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"bin/bash: python: command not found" returned when running docker image

Here is the docker run output:
hausey#ubuntu:~/niso2-jxj934$ docker run niso2-jxj934
Test version: 15:59, Mar 24th 2020
Question 1: Evaluation of expression.
Command failed: /bin/bash -c "python /bin/jxj934.py -question 1 -expr \"(ifleq (ifleq -1.11298616747 1.63619642199 (sub -1.11298616747 -1.11298616747) 1.7699684348) (add (exp -0.822479932786) 1.39992604386) (add -1.11298616747 (exp 0.385042309638)) 0.205973267133)\" -n 10 -x \"-0.168958230447 -0.131749160548 0.0971246476126 1.8706205565 -0.464122426299 2.35887369763 -0.375948313434 -0.613901105864 0.411326743135 -0.149276696072\"" Exit status: exited with code 127 stderr: /bin/bash: python: command not found
Here is the Dockerfile:
FROM pklehre/niso2020-lab2-msc
ADD jxj934.py /bin
CMD ["-username","jxj934", "-submission", "python /bin/jxj934.py"]
Here is check for python:
hausey#ubuntu:~/niso2-jxj934$ which python
/usr/bin/python
Is that related to the PATH of python?

Usually, it is related to the value of PATH but, specifically, that image only has python3. In other words, looking through the filesystem with
find / -name -type f "python*"
Look for regular files named "python*" in /
There were only python3 results.
...
/usr/bin/python3.8
/usr/bin/python3.7
...
A quick solution is to specify python3 in your CMD line (python3 /bin/jxj934.py). Another is to add a soft link (ln -s /usr/bin/python /usr/bin/python3.8). The best solution is to solve it using the package manager. Then again, that depends if you're in control of the Dockerfile + image.
When you queried which python, you did so on your local machine. The container runs in a different filesystem namespace than yours and with a completely different terminal. The container will behave differently than your machine and any such investigations will yield relevant results only when run within the container.
A little unrelated to your question but it might serve you.
docker run has a --entrypoint option that allows you to override the image's entrypoint. You can ask for bash and explore the container.
docker run --it --entrypoint=bash pklehre/niso2020-lab2-msc
Note that bash has to be in the $PATH.

uWSGI will not run in mixed Python environment in order to operate correctly with nginx and run Django app

Environment: Ubuntu 16.04 (with system Python at 2.7.12) running in Vagrant/Virtualbox on Windows 10 host
Python Setup: System python verified by doing python -V with no virtualenv's activated. Python 3.5 is also installed, and I've done pipenv --three to create the virtualenv for this project. Doing python -V within the activated virtualenv (pipenv shell to activate) shows Python 3.5.2.
Additional Background: I'm developing a Wagtail 2 app. Wagtail 2 requires Django 2 which, of course, requires Python 3. I have other Django apps on this machine that were developed in Django 1.11/Python 2.7 and are served by Apache. We are moving to Django 2/Python 3 for development going forward and are moving to nginx/uWSGI for serving the apps.
I have gone through many tutorials/many iterations. All Vagrant port mapping is set up fine with nginx serving media/static files and passing requests upstream to the Django app on a unix socket, but this is giving a 502 Gateway not found error because uWSGI will not run correctly. Therefore, right now I'm simply running the following from the command line to try to get uWSGI to run: uwsgi --ini /etc/uwsgi/sites/my_site.com.ini. This file contains:
[uwsgi]
uid = www-data
gid = www-data
plugin = python35
# Django-related settings
# the base directory (full path)
chdir=/var/sites/my_site
# Django's wsgi file
wsgi-file = my_site.wsgi
# the virtualenv (full path)
virtualenv=/root/.local/share/virtualenvs/my_site-gmmiTMID
# process-related settings
# master
master = True
# maximum number of worker processes
processes = 10
# the socket (use the full path to be safe)
socket = /tmp/my_site.sock
# clear environment on exit
vacuum = True
I've tried installing uWSGI in the following ways:
system-wide with pip install uwsgi as well as pip3 install uwsgi
using apt-get install uwsgi uwsgi-plugin-python3
I've ensured that only one install is in place at a time by uninstalling any previous uwsgi installs. The latter install method places uwsgi-core in usr/bin and also places in usr/bin shortcuts to uwsgi, uwsgi_python3, and uwsgi_python35.
In the .ini file I've also tried plugin = python3. I've also tried from the command line:
uwsgi_python3 --ini /etc/uwsgi/sites/my_site.com.ini
uwsgi_python35 --ini /etc/uwsgi/sites/my_site.com.ini
I've tried executing the uwsgi ... .ini commands from both within the activated virtual environment and with the virtualenv deactivated. Each of the three command line uwsgi ... .ini executions (uwsgi ..., uwsgi_python3 ... and uwsgi_python35 ...) DO cause the .ini file to be executed, but each time I'm getting the following error (the last two lines of the following statements):
[uwsgi] implicit plugin requested python35
[uWSGI] getting INI configuration from /etc/uwsgi/sites/my_site.com.ini
*** Starting uWSGI 2.0.12-debian (64bit) on [Wed Mar 7 03:54:44 2018] ***
compiled with version: 5.4.0 20160609 on 31 August 2017 21:02:04
os: Linux-4.4.0-116-generic #140-Ubuntu SMP Mon Feb 12 21:23:04 UTC 2018
nodename: vagrant-ubuntu-trusty-64
machine: x86_64
clock source: unix
pcre jit disabled
detected number of CPU cores: 2
current working directory: /vagrant/my_site
detected binary path: /usr/bin/uwsgi-core
setgid() to 33
setuid() to 33
chdir() to /var/sites/my_site
your processes number limit is 7743
your memory page size is 4096 bytes
detected max file descriptor number: 1024
lock engine: pthread robust mutexes
thunder lock: disabled (you can enable it with --thunder-lock)
uwsgi socket 0 bound to UNIX address /tmp/my_site.sock fd 3
Python version: 3.5.2 (default, Nov 23 2017, 16:37:01) [GCC 5.4.0 20160609]
Set PythonHome to /root/.local/share/virtualenvs/my_site-gmmiTMID
Fatal Python error: Py_Initialize: Unable to get the locale encoding
ImportError: No module named 'encodings'
If I go into the Python command line within the activated virtualenv and do import encodings, it imports fine (no message - just comes back to command line). A search for this particular error has turned up nothing of use. Any idea why the ImportError: No module named 'encodings' is coming up?
UPDATE - PROBLEM STILL OCCURRING
I'm using pipenv, and it stores individual virtualenvs in the /home/username/.local/share/virtualenvs folder. Though I was able to start uWSGI from the command line by executing the uWSGI config file as the vagrant user (see comment below), I have still not been able start the service with /home/vagrant/.local/share/virtualenvs/my_venv in the uWSGI config file. I tried adding the vagrant user to the www-data group and adding the www-data user to the vagrant group. I also put both read and execute permission for the world on the whole path (including the individual venv), but the uWSGI service will still not start.
A HACKISH WORKAROUND
I did finally get the uWSGI service to start by copying the venv to /opt/virtualenvs/my_venv. I was then able to start the service with sudo service uwsgi start. Ownership of that whole path is root:root.
STILL LOOKING FOR A SOLUTION...
This solution is not optimal since I am now executing from a virtualenv that will have to be updated when the default virtualenv is updated since this location is not the default for pipenv, so I'm still looking for answers. Perhaps it is a Ubuntu permissions error, but I just can't find the problem.

It might be the problem with your virtual environment. Try the following
rm -rf /root/.local/share/virtualenvs/my_site-gmmiTMID
virtualenv -p python3 /root/.local/share/virtualenvs/my_site-gmmiTMID
source /root/.local/share/virtualenvs/my_site-gmmiTMID/bin/activate
pip install -r requirements.txt
and in uwsgi conf try to change
virtualenv=/root/.local/share/virtualenvs/my_site-gmmiTMID
to
home=/root/.local/share/virtualenvs/my_site-gmmiTMID
Reference:
http://uwsgi-docs.readthedocs.io/en/latest/Options.html#virtualenv

python: command not found error

Someone messed up symbolic links on redhat server and I can't use python now, I tried a lot of things. When I try to run python I get python: command not found.
I have this information:
alternatives --display python
python - status is auto.
link currently points to /usr/bin/python2.4
/usr/bin/python2.4 - priority 1
Current `best' version is /usr/bin/python2.4.
When I try to change ln -sf /usr/bin/python /usr/bin/python2.4 I get the following:
ln: accessing `/usr/bin/python2.4': Too many levels of symbolic links
When I remove /usr/bin/python it doesn't help as well.
I also cheched it with these commands:
readlink /usr/bin/python
/etc/alternatives/python
readlink /usr/bin/python2.4
/usr/bin/python
readlink python
/usr/bin/python
It looks like everything should work fine. Any suggestions?

I think you have the ln command backwards. The reason you are getting this error is because you are creating a link python2.4 that points to python, but python is a link pointing to python2.4. Reverse your source and destination in the ln command and it should work.
I've never used alternatives, but you probably shouldn't be manually editing these symlinks.
Edit:
As I mentioned in my comment, you may have overwritten the original python binary. On a RHEL5 system I have access to here's what the /usr/bin directory looks like:
$ ls -l /usr/bin/python*
-rwxr-xr-x 2 root root 8304 Oct 23 2012 /usr/bin/python
lrwxrwxrwx 1 root root 6 Jan 11 2013 /usr/bin/python2 -> python
-rwxr-xr-x 2 root root 8304 Oct 23 2012 /usr/bin/python2.4
And if you look at the inodes of the two non-symlink files you'll see that they are the same file:
$ stat -c %i /usr/bin/python
3290164
$ stat -c %i /usr/bin/python2.4
3290164
So you need to find the original python binary then we can figure out how to link them the original way. And again, I've never used alternatives so maybe it does some magic of moving the binaries around, but I doubt it.

How to setup the same Django Virtual Environemnt in two computers?

currently I need to setup a production Django app in my computer and I would like to know what's the best way to do it? The production server uses virtualenv and I executed the following commands to get some info about the environment. Thanks
$ uname -a
Linux domU-12-31-39-0C-75-E2 2.6.34.7-56.40.amzn1.x86_64 #1 SMP Fri Oct 22 18:48:49 UTC 2010 x86_64 x86_64 x86_64 GNU/Linux
$ pwd
/home/ec2-user/virtenvs/django-1.2.5/
$ ./pip freeze
Cheetah==2.4.1
Django==1.2.5
M2Crypto==0.20.2
Markdown==2.0.1
MySQL-python==1.2.3
PIL==1.1.7
PyYAML==3.05
Pygments==1.1.1
South==0.7.3
boto==2.0b4
cloud-init==0.5.15
configobj==4.6.0
distribute==0.6.10
django-classy-tags==0.3.3
django-cms==2.1.3
django-haystack==1.1.0
django-tinymce==1.5.1a1
iniparse==0.3.1
policycoreutils-default-encoding==0.1
pycurl==7.19.0
pygeoip==0.1.5
pygpgme==0.1
pysolr==2.0.13
pysqlite==2.6.0
python-Levenshtein==0.10.2
pytz==2011c
pywurfl==7.2.1
setools==1.0
urlgrabber==3.9.1
virtualenv==1.5.1
yum-metadata-parser==1.1.2

You should be able to do this on the current server:
pip freeze -l > requirements.txt
Then this on other machines:
pip install -r requirements.txt
There are related pip docs online which describe the functionality.

If you want to have the code open-sourced and able to be developed with others/on other computers... You could use git or mercurial.
http://git-scm.com/ is the homepage for git,
https://github.com/ is the site for storing git repositories, allowing for "social" coding as they describe it, which is explained at...
http://gitready.com/, which teaches you how to use git.

Can you have more than one python in terminal?

I'm a bit confused with what is happening to run my django apps. When I use the command python manage.py runserver I don't get the appropriate response from the server. However, when I use python2.6 manage.py runserver the server actually runs.
Can someone help me with this confusion and also suggest to me how I can simplify this problem? Ideally I don't want different versions of python and only want to be able to type python manage.py runserver

Yes. It is fairly common. You can find out the location of an executable with which, and resolve symlinks with ls.
$ ls -l `which python`
lrwxrwxrwx 1 root root 9 Jul 13 18:50 /usr/bin/python -> python2.6
$ ls -l `which python3`
lrwxrwxrwx 1 root root 9 Jul 27 22:24 /usr/bin/python3 -> python3.1
On Debian and some other systems, you may need to resolve multiple symlinks.
$ ls -l `which nc`
lrwxrwxrwx 1 root root 20 Oct 7 15:16 /bin/nc -> /etc/alternatives/nc
$ ls -l /etc/alternatives/nc
lrwxrwxrwx 1 root root 15 Oct 7 15:16 /etc/alternatives/nc -> /bin/nc.openbsd
If you want to only type python and get the version you want, make an alias. Add a line to your .bashrc file (or wherever you keep such lines):
alias python=python2.6
Note that this will not affect scripts: if you run "python" in a script, it will get the old version, not an alias. Aliases are only for interactive use.

Yes, it is possible to have two versions of python. The easiest way I've found to make python execute python2.6 (without breaking the other version for anyone else) is by using an alias. To do this, simply edit the following and add it to your ~/.profile file:
alias python=/path/to/your/python2.6
Log out and back in, and when you run python it should execute the correct binary. If you wish to revert back, simply delete this line from your ~/.profile.

Yes, you can have multiple versions of Python sitting side-by-side on your computer.
It sounds like python on your host is symbolically linked to a version other than python2.6. You can find out this version by running:
python --version
...or...
python -V
...if that does not work.
Setting the default Python version depends on how you installed Python in the first place.
For Mac OS X, see How can I change the default Python version on Snow Leopard?