18941: Separate get() behavior for prefetch

[arvados.git] / sdk / python / arvados / keep.py

diff --git a/sdk/python/arvados/keep.py b/sdk/python/arvados/keep.py
index 94104586deb46a4c24c05c41e683a50b28c69d1d..43d71f17e4cb160238b729d740390f3f7a5bdde4 100644 (file)
--- a/sdk/python/arvados/keep.py
+++ b/sdk/python/arvados/keep.py
@@ -1045,10 +1045,6 @@ class KeepClient(object):
         else:
             return None
 
-    def has_cache_slot(self, loc_s):
-        locator = KeepLocator(loc_s)
-        return self.block_cache.get(locator.md5sum) is not None
-
     def refresh_signature(self, loc):
         """Ask Keep to get the remote block and return its local signature"""
         now = datetime.datetime.utcnow().isoformat("T") + 'Z'
@@ -1062,7 +1058,7 @@ class KeepClient(object):
     def get(self, loc_s, **kwargs):
         return self._get_or_head(loc_s, method="GET", **kwargs)
 
-    def _get_or_head(self, loc_s, method="GET", num_retries=None, request_id=None, headers=None):
+    def _get_or_head(self, loc_s, method="GET", num_retries=None, request_id=None, headers=None, cache_slot_get=True):
         """Get data from Keep.
 
         This method fetches one or more blocks of data from Keep.  It
@@ -1102,11 +1098,14 @@ class KeepClient(object):
                 slot, first = self.block_cache.reserve_cache(locator.md5sum)
                 if not first:
                     self.hits_counter.add(1)
-                    blob = slot.get()
-                    if blob is None:
-                        raise arvados.errors.KeepReadError(
-                            "failed to read {}".format(loc_s))
-                    return blob
+                    if cache_slot_get:
+                        blob = slot.get()
+                        if blob is None:
+                            raise arvados.errors.KeepReadError(
+                                "failed to read {}".format(loc_s))
+                        return blob
+                    else:
+                        return None
 
             self.misses_counter.add(1)