Expose CLI Options through public API (#1928)

* Expose CLI Options through public API

Expose a public API that can retrieve the processed CLI options for the
current process launched through the debugpy CLI. This enables code to
be able to retrieve options like the port and adapter access token to be
used for launching their own child process' that can be debugged.

* Fix test by sending dict not dataclass object

tests/debugpy/test_cli_args.py

@@ -0,0 +1,35 @@
+# Copyright (c) Microsoft Corporation. All rights reserved.
+# Licensed under the MIT License. See LICENSE in the project root
+# for license information.
+
+from tests import debug
+
+
+def test_cli_options_with_no_debugger():
+    import debugpy
+
+    cli_options = debugpy.get_cli_options()
+    assert cli_options is None
+
+
+def test_cli_options_under_file_connect(pyfile, target, run):
+    @pyfile
+    def code_to_debug():
+        import dataclasses
+        import debugpy
+
+        import debuggee
+        from debuggee import backchannel
+
+        debuggee.setup()
+        backchannel.send(dataclasses.asdict(debugpy.get_cli_options()))
+
+    with debug.Session() as session:
+        backchannel = session.open_backchannel()
+
+        with run(session, target(code_to_debug)):
+            pass
+
+        cli_options = backchannel.receive()
+        assert cli_options['mode'] == 'connect'
+        assert cli_options['target_kind'] == 'file'

tests/debugpy/test_multiproc.py

@@ -630,7 +630,7 @@ def test_subprocess_with_parent_pid(pyfile, target, run):
         import subprocess
         import sys
 
-        from debugpy.server import cli as debugpy_cli
+        import debugpy
 
         debuggee.setup()
 
@@ -642,8 +642,11 @@ def test_subprocess_with_parent_pid(pyfile, target, run):
         else:
             argv = ["/bin/sh", "-c"]
 
-        host, port = debugpy_cli.options.address
-        access_token = debugpy_cli.options.adapter_access_token
+        cli_opts = debugpy.get_cli_options()
+        assert cli_opts, "No CLI options found"
+
+        host, port = cli_opts.address
+        access_token = cli_opts.adapter_access_token
 
         shell_args = [
             sys.executable,