[PATCH v4 4/7] oeqa/utils/qemurunner: support ignoring vt100 escape sequences

["Enrico Jörns" <ejo@pengutronix.de>]

From: Enrico Jorns <ejo@pengutronix.de>

If we talk to terminals that like colors, we need to ignore the vt100
escape sequences when matching strings.

An unprocessed barebox console prompt would e.g. look like:

  ESC[1;32mbarebox@ESC[1;36mARM QEMU virt64:/ESC[0m

where we cannot match for something like "barebox@ARM QEMU virt64:/".
The same applies to colored Linux terminal output of course.

The "\x1b\[" from the regex catches the standard start of ANSI escape
sequence while the rest catches the actual command code executed.

Signed-off-by: Enrico Jorns <ejo@pengutronix.de>
---
 meta/lib/oeqa/utils/qemurunner.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/meta/lib/oeqa/utils/qemurunner.py b/meta/lib/oeqa/utils/qemurunner.py
index cda43aad8c..63fc6f6b53 100644
--- a/meta/lib/oeqa/utils/qemurunner.py
+++ b/meta/lib/oeqa/utils/qemurunner.py
@@ -30,6 +30,8 @@ control_range = list(range(0,32))+list(range(127,160))
 control_chars = [chr(x) for x in control_range
                 if chr(x) not in string.printable]
 re_control_char = re.compile('[%s]' % re.escape("".join(control_chars)))
+# Regex to remove the ANSI (color) control codes from console strings in order to match the text only
+re_vt100 = re.compile(r'(\x1b\[|\x9b)[^@-_a-z]*[@-_a-z]|\x1b[@-_a-z]')
 
 def getOutput(o):
     import fcntl
@@ -681,7 +683,7 @@ class QemuRunner:
                     time.sleep(0.1)
                     answer = self.server_socket.recv(1024)
                     if answer:
-                        data += answer.decode('utf-8')
+                        data += re_vt100.sub("", answer.decode('utf-8'))
                         # Search the prompt to stop
                         if re.search(self.boot_patterns['search_cmd_finished'], data):
                             break
-- 
2.39.2