[英]Extend python/django with c and mod_wsgi with apache
我有一個關於使用c代碼和mod_wsgi擴展python的問題。
我在apache服務器中有一個django應用程序,它查詢postgresql數據庫以生成報告。 在某些報告中,系統會創建包含結果的csv文件。 要創建這個csv文件,有時系統必須使用python處理超過二十萬個寄存器,這顯然非常慢。 為了加速這一點,我們編寫了執行此工作的交流模塊,並且多次提高了速度。 我們嘗試使用ctypes並使用c創建一個python模塊,兩者在runserver中工作正常但在使用apache和mod_wsgi執行時崩潰。
httpd-error.log中的錯誤是:
[Wed Jul 27 02:33:52 2011] [通知]兒童pid 44657退出信號分段故障(11)
¿有什么建議嗎?
代碼是:
# Creates the HttpResponse object with the appropriate CSV header.
response = HttpResponse(mimetype='application/x-zip-compressed')
response['Content-Disposition'] = \
'attachment; filename=' + filename + '.zip'
p0 = 'descarga_' + str(datetime.today()) + '.csv'
p1 = settings.DATABASES['default']['NAME']
p2 = settings.DATABASES['default']['USER']
#lib.generar(string_at(p0),p1,p2,string_at(str(init)),string_at(str(end)),string_at(str(provider)))
import generador
generador.generar(p0,p1,p2,str(init),str(end),str(provider))
在我們調用generador.generar()之后崩潰了,這是一個用C開發的外部模塊
我也試過GDb作為@GrahamDumpleton suggets,這是輸出,不是很有用:(
調試器啟動,當我確定執行調用c模塊的鏈接時,它會在分段錯誤中失敗
(gdb) run -X
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /usr/local/sbin/httpd -X
[New LWP 101064]
[New Thread 28501140 (LWP 101064)]
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 28501140 (LWP 101064)]
0x2847d423 in fwrite () from /lib/libc.so.7
在Segmetation故障之后,我嘗試使用調試器中的'where'命令,這就是它給出的內容:
(gdb) where
#0 0x2847d423 in fwrite () from /lib/libc.so.7
#1 0x293f8d09 in generar () from /ruta/al/codigo/generador.so
#2 0x28912caa in PyCFunction_Call () from /usr/local/lib/libpython2.7.so
#3 0x2896e49a in PyEval_EvalFrameEx () from /usr/local/lib/libpython2.7.so
#4 0x2897044b in PyEval_EvalCodeEx () from /usr/local/lib/libpython2.7.so
#5 0x288feafd in PyClassMethod_New () from /usr/local/lib/libpython2.7.so
#6 0x288d622c in PyObject_Call () from /usr/local/lib/libpython2.7.so
#7 0x2896c27a in PyEval_EvalFrameEx () from /usr/local/lib/libpython2.7.so
#8 0x2896fadc in PyEval_EvalFrameEx () from /usr/local/lib/libpython2.7.so
#9 0x2897044b in PyEval_EvalCodeEx () from /usr/local/lib/libpython2.7.so
#10 0x288fea0a in PyClassMethod_New () from /usr/local/lib/libpython2.7.so
#11 0x288d622c in PyObject_Call () from /usr/local/lib/libpython2.7.so
#12 0x288e4fd8 in PyClass_IsSubclass () from /usr/local/lib/libpython2.7.so
#13 0x288d622c in PyObject_Call () from /usr/local/lib/libpython2.7.so
#14 0x2893044c in _PyObject_LookupSpecial () from /usr/local/lib/libpython2.7.so
#15 0x288d622c in PyObject_Call () from /usr/local/lib/libpython2.7.so
#16 0x28968ec4 in PyEval_CallObjectWithKeywords () from /usr/local/lib/libpython2.7.so
#17 0x2889b229 in Adapter_run (self=0x28b4dd58, object=0x28c7d50c) at mod_wsgi.c:3841
#18 0x2889be50 in wsgi_execute_script (r=0x28cb4058) at mod_wsgi.c:6547
#19 0x2889de66 in wsgi_hook_handler (r=0x28cb4058) at mod_wsgi.c:9080
#20 0x08076b19 in ap_run_handler (r=0x28cb4058) at config.c:157
#21 0x08079dee in ap_invoke_handler (r=0x28cb4058) at config.c:376
#22 0x08084eb0 in ap_process_request (r=0x28cb4058) at http_request.c:282
#23 0x0808201b in ap_process_http_connection (c=0x28b201f0) at http_core.c:190
#24 0x0807de09 in ap_run_process_connection (c=0x28b201f0) at connection.c:43
#25 0x08089791 in child_main (child_num_arg=Variable "child_num_arg" is not available.
) at prefork.c:662
#26 0x080899e3 in make_child (s=0x28510f10, slot=0) at prefork.c:707
#27 0x0808a591 in ap_mpm_run (_pconf=0x2850f018, plog=0x2853d018, s=0x28510f10) at prefork.c:983
#28 0x08064195 in main (argc=676384792, argv=0x28b1e018) at main.c:739
嘗試設置:
WSGIApplicationGroup %{GLOBAL}
並強制應用程序在主Python解釋器中運行。
可能沒有正確編寫C擴展來使用Python子解釋器。
看到:
http://code.google.com/p/modwsgi/wiki/ApplicationIssues#Python_Simplified_GIL_State_API
您的代碼也可能只是錯誤並且在mod_wsgi下使用它會顯示命令行Python的問題。
看到:
http://code.google.com/p/modwsgi/wiki/DebuggingTechniques#Debugging_Crashes_With_GDB
關於如何調試崩潰發生的位置。
更新1
在構建擴展模塊時,為了幫助在gdb中進行調試,請確保在編譯擴展模塊時沒有打開優化,並且調試選項是。
對於setup.py驅動的擴展模塊構建,我發現有必要添加:
from distutils import sysconfig
dummy = sysconfig.get_config_vars('CFLAGS', 'OPT')
config_vars = sysconfig._config_vars
config_vars['CFLAGS'] = config_vars['CFLAGS'].replace(' -Os ', ' ')
config_vars['OPT'] = config_vars['OPT'].replace(' -Os ', ' ')
這種方式可以擺脫-Os選項。 無論是-Os還是-O都取決於您的Python安裝。
在構建擴展模塊時檢查編譯器選項中的-g,並在需要時添加它。
完成后,您可以使用gdb實際轉儲變量值,獲取實際行號等。
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