Support different backends

changelog.d/1392.feature.md

@@ -0,0 +1 @@
+Support different backends (uv, virtualenv, venv) and installers (uv, pip)

docs/backend.md

@@ -0,0 +1,37 @@
+Starting from version 1.8.0, pipx supports different backends and installers.
+
+### Backends supported:
+- `venv` (Default)
+- `uv` (via `uv venv`)
+- `virtualenv`
+
+### Installers supported:
+- `pip` (Default)
+- `uv` (via `uv pip`)
+
+> [!NOTE]
+> If `uv` or `virtualenv` is not present in PATH, you should install them with `pipx install uv` or `pipx install virtualenv` in advance.
+
+If you wish to use a different backend or installer, you can either:
+
+- Pass command line arguments (`--backend`, `--installer`)
+- Set environment variables (`PIPX_DEFAULT_BACKEND`, `PIPX_DEFAULT_INSTALLER`)
+
+> [!NOTE]
+> Command line arguments always have higher precedence than environment variables.
+
+### Examples
+```bash
+# Use uv as backend and installer
+pipx install --backend uv --installer uv black
+
+# Use virtualenv as backend and uv as installer
+pipx install --backend virtualenv --installer uv black
+```
+
+Use environment variables to set backend and installer:
+```bash
+export PIPX_DEFAULT_BACKEND=uv
+export PIPX_DEFAULT_INSTALLER=uv
+pipx install black
+```

docs/examples.md

@@ -21,6 +21,7 @@ pipx install --index-url https://test.pypi.org/simple/ --pip-args='--extra-index
 pipx --global install pycowsay
 pipx install .
 pipx install path/to/some-project
+pipx install --backend uv --installer uv black
 ```
 
 ## `pipx run` examples
@@ -41,6 +42,7 @@ pipx run pycowsay --version  # prints pycowsay version
 pipx run --python pythonX pycowsay
 pipx run pycowsay==2.0 --version
 pipx run pycowsay[dev] --version
+pipx run --backend uv --installer uv pycowsay
 pipx run --spec git+https://github.com/psf/black.git black
 pipx run --spec git+https://github.com/psf/black.git@branch-name black
 pipx run --spec git+https://github.com/psf/black.git@git-hash black

mkdocs.yml

@@ -31,6 +31,7 @@ nav:
   - Getting Started: "getting-started.md"
   - Docs: "docs.md"
   - Troubleshooting: "troubleshooting.md"
+  - Backend: "backend.md"
   - Examples: "examples.md"
   - Comparison to Other Tools: "comparisons.md"
   - How pipx works: "how-pipx-works.md"

noxfile.py

@@ -17,7 +17,14 @@
     "markdown-gfm-admonition",
 ]
 MAN_DEPENDENCIES = ["argparse-manpage[setuptools]"]
-TEST_DEPENDENCIES = ["pytest", "pypiserver[passlib]", 'setuptools; python_version>="3.12"', "pytest-cov"]
+TEST_DEPENDENCIES = [
+    "pytest",
+    "pypiserver[passlib]",
+    'setuptools; python_version>="3.12"',
+    "pytest-cov",
+    "uv",
+    "virtualenv",
+]
 # Packages whose dependencies need an intact system PATH to compile
 # pytest setup clears PATH.  So pre-build some wheels to the pip cache.
 PREBUILD_PACKAGES = {"all": ["jupyter==1.0.0"], "macos": [], "unix": [], "win": []}

src/pipx/backend.py

@@ -0,0 +1,24 @@
+import logging
+import os
+import shutil
+
+DEFAULT_BACKEND = os.getenv("PIPX_DEFAULT_BACKEND", "venv")
+DEFAULT_INSTALLER = os.getenv("PIPX_DEFAULT_INSTALLER", "pip")
+SUPPORTED_VENV_BACKENDS = ("uv", "venv", "virtualenv")
+SUPPORTED_INSTALLERS = ("uv", "pip")
+
+logger = logging.getLogger(__name__)
+
+
+def path_to_exec(executable: str, is_installer: bool = False) -> str:
+    if executable in ("venv", "pip"):
+        return executable
+    path = shutil.which(executable)
+    if path:
+        return path
+    elif is_installer:
+        logger.warning(f"'{executable}' not found on PATH. Falling back to 'pip'.")
+        return ""
+    else:
+        logger.warning(f"'{executable}' not found on PATH. Falling back to 'venv'.")
+        return ""

src/pipx/commands/install.py

@@ -34,6 +34,8 @@ def install(
     preinstall_packages: Optional[List[str]],
     suffix: str = "",
     python_flag_passed=False,
+    backend: str,
+    installer: str,
 ) -> ExitCode:
     """Returns pipx exit code."""
     # package_spec is anything pip-installable, including package_name, vcs spec,
@@ -58,7 +60,7 @@ def install(
         except StopIteration:
             exists = False
 
-        venv = Venv(venv_dir, python=python, verbose=verbose)
+        venv = Venv(venv_dir, python=python, verbose=verbose, backend=backend, installer=installer)
         venv.check_upgrade_shared_libs(pip_args=pip_args, verbose=verbose)
         if exists:
             if not reinstall and force and python_flag_passed:
@@ -214,6 +216,8 @@ def install_all(
                 include_dependencies=main_package.include_dependencies,
                 preinstall_packages=[],
                 suffix=main_package.suffix,
+                backend=venv_metadata.backend,
+                installer=venv_metadata.installer,
             )
 
             # Install the injected packages

src/pipx/commands/interpreter.py

@@ -134,6 +134,8 @@ def upgrade_interpreters(venv_container: VenvContainer, verbose: bool):
                         local_man_dir=paths.ctx.man_dir,
                         python=str(interpreter_python),
                         verbose=verbose,
+                        backend=venv.pipx_metadata.backend,
+                        installer=venv.pipx_metadata.installer,
                     )
                     upgraded.append((venv.name, interpreter_full_version, latest_micro_version))
 

src/pipx/commands/reinstall.py

@@ -25,6 +25,8 @@ def reinstall(
     local_man_dir: Path,
     python: str,
     verbose: bool,
+    backend: str,
+    installer: str,
     force_reinstall_shared_libs: bool = False,
     python_flag_passed: bool = False,
 ) -> ExitCode:
@@ -76,6 +78,8 @@ def reinstall(
         preinstall_packages=[],
         suffix=venv.pipx_metadata.main_package.suffix,
         python_flag_passed=python_flag_passed,
+        backend=backend,
+        installer=installer,
     )
 
     # now install injected packages
@@ -105,6 +109,8 @@ def reinstall_all(
     local_man_dir: Path,
     python: str,
     verbose: bool,
+    backend: str,
+    installer: str,
     *,
     skip: Sequence[str],
     python_flag_passed: bool = False,
@@ -127,6 +133,8 @@ def reinstall_all(
                 local_man_dir=local_man_dir,
                 python=python,
                 verbose=verbose,
+                backend=backend,
+                installer=installer,
                 force_reinstall_shared_libs=first_reinstall,
                 python_flag_passed=python_flag_passed,
             )

src/pipx/commands/run.py

@@ -78,6 +78,8 @@ def run_script(
     venv_args: List[str],
     verbose: bool,
     use_cache: bool,
+    backend: str,
+    installer: str,
 ) -> NoReturn:
     requirements = _get_requirements_from_script(content)
     if requirements is None:
@@ -96,7 +98,7 @@ def run_script(
         if venv_dir.exists():
             logger.info(f"Reusing cached venv {venv_dir}")
         else:
-            venv = Venv(venv_dir, python=python, verbose=verbose)
+            venv = Venv(venv_dir, python=python, verbose=verbose, backend=backend, installer=installer)
             venv.check_upgrade_shared_libs(pip_args=pip_args, verbose=verbose)
             venv.create_venv(venv_args, pip_args)
             venv.install_unmanaged_packages(requirements, pip_args)
@@ -118,6 +120,8 @@ def run_package(
     pypackages: bool,
     verbose: bool,
     use_cache: bool,
+    backend: str,
+    installer: str,
 ) -> NoReturn:
     if which(app):
         logger.warning(
@@ -151,7 +155,7 @@ def run_package(
 
     venv_dir = _get_temporary_venv_path([package_or_url], python, pip_args, venv_args)
 
-    venv = Venv(venv_dir)
+    venv = Venv(venv_dir, backend=backend, installer=installer)
     bin_path = venv.bin_path / app_filename
     _prepare_venv_cache(venv, bin_path, use_cache)
 
@@ -171,6 +175,8 @@ def run_package(
             venv_args,
             use_cache,
             verbose,
+            backend,
+            installer,
         )
 
 
@@ -185,6 +191,8 @@ def run(
     pypackages: bool,
     verbose: bool,
     use_cache: bool,
+    backend: str,
+    installer: str,
 ) -> NoReturn:
     """Installs venv to temporary dir (or reuses cache), then runs app from
     package
@@ -200,7 +208,7 @@ def run(
 
     content = None if spec is not None else maybe_script_content(app, is_path)
     if content is not None:
-        run_script(content, app_args, python, pip_args, venv_args, verbose, use_cache)
+        run_script(content, app_args, python, pip_args, venv_args, verbose, use_cache, backend, installer)
     else:
         package_or_url = spec if spec is not None else app
         run_package(
@@ -213,6 +221,8 @@ def run(
             pypackages,
             verbose,
             use_cache,
+            backend,
+            installer,
         )
 
 
@@ -227,8 +237,10 @@ def _download_and_run(
     venv_args: List[str],
     use_cache: bool,
     verbose: bool,
+    backend: str,
+    installer: str,
 ) -> NoReturn:
-    venv = Venv(venv_dir, python=python, verbose=verbose)
+    venv = Venv(venv_dir, python=python, verbose=verbose, backend=backend, installer=installer)
     venv.check_upgrade_shared_libs(pip_args=pip_args, verbose=verbose)
 
     if venv.pipx_metadata.main_package.package is not None:

src/pipx/commands/upgrade.py

@@ -108,6 +108,8 @@ def _upgrade_venv(
     venv_dir: Path,
     pip_args: List[str],
     verbose: bool,
+    backend: str,
+    installer: str,
     *,
     include_injected: bool,
     upgrading_all: bool,
@@ -137,6 +139,8 @@ def _upgrade_venv(
                 include_dependencies=False,
                 preinstall_packages=None,
                 python_flag_passed=python_flag_passed,
+                backend=backend,
+                installer=installer,
             )
             return 0
         else:
@@ -153,6 +157,9 @@ def _upgrade_venv(
     if python and not install:
         logger.info("Ignoring --python as not combined with --install")
 
+    if (backend or installer) and not install:
+        logger.info("Ignoring --backend or --installer as not combined with --install")
+
     venv = Venv(venv_dir, verbose=verbose)
     venv.check_upgrade_shared_libs(pip_args=pip_args, verbose=verbose)
 
@@ -201,6 +208,8 @@ def upgrade(
     pip_args: List[str],
     venv_args: List[str],
     verbose: bool,
+    backend: str,
+    installer: str,
     *,
     include_injected: bool,
     force: bool,
@@ -214,6 +223,8 @@ def upgrade(
             venv_dir,
             pip_args,
             verbose,
+            backend,
+            installer,
             include_injected=include_injected,
             upgrading_all=False,
             force=force,
@@ -251,6 +262,8 @@ def upgrade_all(
                 venv_dir,
                 venv.pipx_metadata.main_package.pip_args,
                 verbose=verbose,
+                backend=venv.pipx_metadata.backend,
+                installer=venv.pipx_metadata.installer,
                 include_injected=include_injected,
                 upgrading_all=True,
                 force=force,