From 361fb71e907aa84c28ecec79fefc6ca39c39172f Mon Sep 17 00:00:00 2001 From: Richard Purdie Date: Fri, 22 Jun 2012 12:55:55 +0100 Subject: process: Improve _logged_communicate buffering There are two problems with the _logged_communicate that are both caused as a result of buffering I/O issues: 1) log truncation when python fails 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 also flush the log before exiting. This is based on a patch from Jason Wessel with some changes to flush upon exit, abstract the non blocking file descriptor setup and drop the buffer size parameter. Signed-off-by: Richard Purdie --- lib/bb/process.py | 46 +++++++++++++++++++++++++++++++++------------- 1 file changed, 33 insertions(+), 13 deletions(-) (limited to 'lib/bb/process.py') diff --git a/lib/bb/process.py b/lib/bb/process.py index b74cb18066..05b51725f1 100644 --- a/lib/bb/process.py +++ b/lib/bb/process.py @@ -1,6 +1,8 @@ import logging import signal import subprocess +import errno +import select logger = logging.getLogger('BitBake.Process') @@ -68,20 +70,38 @@ def _logged_communicate(pipe, log, input): pipe.stdin.write(input) pipe.stdin.close() - bufsize = 512 outdata, errdata = [], [] - while pipe.poll() is None: - if pipe.stdout is not None: - data = pipe.stdout.read(bufsize) - if data is not None: - outdata.append(data) - log.write(data) - - if pipe.stderr is not None: - data = pipe.stderr.read(bufsize) - if data is not None: - errdata.append(data) - log.write(data) + rin = [] + + if pipe.stdout is not None: + bb.utils.nonblockingfd(pipe.stdout.fileno()) + rin.append(pipe.stdout) + if pipe.stderr is not None: + bb.utils.nonblockingfd(pipe.stderr.fileno()) + rin.append(pipe.stderr) + + try: + while pipe.poll() is 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() + if data is not None: + outdata.append(data) + log.write(data) + + if pipe.stderr in r: + data = pipe.stderr.read() + if data is not None: + errdata.append(data) + log.write(data) + finally: + log.flush() return ''.join(outdata), ''.join(errdata) def run(cmd, input=None, log=None, **options): -- cgit 1.2.3-korg