support filter flag from env

.buildkite/generate_pipeline.py

@@ -244,8 +244,7 @@ def _convert_quick_tests_core(test_files: List[str], filter_flag: List[str]):
 @click.option(
     '--filter-flag',
     type=str,
-    help='Filter to include only a subset of pytest marks, e.g., managed_jobs',
-    default='all')
+    help='Filter to include only a subset of pytest marks, e.g., managed_jobs')
 def main(filter_flag):
     test_files = os.listdir('tests/smoke_tests')
     release_files = []
@@ -259,11 +258,12 @@ def main(filter_flag):
         else:
             release_files.append(test_file_path)
 
-    if filter_flag == 'all':
-        filter_flag = []
-    else:
+    filter_flag = filter_flag or os.getenv('FILTER_FLAG')
+    if filter_flag:
         filter_flag = filter_flag.split(',')
-    print(f'Filter flag: {filter_flag}')
+        print(f'Filter flag: {filter_flag}')
+    else:
+        filter_flag = []
 
     _convert_release(release_files, filter_flag)
     _convert_quick_tests_core(quick_tests_core_files, filter_flag)