teoliphant / depsolver Goto Github PK

This is a prototype for a decent dependency solver for python.

Example:

# Simple scenario: nothing installed, install numpy, 2 versions available
# in the repository
from depsolver import Package, Pool, Repository, Requirement, Solver

numpy_1_6_1 = Package.from_string("numpy-1.6.1")
numpy_1_7_0 = Package.from_string("numpy-1.7.0")

repo = Repository([numpy_1_6_1, numpy_1_7_0])

pool = Pool([repo])

installed_repo = Repository()

# only one operation here: install numpy 1.7.0 (most recent available
# version)
requirement = Requirement.from_string("numpy")
operations = Solver(pool, installed_repo).solve(requirement)

More complex scenarios are also supported, e.g.:

• direct dependencies, obviously (if A depends on B, B is installed first)
• packages can provide other packages
• does not update already installed packages if they satisfy the requirements

Many more are not yet supported:

• declaring conflicts and obsoletes
• real policies that can be customized
• support for update
• version pinning
• repositories that are not in-memory (e.g. remote ones)

Depsolver main planned features are:

• version based on semantic versions RFC (version 2.0.0-rc1 at this time)
• handles dependency in a sane way
• pluggable back-end for metadata storage
• reasonable fast: resolving dependencies should not take too long (not more than a few seconds for a user who has only a few tens of packages currently installed)
• well tested and documented

The design is strongly inspired from PHP Composer packager, itself started as a port of libsolver.

Thanks to Enthought to let me open source this project !