Why is python setup.py saying invalid command 'bdist_wheel' on Travis CI?

If you already have all the required modules installed you probably need to import the setuptools module in your setup.py file. So just add the following line at the leading of setup.py file.

import setuptools
from distutils.core import setup
# other imports and setups

This is also mentioned in wheel's documentation. https://wheel.readthedocs.io/en/stable/#usage

On a AWS Ubuntu 18.04 new machine, below installations are required:

sudo apt-get install gcc libpq-dev -y
sudo apt-get install python-dev  python-pip -y
sudo apt-get install python3-dev python3-pip python3-venv python3-wheel -y
pip3 install wheel

Especially the last line is a must.
However before 3 lines might be required as prerequisites.

Had to install the wheel package. Everything was up to date but still giving the error.

pip install wheel

then

python setup.py bdist_wheel 

worked without issues.

pip install wheel

worked for me, but you can also add this

setup(
    ...
    setup_requires=['wheel']
)

to setup.py and save yourself a pip install command