[Dashboard] Improve handling of logs and errors in dashboard backend (#5857)

* Improve handling of logs and errors in dashboard backend

* Update nested dict comprehension for clarity

python/ray/exceptions.py

@@ -7,6 +7,8 @@ try:
 except ImportError:
     setproctitle = None
 
+import ray
+
 
 class RayError(Exception):
     """Super class of all ray exception types."""
@@ -33,14 +35,14 @@ class RayTaskError(RayError):
                  traceback_str,
                  cause_cls,
                  pid=None,
-                 host=None):
+                 ip=None):
         """Initialize a RayTaskError."""
         if setproctitle:
             self.proctitle = setproctitle.getproctitle()
         else:
             self.proctitle = "ray_worker"
         self.pid = pid or os.getpid()
-        self.host = host or os.uname()[1]
+        self.ip = ip or ray.services.get_node_ip_address()
         self.function_name = function_name
         self.traceback_str = traceback_str
         self.cause_cls = cause_cls
@@ -67,7 +69,7 @@ class RayTaskError(RayError):
         cls.__qualname__ = name
 
         return cls(self.function_name, self.traceback_str, self.cause_cls,
-                   self.pid, self.host)
+                   self.pid, self.ip)
         cls.original = self
         return cls
 
@@ -78,9 +80,9 @@ class RayTaskError(RayError):
         in_worker = False
         for line in lines:
             if line.startswith("Traceback "):
-                out.append("{}{}{} (pid={}, host={})".format(
+                out.append("{}{}{} (pid={}, ip={})".format(
                     colorama.Fore.CYAN, self.proctitle, colorama.Fore.RESET,
-                    self.pid, self.host))
+                    self.pid, self.ip))
             elif in_worker:
                 in_worker = False
             elif "ray/worker.py" in line or "ray/function_manager.py" in line: