Merge pull request #16 from SethHollandsworth/bugfix/caching-template…

…-wide making layer caching work across multiple container groups
SethHollandsworth · Mar 8, 2023 · 0a11154 · 0a11154
2 parents 694fb41 + f3d1646
commit 0a11154
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Showing 2 changed files with 15 additions and 12 deletions.
diff --git a/src/confcom/azext_confcom/rootfs_proxy.py b/src/confcom/azext_confcom/rootfs_proxy.py
@@ -17,6 +17,9 @@
 
 
 class SecurityPolicyProxy:  # pylint: disable=too-few-public-methods
+    # static variable to cache layer hashes between container groups
+    layer_cache = {}
+
     def __init__(self):
         script_directory = os.path.dirname(os.path.realpath(__file__))
         DEFAULT_LIB = "./bin/dmverity-vhd"
@@ -49,9 +52,12 @@ def __init__(self):
     def get_policy_image_layers(
         self, image: str, tag: str, tar_location: str = ""
     ) -> List[str]:
-        policy_bin_str = str(self.policy_bin)
+        image_name = f"{image}:{tag}"
+        # populate layer info
+        if self.layer_cache.get(image_name):
+            return self.layer_cache.get(image_name)
 
-        img = image + ":" + tag
+        policy_bin_str = str(self.policy_bin)
 
         arg_list = [
             f"{policy_bin_str}",
@@ -64,7 +70,7 @@ def get_policy_image_layers(
             arg_list += ["-d"]
 
         # add the image to the end of the parameter list
-        arg_list += ["roothash", "-i", f"{img}"]
+        arg_list += ["roothash", "-i", f"{image_name}"]
 
         outputlines = None
         err = None
@@ -93,5 +99,6 @@ def get_policy_image_layers(
         if err.decode("utf8") != "":
             output = []
             # eprint(err.decode("utf8"))
-
+        # cache output layers
+        self.layer_cache[image_name] = output
         return output
diff --git a/src/confcom/azext_confcom/security_policy.py b/src/confcom/azext_confcom/security_policy.py
@@ -397,7 +397,6 @@ def populate_policy_content_for_all_images(
         )
 
         tar_location = ""
-        layer_cache = {}
         if isinstance(tar_mapping, str):
             tar_location = tar_mapping
         proxy = self._get_rootfs_proxy()
@@ -475,13 +474,10 @@ def populate_policy_content_for_all_images(
                 if isinstance(tar_mapping, dict):
                     tar_location = get_tar_location_from_mapping(tar_mapping, image_name)
                 # populate layer info
-                if layer_cache.get(image_name):
-                    image.set_layers(layer_cache.get(image_name))
-                else:
-                    image.set_layers(proxy.get_policy_image_layers(
-                        image.base, image.tag, tar_location=tar_location if tar else ""
-                    ))
-                    layer_cache[image_name] = image.get_layers()
+                image.set_layers(proxy.get_policy_image_layers(
+                    image.base, image.tag, tar_location=tar_location if tar else ""
+                ))
+
                 progress.update()
             progress.close()
             self.close()