logger: output footer once for multithreaded push/pull errors

dvc/remote/base.py

@@ -515,9 +515,7 @@ class RemoteBASE(object):
                 no_progress_bar=no_progress_bar,
             )
         except Exception:
-            msg = "failed to upload '{}' to '{}'"
-            logger.exception(msg.format(from_info, to_info))
-            return 1  # 1 fail
+            return 1, from_info, to_info, "upload"  # 1 fail
 
         return 0
 
@@ -555,9 +553,7 @@ class RemoteBASE(object):
                 from_info, tmp_file, name=name, no_progress_bar=no_progress_bar
             )
         except Exception:
-            msg = "failed to download '{}' to '{}'"
-            logger.exception(msg.format(from_info, to_info))
-            return 1  # 1 fail
+            return 1, from_info, to_info, "download"  # 1 fail
 
         move(tmp_file, to_info, mode=file_mode)
 

dvc/remote/local.py

@@ -358,11 +358,24 @@ class RemoteLOCAL(RemoteBASE):
         if len(plans[0]) == 0:
             return 0
 
+        fails = 0
+        msgs = ""
         if jobs > 1:
             with TqdmThreadPoolExecutor(max_workers=jobs) as executor:
-                fails = sum(executor.map(func, *plans))
+                failures = executor.map(func, *plans)
         else:
-            fails = sum(map(func, *plans))
+            failures = list(map(func, *plans))
+
+        for it in failures:
+            if not isinstance(it, tuple):
+                continue
+            fails += it[0]
+            from_info, to_info = it[1], it[2]
+            operation = it[3]
+            msgs += f"Failed to {operation} '{from_info}' to '{to_info}'\n"
+
+        if msgs:
+            logger.exception(msgs)
 
         if fails:
             if download: