#20815 closed Bug (fixed)
daemonize.py: unbuffered text IO error (python3)
Reported by: | Owned by: | nobody | |
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Component: | Python 3 | Version: | dev |
Severity: | Normal | Keywords: | python3 runfcgi open |
Cc: | Triage Stage: | Accepted | |
Has patch: | no | Needs documentation: | no |
Needs tests: | no | Patch needs improvement: | no |
Easy pickings: | no | UI/UX: | no |
Description (last modified by )
When trying to run fcgi server I get "ValueError: can't have unbuffered text I/O"
My python version and django version:
$ python --version Python 3.2.3 >>> django.get_version() '1.7.dev20130726184538' Can't start server: (virtenv02)jsmith@thinkpad01:~/virtenv02/mysite$ python manage.py runfcgi host=127.0.0.1 port=8100 Traceback (most recent call last): File "manage.py", line 10, in <module> execute_from_command_line(sys.argv) File "/home/jsmith/virtenv02/django-trunk/django/core/management/__init__.py", line 397, in execute_from_command_line utility.execute() File "/home/jsmith/virtenv02/django-trunk/django/core/management/__init__.py", line 390, in execute self.fetch_command(subcommand).run_from_argv(self.argv) File "/home/jsmith/virtenv02/django-trunk/django/core/management/base.py", line 240, in run_from_argv self.execute(*args, **options.__dict__) File "/home/jsmith/virtenv02/django-trunk/django/core/management/base.py", line 283, in execute output = self.handle(*args, **options) File "/home/jsmith/virtenv02/django-trunk/django/core/management/commands/runfcgi.py", line 22, in handle runfastcgi(args) File "/home/jsmith/virtenv02/django-trunk/django/core/servers/fastcgi.py", line 176, in runfastcgi become_daemon(our_home_dir=options["workdir"], **daemon_kwargs) File "/home/jsmith/virtenv02/django-trunk/django/utils/daemonize.py", line 28, in become_daemon so = open(out_log, 'a+', 0) ValueError: can't have unbuffered text I/O
Server starts successfully and works if I give it daemonize=False option:
(virtenv02)jsmith@thinkpad01:~/virtenv02/mysite$ python manage.py runfcgi host=127.0.0.1 port=8100 daemonize=False
As far as I understand, this issue is specific to python3 and is related to changes in open function introduced in pep-3116
Alex
Change History (7)
follow-up: 4 comment:1 by , 11 years ago
Description: | modified (diff) |
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Triage Stage: | Unreviewed → Accepted |
comment:3 by , 11 years ago
Replying to aaugustin:
Note that FastCGI is deprecated in 1.7.
Interesting decision, why so? Cannot spot any rationale in the 1.7 release notes. Pointers?
However, the error is not really fcgi-related, any code using django/utils/daemonize.py will have the same issue in Py3k.
Log files are text files, and you cannot open them in unbuffered mode.
comment:4 by , 11 years ago
Replying to claudep:
Maybe someone more knowledgeable about buffered/unbuffered output may chime in to enlighten us?
Change it to
open( out_log, 'a+', 1)
This buffers up to the next EOL, which makes sense for log files. (Same for err_log
)
As per Python3 docs:
buffering is an optional integer used to set the buffering policy. Pass 0 to switch buffering off (only allowed in binary mode), 1 to select line buffering (only usable in text mode)
Looking at open() in Python2, line buffering should also work:
- If something goes wrong while writing to
out_log
, you get an exception - I haven't yet seen
traceback
failing in the middle of a line, so it is probably also safe forerr_log
Hope this helps.
comment:6 by , 10 years ago
Resolution: | → fixed |
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Status: | new → closed |
Unfortunately, this is old untested code. I wonder if the solution would be to simply forget the
0
argument (unbuffered) of theopen
call. Maybe someone more knowledgeable about buffered/unbuffered output may chime in to enlighten us?