Bug 1667152 - Add --requirements argument to mach python r=ahal

Differential Revision: https://phabricator.services.mozilla.com/D91313

python/mach_commands.py

@@ -31,6 +31,7 @@ from mach.decorators import (
     CommandProvider,
     Command,
 )
+from mach.util import UserError
 
 here = os.path.abspath(os.path.dirname(__file__))
 
@@ -53,8 +54,15 @@ class MachCommands(MachCommandBase):
         default=False,
         help="Use ipython instead of the default Python REPL.",
     )
+    @CommandArgument(
+        "--requirements",
+        default=None,
+        help="Install this requirements file before running Python",
+    )
     @CommandArgument("args", nargs=argparse.REMAINDER)
-    def python(self, no_virtualenv, no_activate, exec_file, ipython, args):
+    def python(
+        self, no_virtualenv, no_activate, exec_file, ipython, requirements, args
+    ):
         # Avoid logging the command
         self.log_manager.terminal_handler.setLevel(logging.CRITICAL)
 
@@ -63,6 +71,9 @@ class MachCommands(MachCommandBase):
             "PYTHONDONTWRITEBYTECODE": str("1"),
         }
 
+        if requirements and no_virtualenv:
+            raise UserError("Cannot pass both --requirements and --no-virtualenv.")
+
         if no_virtualenv:
             from mach_bootstrap import mach_sys_path
 
@@ -73,6 +84,10 @@ class MachCommands(MachCommandBase):
             if not no_activate:
                 self.virtualenv_manager.activate()
             python_path = self.virtualenv_manager.python_path
+            if requirements:
+                self.virtualenv_manager.install_pip_requirements(
+                    requirements, require_hashes=False
+                )
 
         if exec_file:
             exec(open(exec_file).read())