restore output coloring without IPython

just needed a couple ANSI constants

Author: minrk

ipyparallel/client/client.py

@@ -49,6 +49,7 @@
 from ipyparallel import error, serialize, util
 from ipyparallel.serialize import PrePickled, Reference
 from ipyparallel.util import _OutputProducingThread as Thread
+from ipyparallel.util import _TermColors
 
 from .asyncresult import AsyncHubResult, AsyncResult
 from .futures import MessageFuture, multi_future
@@ -161,11 +162,30 @@ def _plaintext(self) -> str:
         if not text_out:
             return ''
 
+        ip = get_ipython()
+        if ip is None:
+            colors = "NoColor"
+        else:
+            colors = ip.colors
+
+        if colors == "NoColor":
+            out = normal = ""
+        else:
+            out = _TermColors.Red
+            normal = _TermColors.Normal
+
         if '\n' in text_out and not text_out.startswith('\n'):
             # add newline for multiline reprs
             text_out = '\n' + text_out
 
-        return f"Out[{self.metadata['engine_id']}:{self.execution_count}]: {text_out}"
+        return ''.join(
+            [
+                out,
+                f"Out[{self.metadata['engine_id']}:{self.execution_count}]: ",
+                normal,
+                text_out,
+            ]
+        )
 
     def _repr_pretty_(self, p, cycle):
         p.text(self._plaintext())

ipyparallel/util.py

@@ -13,6 +13,7 @@
 import sys
 import warnings
 from datetime import datetime, timezone
+from enum import Enum
 from functools import lru_cache, partial
 from signal import SIGABRT, SIGINT, SIGTERM, signal
 from threading import Thread, current_thread
@@ -836,3 +837,10 @@ def __init__(self, target, **kwargs):
     def _wrapped_target(self, target, *args, **kwargs):
         _detach_thread_output(self.ident)
         return target(*args, **kwargs)
+
+
+# minimal subset of TermColors, removed from IPython
+# not for public consumption
+class _TermColors(Enum):
+    Normal = '\033[0m'
+    Red = '\033[0;31m'