feat: redirect process stdio to file (#2554)

3 files changed, 118 insertions, 11 deletions

diff --git a/js/process.ts b/js/process.ts
index c0a66f311..ce6a05760 100644
--- a/js/process.ts
+++ b/js/process.ts
@@ -28,9 +28,9 @@ export interface RunOptions {
   args: string[];
   cwd?: string;
   env?: { [key: string]: string };
-  stdout?: ProcessStdio;
-  stderr?: ProcessStdio;
-  stdin?: ProcessStdio;
+  stdout?: ProcessStdio | number;
+  stderr?: ProcessStdio | number;
+  stdin?: ProcessStdio | number;
 }
 
 async function runStatus(rid: number): Promise<ProcessStatus> {
@@ -149,6 +149,10 @@ function stdioMap(s: ProcessStdio): msg.ProcessStdio {
   }
 }
 
+function isRid(arg: unknown): arg is number {
+  return !isNaN(arg as number);
+}
+
 /**
  * Spawns new subprocess.
  *
@@ -159,7 +163,8 @@ function stdioMap(s: ProcessStdio): msg.ProcessStdio {
  * mapping.
  *
  * By default subprocess inherits stdio of parent process. To change that
- * `opt.stdout`, `opt.stderr` and `opt.stdin` can be specified independently.
+ * `opt.stdout`, `opt.stderr` and `opt.stdin` can be specified independently -
+ * they can be set to either `ProcessStdio` or `rid` of open file.
  */
 export function run(opt: RunOptions): Process {
   const builder = flatbuffers.createBuilder();
@@ -177,14 +182,49 @@ export function run(opt: RunOptions): Process {
     }
   }
   const envOffset = msg.Run.createEnvVector(builder, kvOffset);
+
+  let stdInOffset = stdioMap("inherit");
+  let stdOutOffset = stdioMap("inherit");
+  let stdErrOffset = stdioMap("inherit");
+  let stdinRidOffset = 0;
+  let stdoutRidOffset = 0;
+  let stderrRidOffset = 0;
+
+  if (opt.stdin) {
+    if (isRid(opt.stdin)) {
+      stdinRidOffset = opt.stdin;
+    } else {
+      stdInOffset = stdioMap(opt.stdin);
+    }
+  }
+
+  if (opt.stdout) {
+    if (isRid(opt.stdout)) {
+      stdoutRidOffset = opt.stdout;
+    } else {
+      stdOutOffset = stdioMap(opt.stdout);
+    }
+  }
+
+  if (opt.stderr) {
+    if (isRid(opt.stderr)) {
+      stderrRidOffset = opt.stderr;
+    } else {
+      stdErrOffset = stdioMap(opt.stderr);
+    }
+  }
+
   const inner = msg.Run.createRun(
     builder,
     argsOffset,
     cwdOffset,
     envOffset,
-    opt.stdin ? stdioMap(opt.stdin) : stdioMap("inherit"),
-    opt.stdout ? stdioMap(opt.stdout) : stdioMap("inherit"),
-    opt.stderr ? stdioMap(opt.stderr) : stdioMap("inherit")
+    stdInOffset,
+    stdOutOffset,
+    stdErrOffset,
+    stdinRidOffset,
+    stdoutRidOffset,
+    stderrRidOffset
   );
   const baseRes = dispatch.sendSync(builder, msg.Any.Run, inner);
   assert(baseRes != null);
diff --git a/js/process_test.ts b/js/process_test.ts
index 6eb4dfd89..6e5fe7947 100644
--- a/js/process_test.ts
+++ b/js/process_test.ts
@@ -1,6 +1,21 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
-import { test, testPerm, assert, assertEquals } from "./test_util.ts";
-const { kill, run, DenoError, ErrorKind } = Deno;
+import {
+  test,
+  testPerm,
+  assert,
+  assertEquals,
+  assertStrContains
+} from "./test_util.ts";
+const {
+  kill,
+  run,
+  DenoError,
+  ErrorKind,
+  readFile,
+  open,
+  makeTempDir,
+  writeFile
+} = Deno;
 
 test(function runPermissions(): void {
   let caughtError = false;
@@ -71,7 +86,7 @@ testPerm(
   { write: true, run: true },
   async function runWithCwdIsAsync(): Promise<void> {
     const enc = new TextEncoder();
-    const cwd = Deno.makeTempDirSync({ prefix: "deno_command_test" });
+    const cwd = await makeTempDir({ prefix: "deno_command_test" });
 
     const exitCodeFile = "deno_was_here";
     const pyProgramFile = "poll_exit.py";
@@ -205,6 +220,57 @@ testPerm({ run: true }, async function runStderrOutput(): Promise<void> {
   p.close();
 });
 
+testPerm(
+  { run: true, write: true, read: true },
+  async function runRedirectStdoutStderr(): Promise<void> {
+    const tempDir = await makeTempDir();
+    const fileName = tempDir + "/redirected_stdio.txt";
+    const file = await open(fileName, "w");
+
+    const p = run({
+      args: [
+        "python",
+        "-c",
+        "import sys; sys.stderr.write('error\\n'); sys.stdout.write('output\\n');"
+      ],
+      stdout: file.rid,
+      stderr: file.rid
+    });
+
+    await p.status();
+    p.close();
+    file.close();
+
+    const fileContents = await readFile(fileName);
+    const decoder = new TextDecoder();
+    const text = decoder.decode(fileContents);
+
+    assertStrContains(text, "error");
+    assertStrContains(text, "output");
+  }
+);
+
+testPerm(
+  { run: true, write: true, read: true },
+  async function runRedirectStdin(): Promise<void> {
+    const tempDir = await makeTempDir();
+    const fileName = tempDir + "/redirected_stdio.txt";
+    const encoder = new TextEncoder();
+    await writeFile(fileName, encoder.encode("hello"));
+    const file = await open(fileName, "r");
+
+    const p = run({
+      args: ["python", "-c", "import sys; assert 'hello' == sys.stdin.read();"],
+      stdin: file.rid
+    });
+
+    const status = await p.status();
+    assertEquals(status.code, 0);
+    p.close();
+    file.close();
+  }
+);
+
 testPerm({ run: true }, async function runEnv(): Promise<void> {
   const p = run({
     args: [
diff --git a/js/test_util.ts b/js/test_util.ts
index 1b9e2f48c..454f26ff2 100644
--- a/js/test_util.ts
+++ b/js/test_util.ts
@@ -16,7 +16,8 @@ export {
   assert,
   assertEquals,
   assertNotEquals,
-  assertStrictEq
+  assertStrictEq,
+  assertStrContains
 } from "./deps/https/deno.land/std/testing/asserts.ts";
 
 interface TestPermissions {