resolvelib_package_dependency_resolver_with_mock_database.py

1import pprint
2from resolvelib import Resolver
3
4# 1. Implement a Provider to define how to find candidates and dependencies.
5class Provider:
6    def identify(self, requirement_or_candidate):
7        return requirement_or_candidate[0]
8
9    def get_preference(self, identifier, resolutions, candidates, information, backtrack_causes):
10        return len(candidates[identifier])
11
12    def find_matches(self, identifier, requirements, inconsistencies):
13        # A mock package database: { name: [versions] }
14        data = {
15            "apple": ["1.0.0", "1.1.0"],
16            "banana": ["2.0.0"],
17        }
18        # A mock dependency database: { (name, version): [dependencies] }
19        deps = {
20            ("apple", "1.1.0"): [("banana", ">=2.0.0")],
21        }
22        for version in data.get(identifier, []):
23            # Check if version satisfies all requirements
24            if all(self.is_satisfied_by(req, (identifier, version)) for req in requirements[identifier]):
25                yield (identifier, version)
26
27    def is_satisfied_by(self, requirement, candidate):
28        name, spec = requirement
29        c_name, c_version = candidate
30        if name != c_name:
31            return False
32        if spec == ">=2.0.0" and c_version < "2.0.0":
33            return False
34        return True
35
36    def get_dependencies(self, candidate):
37        deps = {
38            ("apple", "1.1.0"): [("banana", ">=2.0.0")],
39        }
40        return deps.get(candidate, [])
41
42# 2. Implement a Reporter to monitor the resolution process.
43class Reporter:
44    pass
45
46# 3. Initialize and run the resolver.
47provider = Provider()
48reporter = Reporter()
49resolver = Resolver(provider, reporter)
50
51requirements = [("apple", ">=1.0.0")]
52result = resolver.resolve(requirements)
53
54pprint.pprint(result.mapping)