Add the ability to create symlinks

scone/default/recipes/filesystem.py

@@ -25,6 +25,7 @@ from scone.default.utensils.basic_utensils import (
     Chmod,
     Chown,
     MakeDirectory,
+    MakeSymlink,
     SimpleExec,
     Stat,
 )
@@ -133,6 +134,43 @@ class EnsureDirectory(Recipe):
         k.get_dependency_tracker()
 
 
+class EnsureSymlink(Recipe):
+    """
+    Makes a symbolic link.
+    """
+
+    _NAME = "symlink"
+
+    def __init__(self, recipe_context: RecipeContext, args: dict, head):
+        super().__init__(recipe_context, args, head)
+
+        self.path = check_type(args.get("path"), str)
+        self.target = check_type(args.get("target"), str)
+        self.is_dir = check_type(args.get("is_dir", False), bool)
+        self.checked = check_type(args.get("checked", True), bool)
+
+        # user and permissions don't make sense for symlinks
+
+    def prepare(self, preparation: Preparation, head: "Head"):
+        super().prepare(preparation, head)
+        path = Path(self.path)
+
+        preparation.needs("directory", str(path.parent))
+
+        kind = "directory" if self.is_dir else "file"
+
+        preparation.provides(kind, str(path))
+
+        if self.checked:
+            preparation.needs(kind, str(Path(path, self.target)))
+
+    async def cook(self, k: Kitchen):
+        await k.ut0(MakeSymlink(self.path, self.target))
+
+        # mark as tracked.
+        k.get_dependency_tracker()
+
+
 class ExtractTar(Recipe):
     """
     Extracts a tar archive, expecting to get at least some files.

scone/default/utensils/basic_utensils.py

@@ -63,6 +63,15 @@ class MakeDirectory(Utensil):
         os.umask(oldumask)
 
 
+@attr.s(auto_attribs=True)
+class MakeSymlink(Utensil):
+    path: str
+    target: str
+
+    async def execute(self, channel: Channel, worktop):
+        os.symlink(self.target, self.path)
+
+
 @attr.s(auto_attribs=True)
 class Stat(Utensil):
     path: str