Improve control over ANSI output (#6858)

* Move global console_handler into function scope

Signed-off-by: Mike Seplowitz <mseplowitz@bloomberg.net>

* Improve control over ANSI output

- Disabled parallel logger ANSI output if not attached to a tty.
  The console handler and progress stream already checked whether the
  output stream is a tty, but ParallelStreamWriter did not.

- Added --ansi=(never|always|auto) option to allow clearer control over
  ANSI output. Since --no-ansi is the same as --ansi=never, --no-ansi is
  now deprecated.

Signed-off-by: Mike Seplowitz <mseplowitz@bloomberg.net>

1 files changed, 18 insertions, 0 deletions

diff --git a/compose/cli/colors.py b/compose/cli/colors.py
index a4983a9f..042403a9 100644
--- a/compose/cli/colors.py
+++ b/compose/cli/colors.py
@@ -1,3 +1,6 @@
+import enum
+import os
+
 from ..const import IS_WINDOWS_PLATFORM
 
 NAMES = [
@@ -12,6 +15,21 @@ NAMES = [
 ]
 
 
+@enum.unique
+class AnsiMode(enum.Enum):
+    """Enumeration for when to output ANSI colors."""
+    NEVER = "never"
+    ALWAYS = "always"
+    AUTO = "auto"
+
+    def use_ansi_codes(self, stream):
+        if self is AnsiMode.ALWAYS:
+            return True
+        if self is AnsiMode.NEVER or os.environ.get('CLICOLOR') == '0':
+            return False
+        return stream.isatty()
+
+
 def get_pairs():
     for i, name in enumerate(NAMES):
         yield (name, str(30 + i))