twister: Remove ANSI sequences before writing to handler.log

ANSI color is great for viewing output in a terminal, but currently it
also gets written out to the `handler.log` file. Text editors usually
don't render these, resulting in a hard-to-read file with a lot of
gibberish interspered. This commit strips ANSI sequences from lines
before writing them to the handler log file. This change does not
affect what is printed in Twister's console output, so one would still
see the colors there.

Signed-off-by: Tristan Honscheid <[email protected]>

scripts/pylib/twister/twisterlib/environment.py

@@ -863,6 +863,9 @@ def parse_arguments(parser, args, options = None):
 
     return options
 
+def strip_ansi_sequences(s: str) -> str:
+    """Remove ANSI escape sequences from a string."""
+    return re.sub(r'\x1B(?:[@-Z\\-_]|\[[0-?]*[ -/]*[@-~])', "", s)
 
 class TwisterEnv:
 
@@ -967,8 +970,7 @@ def run_cmake_script(args=[]):
         # for instance if twister is executed from inside a makefile. In such a
         # scenario it is then necessary to remove them, as otherwise the JSON decoding
         # will fail.
-        ansi_escape = re.compile(r'\x1B(?:[@-Z\\-_]|\[[0-?]*[ -/]*[@-~])')
-        out = ansi_escape.sub('', out.decode())
+        out = strip_ansi_sequences(out.decode())
 
         if p.returncode == 0:
             msg = "Finished running %s" % (args[0])

scripts/pylib/twister/twisterlib/handlers.py

@@ -20,7 +20,7 @@
 import time
 
 from queue import Queue, Empty
-from twisterlib.environment import ZEPHYR_BASE
+from twisterlib.environment import ZEPHYR_BASE, strip_ansi_sequences
 from twisterlib.error import TwisterException
 sys.path.insert(0, os.path.join(ZEPHYR_BASE, "scripts/pylib/build_helpers"))
 from domains import Domains
@@ -216,7 +216,7 @@ def _output_handler(self, proc, harness):
                     else:
                         stripped_line = line_decoded.rstrip()
                     logger.debug("OUTPUT: %s", stripped_line)
-                    log_out_fp.write(line_decoded)
+                    log_out_fp.write(strip_ansi_sequences(line_decoded))
                     log_out_fp.flush()
                     harness.handle(stripped_line)
                     if harness.state:
@@ -426,7 +426,7 @@ def monitor_serial(self, ser, halt_event, harness):
                 sl = serial_line.decode('utf-8', 'ignore').lstrip()
                 logger.debug("DEVICE: {0}".format(sl.rstrip()))
 
-                log_out_fp.write(sl.encode('utf-8'))
+                log_out_fp.write(strip_ansi_sequences(sl).encode('utf-8'))
                 log_out_fp.flush()
                 harness.handle(sl.rstrip())
 
@@ -921,7 +921,7 @@ def _thread(handler, timeout, outdir, logfile, fifo_fn, pid_fn, results,
                 continue
 
             # line contains a full line of data output from QEMU
-            log_out_fp.write(line)
+            log_out_fp.write(strip_ansi_sequences(line))
             log_out_fp.flush()
             line = line.rstrip()
             logger.debug(f"QEMU ({pid}): {line}")