[tune] configurable maximum length of trial identifier (#5287)

python/ray/tune/trial.py

@@ -30,7 +30,7 @@ from ray.tune.result import (DEFAULT_RESULTS_DIR, DONE, HOSTNAME, PID,
 from ray.utils import binary_to_hex, hex_to_binary
 
 DEBUG_PRINT_INTERVAL = 5
-MAX_LEN_IDENTIFIER = 130
+MAX_LEN_IDENTIFIER = int(os.environ.get("MAX_LEN_IDENTIFIER", 130))
 logger = logging.getLogger(__name__)