cffi cannot find libzmq.so #395

hydrogen18 · 2013-08-02T01:00:21Z

I have installing libzmq in /home/ericu/local with the --prefix option on its configure script. Pyzmq installs fine under CPython 2.7.5. It does not work under pypy even with the environmental variables set.

ericu@ubuntu-lts-base:~/fairywren$ LIBRARY_PATH=/home/ericu/local/lib C_INCLUDE_PATH=/home/ericu/local/include pypy -c 'import zmq'
Traceback (most recent call last):
  File "app_main.py", line 72, in run_toplevel
  File "app_main.py", line 566, in run_it
  File "<string>", line 1, in <module>
  File "/home/ericu/pypy-ericu/site-packages/zmq/__init__.py", line 52, in <module>
    from zmq.sugar import backend
  File "/home/ericu/pypy-ericu/site-packages/zmq/sugar/__init__.py", line 16, in <module>
    from zmq.sugar import (
  File "/home/ericu/pypy-ericu/site-packages/zmq/sugar/constants.py", line 16, in <module>
    from .backend import constants
  File "/home/ericu/pypy-ericu/site-packages/zmq/sugar/backend.py", line 29, in <module>
    from zmq.cffi_core import (
  File "/home/ericu/pypy-ericu/site-packages/zmq/cffi_core/__init__.py", line 12, in <module>
    from zmq.cffi_core import (constants, error, message, context, socket,
  File "/home/ericu/pypy-ericu/site-packages/zmq/cffi_core/constants.py", line 4, in <module>
    from ._cffi import C, constant_names, zmq_version_info
  File "/home/ericu/pypy-ericu/site-packages/zmq/cffi_core/_cffi.py", line 195, in <module>
    "Please check that you have zeromq headers and libraries." % e)
ImportError: PyZMQ CFFI backend couldn't find zeromq: cannot load library /home/ericu/pypy-ericu/site-packages/zmq/cffi_core/__pycache__/_cffi__g6ed94bfax67d4e236.pypy-21.so: libzmq.so.3: cannot open shared object file: No such file or directory
Please check that you have zeromq headers and libraries.
ericu@ubuntu-lts-base:~/fairywren$

The text was updated successfully, but these errors were encountered:

minrk · 2013-08-02T16:19:16Z

Try setting:

LD_LIBRARY_PATH=/home/ericu/local/lib

hydrogen18 · 2013-08-02T16:22:07Z

It is not shown but it is set to that value.

minrk · 2013-08-02T18:57:22Z

Your paste suggests that you have LIBRARY_PATH set, but not LD_LIBRARY_PATH, is this accurate?

hydrogen18 · 2013-08-02T18:58:55Z

That is not accurate. I have it set in my profile when I login.

minrk · 2013-08-02T19:08:41Z

What do you get from this:

from cffi import FFI

def zmq_version_info():
    ffi = FFI()
    ffi.cdef('void zmq_version(int *major, int *minor, int *patch);')
    libzmq = ffi.verify('#include <zmq.h>',
                                            libraries=['c', 'zmq'])
    major = ffi.new('int*')
    minor = ffi.new('int*')
    patch = ffi.new('int*')

    libzmq.zmq_version(major, minor, patch)

    return (int(major[0]), int(minor[0]), int(patch[0]))

zmq_version_info()

hydrogen18 · 2013-08-02T20:58:31Z

Looks like the same thing.

ericu@ubuntu-lts-base:~$ echo $LD_LIBRARY_PATH
/home/ericu/local/lib
ericu@ubuntu-lts-base:~$ nano minrk.py
ericu@ubuntu-lts-base:~$ cat minrk.py
from cffi import FFI

def zmq_version_info():
    ffi_check = FFI()
    ffi_check.cdef('void zmq_version(int *major, int *minor, int *patch);')
    libzmq = ffi_check.verify('#include <zmq.h>',
                                            libraries=['c', 'zmq'])
    major = ffi.new('int*')
    minor = ffi.new('int*')
    patch = ffi.new('int*')

    libzmq.zmq_version(major, minor, patch)

    return (int(major[0]), int(minor[0]), int(patch[0]))

zmq_version_info()
ericu@ubuntu-lts-base:~$ LIBRARY_PATH=/home/ericu/local/lib/ C_INCLUDE_PATH=/home/ericu/local/include pypy minrk.py
Traceback (most recent call last):
  File "app_main.py", line 72, in run_toplevel
  File "minrk.py", line 16, in <module>
    zmq_version_info()
  File "minrk.py", line 7, in zmq_version_info
    libraries=['c', 'zmq'])
  File "/home/ericu/pypy-ericu/lib_pypy/cffi/api.py", line 311, in verify
    lib = self.verifier.load_library()
  File "/home/ericu/pypy-ericu/lib_pypy/cffi/verifier.py", line 69, in load_library
    return self._load_library()
  File "/home/ericu/pypy-ericu/lib_pypy/cffi/verifier.py", line 143, in _load_library
    return self._vengine.load_library()
  File "/home/ericu/pypy-ericu/lib_pypy/cffi/vengine_gen.py", line 64, in load_library
    module = backend.load_library(self.verifier.modulefilename)
OSError: cannot load library /home/ericu/__pycache__/_cffi__g6ed94bfax67d4e236.pypy-21.so: libzmq.so.3: cannot open shared object file: No such file or directory
ericu@ubuntu-lts-base:~$

minrk · 2013-08-02T21:37:29Z

and what do you get from ls $LD_LIBRARY_PATH?

hydrogen18 · 2013-08-02T21:38:31Z

It looks like libzmq.so.3 is in there.

ericu@ubuntu-lts-base:~$ ls -l $LD_LIBRARY_PATH
total 21764
-r-xr-xr-x  1 ericu ericu 12971050 Jul 31 19:35 libpython2.7.a
-rw-r--r--  1 ericu ericu  6609546 Jul 31 19:38 libzmq.a
-rwxr-xr-x  1 ericu ericu      954 Jul 31 19:38 libzmq.la
lrwxrwxrwx  1 ericu ericu       15 Jul 31 19:38 libzmq.so -> libzmq.so.3.0.0
lrwxrwxrwx  1 ericu ericu       15 Jul 31 19:38 libzmq.so.3 -> libzmq.so.3.0.0
-rwxr-xr-x  1 ericu ericu  2670797 Jul 31 19:38 libzmq.so.3.0.0
drwxr-xr-x  2 ericu ericu     4096 Jul 31 19:38 pkgconfig
drwxr-xr-x 27 ericu ericu    20480 Jul 31 19:35 python2.7
ericu@ubuntu-lts-base:~$

minrk · 2013-08-02T21:42:29Z

Any change if you scrub /home/ericu/__pycache__?

hydrogen18 · 2013-08-02T21:44:46Z

I deleted the directory and I'm getting the same error.

hydrogen18 · 2013-08-02T22:07:21Z

Previously, I had done a ./configure --prefix=/home/ericu/local' when installing zeromq. I redid the install and did ./configure && sudo make install.

Now I get

ericu@ubuntu-lts-base:~$ pypy
Python 2.7.3 (480845e6b1dd219d0944e30f62b01da378437c6c, Aug 01 2013, 22:20:41)
[PyPy 2.1.0 with GCC 4.6.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
And now for something completely different: ``Every time someone argues with
"Smalltalk has always done X", it is always a good hint that something needs to
be changed fast. - Marcus Denker''
>>>> import zmq
>>>>

Your script on the other hand has a problem:

ericu@ubuntu-lts-base:~$ pypy minrk.py 
Traceback (most recent call last):
  File "app_main.py", line 72, in run_toplevel
  File "minrk.py", line 16, in <module>
    zmq_version_info()
  File "minrk.py", line 8, in zmq_version_info
    major = ffi.new('int*')
NameError: global name 'ffi' is not defined
ericu@ubuntu-lts-base:~$

Additionally, this is my dev environment. In my production environment, I cannot install into /usr/local/lib and /usr/local/include . I would still like to figure out why it will not work when installed into /home/ericu/local

minrk · 2013-08-02T22:24:20Z

That NameError was just a typo from a bad copy/paste. Should be fixed above.

minrk · 2013-08-02T22:26:45Z

I'll try to get a test setup working without a system libzmq - it definitely should work (and does work great with CPython). Weirdly enough, all of the documentation I have read suggests that you are doing everything right.

hydrogen18 · 2013-08-02T22:39:19Z

Thanks. I appreciate you looking into the issue.

minrk · 2013-08-02T22:42:08Z

It looks like CFFI ignores [DY]LD_LIBRARY_PATH, but respects LIBRARY_PATH.

I removed libzmq from my system
in libzmq dir (fresh checkout of master): ./configure --prefix=/tmp/libzmq && make && make install
pip install pyzmq (gets 13.1.0)

pypy -c "import zmq; print zmq.zmq_version()" fails to find zmq.h

env/pypy-cffi/site-packages/zmq/cffi_core/__pycache__/_cffi__g6ed94bfax67d4e236.c:25:10: fatal error: 'zmq.h' file not found
#include <zmq.h>

C_INCLUDE_PATH=/tmp/libzmq/include pypy -c "import zmq; print zmq.zmq_version()" finds zmq.h, fails to link:
```
ld: library not found for -lzmq
```
adding DYLD_LIBRARY_PATH=/tmp/libzmq/lib changes nothing (makes sense, because it only affects runtime loading, not compilation)
LIBRARY_PATH=/tmp/libzmq/lib C_INCLUDE_PATH=/tmp/libzmq/include pypy -c "import zmq; print zmq.zmq_version()" compiles successfully and prints 3.3.0.

This is with pypy-2.1.0 on OS X 10.8.4

hydrogen18 · 2013-08-02T22:48:47Z

OK, there must be something very different on Ubuntu. I guess I'l just hold off on pypy for now.

felipecruz · 2013-08-02T23:20:58Z

@hydrogen18 I'm not sure if this affects custom prefixes installations, but in general, in linux, after make && sudo make install you must also run sudo ldconfig

The last example from @minrk LIBRARY_PATH=/tmp/libzmq/lib C_INCLUDE_PATH=/tmp/libzmq/include pypy -c "import zmq; print zmq.zmq_version()" should work

hydrogen18 · 2013-08-02T23:30:15Z

ldconfig only affects linkage defined in /etc/ld.so.conf

Current workaround is:

ericu@ubuntu-lts-base:~$ LD_PRELOAD=/home/ericu/local/lib/libzmq.so.3 pypy -c 'import zmq; print zmq.zmq_version_info()'
(3, 2, 3)
ericu@ubuntu-lts-base:~$

However, using LD_PRELOAD seems to me incredibly hackish.

minrk · 2013-08-02T23:38:45Z

I just ran my sequence above on Ubuntu LTS 12.04 (pypy-2.1.0), and it behaved the same as before. C_INCLUDE_PATH required to find the header, LIBRARY_PATH required to link, and LD_LIBRARY_PATH required at runtime. Note that after the first run which does the compilation, only LD_LIBRARY_PATH is required.

hydrogen18 · 2013-08-02T23:41:16Z

No idea why, but you are right. It only works if you pass in LD_LIBRARY_PATH when invoking pypy

ericu@ubuntu-lts-base:~$ LD_LIBRARY_PATH=/home/ericu/local/lib pypy
Python 2.7.3 (480845e6b1dd219d0944e30f62b01da378437c6c, Aug 01 2013, 22:20:41)
[PyPy 2.1.0 with GCC 4.6.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
And now for something completely different: ``PyPy is too cool for
querystrings.''
>>>> import zmq
>>>> 
ericu@ubuntu-lts-base:~$ echo $LD_LIBRARY_PATH
/home/ericu/local/lib
ericu@ubuntu-lts-base:~$ pypy
Python 2.7.3 (480845e6b1dd219d0944e30f62b01da378437c6c, Aug 01 2013, 22:20:41)
[PyPy 2.1.0 with GCC 4.6.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
And now for something completely different: ``Every time someone argues with
"Smalltalk has always done X", it is always a good hint that something needs to
be changed fast. - Marcus Denker''
>>>> import zmq
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/ericu/pypy-ericu/site-packages/zmq/__init__.py", line 52, in <module>
    from zmq.sugar import backend
  File "/home/ericu/pypy-ericu/site-packages/zmq/sugar/__init__.py", line 16, in <module>
    from zmq.sugar import (
  File "/home/ericu/pypy-ericu/site-packages/zmq/sugar/constants.py", line 16, in <module>
    from .backend import constants
  File "/home/ericu/pypy-ericu/site-packages/zmq/sugar/backend.py", line 29, in <module>
    from zmq.cffi_core import (
  File "/home/ericu/pypy-ericu/site-packages/zmq/cffi_core/__init__.py", line 12, in <module>
    from zmq.cffi_core import (constants, error, message, context, socket,
  File "/home/ericu/pypy-ericu/site-packages/zmq/cffi_core/constants.py", line 4, in <module>
    from ._cffi import C, constant_names, zmq_version_info
  File "/home/ericu/pypy-ericu/site-packages/zmq/cffi_core/_cffi.py", line 195, in <module>
    "Please check that you have zeromq headers and libraries." % e)
ImportError: PyZMQ CFFI backend couldn't find zeromq: cannot load library /home/ericu/pypy-ericu/site-packages/zmq/cffi_core/__pycache__/_cffi__g6ed94bfax67d4e236.pypy-21.so: libzmq.so.3: cannot open shared object file: No such file or directory
Please check that you have zeromq headers and libraries.
>>>>

minrk · 2013-08-03T04:08:03Z

what is the line that sets LD_LIBRARY_PATH in your bashrc?

hydrogen18 · 2013-08-03T12:47:55Z

In my .profile file

LD_LIBRARY_PATH=$HOME/local/lib
LIBRARY_PATH=/home/ericu/local/lib/ 
C_INCLUDE_PATH=/home/ericu/local/include

I really appreciate all your help with this.

minrk · 2013-08-03T16:10:41Z

Aha! You need to export LD_LIBRARY_PATH=... if you want the setting to persist with subprocesses, as opposed to just being a variable for the shell session. You can check this by checking the os.environ dict in Python to see what variables the process has available.

hydrogen18 · 2013-08-03T17:54:46Z

Got it! Thanks for all the help.

klaussfreire · 2013-11-04T18:54:58Z

I have a similar issue, except it's different. The error is the same, and I can get it to work with LD_PRELOAD, the difference is I have zmq 2.1.7 installed on the system, and I built zmq 3.2.2 and installed it in /usr/local. Without LD_PRELOAD, the cffi backend seems to only find system libzmq. This applies at runtime after the first successful import, so it seems to be a matter with dynamic loading of the .so

Any ideas?

hydrogen18 · 2013-11-04T18:57:15Z

I recommend opening a separate issue. I did not have any actual library issues, but a misunderstanding of how environmental variables are passed along to child processes by the bash interpreter.

hydrogen18 closed this as completed Aug 3, 2013

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cffi cannot find libzmq.so #395

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cffi cannot find libzmq.so #395

cffi cannot find libzmq.so #395

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