stages: add org.osbuild.ostree.config

Change OSTree configuration for a repository via `ostree config`.

stages/org.osbuild.ostree.config

@@ -0,0 +1,72 @@
+#!/usr/bin/python3
+"""
+Change OSTree configuration
+
+Change the configuration for an OSTree repository.
+Currently only the following values are supported:
+  - `sysroot.readonly`
+"""
+
+import os
+import sys
+import subprocess
+
+import osbuild.api
+
+
+SCHEMA = """
+"additionalProperties": false,
+"required": ["repo"],
+"properties": {
+  "repo": {
+    "description": "Location of the OSTree repo.",
+    "type": "string"
+  },
+  "config": {
+    "type": "object",
+    "additionalProperties": false,
+    "description": "OSTree configuration groups",
+    "properties": {
+      "sysroot": {
+        "type": "object",
+        "additionalProperties": false,
+        "description": "Options concerning the sysroot",
+        "properties": {
+          "readonly": {
+            "description": "Read only sysroot and boot",
+            "type": "boolean"
+          }
+        }
+      }
+    }
+  }
+}
+"""
+
+
+def ostree(*args, _input=None, **kwargs):
+    args = list(args) + [f'--{k}={v}' for k, v in kwargs.items()]
+    print("ostree " + " ".join(args), file=sys.stderr)
+    subprocess.run(["ostree"] + args,
+                   encoding="utf-8",
+                   stdout=sys.stderr,
+                   input=_input,
+                   check=True)
+
+
+def main(tree, options):
+    repo = os.path.join(tree, options["repo"].lstrip("/"))
+    config = options["config"]
+
+    for group, items in config.items():
+        for key, value in items.items():
+            name = f"{group}.{key}"
+            ostree("config", "set", name, str(value),
+                   repo=repo)
+
+
+if __name__ == '__main__':
+    stage_args = osbuild.api.arguments()
+    r = main(stage_args["tree"],
+             stage_args["options"])
+    sys.exit(r)