How to stop 'import psycopg2' from causing an Exception when starting an Azure Container?

Question

I am trying to deploy a Django REST API using Azure App Service on Linux. I am using a postgresql Database and deploy via pipeline. Azure has postgresql 9.6. After running my pipeline, the Website shows an Server Error (500). The AppLogs show, that the Container couldn't be started due an failed import of psycopg2.

[ERROR] Exception in worker process
Traceback (most recent call last):
   File "/home/site/wwwroot/antenv/lib/python3.7/site-packages/django/db/backends/postgresql/base.py", line 25, in 
     import psycopg2 as Database
   File "/home/site/wwwroot/antenv/lib/python3.7/site-packages/psycopg2/__init__.py", line 50, in 
     from psycopg2._psycopg import (                     # noqa
ImportError: /home/site/wwwroot/antenv/lib/python3.7/site-packages/psycopg2/_psycopg.cpython-37m-x86_64-linux-gnu.so: undefined symbol: PQencryptPasswordConn

In the Build-stage of my pipeline, I set up my environment (python3.7) like this:

- script: |
    python -m venv antenv
    source antenv/bin/activate
    python -m pip install --upgrade pip
    pip install setup
    pip install -r requirements.txt

Where requirements.txt looks like this:

Django==3.0.2
djangorestframework==3.11.0
psycopg2-binary==2.8.4
pandas==0.25.3
pytest==5.3.5
pytest-django==3.8.0
pytest-mock==2.0.0
python-dateutil==2.8.1
sqlparse==0.3.0
whitenoise==5.0.1

BuildJob and DeploymentJob seem to run flawless. the Build-logs indicate that psycopg2_binary-2.8.4-cp37-cp37m-manylinux1_x86_64.whl was correctly downloaded and installed.

Also the App runs fine on my machine when using the database on azure by configuring in the settings.py:

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql',
        'NAME': 'databasename',
        'USER': 'user@postgresqlserver',
        'PASSWORD': 'Password',
        'HOST': 'postgresqlserver.postgres.database.azure.com',
        'PORT': '',
        'OPTIONS': {'sslmode': 'require'}
    }
}  # Of course the info is actually saved in environment variables

This gives me the feeling, that something with the psycopg2 installation is not working... For others the *psycopg2-binary seemed to do the trick but unfortunateley not for me.

Am I right to assume that on azure I'm nether able to install postgresql10 as suggested here https://github.com/psycopg/psycopg2/issues/983 nor can install from source like suggested here https://github.com/psycopg/psycopg2/issues/1018?

There must be something I am missing, I would be grateful for any advice!

EDIT: Taking a look at the library (as suggested here https://stackoverflow.com/a/59652816/13183775) I found that I don't have a PQencryptPasswordConn function but only a PQencryptPassword function. I have the feeling that this is expected for Postgresql9.6 (https://github.com/psycopg/psycopg2/blob/cb3353be1f10590cdc2a894ada42c3b4c171feb7/psycopg/psycopgmodule.c#L466). To check, whether there are multiple versions libpq:

/>find . -name "libpq*"
./var/lib/dpkg/info/libpq5:amd64.symbols
./var/lib/dpkg/info/libpq5:amd64.shlibs
./var/lib/dpkg/info/libpq5:amd64.list
./var/lib/dpkg/info/libpq5:amd64.triggers
./var/lib/dpkg/info/libpq-dev.list
./var/lib/dpkg/info/libpq5:amd64.md5sums
./var/lib/dpkg/info/libpq-dev.md5sums
./usr/share/doc/libpq5
./usr/share/doc/libpq-dev
./usr/share/locale/ko/LC_MESSAGES/libpq5-9.6.mo
./usr/share/locale/it/LC_MESSAGES/libpq5-9.6.mo
./usr/share/locale/pl/LC_MESSAGES/libpq5-9.6.mo
./usr/share/locale/zh_TW/LC_MESSAGES/libpq5-9.6.mo
./usr/share/locale/tr/LC_MESSAGES/libpq5-9.6.mo
./usr/share/locale/cs/LC_MESSAGES/libpq5-9.6.mo
./usr/share/locale/de/LC_MESSAGES/libpq5-9.6.mo
./usr/share/locale/ru/LC_MESSAGES/libpq5-9.6.mo
./usr/share/locale/sv/LC_MESSAGES/libpq5-9.6.mo
./usr/share/locale/pt_BR/LC_MESSAGES/libpq5-9.6.mo
./usr/share/locale/fr/LC_MESSAGES/libpq5-9.6.mo
./usr/share/locale/es/LC_MESSAGES/libpq5-9.6.mo
./usr/share/locale/zh_CN/LC_MESSAGES/libpq5-9.6.mo
./usr/share/locale/ja/LC_MESSAGES/libpq5-9.6.mo
./usr/lib/x86_64-linux-gnu/pkgconfig/libpq.pc
./usr/lib/x86_64-linux-gnu/libpq.so.5
./usr/lib/x86_64-linux-gnu/libpq.so
./usr/lib/x86_64-linux-gnu/libpq.so.5.9
./usr/lib/x86_64-linux-gnu/libpq.a
./usr/include/postgresql/libpq-events.h
./usr/include/postgresql/libpq-fe.h
./usr/include/postgresql/libpq
./usr/include/postgresql/libpq/libpq-fs.h
./usr/include/postgresql/internal/libpq
./usr/include/postgresql/internal/libpq-int.h>

Sadly I'm not able to see here wether there are multiple libpq versions...

How to stop 'import psycopg2' from causing an Exception when starting an Azure Container?

0 Answers