objstorage_checker: Use check method from object storage interface

Instead of reinventing the wheel, prefer to use the check method from the object storage interface for verifying content presence and integrity.

Depends on !65 (merged) and swh-objstorage!178 (merged).

Related to #4694 (closed).

swh/scrubber/base_checker.py

@@ -29,10 +29,14 @@ class BaseChecker(ABC):
     ):
         self.db = db
         self.config_id = config_id
-        self.statsd_constant_tags: Dict[str, Any] = {}
-
         self._config: Optional[ConfigEntry] = None
         self._statsd: Optional[Statsd] = None
+        self.statsd_constant_tags: Dict[str, Any] = {
+            "object_type": self.object_type.name.lower(),
+            "datastore_package": self.datastore.package,
+            "datastore_cls": self.datastore.cls,
+            "datastore_instance": self.datastore.instance,
+        }
 
     @property
     def config(self) -> ConfigEntry:
@@ -59,6 +63,11 @@ class BaseChecker(ABC):
             )
         return self._statsd
 
+    @property
+    def object_type(self) -> swhids.ObjectType:
+        """Returns the type of object being checked."""
+        return self.config.object_type
+
     @property
     def check_hashes(self) -> bool:
         return self.config.check_hashes
@@ -84,17 +93,7 @@ class BasePartitionChecker(BaseChecker):
     ):
         super().__init__(db=db, config_id=config_id)
         self.limit = limit
-        self.statsd_constant_tags = {
-            "object_type": self.object_type,
-            "nb_partitions": self.nb_partitions,
-            "datastore_package": self.datastore.package,
-            "datastore_cls": self.datastore.cls,
-        }
-
-    @property
-    def object_type(self) -> swhids.ObjectType:
-        """Returns the type of object being checked."""
-        return self.config.object_type
+        self.statsd_constant_tags["nb_partitions"] = self.nb_partitions
 
     @property
     def nb_partitions(self) -> int: