Make Compatible with Bazel 5.0 (#28683)

* See what happens when we remove NDK

* Try to debug Kokoro in a super hacky way

* And echo the external IP too

* Attempt to fix NDK installation

* And actually run the portion of the code I need to test out

* Clean up

* Actually test against bazel 5

* Put export in proper file

* Make android an optional dependency

* Escape paths for Windows

* Revert switch to Bazel 5.0

WORKSPACE

@@ -53,18 +53,13 @@ http_archive(
     urls = ["https://github.com/bazelbuild/rules_android/archive/v0.1.1.zip"],
 )
 
-android_sdk_repository(
-    name = "androidsdk",
-    # version 31.0.0 won't work https://stackoverflow.com/a/68036845
-    build_tools_version = "30.0.3",
-)
+load("//third_party/android:android_configure.bzl", "android_configure")
 
-android_ndk_repository(
-    name = "androidndk",
-    # Note that Bazel does not support NDK 22 yet, and Bazel 3.7.1 only
-    # supports up to API level 29 for NDK 21
-    # https://github.com/bazelbuild/bazel/issues/13421
-)
+android_configure(name = "local_config_android")
+
+load("@local_config_android//:android_configure.bzl", "android_workspace")
+
+android_workspace()
 
 # Prevents bazel's '...' expansion from including the following folder.
 # This is required because the BUILD file in the following folder

third_party/android/BUILD

@@ -0,0 +1,3 @@
+exports_files([
+    "android_configure.bzl",
+])

third_party/android/android_configure.bzl

@@ -0,0 +1,62 @@
+"""Repository rule for Android SDK and NDK autoconfiguration.
+
+This rule is a no-op unless the required android environment variables are set.
+"""
+
+# Based on https://github.com/tensorflow/tensorflow/tree/34c03ed67692eb76cb3399cebca50ea8bcde064c/third_party/android
+# Workaround for https://github.com/bazelbuild/bazel/issues/14260
+
+_ANDROID_NDK_HOME = "ANDROID_NDK_HOME"
+_ANDROID_SDK_HOME = "ANDROID_HOME"
+
+def _escape_for_windows(path):
+    """Properly escape backslashes for Windows.
+
+    Ideally, we would do this conditionally, but there is seemingly no way to
+    determine whether or not this is being called from Windows.
+    """
+    return path.replace("\\", "\\\\")
+
+def _android_autoconf_impl(repository_ctx):
+    sdk_home = repository_ctx.os.environ.get(_ANDROID_SDK_HOME)
+    ndk_home = repository_ctx.os.environ.get(_ANDROID_NDK_HOME)
+
+    # version 31.0.0 won't work https://stackoverflow.com/a/68036845
+    sdk_rule = ""
+    if sdk_home:
+        sdk_rule = """
+    native.android_sdk_repository(
+        name="androidsdk",
+        path="{}",
+        build_tools_version="30.0.3",
+    )
+""".format(_escape_for_windows(sdk_home))
+
+    # Note that Bazel does not support NDK 22 yet, and Bazel 3.7.1 only
+    # supports up to API level 29 for NDK 21
+    ndk_rule = ""
+    if ndk_home:
+        ndk_rule = """
+    native.android_ndk_repository(
+        name="androidndk",
+        path="{}",
+    )
+""".format(_escape_for_windows(ndk_home))
+
+    if ndk_rule == "" and sdk_rule == "":
+        sdk_rule = "pass"
+
+    repository_ctx.file("BUILD.bazel", "")
+    repository_ctx.file("android_configure.bzl", """
+def android_workspace():
+    {}
+    {}
+    """.format(sdk_rule, ndk_rule))
+
+android_configure = repository_rule(
+    implementation = _android_autoconf_impl,
+    environ = [
+        _ANDROID_NDK_HOME,
+        _ANDROID_SDK_HOME,
+    ],
+)

tools/internal_ci/helper_scripts/prepare_build_linux_rc

@@ -18,6 +18,9 @@
 # Need to increase open files limit for c tests
 ulimit -n 32768
 
+# This is required by the android_ndk_repository repo rule.
+export ANDROID_NDK_HOME=$ANDROID_HOME/ndk-bundle
+
 # 1. Move docker's storage location to scratch disk so we don't run out of space.
 # 2. Use container registry mirror for pulling docker images (should make downloads faster)
 #    See https://cloud.google.com/container-registry/docs/using-dockerhub-mirroring