feat: node-patches\filesystem patcher. (#1332)

WORKSPACE

@@ -14,7 +14,10 @@
 
 workspace(
     name = "build_bazel_rules_nodejs",
-    managed_directories = {"@npm": ["node_modules"]},
+    managed_directories = {
+        "@npm": ["node_modules"],
+        "@npm_node_patches": ["packages/node-patches/node_modules"],
+    },
 )
 
 load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")
@@ -85,6 +88,12 @@ filegroup(
     yarn_lock = "//:yarn.lock",
 )
 
+npm_install(
+    name = "npm_node_patches",
+    package_json = "//packages/node-patches:package.json",
+    package_lock_json = "//packages/node-patches:package-lock.json",
+)
+
 # Install all Bazel dependencies needed for npm packages that supply Bazel rules
 load("@npm//:install_bazel_dependencies.bzl", "install_bazel_dependencies")
 

common.bazelrc

@@ -4,6 +4,9 @@
 #
 # The full list of Bazel options: https://docs.bazel.build/versions/master/command-line-reference.html
 
+# Cache action outputs on disk so they persist across output_base and bazel shutdown (eg. changing branches)
+build --disk_cache=~/.cache/bazel-disk-cache
+
 # Bazel will create symlinks from the workspace directory to output artifacts.
 # Build results will be placed in a directory called "dist/bin"
 # Other directories will be created like "dist/testlogs"

internal/node/bazel_require_script.js

@@ -1,6 +1,11 @@
 // Adapt node programs to run under Bazel
 // Meant to be run in a --require hook
 
+if(global.BAZEL_NODE_PATCHES) {
+  return;
+}
+global.BAZEL_NODE_PATCHES = true;
+
 const fs = require('fs');
 const path = require('path');
 const orig = {};

packages/node-patches/.gitignore

@@ -0,0 +1,10 @@
+coverage
+node_modules
+build
+.nyc_output
+src/*.js
+src/*.d.ts
+test/**/*.js
+test/**/*.d.ts
+register.js
+register.d.ts

packages/node-patches/.nycrc

@@ -0,0 +1 @@
+{"include":["build/src/**","src/**"]}

packages/node-patches/BUILD.bazel

@@ -0,0 +1,81 @@
+# Copyright 2017 The Bazel Authors. 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.
+
+load("@build_bazel_rules_nodejs//:tools/defaults.bzl", "npm_package")
+load("@npm_node_patches//mocha:index.bzl", "mocha_test")
+load("@npm_node_patches//typescript:index.bzl", "tsc")
+
+package(default_visibility = ["//visibility:public"])
+
+filegroup(
+    name = "node-patches",
+    srcs = [
+        "package.json",
+        ":compile",
+    ],
+)
+
+npm_package(
+    name = "npm_package",
+    srcs = [
+        "README.md",
+    ],
+    deps = [
+        ":node-patches",
+    ],
+)
+
+sources = glob(
+    [
+        "src/*.ts",
+    ],
+    exclude = ["src/*.d.ts"],
+) + ["register.ts"]
+
+tests = glob(
+    ["test/**/*.ts"],
+    exclude = ["test/**/*.d.ts"],
+)
+
+tsc(
+    name = "compile",
+    # TODO: we ought to compile tests separately?
+    outs = [s.replace(".ts", ext) for ext in [
+        ".js",
+        ".d.ts",
+    ] for s in sources + tests],
+    args = [
+        "-p",
+        "$(location tsconfig-bazel.json)",
+        "--outDir",
+        "$@",
+    ],
+    data = sources + tests + [
+        "tsconfig-bazel.json",
+        "@npm_node_patches//:node_modules",
+    ],
+)
+
+test_js = [s.replace(".ts", ".js") for s in tests]
+
+mocha_test(
+    name = "unit_test",
+    args = ["$(location %s)" % s for s in test_js],
+    data = test_js + [s.replace(".ts", ".js") for s in sources] + [
+        "@npm_node_patches//:node_modules",
+    ],
+    tags = [
+        "fix-windows",
+    ],
+)

packages/node-patches/README.md

@@ -0,0 +1,52 @@
+# @bazel/node-patches
+
+Runtime modifications to nodejs internals to help node/npm distributed programs run in bazel
+
+## fs
+
+patch any `fs` like object such that symlinks that point outside a specified directory seem to be their targets instead of links
+
+### example
+
+```js
+const fs = require('fs')
+const path = require('path')
+const patcher = require('@bazel/node-patches')
+
+patcher.fs(fs,'/my/files')
+
+fs.symlinkSync(path.resolve('./node_modules'),'/my/files/node_modules')
+
+// now try to stat.
+
+const stat = fs.lstatSync('/my/files/node_modules')
+
+console.log(stat.isSymbolicLink() === false)// true
+
+console.log(stat.isDirectory() === true) //true
+
+```
+
+this should not change the behavior of any paths that are outside of the root.
+
+### loader
+
+you can use the register script to include it in a -r flag to preload the patch before user code.
+This depends on setting the environment variable BAZEL_PATCH_ROOT
+
+```sh
+BAZEL_PATCH_ROOT=~/.cache/bazel node -r @bazel/node-patches/register <your app js>
+```
+
+### api
+
+`{fs} = require('@bazel/node-patches')`
+  - fs(fsLikeObject: require('fs'), root:string)
+
+## bazel
+
+to use this package as a dependency in bazel depend on it's exposed file group rule.
+
+`:node_patches`
+
+this filegroup will always expose one or more files needed to run this package and will not depend on npm install etc.