resolvelib_dependency_resolver_with_custom_provider_and_reporter.py

1import resolvelib
2
3# Implement the Provider interface
4class Provider:
5    def identify(self, requirement_or_candidate):
6        return requirement_or_candidate
7
8    def get_preference(self, identifier, resolutions, candidates, information, backtrack_causes):
9        return 0
10
11    def find_matches(self, identifier, requirements, incompatibilities):
12        # In a real app, you'd look up candidates in a database or index.
13        # This example just returns the identifier itself as the candidate.
14        return [identifier]
15
16    def is_satisfied_by(self, requirement, candidate):
17        return requirement == candidate
18
19    def get_dependencies(self, candidate):
20        # Define dependencies for each "package"
21        dependencies = {
22            "A": ["B", "C"],
23            "B": ["D"],
24            "C": ["D"],
25            "D": [],
26        }
27        return dependencies.get(candidate, [])
28
29# Create a Reporter (optional, can be empty)
30class Reporter(resolvelib.BaseReporter):
31    pass
32
33# Main execution
34if __name__ == "__main__":
35    provider = Provider()
36    reporter = Reporter()
37    resolver = resolvelib.Resolver(provider, reporter)
38
39    # Resolve dependencies for "A"
40    requirements = ["A"]
41    try:
42        result = resolver.resolve(requirements)
43        print("Resolution successful:")
44        for name, candidate in result.mapping.items():
45            print(f"  {name} -> {candidate}")
46    except resolvelib.ResolutionError as e:
47        print(f"Resolution failed: {e}")