ImportError dependency install resulting in NameError - python

Ive been writing a little script to bootstrap an environment for me, but ran into some confusion when attempting to handle module import errors. My intention was to catch any import error for the yaml module, and then use apt to install the module, and re-import it...
def install_yaml():
print "Attempting to install python-yaml"
print "=============== Begining of Apt Output ==============="
if subprocess.call(["apt-get", "-y", "install", "python-yaml"]) != 0 :
print "Failure whilst installing python-yaml"
sys.exit(1)
print "================= End of Apt Output =================="
#if all has gone to plan attempt to import yaml
import yaml
reload(yaml)
try:
import yaml
except ImportError:
print "Failure whilst importing yaml"
install_yaml()
grains_config = {}
grains_config['bootstrap version'] = __version__
grains_config['bootstrap time'] = "{0}".format(datetime.datetime.now())
with open("/tmp/doc.yaml", 'w+') as grains_file:
yaml.dump(grains_config, grains_file, default_flow_style=False)
Unfortunately when run I get a NameError
Traceback (most recent call last):
File "importtest-fail.py", line 32, in <module>
yaml.dump(grains_config, grains_file, default_flow_style=False)
NameError: name 'yaml' is not defined
After some research I discovered the reload builtin (Reload a previously imported module), which sounded like what I wanted to do, but still results in a NameError on the yaml modules first use.
Does anyone have any suggestions that would allow me to handle the import exception, install the dependencies and "re-import" it?
I could obviously wrap the python script in some bash to do the initial dependency install, but its not a very clean solution.
Thanks

You imported yaml as a local in install_yaml(). You'd have to mark it as a global instead:
global yaml
inside the function, or better still, move the import out of the function and put it right after calling install_yaml().
Personally, I'd never auto-install a dependency this way. Just fail and leave it to the administrator to install the dependency properly. They could be using other means (such as a virtualenv) to manage packages, for example.

Related

"ModuleNotFoundError: No module named 'igdb.wrapper'; 'igdb' is not a package" igdb-api-v4 [duplicate]

I'm trying to make a simple import and use the emailage third party library.
As per their documentation, the way to use their library is as follows:
pip install emailage-official
Then, simply import with:
from emailage.client import EmailageClient
The install works fine with pip - no errors. I double checked to see that the emailage package exists within the proper directory, and it does.
Package exists at:
C:\Users\aaron\AppData\Local\Programs\Python\Python37-32\Lib\site-packages\emailage
This folder has (seemingly) the correct files with an __init__.py and everything. However, both pylint and command line interpreter throw me a
'No module named 'emailage.client'; 'emailage' is not a package' error.
The output of my sys.path is:
[...
'C:\\Users\\aaron\\AppData\\Local\\Programs\\Python\\Python37-32\\lib\\site-packages'
...
]
So the directory where emailage is installed is a part of the path... and lastly I pip-installed numpy just to test if it worked properly. Numpy installed to the same site-packages folder as emailage, and it works fine when it is imported, so I'm stuck.
I don't typically use Python much, so any and all help would be appreciated.
The issue was in the naming of my file.
I hastily named my file emailage.py and then tried to import from emailage.client.
I'm assuming that Python looked in my current directory and matched the names of the file I was working on before checking the installed third party libraries.
After renaming my file everything seems ok.
For others who run into similar problems -- beware of conflicting naming. Sometimes the simplest things trip you up the longest.
I ran into something similar and the answer from OP about namespace collision is what finally clued me in.
I was using the same name for both a sub-package (directory) and a module (file) within it.
For example I had this:
/opt/mylib/myapi
/opt/mylib/myapi/__init__.py
/opt/mylib/myapi/myapi_creds.py # gitignored file for user/pass
/opt/mylib/myapi/myapi.py # base module, load creds and connect
/opt/mylib/myapi/myapi_dostuff.py # call myapi.py and do work
The script 'myapi.py' imports credentials from myapi_creds.py via this statement:
from myapi.myapi_creds import my_user, my_pass
Testing the module 'myapi.py' resulted in this error:
$ ./myapi.py
Traceback (most recent call last):
File "./myapi.py", line 12, in <module>
from myapi.myapi_creds import my_user, my_pass
File "/opt/mylib/myapi/myapi.py", line 12, in <module>
from myapi.myapi_creds import my_user, my_pass
ModuleNotFoundError: No module named 'myapi.myapi_creds'; 'myapi' is not a package
The solution was to rename myapi.py to myapi_base.py so it's name does not collide with the sub-package name.
I took a look at this problem, and even though it is not exactly the same error that I encountered, it helped me solve it. I'll explain the situation I had, since I think some users might find this handy.
So, I was getting the following error log:
Traceback (most recent call last):
File "/home/kemal/Programming/Python/Preference_Articulation/LocalSearch/LS_apriori.py", line 1, in <module>
from LocalSearch.LocalSearch import LocalSearch
ModuleNotFoundError: No module named 'LocalSearch.LocalSearch'; 'LocalSearch' is not a package
The structure of my project is the following (using PyCharm):
View of project structure
The important thing to notice is that I separated my code into several folders, since it makes it more readable. Now, in the folder named LocalSearch I have 4 files, LocalSearch, LS_apriori and some 2 tests files (not relevant). When trying to run the file LS_apriori (which uses methods and classes from file LocalSearch) I was getting the error provided above. The code specifically is not important, and the way I handled the imports was the following:
from LocalSearch.LocalSearch import LocalSearch
The fix was simple. I renamed the py-file LocalSearch to Local_Search (just added an underscore). Afterwards, the error was gone.
So my problem was possessing a folder(package) with the same name as a file(module) inside it, which has a class inside it with the same name. Python didn't like that.
Having modules with the same name as packages inside them is fine however, I guess the class just added extra confusion.

Import not working when file is located in same directory and calling script

I'm not sure if the title of this question is correct, mods please feel free to change it.
I'm working through cs231n Convolutional Neural Networks for Visual Recognition course online and I've hit a weird error. This is my first attempt at any real Python programming so it could be a simple error, or something more complicated.
I'm using Python 2.7, Anaconda, and Windows 7.
When trying to run a script I get the following error;
NameError: global name 'im2col_cython' is not defined
My understanding so far is that this occurs because this fails (and calls the exception);
try:
from cs231n.im2col_cython import col2im_cython, im2col_cython
from cs231n.im2col_cython import col2im_6d_cython
except ImportError:
print 'run the following from the cs231n directory and try again:'
print 'python setup.py build_ext --inplace'
print 'You may also need to restart your iPython kernel'
I've tried to figure out why this may be the case. First off I have to run setup.py to turn im2col_cython.pyx into other files. This seems to run but does at one point have the warning;
warning: extension name 'im2col_cython' does not match fully qualified name 'cs231n.im2col_cython' of 'im2col_cython.pyx'
My figuring here is that it's an issue to do with the fact that the folder tree I have looks like this;
Assignment 2
->cs231n
Inside cs231n is where the setup.py and im2col_cython.pyx files are located. I've installed cython, and I have vc for python2.7 installed. When I run setup.py is creates 2 new files;
im2col_cython.c
im2col_cython.pyd
But I have no idea if that's what it's meant to do or anything. I'm in way over my head with this (0 Python knowledge), but I'm keen to learn!
EDIT 1
The script that imports im2col_cython is here
The im2col_cython file is here
EDIT 2
When including the following in the exception clause;
import traceback; traceback.print_exc()
I get this output;
Traceback (most recent call last):
File "fast_layers.py", line 3, in <module>
from cs231n.im2col_cython import col2im_cython, im2col_cython
ImportError: No module named cs231n.im2col_cython
Add this in the file fast_layer.py before import cs231n.im2col_cython:
import pyximport
pyximport.install()
The problem you mentioned should be fixed.

Import python package after installing it with setup.py, without restarting?

I have a package that I would like to automatically install and use from within my own Python script.
Right now I have this:
>>> # ... code for downloading and un-targzing
>>> from subprocess import call
>>> call(['python', 'setup.py', 'install'])
>>> from <package> import <name>
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: No module named <package>
Then I can continue like this:
>>> exit()
$ python
>>> from <package> import <name>
And it works just fine. For some reason, Python is able to pick up the package just fine if I restart after running the setup.py file, but not if I don't. How can I make it work without having the restart step in the middle?
(Also, is there a superior alternative to using subprocess.call() to run setup.py within a python script? Seems silly to spawn a whole new Python interpreter from within one, but I don't know how else to pass that install argument.)
Depending on your Python version, you want to look into imp or importlib.
e.g. for Python 3, you can do:
from importlib.machinery import SourceFileLoader
directory_name = # os.path to module
# where __init__.py is the module entry point
s = SourceFileloader(directory_name, __init__.py).load_module()
or, if you're feeling brave that your Python path knows about the directory:
map(__import__, 'new_package_name')
Hope this helps,
I downloaded from seaborn from GitHub.
Through command prompt, cd to downloads\seaborn folder
python install setup.py
Then using spyder from anaconda, checked if it was installed by running the following in a console
import pip
sorted(["%s==%s" % (i.key, i.version)
for i in pip.get_installed_distributions()])
Seeing that it was not there, go to tools and select "Update module names list"
Again trying the previous code in a python console, the lib was still not showing.
Restarting Spyder and trying import seaborn worked.
Hope this helps.

Installed package stealing namespace

I'm developing a package "jw.data" in Python 2.7.9, with a namespace of jw and a package data in in. I have put the canonical
try:
__import__('pkg_resources').declare_namespace(__name__)
except ImportError:
from pkgutil import extend_path
__path__ = extend_path(__path__, __name__)
in jw/__init__.py. When I run ./setup.py develop (in setup.py I have put namespace_packages=['jw']), then I have "jw" in jw.data.egg-info/namespace_packages.txt. Doing a
import jw.data
import jw.data.model
just works fine. So I guess I have set up the namespace package correctly.
Now I have written a package "jw.util", also in namespace jw, with a package util in it. As soon as I install it, importing jw.data or anything below it fails:
>>> import jw.data
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: No module named data
After uninstalling jw.util it works again.
I used jw.util elsewhere, but not yet in a package within the jw namespace. It looks like jw.util is reserving the jw namespace.
I had the same problem with another namespace. There I noticed the package name in setup.py is just the same as the namespace plus package. I renamed all the packages from "namespace.packagex" to "namespace-packagex", and astonishingly enough it worked. I tried the same with jw.util and jw.data, but here that trick doesn't work. And I don't really believe the package name in setup.py has anything to do with the package hierarchy it contains, or has it?
Anyway, anybody got an idea what's going on here?
Seems to be a long-known bug in Python.
But there's a solution in https://github.com/pypa/setuptools/issues/250:
Put simply, append
;import pkg_resources; pkg_resources.fixup_namespace_packages('')
to the single line in module-nspkg.pth of the competing package in site-packages. The semicolon is required.

Check if Python Package is installed

What's a good way to check if a package is installed while within a Python script? I know it's easy from the interpreter, but I need to do it within a script.
I guess I could check if there's a directory on the system that's created during the installation, but I feel like there's a better way. I'm trying to make sure the Skype4Py package is installed, and if not I'll install it.
My ideas for accomplishing the check
check for a directory in the typical install path
try to import the package and if an exception is throw, then install package
If you mean a python script, just do something like this:
Python 3.3+ use sys.modules and find_spec:
import importlib.util
import sys
# For illustrative purposes.
name = 'itertools'
if name in sys.modules:
print(f"{name!r} already in sys.modules")
elif (spec := importlib.util.find_spec(name)) is not None:
# If you choose to perform the actual import ...
module = importlib.util.module_from_spec(spec)
sys.modules[name] = module
spec.loader.exec_module(module)
print(f"{name!r} has been imported")
else:
print(f"can't find the {name!r} module")
Python 3:
try:
import mymodule
except ImportError as e:
pass # module doesn't exist, deal with it.
Python 2:
try:
import mymodule
except ImportError, e:
pass # module doesn't exist, deal with it.
As of Python 3.3, you can use the find_spec() method
import importlib.util
# For illustrative purposes.
package_name = 'pandas'
spec = importlib.util.find_spec(package_name)
if spec is None:
print(package_name +" is not installed")
Updated answer
A better way of doing this is:
import subprocess
import sys
reqs = subprocess.check_output([sys.executable, '-m', 'pip', 'freeze'])
installed_packages = [r.decode().split('==')[0] for r in reqs.split()]
The result:
print(installed_packages)
[
"Django",
"six",
"requests",
]
Check if requests is installed:
if 'requests' in installed_packages:
# Do something
Why this way? Sometimes you have app name collisions. Importing from the app namespace doesn't give you the full picture of what's installed on the system.
Note, that proposed solution works:
When using pip to install from PyPI or from any other alternative source (like pip install http://some.site/package-name.zip or any other archive type).
When installing manually using python setup.py install.
When installing from system repositories, like sudo apt install python-requests.
Cases when it might not work:
When installing in development mode, like python setup.py develop.
When installing in development mode, like pip install -e /path/to/package/source/.
Old answer
A better way of doing this is:
import pip
installed_packages = pip.get_installed_distributions()
For pip>=10.x use:
from pip._internal.utils.misc import get_installed_distributions
Why this way? Sometimes you have app name collisions. Importing from the app namespace doesn't give you the full picture of what's installed on the system.
As a result, you get a list of pkg_resources.Distribution objects. See the following as an example:
print installed_packages
[
"Django 1.6.4 (/path-to-your-env/lib/python2.7/site-packages)",
"six 1.6.1 (/path-to-your-env/lib/python2.7/site-packages)",
"requests 2.5.0 (/path-to-your-env/lib/python2.7/site-packages)",
]
Make a list of it:
flat_installed_packages = [package.project_name for package in installed_packages]
[
"Django",
"six",
"requests",
]
Check if requests is installed:
if 'requests' in flat_installed_packages:
# Do something
If you want to have the check from the terminal, you can run
pip3 show package_name
and if nothing is returned, the package is not installed.
If perhaps you want to automate this check, so that for example you can install it if missing, you can have the following in your bash script:
pip3 show package_name 1>/dev/null #pip for Python 2
if [ $? == 0 ]; then
echo "Installed" #Replace with your actions
else
echo "Not Installed" #Replace with your actions, 'pip3 install --upgrade package_name' ?
fi
Open your command prompt type
pip3 list
As an extension of this answer:
For Python 2.*, pip show <package_name> will perform the same task.
For example pip show numpy will return the following or alike:
Name: numpy
Version: 1.11.1
Summary: NumPy: array processing for numbers, strings, records, and objects.
Home-page: http://www.numpy.org
Author: NumPy Developers
Author-email: numpy-discussion#scipy.org
License: BSD
Location: /home/***/anaconda2/lib/python2.7/site-packages
Requires:
Required-by: smop, pandas, tables, spectrum, seaborn, patsy, odo, numpy-stl, numba, nfft, netCDF4, MDAnalysis, matplotlib, h5py, GridDataFormats, dynd, datashape, Bottleneck, blaze, astropy
In the Terminal type
pip show some_package_name
Example
pip show matplotlib
You can use the pkg_resources module from setuptools. For example:
import pkg_resources
package_name = 'cool_package'
try:
cool_package_dist_info = pkg_resources.get_distribution(package_name)
except pkg_resources.DistributionNotFound:
print('{} not installed'.format(package_name))
else:
print(cool_package_dist_info)
Note that there is a difference between python module and a python package. A package can contain multiple modules and module's names might not match the package name.
if pip list | grep -q \^'PACKAGENAME\s'
# installed ...
else
# not installed ...
fi
You can use this:
class myError(exception):
pass # Or do some thing like this.
try:
import mymodule
except ImportError as e:
raise myError("error was occurred")
Method 1
to search weather a package exists or not use pip3 list command
#**pip3 list** will display all the packages and **grep** command will search for a particular package
pip3 list | grep your_package_name_here
Method 2
You can use ImportError
try:
import your_package_name
except ImportError as error:
print(error,':( not found')
Method 3
!pip install your_package_name
import your_package_name
...
...
I'd like to add some thoughts/findings of mine to this topic.
I'm writing a script that checks all requirements for a custom made program. There are many checks with python modules too.
There's a little issue with the
try:
import ..
except:
..
solution.
In my case one of the python modules called python-nmap, but you import it with import nmap and as you see the names mismatch. Therefore the test with the above solution returns a False result, and it also imports the module on hit, but maybe no need to use a lot of memory for a simple test/check.
I also found that
import pip
installed_packages = pip.get_installed_distributions()
installed_packages will have only the packages has been installed with pip.
On my system pip freeze returns over 40 python modules, while installed_packages has only 1, the one I installed manually (python-nmap).
Another solution below that I know it may not relevant to the question, but I think it's a good practice to keep the test function separate from the one that performs the install it might be useful for some.
The solution that worked for me. It based on this answer How to check if a python module exists without importing it
from imp import find_module
def checkPythonmod(mod):
try:
op = find_module(mod)
return True
except ImportError:
return False
NOTE: this solution can't find the module by the name python-nmap too, I have to use nmap instead (easy to live with) but in this case the module won't be loaded to the memory whatsoever.
I would like to comment to #ice.nicer reply but I cannot, so ...
My observations is that packages with dashes are saved with underscores, not only with dots as pointed out by #dwich comment
For example, you do pip3 install sphinx-rtd-theme, but:
importlib.util.find_spec(sphinx_rtd_theme) returns an Object
importlib.util.find_spec(sphinx-rtd-theme) returns None
importlib.util.find_spec(sphinx.rtd.theme) raises ModuleNotFoundError
Moreover, some names are totally changed.
For example, you do pip3 install pyyaml but it is saved simply as yaml
I am using python3.8
If you'd like your script to install missing packages and continue, you could do something like this (on example of 'krbV' module in 'python-krbV' package):
import pip
import sys
for m, pkg in [('krbV', 'python-krbV')]:
try:
setattr(sys.modules[__name__], m, __import__(m))
except ImportError:
pip.main(['install', pkg])
setattr(sys.modules[__name__], m, __import__(m))
A quick way is to use python command line tool.
Simply type import <your module name>
You see an error if module is missing.
$ python
Python 2.7.6 (default, Jun 22 2015, 17:58:13)
>>> import sys
>>> import jocker
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: No module named jocker
$
Hmmm ... the closest I saw to a convenient answer was using the command line to try the import. But I prefer to even avoid that.
How about 'pip freeze | grep pkgname'? I tried it and it works well. It also shows you the version it has and whether it is installed under version control (install) or editable (develop).
I've always used pylibcheck to check if a lib is installed or not, simply download it by doing pip install pylibcheck and the could could be like this
import pylibcheck
if not pylibcheck.checkPackage("mypackage"):
#not installed
it also supports tuples and lists so you can check multiple packages and if they are installed or not
import pylibcheck
packages = ["package1", "package2", "package3"]
if pylibcheck.checkPackage(packages):
#not installed
you can also install libs with it if you want to do that, recommend you check the official pypi
The top voted solution which uses techniques like importlib.util.find_spec and sys.modules and catching import exceptions works for most packages but fails in some edge cases (such as the beautifulsoup package) where the package name used in imports is somewhat different (bs4 in this case) than the one used in setup file configuration. For these edge cases, this solution doesn't work unless you pass the package name used in imports instead of the one used in requirements.txt or pip installations.
For my use case, I needed to write a package checker that checks installed packages based on requirements.txt, so this solution didn't work. What I ended up using was subprocess.check to call the pip module explicitly to check for the package installation:
import subprocess
for pkg in packages:
try:
subprocess.check_output('py -m pip show ' + pkg)
except subprocess.CalledProcessError as ex:
not_found.append(pkg)
It's a bit slower than the other methods but more reliable and handles the edge cases.
Go option #2. If ImportError is thrown, then the package is not installed (or not in sys.path).
Is there any chance to use the snippets given below? When I run this code, it returns "module pandas is not installed"
a = "pandas"
try:
import a
print("module ",a," is installed")
except ModuleNotFoundError:
print("module ",a," is not installed")
But when I run the code given below:
try:
import pandas
print("module is installed")
except ModuleNotFoundError:
print("module is not installed")
It returns "module pandas is installed".
What is the difference between them?

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