With apache2.4.6 and mod_wsgi4.7.1 process requests of 30 seconds or more fail to render any results.
Alan Batakis
I getting a rendering hang if a process request takes more that 30
seconds to complete. I am not sure whether the hang is caused by Apache
or mod_wsgi. I get no errors and nothing in any log file to indicate
there is a problem.
I am moving an application from apache2.2/mod_python to
apache2.4.6/mod_wsgi and everything runs just fine, except that my
application occasionally takes more than 30 seconds to assemble all the
data needed to process a request. When this happens the page never
renders and I cannot find anything to debug... To simplify things for
testing I've used a bare bones "hello world" python program (below) with a
time.sleep(30) in it and that also fails to render the page, again a time delay of 29 seconds or less and everything works fine. The results
are consistent on Chrome/FF/IE browsers.
I am using:
mod_wsgi 4.7.1
python 2.7.5, and Django
Oracle HTTP Server 12.2.1.3 which runs Apache 2.4.6 (see long listing below)
Red Hat Enterprise Linux Server release 7.4 (Maipo)
Googling around I've found lots advice and I've tweaked both Apache
and mod_wsgi settings but nothing seems to make a difference. The most
promising setting I came across was "queue-timeout" but setting that
didn't seem to make a difference:
--queue-timeout SECONDS
Maximum number of seconds allowed for a request to be
accepted by a worker process to be handled, taken from
the time when the Apache child process originally
accepted the request. Defaults to 30 seconds.
I am at a lost for how to fix this issue or even how to better debug it, any advice or suggestions would be very welcome.
---------------------------- more detail -----------------------------
I get the same results whether I am in embedded or Daemon mod_wsgi mode.
-----------------------------my httpd.conf "tweaks" -------------
<Directory /scratch/ohs>
Require all granted
</Directory>
LoadModule wsgi_module "${PRODUCT_HOME}/modules/mod_wsgi.so"
WSGIDaemonProcess localhost:7780 processes=2 threads=15 request-timeout=0 socket-timeout=1000 queue-timeout=60
WSGIApplicationGroup %{GLOBAL}
WSGIProcessGroup localhost:7780
WSGIScriptAlias /test /scratch/ohs/test_app/test_thirty
--------------------------- my trivial application ---------------------------
import time
def application(environ, start_response):
status = '200 OK'
output = 'Testing with a 30 second sleep.'
time.sleep(30)
response_headers = [('Content-type', 'text/plain'),
('Content-Length', str(len(output)))]
start_response(status, response_headers)
return [output]
---------------------- some of my environment setup results from https://code.google.com/archive/p/modwsgi/wikis/CheckingYourInstallation.wiki#Sub_Interpreter_Being_Used
$ /usr/sbin/httpd -V
Server version: Apache/2.4.6 ()
Server built: Aug 7 2019 04:35:38
Server's Module Magic Number: 20120211:24
Server loaded: APR 1.4.8, APR-UTIL 1.5.2
Compiled using: APR 1.4.8, APR-UTIL 1.5.2
Architecture: 64-bit
Server MPM: prefork
threaded: no
forked: yes (variable process count)
Server compiled with....
-D APR_HAS_SENDFILE
-D APR_HAS_MMAP
-D APR_HAVE_IPV6 (IPv4-mapped addresses enabled)
-D APR_USE_SYSVSEM_SERIALIZE
-D APR_USE_PTHREAD_SERIALIZE
-D SINGLE_LISTEN_UNSERIALIZED_ACCEPT
-D APR_HAS_OTHER_CHILD
-D AP_HAVE_RELIABLE_PIPED_LOGS
-D DYNAMIC_MODULE_LIMIT=256
-D HTTPD_ROOT="/etc/httpd"
-D SUEXEC_BIN="/usr/sbin/suexec"
-D DEFAULT_PIDLOG="/run/httpd/httpd.pid"
-D DEFAULT_SCOREBOARD="logs/apache_runtime_status"
-D DEFAULT_ERRORLOG="logs/error_log"
-D AP_TYPES_CONFIG_FILE="conf/mime.types"
-D SERVER_CONFIG_FILE="conf/httpd.conf"
$ /usr/sbin/httpd -l
Compiled in modules:
core.c
mod_so.c
http_core.c
$ /usr/sbin/httpd -M
Loaded Modules:
core_module (static)
so_module (static)
http_module (static)
access_compat_module (shared)
actions_module (shared)
alias_module (shared)
allowmethods_module (shared)
auth_basic_module (shared)
auth_digest_module (shared)
authn_anon_module (shared)
authn_core_module (shared)
authn_dbd_module (shared)
authn_dbm_module (shared)
authn_file_module (shared)
authn_socache_module (shared)
authz_core_module (shared)
authz_dbd_module (shared)
authz_dbm_module (shared)
authz_groupfile_module (shared)
authz_host_module (shared)
authz_owner_module (shared)
authz_user_module (shared)
autoindex_module (shared)
cache_module (shared)
cache_disk_module (shared)
data_module (shared)
dbd_module (shared)
deflate_module (shared)
dir_module (shared)
dumpio_module (shared)
echo_module (shared)
env_module (shared)
expires_module (shared)
ext_filter_module (shared)
filter_module (shared)
headers_module (shared)
include_module (shared)
info_module (shared)
log_config_module (shared)
logio_module (shared)
mime_magic_module (shared)
mime_module (shared)
negotiation_module (shared)
remoteip_module (shared)
reqtimeout_module (shared)
rewrite_module (shared)
setenvif_module (shared)
slotmem_plain_module (shared)
slotmem_shm_module (shared)
socache_dbm_module (shared)
socache_memcache_module (shared)
socache_shmcb_module (shared)
status_module (shared)
substitute_module (shared)
suexec_module (shared)
unique_id_module (shared)
unixd_module (shared)
userdir_module (shared)
version_module (shared)
vhost_alias_module (shared)
dav_module (shared)
dav_fs_module (shared)
dav_lock_module (shared)
lua_module (shared)
mpm_prefork_module (shared)
proxy_module (shared)
lbmethod_bybusyness_module (shared)
lbmethod_byrequests_module (shared)
lbmethod_bytraffic_module (shared)
lbmethod_heartbeat_module (shared)
proxy_ajp_module (shared)
proxy_balancer_module (shared)
proxy_connect_module (shared)
proxy_express_module (shared)
proxy_fcgi_module (shared)
proxy_fdpass_module (shared)
proxy_ftp_module (shared)
proxy_http_module (shared)
proxy_scgi_module (shared)
proxy_wstunnel_module (shared)
systemd_module (shared)
cgi_module (shared)
wsgi_module (shared)
$ ldd /scratch/ohs/middleware/ohs/modules/mod_wsgi.so
linux-vdso.so.1 => (0x00007ffd21c67000)
libpython2.7.so.1.0 => /usr/lib64/libpython2.7.so.1.0 (0x00007fa03afac000)
libpthread.so.0 => /usr/lib64/libpthread.so.0 (0x00007fa03ad8f000)
libc.so.6 => /usr/lib64/libc.so.6 (0x00007fa03a9c1000)
libdl.so.2 => /usr/lib64/libdl.so.2 (0x00007fa03a7bd000)
libutil.so.1 => /usr/lib64/libutil.so.1 (0x00007fa03a5b9000)
libm.so.6 => /usr/lib64/libm.so.6 (0x00007fa03a2b7000)
/lib64/ld-linux-x86-64.so.2 (0x000055f61a899000)
Graham Dumpleton
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