Refine bulk load tests with data preparation (#16998)

Signed-off-by: Nyanliang567 <yanliang.qiao@zilliz.com>

tests/python_client/bulk_load/minio_comm.py

+import os
+from minio import Minio
+from minio.error import S3Error
+from utils.util_log import test_log as log
+
+
+def copy_files_to_bucket(client, r_source, target_files, bucket_name, force=False):
+    # check the bucket exist
+    found = client.bucket_exists(bucket_name)
+    if not found:
+        log.error(f"Bucket {bucket_name} not found.")
+        return
+
+    # copy target files from root source folder
+    os.chdir(r_source)
+    for target_file in target_files:
+        found = False
+        try:
+            result = client.stat_object(bucket_name, target_file)
+            found = True
+        except S3Error as exc:
+            pass
+
+        if force or not found:
+            res = client.fput_object(bucket_name, target_file, f"{r_source}/{target_file}")
+            log.info(f"copied {res.object_name} to minio")
+        else:
+            log.info(f"skip copy {res.object_name} to minio")
+
+
+def copy_files_to_minio(host, r_source, files, bucket_name, access_key="minioadmin", secret_key="minioadmin",
+                        secure=False, force=False):
+    client = Minio(
+        host,
+        access_key=access_key,
+        secret_key=secret_key,
+        secure=secure,
+    )
+    try:
+        copy_files_to_bucket(client, r_source=r_source, target_files=files, bucket_name=bucket_name, force=force)
+    except S3Error as exc:
+        log.error("fail to copy files to minio", exc)
+