Category Archives: Uncategorized

Issue w/ pipenv python versions after upgrading asdf’s python

I recently upgraded from python 3.9.12 to 3.9.14 using asdf, and it was pretty simple:

sudo apt-get install liblzma-dev
asdf install python 3.9.14
asdf global python 3.9.14

But when I tried to run my pipenv, it didn’t work as planned

pipenv shell
No preset version installed for command pipenv
Please install a version by running one of the following:

asdf install python 3.9.14

or add one of the following versions in your config file at /home/mark/.tool-versions
python 3.9.12

After a lot of failed attemps to use asdf reshim and asdf update, I finally remembered the magic steps to use:

python -m pip install --upgrade pip
pip install pipenv

asdf update
asdf reshim python 3.9.14   # or whatever newest version is

pipenv install
pipenv shell
pipenv update   # To actually install what was in Pipfile

The last trick that I needed to do was make sure that my .env gets read so that any Python environment variables I set are correctly read in.

vi ~/.local/share/virtualenvs/hostname-RANDOM/bin/activate

And add these 2 lines starting at line 4 of the activate script:

# Use this sequence to load up the environnment variables from your .env file in a Bash console:
#
set -a; source /home/mark/home/aei/aeicloud.22/.env; set +a

Ubuntu 22 LTS on WSL / asdf / python / django

I’ll be using asdf to help control what version of Python I’m running.

I like pipenv to help manage my Python virtual environments.

I like to use PostgreSQL with Django, so lets’ first make sure that it’s installed:

sudo apt install postgresql 
sudo apt install libpq-dev

# make sure it's running
# You should see it listening to lots of ports
ss -nlt

asdf

git clone https://github.com/asdf-vm/asdf.git ~/.asdf --branch v0.10.0

# modify .bashrc files, exit terminal and restart terminal
sudo apt-get update
sudo apt-get upgrade

# install packages necessary to build stuff
sudo apt install wget build-essential libreadline-dev libncursesw5-dev libssl-dev libsqlite3-dev tk-dev libgdbm-dev libc6-dev libbz2-dev libffi-dev zlib1g-dev liblzma-dev
asdf install python 3.9.12
asdf global python 3.9.12

If the correct version of Python isn’t detected, you might need to reshim.

python -m pip install --upgrade pip
pip install pipenv

asdf update
asdf reshim python 3.9.12

pipenv install

[pipenv.exceptions.ResolutionFailure]: Warning: Your dependencies could not be resolved. You likely have a mismatch in your sub-dependencies.
You can use $ pipenv install –skip-lock to bypass this mechanism, then run $ pipenv graph to inspect the situation.
Hint: try $ pipenv lock –pre if it is a pre-release dependency.
ERROR: metadata generation failed

Turned out the above error, was because I didn’t have postgres installed on the new box (and my django uses postgres)

 Error: pg_config executable not found.

I got much futher along

# how to know things are almost all the way there
./manage.py shell
python manage.py dbshell

# If you didn't setup your postgres, you'll get an error like:
# python manage.py dbshell
# psql: error: connection to server at "127.0.0.1", port 5432 failed: Connection refused
#         Is the server running on that host and accepting TCP/IP connections?

You’ll need to start the server:

sudo service postgresql start

Then try

python manage.py dbshell
psql: error: connection to server at "127.0.0.1", port 5432 failed: FATAL:  password authentication failed for user "abcuser"
connection to server at "127.0.0.1", port 5432 failed: FATAL:  password authentication failed for user "abcuser"

The user and database don’t appear to exist — so let’s create them:

sudo su - postgres
# skipping the lines as you login as user postgres


psql
# now you are in the postgres shell

CREATE DATABASE abcdb;
CREATE USER abcuser WITH PASSWORD 'abc123';

\q     # that exists the postgres shell

exit   # that logs out the postgres user

You should now be able to init the DB

python manage.py migrate
python manage.py createsuperuser

# then run any bootstrapping that you need to
# python manage.py loaddata  xyz.json
# needed for pango and weasyprint (creating PDFs)
sudo apt-get install libpangocairo-1.0-0

Now, to get django working in VSCode

  1. install the Python extension for Visual Studio Code
  2. Press F1, then choose Python: Select Interpreter and make sure you are pointing to your correct venv
  3. Press the Run and Debug Icon

WSL2 – Adding distro not in store

What if you wanted to add an older linux distro to your WSL2 bullpen? Visiting https://docs.microsoft.com/en-us/windows/wsl/install-manual#installing-your-distro will show you a large number of options where you can download the appropriate .appx file.

This will cause the <distro>.appx packages to download to a folder of your choosing. Follow the installation instructions to install your downloaded distro(s).

If you’re using Windows 10 you can install your distro with PowerShell. Simply navigate to folder containing the distro downloaded from above, and in that directory run the following command where app_name is the name of your distro .appx file.PowershellCopy

Add-AppxPackage .\app_name.appx

If that doesn’t work as expected, you could try any of these links that will get the distro from the Microsoft Store

he following links will open the Microsoft store page for each distribution:

Generating requirements.txt from Pipfile.lock

I have been using pipenv to help me manage my python virtual environments.

I also use Heroku for some of my sites…and Heroku relies on the requirements.txt file rather than Pipfile/Pipfile.lock that pipenv uses.

Here is an easy way to generate a requirements.txt file from a Pipfile.lock

jq -r '.default
| to_entries[]
| .key + .value.version' \
Pipfile.lock > requirements.txt

NOTE: You will need the program ‘jq‘ (like sed for JSON data) installed, which can be done via:

sudo apt install jq

I believe that I learned about this method inside the issues tracker for pipenv on GitHub.

Adding django via pipenv

Pip environments with python and django have evolved over the years, but once constant has remained: virtual environments to run the code and packages in. The latest consensus is to use pipenv to keep things separated. Let’s see how.

First, I’ll assume that you already have python 3.7 installed. If you need help, check out this other post I wrote: https://markcerv.com/2019/03/adding-python-3-7-to-ubuntu-18-x/

Next:

sudo apt install python-pip
sudo pip install pipenv

pipenv --python 3.7 install django

In order to use pipenv, you will need to cd to the directory where you want to put your code, and then:

cd  somename
pipenv --python 3.7 install django django-cors-headers \
         djangorestframework pytz
# a bunch of things will happen, including that a virtualenv
# will get get created like:
# ~/.local/share/virtualenvs/somename-oYSXMPkF

# to actually fire up the environment
pipenv shell

Next, you’ll need to setup a minimum of files to get django going. :

django-admin startproject test2

cd test2

python manage.py migrate     #will setup the needed database stuff
python manage.py createsuperuser    # lets you make a u/p for login

./manage.py  runserver  0.0.0.0:8000

You can now jump over to a browser, and visit http://127.0.0.1:8000/admin/ and sign in to your app. It’s pretty boring right now, but you can fix that.

Adding python 3.7 to ubuntu 18.x

If you quickly want to get the latest version of Python installed on Ubuntu and get future updates automatically, then you can install it from the below third-party PPA repository…

To do that, run the commands below to add the PPA.

First install Ubuntu software properties package if it’s not already installed on your system..

sudo apt update
sudo apt install software-properties-common

After that run the commands to add the PPA..

 sudo add-apt-repository ppa:deadsnakes/ppa 

Finally, run the commands below to install Python 3.7

sudo apt update
sudo apt install python3.7

That’s it!


Brother HL3140CW Printer – Reset ‘out of toner’ message

How to reset the fake “out of toner message” and instantly make the printer work again:

1. Open the top lid of the printer and leave it open.
2. Press and hold the “Secure” and “X Cancel” buttons at the same time.
3. Use the arrow keys to select the cartridge model you would like to reset and press “OK”.
4. Press the UP arrow to reset the cartridge.

Once reset is selected you will see “ACCEPTED” on the screen.

Reset them all by scrolling through the various colors on the menu.

5. Close the top lid. It will make a bunch of noise for a minute or so, then it will print like new again.

Now the printer thinks you installed brand new toner cartridges, and you will get double or more the amount of printed pages from the same old “out” toner. When you notice the quality of the printouts degrading, THEN its time to replace the toner. Not before. While you are waiting for your new toner to arrive, take the old one out and shake it- prints will look new again for a short period of time. Buy toner when you are out, not when the machine tries to tell you what to do.

Moving over VirtualBox/Vagrant the hard way

There is a right way to move/copy over a VirtualBox to a new computer/colleague/etc.

And then there is the hard way.  What is the hard way?  The hard way is when you need to manually copy over .vbx and .box files and edit .xml files. 

Step 1 – Copy files over from the old drive.

Copy over the directory that contains the .vagrant folder. The way I have my environment it’s “c:\home\blah”.  I do by having 2 windows explorer windows open, and dragging and right-clicking on the destination folder, then clicking “Copy here” or “TerraCopy here.”

Take note of the value of c:\home\blah\.vagrant\machines\default\virtualboxes\id

067c8f42-0e93-4825-a02a-8ecf3a6586d3

Next, copy over the c:\Users\YOURNAME\VirtualBox VMs\xxx folder that corresponds/correlates to your Vagrant box.

Then, double click on the .vbox file in the directory you just copied over. This should automatically import it into VirtualBox.

Finally, open up c:\Users\YOURNAME\.VirtualBox\VirtualBox.xml and check that the uuid matches.

      <MachineEntry uuid="{aaaaaaa-bbbb-cccc-dddd-eeeeeeeeee}" src="C:/Users/YOURNAME/VirtualBox VMs/xxx/xxx.vbox"/>
    </MachineRegistry

Fire up your cmd prompt, switch to the c:\home\xxx\ directory and

vagrant up

Celebrate!