O_NONBLOCK)
+ rin.append(pipe.stdout)
+ if pipe.stderr is not None:
+ fd = pipe.stderr.fileno()
+ fl = fcntl.fcntl(fd, fcntl.F_GETFL)
+ fcntl.fcntl(fd, fcntl.F_SETFL, fl | os.O_NONBLOCK)
+ rin.append(pipe.stderr)
+
while pipe.poll() is None:
- if pipe.stdout is not None:
+ rlist = rin
+ try:
+ r,w,e = select.select (rlist, [], [])
+ except OSError, e:
+ if e.errno != errno.EINTR:
+ raise
+
+ if pipe.stdout in r:
data = pipe.stdout.read(bufsize)
if data is not None:
outdata.append(data)
log.write(data)
+ log.flush()
- if pipe.stderr is not None:
+ if pipe.stderr in r:
data = pipe.stderr.read(bufsize)
if data is not None:
errdata.append(data)
log.write(data)
+ log.flush()
return ''.join(outdata), ''.join(errdata)
def run(cmd, input=None, log=None, **options):
There are two problems with the _logged_communicate that are both caused as a result of buffering I/O, instead of flushing it out to the log files as it arrives. 1) log truncation when python dumps I have seen the task logs missing data that was not flushed when bitbake crashes. 2) While a bitbake task is running it is impossible to see what is going on if it is only writing a small incremental log that is smaller than the buffer, or you get only a partial log, up until the task exists. It is worse in the case that stderr and stdout are separate file handles, because previous code blocks on the read of stdout and then stderr, serially. The right approach is simply to use select() to determine if there is data available and then to flush the log buffers as they arrive. This still makes use of buffering in the cases where there is more than 1 byte of data, but the buffers are much more dynamic. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> --- lib/bb/process.py | 29 +++++++++++++++++++++++++++-- 1 file changed, 27 insertions(+), 2 deletions(-)