Only push the cache when pushing the image

Author: bschwedler

posit-bakery/posit_bakery/config/config.py

@@ -752,7 +752,7 @@ def build_targets(
         :param fail_fast: If True, stop building targets on the first failure.
         """
         if strategy == ImageBuildStrategy.BAKE:
-            bake_plan = BakePlan.from_image_targets(context=self.base_path, image_targets=self.targets)
+            bake_plan = BakePlan.from_image_targets(context=self.base_path, image_targets=self.targets, push=push)
             set_opts = None
             if self.settings.temp_registry is not None and push:
                 set_opts = {

posit-bakery/posit_bakery/image/bake/bake.py

@@ -90,7 +90,7 @@ def serialize_path(value: Path | str) -> str:
         return str(value)
 
     @classmethod
-    def from_image_target(cls, image_target: ImageTarget) -> "BakeTarget":
+    def from_image_target(cls, image_target: ImageTarget, push: bool = False) -> "BakeTarget":
         """Create a BakeTarget from an ImageTarget."""
         kwargs = {"tags": image_target.tags}
         platforms = image_target.image_os.platforms if image_target.image_os is not None else DEFAULT_PLATFORMS
@@ -101,7 +101,8 @@ def from_image_target(cls, image_target: ImageTarget) -> "BakeTarget":
             platform_suffix = "-".join(p.removeprefix("linux/").replace("/", "-") for p in platforms)
             cache_name = f"{cache_name}-{platform_suffix}"
             kwargs["cache_from"] = [{"type": "registry", "ref": cache_name}]
-            kwargs["cache_to"] = [{"type": "registry", "ref": cache_name, "mode": "max"}]
+            if push:
+                kwargs["cache_to"] = [{"type": "registry", "ref": cache_name, "mode": "max"}]
 
         if image_target.temp_name is not None:
             kwargs["tags"] = [image_target.temp_name.rsplit(":", 1)[0]]
@@ -157,11 +158,12 @@ def update_groups(
         return groups
 
     @classmethod
-    def from_image_targets(cls, context: Path, image_targets: list[ImageTarget]) -> "BakePlan":
+    def from_image_targets(cls, context: Path, image_targets: list[ImageTarget], push: bool = False) -> "BakePlan":
         """Create a BakePlan from a list of ImageTarget objects.
 
         :param context: The absolute path to the build context directory.
         :param image_targets: A list of ImageTarget objects to include in the bake plan.
+        :param push: Whether images will be pushed. Controls cache_to behavior.
 
         :return: A BakePlan object containing the context, groups, and targets.
         """
@@ -171,7 +173,7 @@ def from_image_targets(cls, context: Path, image_targets: list[ImageTarget]) ->
         targets: dict[str, BakeTarget] = {}
 
         for image_target in image_targets:
-            bake_target = BakeTarget.from_image_target(image_target=image_target)
+            bake_target = BakeTarget.from_image_target(image_target=image_target, push=push)
             groups = cls.update_groups(
                 groups=groups,
                 uid=image_target.uid,