1 files changed, 137 insertions, 0 deletions
diff --git a/python/mozbuild/mozbuild/action/node.py b/python/mozbuild/mozbuild/action/node.py
new file mode 100644
index 0000000000..fca0745b80
--- /dev/null
+++ b/python/mozbuild/mozbuild/action/node.py
@@ -0,0 +1,137 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import pipes
+import subprocess
+import sys
+
+import buildconfig
+import six
+
+SCRIPT_ALLOWLIST = [buildconfig.topsrcdir + "/devtools/client/shared/build/build.js"]
+
+ALLOWLIST_ERROR = """
+%s is not
+in SCRIPT_ALLOWLIST in python/mozbuild/mozbuild/action/node.py.
+Using NodeJS from moz.build is currently in beta, and node
+scripts to be executed need to be added to the allowlist and
+reviewed by a build peer so that we can get a better sense of
+how support should evolve. (To consult a build peer, raise a
+question in the #build channel at https://chat.mozilla.org.)
+"""
+
+
+def is_script_in_allowlist(script_path):
+    if script_path in SCRIPT_ALLOWLIST:
+        return True
+
+    return False
+
+
+def execute_node_cmd(node_cmd_list):
+    """Execute the given node command list.
+
+    Arguments:
+    node_cmd_list -- a list of the command and arguments to be executed
+
+    Returns:
+    The set of dependencies which should trigger this command to be re-run.
+    This is ultimately returned to the build system for use by the backend
+    to ensure that incremental rebuilds happen when any dependency changes.
+
+    The node script is expected to output lines for all of the dependencies
+    to stdout, each prefixed by the string "dep:".  These lines will make up
+    the returned set of dependencies.  Any line not so-prefixed will simply be
+    printed to stderr instead.
+    """
+
+    try:
+        printable_cmd = " ".join(pipes.quote(arg) for arg in node_cmd_list)
+        print('Executing "{}"'.format(printable_cmd), file=sys.stderr)
+        sys.stderr.flush()
+
+        # We need to redirect stderr to a pipe because
+        # https://github.com/nodejs/node/issues/14752 causes issues with make.
+        proc = subprocess.Popen(
+            node_cmd_list, stdout=subprocess.PIPE, stderr=subprocess.PIPE
+        )
+
+        stdout, stderr = proc.communicate()
+        retcode = proc.wait()
+
+        if retcode != 0:
+            print(stderr, file=sys.stderr)
+            sys.stderr.flush()
+            sys.exit(retcode)
+
+        # Process the node script output
+        #
+        # XXX Starting with an empty list means that node scripts can
+        # (intentionally or inadvertently) remove deps.  Do we want this?
+        deps = []
+        for line in stdout.splitlines():
+            line = six.ensure_text(line)
+            if "dep:" in line:
+                deps.append(line.replace("dep:", ""))
+            else:
+                print(line, file=sys.stderr)
+                sys.stderr.flush()
+
+        return set(deps)
+
+    except subprocess.CalledProcessError as err:
+        # XXX On Mac (and elsewhere?) "OSError: [Errno 13] Permission denied"
+        # (at least sometimes) means "node executable not found".  Can we
+        # disambiguate this from real "Permission denied" errors so that we
+        # can log such problems more clearly?
+        print(
+            """Failed with %s.  Be sure to check that your mozconfig doesn't
+            have --disable-nodejs in it.  If it does, try removing that line and
+            building again."""
+            % str(err),
+            file=sys.stderr,
+        )
+        sys.exit(1)
+
+
+def generate(output, node_script, *files):
+    """Call the given node_script to transform the given modules.
+
+    Arguments:
+    output -- a dummy file, used by the build system.  Can be ignored.
+    node_script -- the script to be executed.  Must be in the SCRIPT_ALLOWLIST
+    files -- files to be transformed, will be passed to the script as arguments
+
+    Returns:
+    The set of dependencies which should trigger this command to be re-run.
+    This is ultimately returned to the build system for use by the backend
+    to ensure that incremental rebuilds happen when any dependency changes.
+    """
+
+    node_interpreter = buildconfig.substs.get("NODEJS")
+    if not node_interpreter:
+        print(
+            """NODEJS not set.  Be sure to check that your mozconfig doesn't
+            have --disable-nodejs in it.  If it does, try removing that line
+            and building again.""",
+            file=sys.stderr,
+        )
+        sys.exit(1)
+
+    node_script = six.ensure_text(node_script)
+    if not isinstance(node_script, six.text_type):
+        print(
+            "moz.build file didn't pass a valid node script name to execute",
+            file=sys.stderr,
+        )
+        sys.exit(1)
+
+    if not is_script_in_allowlist(node_script):
+        print(ALLOWLIST_ERROR % (node_script), file=sys.stderr)
+        sys.exit(1)
+
+    node_cmd_list = [node_interpreter, node_script]
+    node_cmd_list.extend(files)
+
+    return execute_node_cmd(node_cmd_list)