The challenges of using PIP on z/OS.

Using Python PIP on z/OS, was not as smooth as I had expected. Some problems I worked around, some I just had to live with.

PIP is the standard package installer for Python. It is documented here.

To get information about PIP.

The following command gives lots of data about PIP.

python3 -m pip debug –verbose

Valid wheel types

“Wheels” are used to create and install Python packages; see here.

For example what are the names of valid “wheel types on my system” (needed when creating a package). Amongst the data this gave, was

Compatible tags: 30
py3-none-any
py37-none-any

This means PIP install will accept a package with

pymqi-1.12.0-py3-none-any.whl

A package like pymqi-1.12.0-py3-none-zos.whl is not in the list and will not install.

Configuration parameters

python3 -m pip debug –verbose

Configuration data is stored in several places

global:
  /etc/xdg/pip/pip.conf
  /etc/pip.conf
site:
  /usr/lpp/IBM/cyp/v3r8/pyz/pip.conf
user:
  $HOME/.pip/pip.conf
  $HOME/.config/pip/pip.conf

The documentation said $VIRTUAL_ENV/pip.conf will be used. $VIRTUAL_ENV was set on my system, but did not show up in the list.

Initially my $HOME was /u, and this caused problems as my userid was not authorised to write to /u/.pip…

Check your $HOME is set to an appropriate value.

Show the configuration files: python3 -m pip config debug

env_var:                                                                   
env
global:                                                      
  /etc/xdg/pip/pip.conf, exists: False                       
  /etc/pip.conf, exists: False                               
site:                                                        
  /usr/lpp/IBM/cyp/v3r8/pyz/pip.conf, exists: False          
user:                                                        
  /u/tmp/pymqi2/.pip/pip.conf, exists: False                 
  /u/tmp/pymqi2/.config/pip/pip.conf, exists: False          

python3 -m pip config list

gave me

[33]WARNING: The directory ‘/u/.cache/pip’ or its parent directory is not owned or is not writable by the current user. The cache has been disabled. Check the permissions and owner of that directory. If executing pip with sudo, you may want sudo’s -H flag.-[0]

because HOME was not pointing to a value writeable directory.

Updating configuration:

Once I had set HOME to a valid value, I could set configuration values.

  • python3 -m pip config –user set user.colin yes
  • python3 -m pip config –user set site.colin yes

gave me

Writing to /u/tmp/pymqi2/.config/pip/pip.conf

This file had

[site]
colin = yes

[user]
colin = yes

python3 -m pip config –global set user.colin yes

gave me ( as expected)

Writing to /etc/pip.conf
[31]ERROR: Unable to save configuration. Please report this as a bug.
PermissionError: [Errno 111] EDC5111I Permission denied.: ‘/etc/pip.conf’

I would need use a suitably authorised userid to do this.

To edit a config file

You need to specify the editor to use

python3 -m pip config –user –editor /bin/oedit edit

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