Make Python and PyPy install mirrors configurable in uv.toml (#8695)

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## Summary

Adds python-install-mirror and pypy-install-mirror as keys for uv.toml,
and cli args for `uv python install`.

Could leave the cli args out if we think the env vars and configs are
sufficient.

Fixes #8186 

<!-- What's the purpose of the change? What does it do, and why? -->

---------

Co-authored-by: Zanie Blue <[email protected]>

crates/uv-cli/src/lib.rs

@@ -3938,6 +3938,22 @@ pub struct PythonInstallArgs {
     /// See `uv help python` to view supported request formats.
     pub targets: Vec<String>,
 
+    /// Set the URL to use as the source for downloading Python installations.
+    ///
+    /// The provided URL will replace `https://github.com/indygreg/python-build-standalone/releases/download` in, e.g., `https://github.com/indygreg/python-build-standalone/releases/download/20240713/cpython-3.12.4%2B20240713-aarch64-apple-darwin-install_only.tar.gz`.
+    ///
+    /// Distributions can be read from a local directory by using the `file://` URL scheme.
+    #[arg(long, env = EnvVars::UV_PYTHON_INSTALL_MIRROR)]
+    pub mirror: Option<String>,
+
+    /// Set the URL to use as the source for downloading PyPy installations.
+    ///
+    /// The provided URL will replace `https://downloads.python.org/pypy` in, e.g., `https://downloads.python.org/pypy/pypy3.8-v7.3.7-osx64.tar.bz2`.
+    ///
+    /// Distributions can be read from a local directory by using the `file://` URL scheme.
+    #[arg(long, env = EnvVars::UV_PYPY_INSTALL_MIRROR)]
+    pub pypy_mirror: Option<String>,
+
     /// Reinstall the requested Python version, if it's already installed.
     ///
     /// By default, uv will exit successfully if the version is already

crates/uv-python/src/downloads.rs

@@ -466,9 +466,11 @@ impl ManagedPythonDownload {
         installation_dir: &Path,
         cache_dir: &Path,
         reinstall: bool,
+        python_install_mirror: Option<String>,
+        pypy_install_mirror: Option<String>,
         reporter: Option<&dyn Reporter>,
     ) -> Result<DownloadResult, Error> {
-        let url = self.download_url()?;
+        let url = self.download_url(python_install_mirror, pypy_install_mirror)?;
         let path = installation_dir.join(self.key().to_string());
 
         // If it is not a reinstall and the dir already exists, return it.
@@ -585,10 +587,14 @@ impl ManagedPythonDownload {
 
     /// Return the [`Url`] to use when downloading the distribution. If a mirror is set via the
     /// appropriate environment variable, use it instead.
-    fn download_url(&self) -> Result<Url, Error> {
+    fn download_url(
+        &self,
+        python_install_mirror: Option<String>,
+        pypy_install_mirror: Option<String>,
+    ) -> Result<Url, Error> {
         match self.key.implementation {
             LenientImplementationName::Known(ImplementationName::CPython) => {
-                if let Ok(mirror) = std::env::var(EnvVars::UV_PYTHON_INSTALL_MIRROR) {
+                if let Some(mirror) = python_install_mirror {
                     let Some(suffix) = self.url.strip_prefix(
                         "https://github.com/indygreg/python-build-standalone/releases/download/",
                     ) else {
@@ -601,7 +607,7 @@ impl ManagedPythonDownload {
             }
 
             LenientImplementationName::Known(ImplementationName::PyPy) => {
-                if let Ok(mirror) = std::env::var(EnvVars::UV_PYPY_INSTALL_MIRROR) {
+                if let Some(mirror) = pypy_install_mirror {
                     let Some(suffix) = self.url.strip_prefix("https://downloads.python.org/pypy/")
                     else {
                         return Err(Error::Mirror(EnvVars::UV_PYPY_INSTALL_MIRROR, self.url));

crates/uv-python/src/installation.rs

@@ -86,6 +86,8 @@ impl PythonInstallation {
         client_builder: &BaseClientBuilder<'a>,
         cache: &Cache,
         reporter: Option<&dyn Reporter>,
+        python_install_mirror: Option<String>,
+        pypy_install_mirror: Option<String>,
     ) -> Result<Self, Error> {
         let request = request.unwrap_or_else(|| &PythonRequest::Default);
 
@@ -100,7 +102,16 @@ impl PythonInstallation {
             {
                 if let Some(request) = PythonDownloadRequest::from_request(request) {
                     debug!("Requested Python not found, checking for available download...");
-                    match Self::fetch(request.fill()?, client_builder, cache, reporter).await {
+                    match Self::fetch(
+                        request.fill()?,
+                        client_builder,
+                        cache,
+                        reporter,
+                        python_install_mirror,
+                        pypy_install_mirror,
+                    )
+                    .await
+                    {
                         Ok(installation) => Ok(installation),
                         Err(Error::Download(downloads::Error::NoDownloadFound(_))) => {
                             Err(Error::MissingPython(err))
@@ -121,6 +132,8 @@ impl PythonInstallation {
         client_builder: &BaseClientBuilder<'a>,
         cache: &Cache,
         reporter: Option<&dyn Reporter>,
+        python_install_mirror: Option<String>,
+        pypy_install_mirror: Option<String>,
     ) -> Result<Self, Error> {
         let installations = ManagedPythonInstallations::from_settings()?.init()?;
         let installations_dir = installations.root();
@@ -132,7 +145,15 @@ impl PythonInstallation {
 
         info!("Fetching requested Python...");
         let result = download
-            .fetch(&client, installations_dir, &cache_dir, false, reporter)
+            .fetch(
+                &client,
+                installations_dir,
+                &cache_dir,
+                false,
+                python_install_mirror,
+                pypy_install_mirror,
+                reporter,
+            )
             .await?;
 
         let path = match result {

crates/uv-settings/src/settings.rs

@@ -14,6 +14,7 @@ use uv_pep508::Requirement;
 use uv_pypi_types::{SupportedEnvironments, VerbatimParsedUrl};
 use uv_python::{PythonDownloads, PythonPreference, PythonVersion};
 use uv_resolver::{AnnotationStyle, ExcludeNewer, PrereleaseMode, ResolutionMode};
+use uv_static::EnvVars;
 
 /// A `pyproject.toml` with an (optional) `[tool.uv]` section.
 #[allow(dead_code)]
@@ -41,6 +42,9 @@ pub struct Options {
     #[serde(flatten)]
     pub top_level: ResolverInstallerOptions,
 
+    #[serde(flatten)]
+    pub install_mirrors: PythonInstallMirrors,
+
     #[serde(flatten)]
     pub publish: PublishOptions,
 
@@ -676,6 +680,61 @@ pub struct ResolverInstallerOptions {
     pub no_binary_package: Option<Vec<PackageName>>,
 }
 
+/// Shared settings, relevant to all operations that might create managed python installations.
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, CombineOptions, OptionsMetadata)]
+#[serde(rename_all = "kebab-case")]
+#[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
+pub struct PythonInstallMirrors {
+    /// Mirror URL for downloading managed Python installations.
+    ///
+    /// By default, managed Python installations are downloaded from [`python-build-standalone`](https://github.com/indygreg/python-build-standalone).
+    /// This variable can be set to a mirror URL to use a different source for Python installations.
+    /// The provided URL will replace `https://github.com/indygreg/python-build-standalone/releases/download` in, e.g., `https://github.com/indygreg/python-build-standalone/releases/download/20240713/cpython-3.12.4%2B20240713-aarch64-apple-darwin-install_only.tar.gz`.
+    ///
+    /// Distributions can be read from a local directory by using the `file://` URL scheme.
+    #[option(
+        default = "None",
+        value_type = "str",
+        example = r#"
+            python-install-mirror = "https://github.com/indygreg/python-build-standalone/releases/download"
+        "#
+    )]
+    pub python_install_mirror: Option<String>,
+    /// Mirror URL to use for downloading managed PyPy installations.
+    ///
+    /// By default, managed PyPy installations are downloaded from [downloads.python.org](https://downloads.python.org/).
+    /// This variable can be set to a mirror URL to use a different source for PyPy installations.
+    /// The provided URL will replace `https://downloads.python.org/pypy` in, e.g., `https://downloads.python.org/pypy/pypy3.8-v7.3.7-osx64.tar.bz2`.
+    ///
+    /// Distributions can be read from a
+    /// local directory by using the `file://` URL scheme.
+    #[option(
+        default = "None",
+        value_type = "str",
+        example = r#"
+            pypy-install-mirror = "https://downloads.python.org/pypy"
+        "#
+    )]
+    pub pypy_install_mirror: Option<String>,
+}
+
+impl Default for PythonInstallMirrors {
+    fn default() -> Self {
+        PythonInstallMirrors::resolve(None, None)
+    }
+}
+
+impl PythonInstallMirrors {
+    pub fn resolve(python_mirror: Option<String>, pypy_mirror: Option<String>) -> Self {
+        let python_mirror_env = std::env::var(EnvVars::UV_PYTHON_INSTALL_MIRROR).ok();
+        let pypy_mirror_env = std::env::var(EnvVars::UV_PYPY_INSTALL_MIRROR).ok();
+        PythonInstallMirrors {
+            python_install_mirror: python_mirror_env.or(python_mirror),
+            pypy_install_mirror: pypy_mirror_env.or(pypy_mirror),
+        }
+    }
+}
+
 /// Settings that are specific to the `uv pip` command-line interface.
 ///
 /// These values will be ignored when running commands outside the `uv pip` namespace (e.g.,
@@ -1544,6 +1603,11 @@ pub struct OptionsWire {
     no_binary: Option<bool>,
     no_binary_package: Option<Vec<PackageName>>,
 
+    // #[serde(flatten)]
+    // install_mirror: PythonInstallMirrors,
+    python_install_mirror: Option<String>,
+    pypy_install_mirror: Option<String>,
+
     // #[serde(flatten)]
     // publish: PublishOptions
     publish_url: Option<Url>,
@@ -1581,6 +1645,8 @@ impl From<OptionsWire> for Options {
             preview,
             python_preference,
             python_downloads,
+            python_install_mirror,
+            pypy_install_mirror,
             concurrent_downloads,
             concurrent_builds,
             concurrent_installs,
@@ -1673,6 +1739,10 @@ impl From<OptionsWire> for Options {
             override_dependencies,
             constraint_dependencies,
             environments,
+            install_mirrors: PythonInstallMirrors::resolve(
+                python_install_mirror,
+                pypy_install_mirror,
+            ),
             conflicting_groups,
             publish: PublishOptions {
                 publish_url,

crates/uv/src/commands/build_frontend.rs

@@ -28,6 +28,7 @@ use uv_python::{
 };
 use uv_requirements::RequirementsSource;
 use uv_resolver::{ExcludeNewer, FlatIndex, RequiresPython};
+use uv_settings::PythonInstallMirrors;
 use uv_types::{BuildContext, BuildIsolation, HashStrategy};
 use uv_workspace::{DiscoveryOptions, Workspace, WorkspaceError};
 
@@ -52,6 +53,7 @@ pub(crate) async fn build_frontend(
     build_constraints: Vec<RequirementsSource>,
     hash_checking: Option<HashCheckingMode>,
     python: Option<String>,
+    install_mirrors: PythonInstallMirrors,
     settings: ResolverSettings,
     no_config: bool,
     python_preference: PythonPreference,
@@ -75,6 +77,7 @@ pub(crate) async fn build_frontend(
         &build_constraints,
         hash_checking,
         python.as_deref(),
+        install_mirrors,
         settings.as_ref(),
         no_config,
         python_preference,
@@ -116,6 +119,7 @@ async fn build_impl(
     build_constraints: &[RequirementsSource],
     hash_checking: Option<HashCheckingMode>,
     python_request: Option<&str>,
+    install_mirrors: PythonInstallMirrors,
     settings: ResolverSettingsRef<'_>,
     no_config: bool,
     python_preference: PythonPreference,
@@ -251,6 +255,7 @@ async fn build_impl(
             source.clone(),
             output_dir,
             python_request,
+            install_mirrors.clone(),
             no_config,
             workspace.as_ref(),
             python_preference,
@@ -346,6 +351,7 @@ async fn build_package(
     source: AnnotatedSource<'_>,
     output_dir: Option<&Path>,
     python_request: Option<&str>,
+    install_mirrors: PythonInstallMirrors,
     no_config: bool,
     workspace: Result<&Workspace, &WorkspaceError>,
     python_preference: PythonPreference,
@@ -424,6 +430,8 @@ async fn build_package(
         client_builder,
         cache,
         Some(&PythonDownloadReporter::single(printer)),
+        install_mirrors.python_install_mirror,
+        install_mirrors.pypy_install_mirror,
     )
     .await?
     .into_interpreter();

crates/uv/src/commands/project/add.rs

@@ -33,6 +33,7 @@ use uv_python::{
 use uv_requirements::{NamedRequirementsResolver, RequirementsSource, RequirementsSpecification};
 use uv_resolver::{FlatIndex, InstallTarget};
 use uv_scripts::{Pep723Item, Pep723Script};
+use uv_settings::PythonInstallMirrors;
 use uv_types::{BuildIsolation, HashStrategy};
 use uv_warnings::warn_user_once;
 use uv_workspace::pyproject::{DependencyType, Source, SourceError};
@@ -71,6 +72,7 @@ pub(crate) async fn add(
     extras: Vec<ExtraName>,
     package: Option<PackageName>,
     python: Option<String>,
+    install_mirrors: PythonInstallMirrors,
     settings: ResolverInstallerSettings,
     script: Option<PathBuf>,
     python_preference: PythonPreference,
@@ -140,6 +142,7 @@ pub(crate) async fn add(
         } else {
             let requires_python = init_script_python_requirement(
                 python.as_deref(),
+                install_mirrors.clone(),
                 project_dir,
                 false,
                 python_preference,
@@ -173,6 +176,8 @@ pub(crate) async fn add(
             &client_builder,
             cache,
             Some(&reporter),
+            install_mirrors.python_install_mirror,
+            install_mirrors.pypy_install_mirror,
         )
         .await?
         .into_interpreter();
@@ -227,6 +232,7 @@ pub(crate) async fn add(
                 connectivity,
                 native_tls,
                 allow_insecure_host,
+                install_mirrors.clone(),
                 no_config,
                 cache,
                 printer,
@@ -240,6 +246,7 @@ pub(crate) async fn add(
             let venv = project::get_or_init_environment(
                 project.workspace(),
                 python.as_deref().map(PythonRequest::parse),
+                install_mirrors.clone(),
                 python_preference,
                 python_downloads,
                 connectivity,

crates/uv/src/commands/project/export.rs

@@ -4,6 +4,7 @@ use anyhow::{Context, Result};
 use itertools::Itertools;
 use owo_colors::OwoColorize;
 use std::path::{Path, PathBuf};
+use uv_settings::PythonInstallMirrors;
 
 use uv_cache::Cache;
 use uv_client::Connectivity;
@@ -42,6 +43,7 @@ pub(crate) async fn export(
     frozen: bool,
     include_header: bool,
     python: Option<String>,
+    install_mirrors: PythonInstallMirrors,
     settings: ResolverSettings,
     python_preference: PythonPreference,
     python_downloads: PythonDownloads,
@@ -107,6 +109,7 @@ pub(crate) async fn export(
             connectivity,
             native_tls,
             allow_insecure_host,
+            install_mirrors,
             no_config,
             cache,
             printer,