[tune] add accessible trial_info (#7378)

* add accessible trial_info

* trial name and info

* doc

* fix
gp

* Update doc/source/tune-package-ref.rst

* Apply suggestions from code review

* fix

* trial

* fixtest

* testfix

python/ray/tune/function_runner.py

@@ -29,10 +29,17 @@ class StatusReporter:
         >>>     reporter(timesteps_this_iter=1)
     """
 
-    def __init__(self, result_queue, continue_semaphore, logdir=None):
+    def __init__(self,
+                 result_queue,
+                 continue_semaphore,
+                 trial_name=None,
+                 trial_id=None,
+                 logdir=None):
         self._queue = result_queue
         self._last_report_time = None
         self._continue_semaphore = continue_semaphore
+        self._trial_name = trial_name
+        self._trial_id = trial_id
         self._logdir = logdir
 
     def __call__(self, **kwargs):
@@ -78,6 +85,16 @@ class StatusReporter:
     def logdir(self):
         return self._logdir
 
+    @property
+    def trial_name(self):
+        """Trial name for the corresponding trial of this Trainable."""
+        return self._trial_name
+
+    @property
+    def trial_id(self):
+        """Trial id for the corresponding trial of this Trainable."""
+        return self._trial_id
+
 
 class _RunnerThread(threading.Thread):
     """Supervisor thread that runs your script."""
@@ -133,7 +150,11 @@ class FunctionRunner(Trainable):
         self._error_queue = queue.Queue(1)
 
         self._status_reporter = StatusReporter(
-            self._results_queue, self._continue_semaphore, self.logdir)
+            self._results_queue,
+            self._continue_semaphore,
+            trial_name=self.trial_name,
+            trial_id=self.trial_id,
+            logdir=self.logdir)
         self._last_result = {}
         config = config.copy()