Expose SHA512SUM on successful upload

This gives user the possibility to check what was uploaded to shacache.

slapcache/signature.py

@@ -236,12 +236,17 @@ class Signature:
       'token': ''.join([choice(ascii_lowercase) for _ in range(128)]) 
     }
     try:
-      if shacache.upload(path=path,
-                         metadata_dict=metadata_dict):
-        self.log('Uploaded %s to cache (using %s key).', path, shacache.directory_key)
-        if shacache.upload(path=sha256path, 
-                         metadata_dict=metadata_dict, is_sha256file=True):
-          self.log('Uploaded %s to cache (using %s key).', sha256path, shacache.directory_key)
+      sha512sum = shacache.upload(path=path, metadata_dict=metadata_dict)
+      if sha512sum:
+        self.log(
+          'Uploaded %s to cache (using %s key) with SHA512 %s.', path,
+          shacache.directory_key, sha512sum)
+        sha512sum_path = shacache.upload(
+          path=sha256path, metadata_dict=metadata_dict, is_sha256file=True)
+        if sha512sum_path:
+          self.log(
+            'Uploaded %s to cache (using %s key) with SHA512 %s.', sha256path,
+            shacache.directory_key, sha512sum_path)
         else:
           self.log('Fail to upload sha256file file to cache.')
       else: