Embed typing_extensions package to support Python < 3.8

.bazelignore

@@ -0,0 +1 @@
+example/

README.md

@@ -1,31 +1,59 @@
 # Bazel rules for creating Python virtual environments.
+
 See `example/` for an example.
 
 ## Installation
+
 Add the following to your `WORKSPACE`.
 
 (Note: see the releases page for release-specific `WORKSPACE` config)
 
-```
+```starlark
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 
 http_archive(
     name = "rules_pyvenv",
     strip_prefix = "rules_pyvenv-main",
     url = "https://github.com/cedarai/rules_pyvenv/archive/main.tar.gz",
 )
+
+load("@rules_pyvenv//:repositories.bzl", "py_venv_repositories")
+
+py_venv_repositories(
+    name = "py_venv",
+)
+```
+
+Add the following to your `BUILD`.
+
+```starlark
+load("@py_venv//:venv.bzl", "py_venv")
+
+py_venv(
+    name = "venv",
+    ...
+)
+
+```
+
+Run the following command to create a venv in directory _env_.
+
+```
+bazel run //:venv env
 ```
 
 These rules require a recent version of Python 3.6+ and `rules_python`.
 The environment is built using the `venv` library that ships with the Python standard library.
 If using the system-provided Python on Debian/Ubuntu, you may need to run
+
 ```
 apt install python3.8-venv
 ```
 
 On Windows, [you need to enable symlink support](https://bazel.build/configure/windows#symlink).
 
 ## Example
+
 ```
 $ cd example
 $ bazel run //:venv env

build_env.py

@@ -144,7 +144,7 @@ def install_data_file(env_path: pathlib.Path, file: EnvFile) -> None:
 
 def install_site_file(site_packages_path: pathlib.Path, file: EnvFile) -> None:
     site_path = site_packages_path / file.site_packages_path
-    if not site_path.exists():
+    if not site_path.exists() and file.path.exists():
         site_path.parent.mkdir(parents=True, exist_ok=True)
         site_path.symlink_to(file.path.resolve())
 

example/BUILD.bazel

@@ -12,22 +12,22 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-package(default_visibility = ["//visibility:public"])
-
-load("@rules_pyvenv//:venv.bzl", "py_venv")
+load("@py_venv//:venv.bzl", "py_venv")
 load("@example_deps//:requirements.bzl", "requirement")
 load("@rules_python//python/pip_install:requirements.bzl", "compile_pip_requirements")
 
+package(default_visibility = ["//visibility:public"])
+
 py_venv(
     name = "venv",
+    extra_pip_commands = [
+        #        "install ipython jupyter-console",
+    ],
     deps = [
-	"//libraries/liba",
+        "//libraries/liba",
         requirement("black"),
         requirement("numpy"),
     ],
-    extra_pip_commands = [
-#        "install ipython jupyter-console",
-    ]
 )
 
 py_venv(
@@ -40,11 +40,11 @@ py_venv(
 
 py_venv(
     name = "venv_only_local_always_link",
+    always_link = True,
     deps = [
         "//libraries/liba",
         "//libraries/libb",
     ],
-    always_link = True,
 )
 
 py_venv(

example/WORKSPACE

@@ -36,14 +36,21 @@ python_register_toolchains(
 # For this example, we load rules_pyvenv locally. But you'd use http_archive.
 local_repository(
     name = "rules_pyvenv",
-    path = "../"
+    path = "../",
+)
+
+load("@rules_pyvenv//:repositories.bzl", "py_venv_repositories")
+
+py_venv_repositories(
+    name = "py_venv",
 )
 
 # Fetch some python packages to install in the venv,
 load("@rules_python//python:pip.bzl", "pip_parse")
+
 pip_parse(
-   name = "example_deps",
-   requirements_lock = "//:requirements.txt",
+    name = "example_deps",
+    requirements_lock = "//:requirements.txt",
 )
 
 load("@example_deps//:requirements.bzl", "install_deps")

repositories.bzl

@@ -0,0 +1,92 @@
+# Copyright 2023 cedar.ai. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+def _impl(rctx):
+    rctx.file("BUILD.bazel", """
+package(default_visibility = ["//visibility:public"])
+
+exports_files(["venv.bzl"])
+""")
+
+    rctx.download_and_extract(
+        output = "importlib_metadata",
+        sha256 = "9e6fafdbf0601a5825c53a842f7bb6928c8e8eb6c46a228199ca02396cf6007a",
+        stripPrefix = "importlib_metadata-6.0.0",
+        url = "https://github.com/python/importlib_metadata/archive/refs/tags/v6.0.0.tar.gz",
+    )
+
+    rctx.file("importlib_metadata/BUILD.bazel", """
+package(default_visibility = ["//visibility:public"])
+
+py_library(
+    name = "importlib_metadata",
+    srcs = glob(["importlib_metadata/*.py"]),
+    imports = ["."],
+    deps = [
+        "@{name}//typing_extensions",
+        "@{name}//zipp",
+    ],
+)
+""".format(
+        name = rctx.name,
+    ))
+
+    rctx.download_and_extract(
+        output = "typing_extensions",
+        sha256 = "c8fd5561e1bd88b743ef2ee065a5e661b2fd7b56e9cbe9ae2aeb928f41438819",
+        stripPrefix = "typing_extensions-4.5.0/src",
+        url = "https://github.com/python/typing_extensions/archive/refs/tags/4.5.0.tar.gz",
+    )
+
+    rctx.file("typing_extensions/BUILD.bazel", """
+package(default_visibility = ["//visibility:public"])
+
+py_library(
+    name = "typing_extensions",
+    srcs = [
+        "typing_extensions.py",
+    ],
+    imports = ["."],
+)
+""")
+
+    rctx.download_and_extract(
+        output = "zipp",
+        sha256 = "a2e6a09c22d6d36221e2d37f08d9566554f4de9e6e3ed8eb9ddcc0b0440162c0",
+        stripPrefix = "zipp-3.15.0",
+        url = "https://github.com/jaraco/zipp/archive/refs/tags/v3.15.0.tar.gz",
+    )
+
+    rctx.file("zipp/BUILD.bazel", """
+package(default_visibility = ["//visibility:public"])
+
+py_library(
+    name = "zipp",
+    srcs = glob(["zipp/*.py"]),
+    imports = ["."],
+)
+""")
+
+    rctx.template("venv.bzl", rctx.attr._template, {
+        "%%NAME%%": rctx.name,
+    })
+
+py_venv_repositories = repository_rule(
+    implementation = _impl,
+    attrs = {
+        "_template": attr.label(
+            default = ":venv.bzl.tmpl",
+        ),
+    },
+)