Modularized client for state management (#114)

Author: RulerOfCakes

micropip/_commands/install.py

@@ -130,7 +130,7 @@ async def install(
         index_urls = package_index.INDEX_URLS[:]
 
     transaction = Transaction(
-        ctx=ctx,
+        ctx=ctx,  # type: ignore[arg-type]
         ctx_extras=[],
         keep_going=keep_going,
         deps=deps,

micropip/package_manager.py

@@ -0,0 +1,72 @@
+from typing import (  # noqa: UP035 List import is necessary due to the `list` method
+    Any,
+    List,
+)
+
+from micropip import package_index
+
+
+class PackageManager:
+    """
+    PackageManager provides an extensible interface for customizing micropip's behavior.
+
+    Each Manager instance holds its own local state that is
+    independent of other instances.
+
+    TODO: Implement all of the following global commands to utilize local state.
+    """
+
+    def __init__(self) -> None:
+        self.index_urls = package_index.DEFAULT_INDEX_URLS
+
+        # TODO: initialize the compatibility layer
+        self.repodata_packages: dict[str, dict[str, Any]] = {}
+        self.repodata_info: dict[str, str] = {}
+
+        pass
+
+    def install(self):
+        raise NotImplementedError()
+
+    def list(self):
+        raise NotImplementedError()
+
+    def freeze(self):
+        raise NotImplementedError()
+
+    def add_mock_package(self):
+        raise NotImplementedError()
+
+    def list_mock_packages(self):
+        raise NotImplementedError()
+
+    def remove_mock_package(self):
+        raise NotImplementedError()
+
+    def uninstall(self):
+        raise NotImplementedError()
+
+    def set_index_urls(self, urls: List[str] | str):  # noqa: UP006
+        """
+        Set the index URLs to use when looking up packages.
+
+        - The index URL should support the
+            `JSON API <https://warehouse.pypa.io/api-reference/json/>`__ .
+
+        - The index URL may contain the placeholder {package_name} which will be
+            replaced with the package name when looking up a package. If it does not
+            contain the placeholder, the package name will be appended to the URL.
+
+        - If a list of URLs is provided, micropip will try each URL in order until
+            it finds a package. If no package is found, an error will be raised.
+
+        Parameters
+        ----------
+        urls
+            A list of URLs or a single URL to use as the package index.
+        """
+
+        if isinstance(urls, str):
+            urls = [urls]
+
+        self.index_urls = urls[:]

tests/test_package_manager.py

@@ -0,0 +1,29 @@
+import micropip.package_index as package_index
+from micropip.package_manager import PackageManager
+
+
+def test_package_manager() -> PackageManager:
+    package_manager = PackageManager()
+    assert package_manager.index_urls == package_index.DEFAULT_INDEX_URLS
+
+    return package_manager
+
+
+def test_set_index_urls():
+    manager = test_package_manager()
+
+    default_index_urls = package_index.DEFAULT_INDEX_URLS
+    assert manager.index_urls == default_index_urls
+
+    valid_url1 = "https://pkg-index.com/{package_name}/json/"
+    valid_url2 = "https://another-pkg-index.com/{package_name}"
+    valid_url3 = "https://another-pkg-index.com/simple/"
+    try:
+        manager.set_index_urls(valid_url1)
+        assert manager.index_urls == [valid_url1]
+
+        manager.set_index_urls([valid_url1, valid_url2, valid_url3])
+        assert manager.index_urls == [valid_url1, valid_url2, valid_url3]
+    finally:
+        manager.set_index_urls(default_index_urls)
+        assert manager.index_urls == default_index_urls