feat(builtin): support for substitutions

docs/stamping.md

@@ -20,7 +20,10 @@ Bazel provides a couple of statuses by default, such as `BUILD_EMBED_LABEL` whic
 argument, as well as `BUILD_HOST` and `BUILD_USER`. You can supply more with the workspace status script, see below.
 
 Some rules accept an attribute that uses the status variables.
-For example, in a `pkg_npm` you can use the `substitutions` attribute like:
+
+## Substitutions attribute
+
+In a `pkg_npm` or `pkg_web` you can use the `substitutions` attribute like:
 
 ```python
 pkg_npm(
@@ -32,7 +35,10 @@ pkg_npm(
 In a `--stamp` build, this will replace the string "0.0.0-PLACEHOLDER" in any file included in the package with the current value of the `STABLE_GIT_COMMIT` variable.
 However without stamping the placeholder will be left as-is.
 
+## Read the status files
+
 The `rollup_bundle` rule just exposes the Bazel status files so that your custom `rollup.config.js` can read it.
+See [Rollup](Rollup).
 
 ## Stamping with a Workspace status script
 

internal/node/context.bzl

@@ -4,7 +4,7 @@ load("@build_bazel_rules_nodejs//:providers.bzl", "NodeContextInfo")
 
 _DOC = """node_context_data gathers information about the build configuration.
 It is a common dependency of all targets that are sensitive to configuration.
-(currently pkg_npm and rollup_bundle)"""
+(currently pkg_npm, pkg_web, and rollup_bundle)"""
 
 def _impl(ctx):
     return [NodeContextInfo(stamp = ctx.attr.stamp)]

internal/pkg_web/BUILD.bazel

@@ -21,7 +21,10 @@ filegroup(
 
 nodejs_binary(
     name = "assembler",
-    data = ["assembler.js"],
+    data = [
+        "assembler.js",
+        "//third_party/github.com/gjtorikian/isBinaryFile",
+    ],
     entry_point = ":assembler.js",
     node_modules = ":node_modules_none",
 )
@@ -32,6 +35,7 @@ jasmine_node_test(
     srcs = ["assembler_spec.js"],
     deps = [
         "assembler.js",
+        "//third_party/github.com/gjtorikian/isBinaryFile",
     ],
 )
 

internal/pkg_web/assembler.js

@@ -17,6 +17,7 @@
 
 const fs = require('fs');
 const path = require('path');
+const isBinary = require('isbinaryfile').isBinaryFileSync;
 
 /**
  * Create a new directory and any necessary subdirectories
@@ -29,9 +30,58 @@ function mkdirp(p) {
   }
 }
 
+function unquoteArgs(s) {
+  return s.replace(/^'(.*)'$/, '$1');
+}
+
+function getBazelStatusMappings(statusFilePath) {
+  if (!statusFilePath) return {};
+  const stampFileLines = fs.readFileSync(statusFilePath, {encoding: 'utf-8'}).trim().split('\n');
+  const stampMap = {};
+  for (const line of stampFileLines) {
+    const [key, value] = line.split(' ');
+    stampMap[key] = value;
+  }
+  return stampMap;
+}
+
+function normalizeSubstitutions(substitutionsArg, stampMap) {
+  const substitutions = JSON.parse(substitutionsArg);
+
+  const normalizedSubstitutions = {};
+
+  for (const occurrence in substitutions) {
+    let substituteWith = substitutions[occurrence];
+    if (substituteWith.match(/^{.*?}$/)) {
+      substituteWith = substituteWith.replace(/^{(.*?)}$/, '$1');
+      if (!stampMap[substituteWith]) {
+        throw new Error(`Could not find ${substituteWith} key in status file.`);
+      }
+      substituteWith = stampMap[substituteWith];
+    }
+    normalizedSubstitutions[occurrence] = substituteWith;
+  }
+  return normalizedSubstitutions;
+}
+
 function main(params) {
   const outdir = params.shift();
 
+  const volatileFilePath = params.shift();
+
+  const stableFilePath = params.shift();
+
+  const rawSubstitutions = params.shift().replace(/^'(.*)'$/, '$1');
+
+  const stampMap = {
+    ...getBazelStatusMappings(volatileFilePath),
+    ...getBazelStatusMappings(stableFilePath),
+  };
+
+  const normalizedSubstitutions = normalizeSubstitutions(rawSubstitutions, stampMap)
+
+  const substitutions = Object.entries(normalizedSubstitutions);
+
   const rootDirs = [];
   while (params.length && params[0] !== '--assets') {
     let r = params.shift();
@@ -42,6 +92,7 @@ function main(params) {
   }
   // Always trim the longest prefix
   rootDirs.sort((a, b) => b.length - a.length);
+
   params.shift(); // --assets
 
   function relative(execPath) {
@@ -56,12 +107,20 @@ function main(params) {
     return execPath;
   }
 
-  function copy(f) {
+  function copy(f, substitutions) {
     if (fs.statSync(f).isDirectory()) {
       for (const file of fs.readdirSync(f)) {
         // Change paths to posix
-        copy(path.join(f, file).replace(/\\/g, '/'));
+        copy(path.join(f, file).replace(/\\/g, '/'), substitutions);
       }
+    } else if (!isBinary(f)) {
+      const dest = path.join(outdir, relative(f));
+      let content = fs.readFileSync(f, {encoding: 'utf-8'});
+      substitutions.forEach(([occurrence, replaceWith]) => {
+        content = content.replace(occurrence, replaceWith);
+      });
+      fs.mkdirSync(path.dirname(dest), {recursive: true});
+      fs.writeFileSync(dest, content);
     } else {
       const dest = path.join(outdir, relative(f));
       mkdirp(path.dirname(dest));
@@ -75,7 +134,7 @@ function main(params) {
   // copied from within bazel-bin.
   // See https://github.com/bazelbuild/rules_nodejs/pull/546.
   for (const f of new Set(params)) {
-    copy(f);
+    copy(f, substitutions);
   }
   return 0;
 }
@@ -85,6 +144,9 @@ module.exports = {main};
 if (require.main === module) {
   // We always require the arguments are encoded into a flagfile
   // so that we don't exhaust the command-line limit.
-  const params = fs.readFileSync(process.argv[2], {encoding: 'utf-8'}).split('\n').filter(l => !!l);
+  const params = fs.readFileSync(process.argv[2], {encoding: 'utf-8'})
+                     .split('\n')
+                     .filter(l => !!l)
+                     .map(unquoteArgs);
   process.exitCode = main(params);
 }

internal/pkg_web/assembler_spec.js

@@ -3,32 +3,54 @@ const path = require('path');
 const fs = require('fs');
 
 describe('assembler', () => {
-    const outdir = 'output';
-    let testCount = 0;
-    beforeEach(() => {
-      const now = Date.now() + String(testCount++);
-      // prevent test isolation failures by running each spec in a separate dir
-      const uniqueDir = path.join(process.env['TEST_TMPDIR'], String(now));
-      fs.mkdirSync(uniqueDir);
-      process.chdir(uniqueDir);
-      fs.mkdirSync('path');
-      fs.mkdirSync('path/to');
-      fs.writeFileSync('path/to/thing1.txt', 'some content', {encoding: 'utf-8'});
-    });
+  const outdir = 'output';
+  const volatilePath = 'path/to/volatile-status.txt';
+  const stablePath = 'path/to/stable-status.txt';
+  let testCount = 0;
+  beforeEach(() => {
+    const now = Date.now() + String(testCount++);
+    // prevent test isolation failures by running each spec in a separate dir
+    const uniqueDir = path.join(process.env['TEST_TMPDIR'], String(now));
+    fs.mkdirSync(uniqueDir);
+    process.chdir(uniqueDir);
+    fs.mkdirSync('path');
+    fs.mkdirSync('path/to');
+    fs.writeFileSync('path/to/thing1.txt', 'some content', {encoding: 'utf-8'});
+    fs.writeFileSync(volatilePath, 'TEST_KEY 41561')
+    fs.writeFileSync(stablePath, 'STABLE_GIT_VERSION 123abc')
+  });
 
-    it('should copy files', () => {
-        assembler.main([outdir, '--assets', 'path/to/thing1.txt']);
-        expect(fs.readdirSync('output/path/to')).toContain('thing1.txt');
-        expect(fs.readFileSync('output/path/to/thing1.txt', {encoding: 'utf-8'})).toBe('some content');
-    });
+  it('should copy files', () => {
+    assembler.main([outdir, '', '', '{}', '--assets', 'path/to/thing1.txt']);
+    expect(fs.readdirSync('output/path/to')).toContain('thing1.txt');
+    expect(fs.readFileSync('output/path/to/thing1.txt', {encoding: 'utf-8'})).toBe('some content');
+  });
 
-    it('should strip longest rootdir', () => {
-        assembler.main([outdir, 'path', 'path/to', '--assets', 'path/to/thing1.txt']);
-        expect(fs.readdirSync('output')).toContain('thing1.txt');
-    });
+  it('should strip longest rootdir', () => {
+    assembler.main([outdir, '', '', '{}', 'path', 'path/to', '--assets', 'path/to/thing1.txt']);
+    expect(fs.readdirSync('output')).toContain('thing1.txt');
+  });
 
-    it('should handle nested directories', () => {
-        assembler.main([outdir, 'path', '--assets', 'path/to']);
-        expect(fs.readdirSync('output/to')).toContain('thing1.txt');
-    });
-});
+  it('should handle nested directories', () => {
+    assembler.main([outdir, '', '', '{}', 'path', '--assets', 'path/to']);
+    expect(fs.readdirSync('output/to')).toContain('thing1.txt');
+  });
+
+  it('should replace contents with static text', () => {
+    assembler.main([
+      outdir, '', '', '{"some content":"some other content"}', '--assets', 'path/to/thing1.txt'
+    ]);
+    expect(fs.readFileSync('output/path/to/thing1.txt', {
+      encoding: 'utf-8'
+    })).toBe('some other content');
+  })
+
+
+  it('should replace contents with dynamic text from Bazel workspace status', () => {
+    assembler.main([
+      outdir, volatilePath, stablePath, '{"some":"{STABLE_GIT_VERSION}", "content":"{TEST_KEY}"}',
+      '--assets', 'path/to/thing1.txt'
+    ]);
+    expect(fs.readFileSync('output/path/to/thing1.txt', {encoding: 'utf-8'})).toBe('123abc 41561');
+  })
+});

internal/pkg_web/pkg_web.bzl

@@ -15,30 +15,44 @@
 """Contains the pkg_web rule.
 """
 
+load("//:providers.bzl", "NODE_CONTEXT_ATTRS", "NodeContextInfo")
+
 _DOC = """Assembles a web application from source files."""
 
-_ATTRS = {
+_ATTRS = dict(NODE_CONTEXT_ATTRS, **{
     "additional_root_paths": attr.string_list(
         doc = """Path prefixes to strip off all srcs, in addition to the current package. Longest wins.""",
     ),
     "srcs": attr.label_list(
         allow_files = True,
         doc = """Files which should be copied into the package""",
     ),
+    "substitutions": attr.string_dict(
+        doc = """Key-value pairs which are replaced in all the files while building the package.
+
+        You can use values from the workspace status command using curly braces, for example
+        `{"0.0.0-PLACEHOLDER": "{STABLE_GIT_VERSION}"}`.
+        See the section on stamping in the README.""",
+    ),
     "_assembler": attr.label(
         default = "@build_bazel_rules_nodejs//internal/pkg_web:assembler",
         executable = True,
         cfg = "host",
     ),
-}
+})
 
-def move_files(output_name, files, action_factory, var, assembler, root_paths):
+def move_files(output_name, substitutions, version_file, info_file, stamp, files, action_factory, var, assembler, root_paths):
     """Moves files into an output directory
 
     Args:
       output_name: The name of the output directory
+      substitutions: key/value pairs to replace
+      version_file: bazel-out/volatile-status.txt
+      info_file: bazel-out/stable-status.txt
+      stamp: whether the build is performed with --stamp
       files: The files to move
       action_factory: Bazel's actions module from ctx.actions - see https://docs.bazel.build/versions/master/skylark/lib/actions.html
+      var: environment variables
       assembler: The assembler executable
       root_paths: Path prefixes to strip off all srcs. Longest wins.
 
@@ -47,13 +61,23 @@ def move_files(output_name, files, action_factory, var, assembler, root_paths):
     """
     www_dir = action_factory.declare_directory(output_name)
     args = action_factory.args()
+    inputs = files[:]
     args.add(www_dir.path)
+    if stamp:
+        args.add(version_file.path)
+        inputs.append(version_file)
+        args.add(info_file.path)
+        inputs.append(info_file)
+    else:
+        args.add_all(["", ""])
+    args.add(substitutions)
     args.add_all(root_paths)
     args.add("--assets")
     args.add_all([f.path for f in files])
     args.use_param_file("%s", use_always = True)
+
     action_factory.run(
-        inputs = files,
+        inputs = inputs,
         outputs = [www_dir],
         executable = assembler,
         arguments = [args],
@@ -86,9 +110,12 @@ def additional_root_paths(ctx):
 
 def _impl(ctx):
     root_paths = additional_root_paths(ctx)
-
     package_layout = move_files(
         ctx.label.name,
+        ctx.attr.substitutions,
+        ctx.version_file,
+        ctx.info_file,
+        ctx.attr.node_context_data[NodeContextInfo].stamp,
         ctx.files.srcs,
         ctx.actions,
         ctx.var,

internal/pkg_web/test/BUILD.bazel

@@ -1,5 +1,6 @@
 load("@build_bazel_rules_nodejs//:index.bzl", "pkg_web")
 load("@npm//@babel/cli:index.bzl", "babel")
+load("//internal/node:context.bzl", "node_context_data")
 load("//packages/jasmine:index.bzl", "jasmine_node_test")
 load("//packages/rollup:index.bzl", "rollup_bundle")
 load("//packages/terser:index.bzl", "terser_minified")
@@ -62,6 +63,11 @@ terser_minified(
     debug = True,
 )
 
+node_context_data(
+    name = "force_stamp",
+    stamp = True,
+)
+
 pkg_web(
     name = "pkg",
     srcs = [
@@ -73,16 +79,14 @@ pkg_web(
         ":bundle.min_debug",
         ":bundle.min_debug.es2015",
     ],
+    node_context_data = ":force_stamp",
+    substitutions = {
+        "${version}": "{BUILD_SCM_VERSION}",
+    },
 )
 
 jasmine_node_test(
     name = "test",
     srcs = ["spec.js"],
-    data = [
-        "index_golden.html_",
-        ":pkg",
-    ],
-    tags = [
-        "fix-windows",
-    ],
+    data = [":pkg"],
 )

internal/pkg_web/test/script.ts

@@ -1,4 +1,5 @@
 const el = document.createElement('div');
-const text: string = 'Hello, World';
+const version = '0.0.0-PLACEHOLDER';
+const text: string = `Hello, World v${version}`;
 el.innerText = text;
 document.body.appendChild(el);