[tune] Fix Trial Logging File name (#1466)

python/ray/tune/trial.py

@@ -17,6 +17,7 @@ from ray.tune.result import TrainingResult, DEFAULT_RESULTS_DIR, pretty_print
 from ray.utils import random_string, binary_to_hex
 
 DEBUG_PRINT_INTERVAL = 5
+MAX_LEN_IDENTIFIER = 130
 
 
 class Resources(
@@ -337,6 +338,11 @@ class Trial(object):
             logger_creator=logger_creator)
 
     def __str__(self):
+        """Combines ``env`` with ``trainable_name`` and ``experiment_tag``.
+
+        Truncates to MAX_LEN_IDENTIFIER (default is 130) to avoid problems
+        when creating logging directories.
+        """
         if "env" in self.config:
             identifier = "{}_{}".format(
                 self.trainable_name, self.config["env"])
@@ -344,4 +350,4 @@ class Trial(object):
             identifier = self.trainable_name
         if self.experiment_tag:
             identifier += "_" + self.experiment_tag
-        return identifier
+        return identifier[:MAX_LEN_IDENTIFIER]

python/ray/tune/variant_generator.py

@@ -128,10 +128,17 @@ def _format_vars(resolved_vars):
                 last_string = False
                 pieces.append(k)
         pieces.reverse()
-        out.append("_".join(pieces) + "=" + str(value))
+        out.append("_".join(pieces) + "=" + _clean_value(value))
     return ",".join(out)
 
 
+def _clean_value(value):
+    if isinstance(value, float):
+        return "{:.5}".format(value)
+    else:
+        return str(value)
+
+
 def _generate_variants(spec):
     spec = copy.deepcopy(spec)
     unresolved = _unresolved_values(spec)