stages/mkdir: add exist_ok option to not fail if directory exists

Add a new optional stage option to not fail if the specified directory
already exists. This will make it easier to support creation of custom
repositories via customizations in osbuild-composer. The reason is that
if a specified directory exists in an image, because it was created by
an RPM, then creating it would fail. However, the user may have
specified different mode for the directory, than it already has. Since
there is no way to know for sure if the directory already exists on the
image, without building the image itself, it is desired to handle this
case gracefully as valid in specific use cases.

The default behavior stays the same - specifying an existing directory
path will lead to an error.

Signed-off-by: Tomáš Hozza <thozza@redhat.com>

stages/org.osbuild.mkdir

@@ -36,8 +36,12 @@ SCHEMA_2 = r"""
             "type": "boolean",
             "description": "Create intermediate directories",
             "default": false
+          },
+          "exist_ok": {
+            "type": "boolean",
+            "description": "Do not fail if the directory already exists",
+            "default": false
           }
-
         }
       }
     }
@@ -50,17 +54,21 @@ def main(tree, options):
     for item in options["paths"]:
         path = item["path"]
         mode = item.get("mode", 0o777)
-
         parents = item.get("parents", False)
+        exist_ok = item.get("exist_ok", False)
 
         target = os.path.join(tree, path.lstrip("/"))
         if not in_tree(target, tree):
             raise ValueError(f"path {path} not in tree")
 
         if parents:
-            os.makedirs(target, mode=mode)
+            os.makedirs(target, mode=mode, exist_ok=exist_ok)
         else:
-            os.mkdir(target, mode)
+            try:
+                os.mkdir(target, mode)
+            except FileExistsError:
+                if not exist_ok:
+                    raise
 
         # Documentation for os.mkdir() says that the mode is
         # ignored on some systems. Also umask value may affect

test/data/stages/mkdir/a.json

@@ -362,6 +362,10 @@
             "paths": [
               {
                 "path": "a"
+              },
+              {
+                "path": "c/d",
+                "parents": true
               }
             ]
           }

test/data/stages/mkdir/a.mpp.json

@@ -18,6 +18,10 @@
             "paths": [
               {
                 "path": "a"
+              },
+              {
+                "path": "c/d",
+                "parents": true
               }
             ]
           }

test/data/stages/mkdir/b.json

@@ -363,6 +363,10 @@
               {
                 "path": "a"
               },
+              {
+                "path": "c/d",
+                "parents": true
+              },
               {
                 "path": "a/b",
                 "mode": 448
@@ -370,6 +374,11 @@
               {
                 "path": "b/c/d",
                 "parents": true
+              },
+              {
+                "path": "c",
+                "mode": 448,
+                "exist_ok": true
               }
             ]
           }

test/data/stages/mkdir/b.mpp.json

@@ -19,6 +19,10 @@
               {
                 "path": "a"
               },
+              {
+                "path": "c/d",
+                "parents": true
+              },
               {
                 "path": "a/b",
                 "mode": 448
@@ -26,6 +30,11 @@
               {
                 "path": "b/c/d",
                 "parents": true
+              },
+              {
+                "path": "c",
+                "mode": 448,
+                "exist_ok": true
               }
             ]
           }

test/data/stages/mkdir/diff.json

@@ -6,5 +6,5 @@
     "/b/c/d"
   ],
   "deleted_files": [],
-  "differences": {}
+  "differences": {"/c": {"mode": [16877, 16832]}}
 }