feat: adds support for python and pypy distribution mirrors

docs/plugins/environment/virtual.md

@@ -75,6 +75,8 @@ Some distributions have [variants](https://gregoryszorc.com/docs/python-build-st
 | Linux | <ul><li><code>v1</code></li><li><code>v2</code></li><li><code>v3</code> (default)</li><li><code>v4</code></li></ul> |
 | Windows | <ul><li><code>shared</code> (default)</li><li><code>static</code></li></ul> |
 
+You can configure Hatch to use a mirror of these distributions by setting the `HATCH_CUSTOM_CPYTHON_SOURCE` environment variable to your mirror. The custom source is expected to contain the releases following the upstreams structure `<calver>/cpython-X.Y.Z%2B<calver>-aarch64-unknown-linux-gnu-install_only.tar.gz`.
+
 ### PyPy
 
 | ID |
@@ -85,6 +87,8 @@ Some distributions have [variants](https://gregoryszorc.com/docs/python-build-st
 
 The source of distributions is the [PyPy](https://www.pypy.org) project.
 
+You can configure Hatch to use a mirror of these distributions by setting the `HATCH_CUSTOM_PYPY_SOURCE` environment variable to your mirror. The custom source is expected to contain the releases following the upstreams structure `pypyX.Y-vA.B.C-aarch64.tar.bz2`.
+
 ## Troubleshooting
 
 ### macOS SIP

src/hatch/cli/python/install.py

@@ -36,6 +36,11 @@ def install(app: Application, *, names: tuple[str, ...], private: bool, update:
     ```
     hatch python install all
     ```
+
+    If you run your own mirror you can tell Hatch to use it by setting these environment variables to your mirrors URL:
+
+    * ``HATCH_CUSTOM_CPYTHON_SOURCE``
+    * ``HATCH_CUSTOM_PYPY_SOURCE``
     """
     from hatch.errors import PythonDistributionResolutionError, PythonDistributionUnknownError
     from hatch.python.distributions import ORDERED_DISTRIBUTIONS

src/hatch/python/resolve.py

@@ -83,6 +83,17 @@ def python_path(self) -> str:
 
 
 class CPythonStandaloneDistribution(Distribution):
+    @property
+    def source(self) -> str:
+        source = super().source
+        custom_source = os.environ.get('HATCH_CUSTOM_CPYTHON_SOURCE')
+        if custom_source:
+            source = super().source.replace(
+                'https://github.com/indygreg/python-build-standalone/releases/download/',
+                custom_source.rstrip('/') + '/',
+            )
+        return source
+
     @cached_property
     def version(self) -> Version:
         from packaging.version import Version
@@ -110,6 +121,14 @@ def python_path(self) -> str:
 
 
 class PyPyOfficialDistribution(Distribution):
+    @property
+    def source(self) -> str:
+        source = super().source
+        custom_source = os.environ.get('HATCH_CUSTOM_PYPY_SOURCE')
+        if custom_source:
+            source = super().source.replace('https://downloads.python.org/pypy/', custom_source.rstrip('/') + '/')
+        return source
+
     @cached_property
     def version(self) -> Version:
         from packaging.version import Version