McM Scripts

Repository for using McM scripts and example scripts

How to run this

Prerequisite

Create an isolated virtual environment using a Python version >= 3.9 via:

python3.9 -m venv venv && source ./venv/bin/activate

Development version

If you want to set up a development environment to contribute to this project:

Install poetry and the required dependencies.

pip install poetry && poetry install

Run the test suite via: poetry run pytest -s -vv

Important

Make sure your execution environment has a valid Kerberos ticket to consume CERN services!

Build package

If you just want to use this package in your own project, install it via:

pip install git+https://github.com/cms-PdmV/mcm_scripts.git

Make sure to remove the sys.path.append(...) statements to avoid overloading old versions from AFS.

Basic info

• Link to McM: https://cms-pdmv-prod.web.cern.ch/mcm/
• McM Rest API: https://cms-pdmv-prod.web.cern.ch/mcm/restapi
• Public APIs do not require SSO credentials. Index of public API: https://cms-pdmv-prod.web.cern.ch/mcm/public/restapi/

SSO credentials

McM supports two authentication mechanisms: Session cookies and ID tokens

Session cookies

• Use auth-get-sso-cookie command line tool to generate it:
  • auth-get-sso-cookie --url https://cms-pdmv-dev.web.cern.ch/mcm/ -o dev-cookie.txt
  • auth-get-sso-cookie --url https://cms-pdmv-prod.web.cern.ch/mcm/ -o prod-cookie.txt
• auth-get-sso-cookie is already available in lxplus nodes
• It expires after ~10 hours, so be sure to regenerate it
• Dev cookie is valid only for the development environment and the production cookie is valid only for the production environment
• This method doesn't work if 2FA is enabled. If you are using it, please use the following alternative instead of this package.

ID tokens

• Configure the McM SDK to request and send ID tokens to authenticate your actions. To achieve this, instantiate it like the following: McM(id='oidc')
• Instead of requesting a session cookie, this configuration will start an authentication flow using Device Authorization Grant to request an ID token. Therefore, it requires human intervention to complete the authentication flow using a browser.

If you want to know more details about how it works, check the code available in rest.py module and its unit tests rest_test.py

Priority change

• If you want to use priority-changing scripts or do anything else related to cmsweb, you'll have to use voms-proxy:
  • voms-proxy-init -voms cms
  • export X509_USER_PROXY=$(voms-proxy-info --path)