yaml conf: make 'export yaml config' a user invokable feature

docs/source/dev/index.rst

@@ -16,3 +16,4 @@ Developer documentation
     sample-changer-changes-and-maintenance.md
     tutorial.md
     deployment.md
+    yaml_conf_migration.md

docs/source/dev/yaml_conf_migration.md

@@ -0,0 +1,15 @@
+# YAML configuration migration
+
+Historically MXCuBE used XML files for configuring hardware objects.
+Now it's possible to use YAML files instead of XML files.
+To help with migration to YAML files, MXCuBE-Web can export loaded hardware objects configurations as YAML files.
+
+Use `--export-yaml-config` argument when starting MXCuBE-web to enable YAML export.
+For example, if you use:
+
+```
+    $ mxcubeweb-server --export-yaml-config <my-yaml-dir>
+```
+
+`mxcubeweb-server` will load your hardware object configuration as normal.
+Then it will write the loaded configuration into the `<my-yaml-dir>`.

mxcubeweb/__init__.py

@@ -10,6 +10,7 @@
 import redis  # noqa: E402
 import sys  # noqa: E402
 import traceback  # noqa: E402
+from pathlib import Path  # noqa: E402
 
 from mxcubeweb.server import Server as server  # noqa: E402
 from mxcubeweb.app import MXCUBEApplication as mxcube  # noqa: E402
@@ -99,6 +100,13 @@ def parse_args(argv):
         default=False,
     )
 
+    opt_parser.add_argument(
+        "--export-yaml-config",
+        dest="yaml_export_directory",
+        type=Path,
+        help="write YAML configuration to specified path",
+    )
+
     # If `argv` is `None`, then `argparse.ArgumentParser.parse_args`
     # will know to read from `sys.argv` instead.
     return opt_parser.parse_args(argv)
@@ -119,7 +127,9 @@ def build_server_and_config(test=False, argv=None):
         # as the hwr_directory. I need it for sensible managing of a multi-beamline test set-up
         # without continuously editing the main config files.
         # Note that the machinery was all there in the core already. rhfogh.
-        HWR.init_hardware_repository(cmdline_options.hwr_directory)
+        HWR.init_hardware_repository(
+            cmdline_options.hwr_directory, cmdline_options.yaml_export_directory
+        )
         config_path = HWR.get_hardware_repository().find_in_repository("mxcube-web")
 
         cfg = Config(config_path)