SSL backend error when using OpenSSL

Question

I was trying to install pycurl in a virtualenv using pip and I got this error

ImportError: pycurl: libcurl link-time ssl backend (openssl) is different from         


        

Answer 1

FWIW, I ran into a lot of issues getting this working via AWS Elastic Beanstalk and finally was able to get it working with:

packages:
  yum:
    openssl-devel: []
    libcurl-devel: []

container_commands:
  # Reinstall PyCurl with correct ssl backend
  05_reinstall_pycurl:
    command: |
      pip install --upgrade pip
      pip uninstall -y pycurl
      pip install --global-option='--with-openssl' pycurl

Answer 2

This worked for me:

pip uninstall pycurl
export PYCURL_SSL_LIBRARY=nss
easy_install pycurl

None of this worked for me (note the difference is simply easy_install vs pip):

pip uninstall pycurl
export PYCURL_SSL_LIBRARY=[nss|openssl|ssl|gnutls]
pip install pycurl
#xor
curl -O https://pypi.python.org/packages/source/p/pycurl/pycurl-7.19.3.1.tar.gz
#...
python setup.py --with-[nss|openssl|ssl|gnutls] install

Answer 3

I am running this on OS X and some of the above solutions weren't working. Similar to Edward Newell's comment the PYCURL_SSL_LIBRARY variable seemed to have been completely ignored.
Further reading of the PycURL installation doc revealed the following:

pip may reinstall the package it has previously compiled instead of recompiling pycurl with newly specified options

Therefore, I had to force it to compile with:

pip install --compile pycurl

That works on a number of cases. However, I did run into a few systems that continued to ignore the variable so, similar to maharg101's answer, I resorted to the install options which through pip can be set like this:

pip install pycurl --global-option="--with-[ssl|gnutls|nss]"

where you select one of the three options inside the square brackets. Notice that the available option is ssl and not openssl. If you specify --with-openssl you'll get an error. Also note that if you were messing around with the PYCURL_SSL_LIBRARY variable and switching it to funky values to see what would happen this last command will definitely catch it and throw an error if the value is set but not valid.

Answer 4

Reinstallation of curl

I tried every suggestion from this discussion but no one worked for me. As solution I have reinstalled curl and curlib. After that I was able to install pycurl with ssl support inside environment.

At start:

'PycURL/7.43.0 libcurl/7.47.0 GnuTLS/3.4.10 zlib/1.2.8 libidn/1.32 librtmp/2.3'

Part 1.Re/Installation with pip

Firstly I have removed pycurl from virtualenv using pip as was suggested previous answers:

pip uninstall pycurl
export PYCURL_SSL_LIBRARY=openssl
pip install pycurl --global-option="--with-openssl"

The idea here is that package was cached and we just reintstall it with openssl option.

I also tried to recompile pycurl with pip using:

pip install pycurl --compile pycurl --no-cache

..but had the same error after running:

python
import pycurl
pycurl.version

ImportError: pycurl: libcurl link-time ssl backend (gnutls) is different from compile-time ssl backend (openssl)

Part 2. Installation from tar

After previous method didn't work I have decidede to install pycurl from tar with:

curl -O https://pypi.python.org/packages/source/p/pycurl/pycurl-7.43.0.tar.gz
sudo tar -xzvf pycurl-7.43.0.tar.gz
cd pycurl-7.43.0/
sudo python setup.py --with-ssl install

It has installed pycurl globally but not within virtualenv. I also didn't check if it was installed with SSL support or not but think that still without ssl.

Part 3. Reinstallation of curl and curllib

Finally I understood that pycurl doesn't installs normally into environment because global curl and libcurl are compiled with gnutls.

Before starting check it with:

curl-config --configure

One of the output lines will be

'--without-ssl' '--with-gnutls'

To recompile it:

Firstly remove curl:

sudo apt-get purge curl

Install any build dependencies needed for curl

sudo apt-get build-dep curl

Get latest (as of Dec 20, 2016) libcurl

mkdir ~/curl
wget http://curl.haxx.se/download/curl-7.51.0.tar.bz2
tar -xvjf curl-7.51.0.tar.bz2
cd curl-7.51.0

The usual steps for building an app from source

./configure
./make
 sudo make install

If openssl installed correctly then configure will find it automatically. The output will be:

curl version: 7.51.0
Host setup: x86_64-pc-linux-gnu
Install prefix: /usr/local
Compiler: gcc
SSL support: enabled (OpenSSL) ...

Resolve any issues of C-level lib location caches ("shared library cache")

sudo ldconfig

Now try to reinstall pycurl within environment:

curl -O https://pypi.python.org/packages/source/p/pycurl/pycurl-7.43.0.tar.gz
pip install pycurl-7.43.0.tar.gz --global-option="--with-openssl"

The result should be:

python
import pycurl
pycurl.version

'PycURL/7.43.0 libcurl/7.51.0 OpenSSL/1.0.2g zlib/1.2.8 librtmp/2.3'

Answer 5

helloworld2013's answer is correct, but the key is matching the SSL library that pycurl is expecting. The error will be something like:

pycurl: libcurl link-time ssl backend (<library>) is different from compile-time ssl backend (<library> or "none/other")

To fix it, you have to use the library pycurl is expecting. In my case, my error was "pycurl: libcurl link-time ssl backend (nss) is different from compile-time ssl backend (openssl)", so my fix was:

pip uninstall pycurl
export PYCURL_SSL_LIBRARY=nss
pip install pycurl

Answer 6

Following worked for me with Python3.6

MacOS High-Sierra

sudo pip3 uninstall pycurl
sudo pip3 install --compile --install-option="--with-openssl" pycurl 

CentOS 7

sudo pip3 uninstall pycurl
sudo pip3 install --compile --install-option="--with-nss" pycurl