openstack/requirements
Code Issues Proposed changes
773b134b78
requirements/README.rst
Doug Hellmann 9fa26daf57 add build-lower-constraints command 
Add a command to merge lower constraints lists together, as a
precursor to removing the global lower-constraints.txt list in this
repository.

Change-Id: Ia238607b9feb292842971d0fc161ae6294150e1f
Signed-off-by: Doug Hellmann <doug@doughellmann.com>
2018-07-02 11:29:34 -04:00

4.1 KiB
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Global Requirements for OpenStack Projects

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Why Global Requirements?

Refer to the Dependency Management section of the Project Team Guide for information about the history of the project and the files involved.

Tools

All the tools require openstack_requirements to be installed (e.g. in a Python virtualenv). They all have help, which is the authoritative documentation.

update-requirements

This will update the requirements in a project from the global requirements file found in .. Alternatively, pass --source to use a different global requirements file:

update-requirements --source /opt/stack/requirements /opt/stack/nova

Entries in all requirements files will have their versions updated to match the entries listed in the global requirements. Excess entries will cause errors in hard mode (the default) or be ignored in soft mode.

generate-constraints

Compile a constraints file showing the versions resulting from installing all of global-requirements.txt:

generate-constraints -p /usr/bin/python2.7 -p /usr/bin/python3 \
  -b blacklist.txt -r global-requirements.txt > new-constraints.txt

edit-constraints

Replace all references to a package in a constraints file with a new specification. Used by DevStack to enable git installations of libraries that are normally constrained:

edit-constraints oslo.db "-e file://opt/stack/oslo.db#egg=oslo.db"

build-lower-constraints

Combine multiple lower-constraints.txt files to produce a list of the highest version of each package mentioned in the files. This can be used to produce the "highest minimum" for a global lower constraints list (a.k.a., the "TJ Maxx").

To use the script, run:

$ tox -e venv -- build-lower-constraints input1.txt input2.txt

Where the input files are lower-constraints.txt or requirements.txt files from one or more projects.

If the inputs are requirements files, a lower constraints list for the requirements is produced. If the inputs are lower-constraints.txt, the output includes the highest version of each package referenced in the files.

Proposing changes

Look at the Review Guidelines and make sure your change meets them.

All changes to global-requirements.txt may dramatically alter the contents of upper-constraints.txt due to adding or removing transitive dependencies. As such you should always generate a diff against the current merged constraints, otherwise your change may fail if it is incompatible with the current tested constraints.

A change to the minimum specified vesion of a library in global-requirements.txt currenty requires adjusting the lower-constraints.txt file alongside with the new constrainted coinstallable version of minimums.

Regenerating involves five steps.

  1. Install the dependencies needed to compile various Python packages:

    sudo apt-get install $(bindep -b)

  2. Create a reference file (do this without your patch applied):

    generate-constraints -p /usr/bin/python2.7 -p /usr/bin/python3 \
  -b blacklist.txt -r global-requirements.txt > baseline

  3. Apply your patch and generate a new reference file:

    generate-constraints -p /usr/bin/python2.7 -p /usr/bin/python3 \
  -b blacklist.txt -r global-requirements.txt > updated

  4. Diff them:

    diff -p baseline updated

  5. Apply the patch to upper-constraints.txt. This may require some fiddling. edit-constraint can do this for you when the change does not involve multiple lines for one package.

Resources