After upgrading mac os to High Sierra, using python3.6 sqlanydb in flask app gives error: Could not load dbcapi

[Former Member]

I recently upgraded my OS to High Sierra, and since then I have not been able to use the sqlanydb library with my flask app. I was using SQLAnywhere16 and recently upgraded to SQLAnywhere17 after reading that it might solve problem, but it did not.

I start by sourcing sa_config.sh located at /Applications/SQLAnywhere17/System/bin64/sa_config.sh. Then I run my flask app. In the initialization of my app, I create a connection using sqlanydb.connect(), and I am met with the following traceback.

File "/usr/local/lib/python3.6/site-packages/lib/python/site-packages/sqlanydb.py", line 522, in connect return Connection(args, kwargs) File "/usr/local/lib/python3.6/site-packages/lib/python/site-packages/sqlanydb.py", line 538, in __init__ parent = Connection.cls_parent = Root("PYTHON") File "/usr/local/lib/python3.6/site-packages/lib/python/site-packages/sqlanydb.py", line 464, in __init__ 'libdbcapi_r.dylib') File "/usr/local/lib/python3.6/site-packages/lib/python/site-packages/sqlanydb.py", line 456, in load_library raise InterfaceError("Could not load dbcapi. Tried: " + ','.join(map(str, names))) sqlanydb.InterfaceError: (u'Could not load dbcapi. Tried: None,dbcapi.dll,libdbcapi_r.so,libdbcapi_r.dylib', 0)

When I run the python3.6 interpreter, I am able to import the sqlanydb and connect to my database just fine, with no error. But when I try to connect inside my flask app, I get this error.

[Former Member]

Update.

When I open a python interpreter, or just run a plain python script, I added these lines to make sure that sourcing sa_config.sh was definitely adding the paths to my environment.

print(os.environ['PATH']) print(os.environ['NODE_PATH']) print(os.environ['DYLD_LIBRARY_PATH'])

Running those lines in the python interpreter or in a plain python script, it prints out the correct paths. However, when I added those three lines to just above the line where my flask app was breaking, it prints out the correct paths for the first two, but a key error is raised on $DYLD_LIBRARY_PATH. Apparently flask is unable to see the library path added by sa_config.sh. When I run

echo $DYLD_LIBRARY_PATH

in a terminal, it prints the path just fine. So then is flask not using the right environment? Why is flask unable to see the updated library path?

[Former Member · Accepted solution]

I'm posting this as a solution because it at least solves my current problem. However, I think this is worth looking into more, and I'll be taking this problem to the Flask contributors.

It seems that when I run flask the following way, I get all of the errors that I have mentioned.

export FLASK_APP=modules export FLASK_DEBUG=1 flask run

This seems to wipe out the added key: $DYLD_LIBRARY_PATH. However, when starting flask the following way, by calling app.run(), the key is not wiped out and sqlanydb is able to correctly locate the library files.

from myapp import app

if __name__== '__main__': app.run(debug=True)

If anyone on this forum has an explanation for what I'm seeing, I'm all ears. This is all very confusing. Again, everything worked just fine until I upgraded to High Sierra, so I suspect that must have some part to play.

[jeff_albion]

High Sierra will "purge" DYLD_LIBRARY_PATH now for protected processes - see the docs from Apple.

[Former Member]

Ah, I see. Thank you for pointing me in the right direction.