My notes on several issues when installing and running uWSGI.
When I try to install uwsgi using pip, there are compilation errors. After some search, based on discussions here, I find the cause of this issue is that the version of gcc is too high. I am using Ubuntu 18.04, and the default gcc version is 7.4.0.
Based on this post, the minimum gcc we can install from the default Ubuntu 18.04 remote repo is gcc-4.8. There is no gcc-4.7 available for install. It turns out that gcc-4.8 works fine:
apt-get update && apt-get install gcc-4.8 g++-4.8Then we need to change the gcc command to point to gcc-4.8:
rm /usr/bin/gcc && ln -s /usr/bin/gcc-4.8 /usr/bin/gccAfter that, I can install uwsgi successfully using pip. Finally, let’s revert the gcc version to its old state:
rm /usr/bin/gcc && ln -s /usr/bin/gcc-7 /usr/bin/gccI use the following command to install uwsgi with conda:
conda create -n py36 -c conda-forge python==3.6.5 uwsgiWhen I run uwsgi --version, I see the following error message:
error while loading shared libraries: libicui18n.so.58: cannot open shared object file: No such file or directory
The solution is to run conda install icu=58, ref here.
I am using uwsgi 2.0.18 (installed via conda install -c conda-forge uwsgi) with python 3.7.7 from Miniconda.
When I use uwsgi to server a simple Flask application, I see segmentation errors below:
uwsgi(uwsgi_backtrace+0x2c) [0x5638f8685bbc]
uwsgi(uwsgi_segfault+0x32) [0x5638f8685ff2]
/lib/x86_64-linux-gnu/libc.so.6(+0x3ef20) [0x7f8c09c22f20]
/opt/miniconda/lib/python3.7/lib-dynload/_queue.cpython-37m-x86_64-linux-gnu.so(+0x2932) [0x7f8c07fe9932]
uwsgi(_PyDict_DelItem_KnownHash+0x36b) [0x5638f860ec1b]
uwsgi(_PyEval_EvalFrameDefault+0x2510) [0x5638f85a1680]
uwsgi(_PyEval_EvalCodeWithName+0x2f9) [0x5638f862abc9]
uwsgi(_PyFunction_FastCallDict+0x1d7) [0x5638f86045a7]
uwsgi(+0x1ed7a3) [0x5638f86057a3]
uwsgi(PyObject_CallFunctionObjArgs+0x99) [0x5638f8605a09]
uwsgi(PyObject_ClearWeakRefs+0x33c) [0x5638f86010fc]
uwsgi(+0x1a638c) [0x5638f85be38c]
uwsgi(+0x1b9a27) [0x5638f85d1a27]
uwsgi(+0x1f70b8) [0x5638f860f0b8]
uwsgi(+0x1a6435) [0x5638f85be435]
uwsgi(_PyFunction_FastCallKeywords+0x290) [0x5638f8604020]
uwsgi(_PyEval_EvalFrameDefault+0x40a) [0x5638f859f57a]
uwsgi(_PyFunction_FastCallDict+0x10b) [0x5638f86044db]
uwsgi(_PyEval_EvalFrameDefault+0x1e1d) [0x5638f85a0f8d]
uwsgi(_PyFunction_FastCallKeywords+0xfb) [0x5638f8603e8b]
uwsgi(_PyEval_EvalFrameDefault+0x6d4) [0x5638f859f844]
uwsgi(_PyFunction_FastCallKeywords+0xfb) [0x5638f8603e8b]
uwsgi(_PyEval_EvalFrameDefault+0x6d4) [0x5638f859f844]
uwsgi(_PyFunction_FastCallKeywords+0xfb) [0x5638f8603e8b]
uwsgi(_PyEval_EvalFrameDefault+0x6d4) [0x5638f859f844]
uwsgi(_PyFunction_FastCallDict+0x10b) [0x5638f86044db]
uwsgi(_PyObject_Call_Prepend+0x63) [0x5638f86054b3]
uwsgi(+0x1b56fa) [0x5638f85cd6fa]
uwsgi(PyObject_Call+0x6b) [0x5638f8604bdb]
uwsgi(python_call+0x12) [0x5638f869ffa2]
uwsgi(uwsgi_request_wsgi+0x266) [0x5638f86a2556]
uwsgi(wsgi_req_recv+0xa7) [0x5638f8633557]
uwsgi(simple_loop_run+0xd1) [0x5638f8681521]
uwsgi(simple_loop+0x11) [0x5638f8681301]
uwsgi(uwsgi_ignition+0x315) [0x5638f8686395]
uwsgi(uwsgi_worker_run+0x2b4) [0x5638f868aef4]
uwsgi(uwsgi_run+0x525) [0x5638f868b575]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xe7) [0x7f8c09c05b97]
uwsgi(+0x21abed) [0x5638f8632bed]
*** end of backtrace ***My MWE flask application:
import concurrent.futures
from flask import Flask
app = Flask(__name__)
@app.route("/toy", methods=["GET"])
def process_request():
results = do_concurrent()
if not results:
return "Fail."
return "Success"
def simple_task(num):
return 1
def do_concurrent():
dummy_list = list(range(100))
with concurrent.futures.ThreadPoolExecutor(max_workers=10) as executor:
results = list(executor.map(simple_task, dummy_list))
return resultsThe uwsgi command to run flask application:
uwsgi --http 0.0.0.0:6012 --wsgi-file flask_demo.py --callable app --processes 1 --threads 1The scrip to test this service:
import requests
url = "http://0.0.0.0:6012/toy"
r = requests.get(url, timeout=5)
print(r)When I request the service, I see the above segmentation errors.
If I create a conda virtual env with python version 3.6:
conda create -n py36 -c conda-forge python==3.6.5 uwsgi icu=58 flaskrun the service using uwsgi and request again, the error disappears.
If I do not use concurrent.futures, I see no errors both for python 3.7 and python 3.6.
I am not knowledgeable enough to know the exact cause of this issue.
It seems there is some compatibility issue with uwsgi, python version and concurrent package.
I am using Python 3.7 installed via Anaconda, and uWSGI is installed via pip. When I run my simple Flask application, I see the following error:
ImportError: dlopen(/Users/jdhao/anaconda3/lib/python3.7/lib-dynload/math.cpython-37m-darwin.so, 2): Symbol not found: _PyExc_MemoryErrorImportError: dlopen(/Users/jdhao/anaconda3/lib/python3.7/lib-dynload/math.cpython-37m-darwin.so, 2): Symbol not found: _PyExc_MemoryError
Referenced from: /Users/jdhao/anaconda3/lib/python3.7/lib-dynload/math.cpython-37m-darwin.so
Expected in: flat namespaceThis seems to be a compatibility issue between uWSGI and Anaconda python. There are two solutions:
Uninstall uWSGI installed via pip and install it using conda:
# uWSGI is provided by the conda-forge channel
conda install -c conda-forge uwsgiUsing Python 3.6 with uWSGI. We can create a new virtual env with Python 3.6.5 and intall uWSGI inside.
conda create -n py36 python==3.6.5 flaskAfter that, activate the virtual env and install uWSGI inside:
conda activate py36
pip install uwsgi此内容由惯性聚合(RSS阅读器)自动聚合整理，仅供阅读参考。 原文来自 — 版权归原作者所有。