move rules_python_external out of experimental

- mv experimental/rules_python_external -> python/pip_install
- mv examples/rules_python_external -> examples/pip_install

This promotes rules_python_external as a public API in rules_python.
In a follow-up PR we'll update the documentation to indicate this and instruct users how to switch.

Author: Alex Eagle

.bazelrc

@@ -3,7 +3,7 @@
 # This lets us glob() up all the files inside the examples to make them inputs to tests
 # (Note, we cannot use `common --deleted_packages` because the bazel version command doesn't support it)
 # To update these lines, run tools/bazel_integration_test/update_deleted_packages.sh
-build --deleted_packages=examples/pip/boto,examples/pip/extras,examples/pip/helloworld,examples/rules_python_external
-query --deleted_packages=examples/pip/boto,examples/pip/extras,examples/pip/helloworld,examples/rules_python_external
+build --deleted_packages=examples/pip/boto,examples/pip/extras,examples/pip/helloworld,examples/pip_install
+query --deleted_packages=examples/pip/boto,examples/pip/extras,examples/pip/helloworld,examples/pip_install
 
 test --test_output=errors

BUILD

@@ -27,7 +27,7 @@ filegroup(
         "LICENSE",
         "internal_deps.bzl",
         "internal_setup.bzl",
-        "//experimental/rules_python_external:distribution",
+        "//python/pip_install:distribution",
         "//python:distribution",
         "//tools:distribution",
     ],

docs/BUILD

@@ -38,6 +38,13 @@ bzl_library(
     ],
 )
 
+bzl_library(
+    name = "bazel_repo_tools",
+    srcs = [
+        "@bazel_tools//tools:bzl_srcs",
+    ]
+)
+
 bzl_library(
     name = "defs",
     srcs = [
@@ -62,6 +69,10 @@ stardoc(
     name = "pip-docs",
     out = "pip.md",
     input = "//python:pip.bzl",
+    deps = [
+        ":bazel_repo_tools",
+        "//python/pip_install:bzl",
+    ],
 )
 
 stardoc(

examples/BUILD

@@ -23,6 +23,6 @@ bazel_integration_test(
 )
 
 bazel_integration_test(
-    name = "rules_python_external_example",
+    name = "pip_install_example",
     timeout = "long",
 )

examples/rules_python_external/BUILD renamed to examples/pip_install/BUILD

@@ -0,0 +1,4 @@
+# pip_install example
+
+This example shows how to use pip to fetch external dependencies from a requirements.txt file,
+then use them in BUILD files as dependencies of Bazel targets.

examples/pip_install/README.md

@@ -12,7 +12,7 @@ load("@rules_python//python:repositories.bzl", "py_repositories")
 
 py_repositories()
 
-load("@rules_python//experimental/rules_python_external:defs.bzl", "pip_install")
+load("@rules_python//python:pip.bzl", "pip_install")
 
 pip_install(
     # (Optional) You can provide extra parameters to pip.