feat(typescript): worker mode for ts_project

internal/node/node.bzl

@@ -37,7 +37,7 @@ def _trim_package_node_modules(package_name):
     for n in package_name.split("/"):
         if n == "node_modules":
             break
-        segments += [n]
+        segments.append(n)
     return "/".join(segments)
 
 def _compute_node_modules_root(ctx):
@@ -250,7 +250,15 @@ fi
     expanded_args = [expand_location_into_runfiles(ctx, a, ctx.attr.data) for a in expanded_args]
 
     # Next expand predefined variables & custom variables
-    expanded_args = [ctx.expand_make_variables("templated_args", e, {}) for e in expanded_args]
+    rule_dir = [f for f in [
+        ctx.bin_dir.path,
+        ctx.label.workspace_root,
+        ctx.label.package,
+    ] if f]
+    additional_substitutions = {}
+    additional_substitutions["@D"] = "/".join([o for o in rule_dir if o])
+    additional_substitutions["RULEDIR"] = "/".join([o for o in rule_dir if o])
+    expanded_args = [ctx.expand_make_variables("templated_args", e, additional_substitutions) for e in expanded_args]
 
     substitutions = {
         # TODO: Split up results of multifile expansions into separate args and qoute them with

packages/typescript/internal/ts_project.bzl

@@ -2,6 +2,7 @@
 
 load("@build_bazel_rules_nodejs//:providers.bzl", "DeclarationInfo", "NpmPackageInfo", "declaration_info", "js_module_info", "run_node")
 load("@build_bazel_rules_nodejs//internal/linker:link_node_modules.bzl", "module_mappings_aspect")
+load("@build_bazel_rules_nodejs//internal/node:node.bzl", "nodejs_binary")
 
 _DEFAULT_TSC = (
     # BEGIN-INTERNAL
@@ -22,7 +23,14 @@ _ATTRS = {
     # if you swap out the `compiler` attribute (like with ngtsc)
     # that compiler might allow more sources than tsc does.
     "srcs": attr.label_list(allow_files = True, mandatory = True),
-    "tsc": attr.label(default = Label(_DEFAULT_TSC), executable = True, cfg = "host"),
+    "supports_workers": attr.bool(
+        doc = """Experimental! Use only with caution.
+
+Allows you to enable the Bazel Worker strategy for this project.
+This requires that the tsc binary support it.""",
+        default = False,
+    ),
+    "tsc": attr.label(default = Label(_DEFAULT_TSC), executable = True, cfg = "target"),
     "tsconfig": attr.label(mandatory = True, allow_single_file = [".json"]),
 }
 
@@ -50,6 +58,13 @@ def _join(*elements):
 
 def _ts_project_impl(ctx):
     arguments = ctx.actions.args()
+    execution_requirements = {}
+
+    if ctx.attr.supports_workers:
+        # Set to use a multiline param-file for worker mode
+        arguments.use_param_file("@%s", use_always = True)
+        arguments.set_param_file_format("multiline")
+        execution_requirements["supports-workers"] = "1"
 
     # Add user specified arguments *before* rule supplied arguments
     arguments.add_all(ctx.attr.args)
@@ -128,6 +143,7 @@ def _ts_project_impl(ctx):
             arguments = [arguments],
             outputs = outputs,
             executable = "tsc",
+            execution_requirements = execution_requirements,
             progress_message = "Compiling TypeScript project %s [tsc -p %s]" % (
                 ctx.label,
                 ctx.file.tsconfig.short_path,
@@ -238,6 +254,7 @@ def ts_project_macro(
         emit_declaration_only = False,
         tsc = None,
         validate = True,
+        supports_workers = False,
         declaration_dir = None,
         out_dir = None,
         root_dir = None,
@@ -366,6 +383,11 @@ def ts_project_macro(
 
         validate: boolean; whether to check that the tsconfig settings match the attributes.
 
+        supports_workers: Experimental! Use only with caution.
+
+            Allows you to enable the Bazel Worker strategy for this project.
+            This requires that the tsc binary support it.
+
         root_dir: a string specifying a subdirectory under the input package which should be consider the
             root directory of all the input files.
             Equivalent to the TypeScript --rootDir option.
@@ -421,6 +443,35 @@ def ts_project_macro(
         )
         extra_deps.append("_validate_%s_options" % name)
 
+    is_windows = select({
+        "@bazel_tools//src/conditions:host_windows": True,
+        "//conditions:default": False,
+    })
+    supports_workers = supports_workers and not is_windows
+    if supports_workers:
+        worker_name = name + "_worker"
+        nodejs_binary(
+            name = worker_name,
+            data = [
+                tsconfig,
+                "//packages/typescript/internal/worker:copy_worker_js",
+                "//packages/typescript/internal/worker:copy_worker_proto",
+                "//packages/typescript/internal/worker:worker_adapter",
+                tsc,
+            ],
+            entry_point = "//packages/typescript/internal/worker:worker_adapter",
+            templated_args = [
+                "--nobazel_patch_module_resolver",
+                "$(rootpath {tsc})".format(tsc = tsc),
+                "--project",
+                "$(execpath {tsconfig})".format(tsconfig = tsconfig),
+                "--outDir",
+                "$(RULEDIR)",
+                "--watch",
+            ],
+        )
+        tsc = ":" + worker_name
+
     typings_out_dir = declaration_dir if declaration_dir else out_dir
 
     ts_project(

packages/typescript/internal/worker/BUILD.bazel

@@ -0,0 +1,27 @@
+load("//internal/common:copy_to_bin.bzl", "copy_to_bin")
+load("//third_party/github.com/bazelbuild/bazel-skylib:rules/copy_file.bzl", "copy_file")
+
+# Copy the proto file to a matching third_party/... nested directory
+# so the runtime require() statements still work
+_worker_proto_dir = "third_party/github.com/bazelbuild/bazel/src/main/protobuf"
+
+genrule(
+    name = "copy_worker_js",
+    srcs = ["//packages/worker:npm_package"],
+    outs = ["worker.js"],
+    cmd = "cp $(execpath //packages/worker:npm_package)/index.js $@",
+    visibility = ["//visibility:public"],
+)
+
+copy_file(
+    name = "copy_worker_proto",
+    src = "@build_bazel_rules_typescript//%s:worker_protocol.proto" % _worker_proto_dir,
+    out = "%s/worker_protocol.proto" % _worker_proto_dir,
+    visibility = ["//visibility:public"],
+)
+
+copy_to_bin(
+    name = "worker_adapter",
+    srcs = ["worker_adapter.js"],
+    visibility = ["//visibility:public"],
+)

packages/typescript/internal/worker/worker_adapter.js

@@ -0,0 +1,40 @@
+const child_process = require('child_process');
+
+const worker = require('./worker');
+
+const workerArg = process.argv.indexOf('--persistent_worker')
+if (workerArg > 0) {
+  process.argv.splice(workerArg, 1)
+
+  if (process.platform !== 'linux' && process.platform !== 'darwin') {
+    throw new Error('Worker mode is only supported on unix type systems.');
+  }
+
+  worker.runWorkerLoop(awaitOneBuild);
+}
+
+const [tscBin, ...tscArgs] = process.argv.slice(2);
+
+const child = child_process.spawn(
+    tscBin,
+    tscArgs,
+    {stdio: 'pipe'},
+);
+
+function awaitOneBuild() {
+  child.kill('SIGCONT')
+
+  return new Promise((res) => {
+    function awaitBuild(s) {
+      if (s.includes('Watching for file changes.')) {
+        child.kill('SIGSTOP')
+
+        const success = s.includes('Found 0 errors.');
+        res(success);
+
+        child.stdout.removeListener('data', awaitBuild);
+      }
+    };
+    child.stdout.on('data', awaitBuild);
+  });
+}

packages/typescript/test/ts_project/worker/BUILD.bazel

@@ -0,0 +1,6 @@
+load("//packages/typescript:index.bzl", "ts_project")
+
+ts_project(
+    declaration = True,
+    supports_workers = True,
+)

packages/typescript/test/ts_project/worker/big.ts

@@ -0,0 +1,3 @@
+// TODO: make it big enough to slow down tsc
+
+export const a: number = 45;

packages/typescript/test/ts_project/worker/tsconfig.json

@@ -0,0 +1,6 @@
+{
+    "compilerOptions": {
+        "types": [],
+        "declaration": true
+    }
+}

packages/typescript/test/ts_project/worker/worker_adapter.js

@@ -0,0 +1,40 @@
+const child_process = require('child_process');
+
+const worker = require('./worker');
+
+const workerArg = process.argv.indexOf('--persistent_worker')
+if (workerArg > 0) {
+  process.argv.splice(workerArg, 1)
+
+  if (process.platform !== 'linux' && process.platform !== 'darwin') {
+    throw new Error('Worker mode is only supported on unix type systems.');
+  }
+
+  worker.runWorkerLoop(awaitOneBuild);
+}
+
+const [tscBin, ...tscArgs] = process.argv.slice(2);
+
+const child = child_process.spawn(
+    tscBin,
+    tscArgs,
+    {stdio: 'pipe'},
+);
+
+function awaitOneBuild() {
+  child.kill('SIGCONT')
+
+  return new Promise((res) => {
+    function awaitBuild(s) {
+      if (s.includes('Watching for file changes.')) {
+        child.kill('SIGSTOP')
+
+        const success = s.includes('Found 0 errors.');
+        res(success);
+
+        child.stdout.removeListener('data', awaitBuild);
+      }
+    };
+    child.stdout.on('data', awaitBuild);
+  });
+}