$ show conan-io/conan
Conan is a decentralized C/C++ package manager shipped as a Python CLI and programmatic API. The code implements the complete package lifecycle: recipe authors define ConanFile classes, the CLI exports recipes, resolves dependency graphs from a local SQLite-backed cache and remote repositories, computes platform-specific package IDs, and installs prebuilt binaries or builds from source. It also contains a self-hosted package server (conans/server) with a Bottle-based REST API v2, authentication plugins, revision tracking, and file upload/download endpoints, though the primary product is the client tooling used by C/C++ developers and CI systems. Architecture is layered and modular. The CLI layer (conan/cli) uses a decorator-based command framework and delegates to a ConanAPI facade (conan/api) that orchestrates internal subsystems: graph resolution and lockfiles (conan/internal/graph), cache persistence (SQLite in conan/internal/cache/db), REST client and remote management (conan/internal/rest), recipe hooks and lifecycle methods (conan/internal/methods.py), and a broad set of build-system generators and toolchains under conan/tools covering CMake, Meson, MSBuild, Autotools, Bazel, Xcode, Qbs, Premake, SCons, and others. The main entry points are conans/conan.py:run for the CLI and conans/conan_server.py for the server. Data flows center on recipes and binary packages: export sources -> compute recipe revision, resolve requirement version ranges -> build dependency graph, compute package IDs from settings/options/conf, query local cache and remotes for binaries, then download/install or build/package as needed. Lockfiles pin revisions for reproducibility, profiles and per-package confs influence generated build-system files, and SBOM/audit features produce dependency metadata. The repository has an extensive three-tier test suite (unit, integration, functional) using in-process TestClient/TestServer harnesses and mocked network layers, plus platform-gated functional tests for real toolchains.
The LLM identified 6 files worth highlighting for reuse:
A self-contained, robust version model implementing parsing, comparison, bumping, and range matching with pre-release and build-metadata handling. It powers Conan's requirement version ranges and lockfiles but is written as a standalone utility that could be extracted for any Python project needing strict semver-like version semantics.
Implements a content-addressed download cache with inter-process and thread-safe file locking, dirty-file markers, and atomic writes. It solves recurring problems around concurrent cache access and corrupted partial downloads, and the pattern is directly reusable in other Python tools that need resilient local caching of remote files.
A generic SQLite table abstraction that handles schema creation, row-to-namedtuple mapping, per-file locking, timeouts, and CRUD operations without embedding business logic. It separates the cache database plumbing from Conan-specific recipe/package tables, making it a clean reusable data-access foundation for any small embedded SQLite storage need.
A wrapper around patch_ng that applies patches from strings, files, or conandata.yml definitions, with logging, error context, and support for extra patch directories. It is a well-isolated file-operation helper that any project needing deterministic source-tree patching could extract and reuse.
A cross-platform Environment model that accumulates variable assignments, appends/prepends/unset operations, and renders activation scripts for Windows (.bat), Unix (.sh), and PowerShell. It abstracts away shell-specific quoting and activation semantics, making it reusable for any tool that needs to generate environment setup scripts for multiple platforms.
A decorator-based CLI framework that builds argparse parsers from command docstrings, supports nested subcommands, and dispatches to pluggable output formatters (text, json, html). It demonstrates a clean separation between command definition, argument parsing, and presentation, and could be lifted into a standalone Python CLI library.