_artifactcache: Add key parameter to extract() method

Contain cache key logic in Element class.

4 files changed, 22 insertions, 22 deletions

diff --git a/buildstream/_artifactcache/artifactcache.py b/buildstream/_artifactcache/artifactcache.py
index aef2cde1d..927876dfb 100644
--- a/buildstream/_artifactcache/artifactcache.py
+++ b/buildstream/_artifactcache/artifactcache.py
@@ -164,6 +164,7 @@ class ArtifactCache():
     #
     # Args:
     #     element (Element): The Element to extract
+    #     key (str): The cache key to use
     #
     # Raises:
     #     ArtifactError: In cases there was an OSError, or if the artifact
@@ -171,7 +172,7 @@ class ArtifactCache():
     #
     # Returns: path to extracted artifact
     #
-    def extract(self, element):
+    def extract(self, element, key):
         raise ImplError("Cache '{kind}' does not implement extract()"
                         .format(kind=type(self).__name__))
 
diff --git a/buildstream/_artifactcache/ostreecache.py b/buildstream/_artifactcache/ostreecache.py
index f50d6ae99..cae4f7269 100644
--- a/buildstream/_artifactcache/ostreecache.py
+++ b/buildstream/_artifactcache/ostreecache.py
@@ -213,6 +213,7 @@ class OSTreeCache(ArtifactCache):
     #
     # Args:
     #     element (Element): The Element to extract
+    #     key (str): The cache key to use
     #
     # Raises:
     #     ArtifactError: In cases there was an OSError, or if the artifact
@@ -220,18 +221,12 @@ class OSTreeCache(ArtifactCache):
     #
     # Returns: path to extracted artifact
     #
-    def extract(self, element):
-        ref = buildref(element, element._get_strict_cache_key())
+    def extract(self, element, key):
+        ref = buildref(element, key)
 
         # resolve ref to checksum
         rev = _ostree.checksum(self.repo, ref)
 
-        # resolve weak cache key, if artifact is missing for strong cache key
-        # and the context allows use of weak cache keys
-        if not rev and not element._get_strict():
-            ref = buildref(element, element._get_cache_key(strength=_KeyStrength.WEAK))
-            rev = _ostree.checksum(self.repo, ref)
-
         if not rev:
             raise ArtifactError("Artifact missing for {}".format(ref))
 
diff --git a/buildstream/_artifactcache/tarcache.py b/buildstream/_artifactcache/tarcache.py
index d1d6c035a..d0d019649 100644
--- a/buildstream/_artifactcache/tarcache.py
+++ b/buildstream/_artifactcache/tarcache.py
@@ -283,18 +283,12 @@ class TarCache(ArtifactCache):
     #
     # Implements artifactcache.extract().
     #
-    def extract(self, element):
+    def extract(self, element, key):
 
-        key = element._get_strict_cache_key()
         ref = buildref(element, key)
         path = tarpath(element, key)
 
         if not os.path.isfile(os.path.join(self.tardir, path)):
-            key = element._get_cache_key(strength=_KeyStrength.WEAK)
-            ref = buildref(element, key)
-            path = tarpath(element, key)
-
-        if not os.path.isfile(os.path.join(self.tardir, path)):
             raise ArtifactError("Artifact missing for {}".format(ref))
 
         # If the destination already exists, the artifact has been extracted
diff --git a/buildstream/element.py b/buildstream/element.py
index 3338f388b..0d67f8dae 100644
--- a/buildstream/element.py
+++ b/buildstream/element.py
@@ -421,7 +421,7 @@ class Element(Plugin):
 
         with self.timed_activity("Staging {}/{}".format(self.name, self._get_display_key())):
             # Get the extracted artifact
-            artifact = os.path.join(self.__artifacts.extract(self), 'files')
+            artifact = os.path.join(self.__extract(), 'files')
 
             # Hard link it into the staging area
             #
@@ -1251,7 +1251,7 @@ class Element(Plugin):
         if self.__workspaced_artifact is None:
             self._assert_cached()
 
-            metadir = os.path.join(self.__artifacts.extract(self), 'meta')
+            metadir = os.path.join(self.__extract(), 'meta')
             meta = _yaml.load(os.path.join(metadir, 'artifact.yaml'))
             if 'workspaced' in meta:
                 self.__workspaced_artifact = meta['workspaced']
@@ -1265,7 +1265,7 @@ class Element(Plugin):
         if self.__workspaced_dependencies_artifact is None:
             self._assert_cached()
 
-            metadir = os.path.join(self.__artifacts.extract(self), 'meta')
+            metadir = os.path.join(self.__extract(), 'meta')
             meta = _yaml.load(os.path.join(metadir, 'artifact.yaml'))
             if 'workspaced_dependencies' in meta:
                 self.__workspaced_dependencies_artifact = meta['workspaced_dependencies']
@@ -1573,7 +1573,7 @@ class Element(Plugin):
                 pass
             elif self._cached():
                 # Load the strong cache key from the artifact
-                metadir = os.path.join(self.__artifacts.extract(self), 'meta')
+                metadir = os.path.join(self.__extract(), 'meta')
                 meta = _yaml.load(os.path.join(metadir, 'artifact.yaml'))
                 self.__cache_key = meta['keys']['strong']
             elif self._buildable():
@@ -1773,7 +1773,7 @@ class Element(Plugin):
         }
 
     def __compute_splits(self, include=None, exclude=None, orphans=True):
-        basedir = os.path.join(self.__artifacts.extract(self), 'files')
+        basedir = os.path.join(self.__extract(), 'files')
 
         # No splitting requested, just report complete artifact
         if orphans and not (include or exclude):
@@ -1823,12 +1823,22 @@ class Element(Plugin):
             if include_file and not exclude_file:
                 yield filename.lstrip(os.sep)
 
+    def __extract(self):
+        key = self.__strict_cache_key
+
+        # Use weak cache key, if artifact is missing for strong cache key
+        # and the context allows use of weak cache keys
+        if not self._get_strict() and not self.__artifacts.contains(self, key):
+            key = self._get_cache_key(strength=_KeyStrength.WEAK)
+
+        return self.__artifacts.extract(self, key)
+
     def _load_public_data(self):
         self._assert_cached()
         assert(self.__dynamic_public is None)
 
         # Load the public data from the artifact
-        metadir = os.path.join(self.__artifacts.extract(self), 'meta')
+        metadir = os.path.join(self.__extract(), 'meta')
         self.__dynamic_public = _yaml.load(os.path.join(metadir, 'public.yaml'))
 
     def _subst_string(self, value):