Interaction with the console has been a problem in our avocado
tests. In some cases, the expected string does not match in the
output, causing the test to fail with a timeout. These were worked
around by sleeping before reading the console and even with SSH
connections in some places.
To fix, process the console output char by char and not with
readline. This routine was largely inspired by console_wait() in
tests/vm/basevm.py.
Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
tests/functional/qemu_test/cmd.py | 22 ++++++++++++++++++++--
1 file changed, 20 insertions(+), 2 deletions(-)
diff --git a/tests/functional/qemu_test/cmd.py b/tests/functional/qemu_test/cmd.py
index cbabb1ceed3c..5bca29d1d721 100644
--- a/tests/functional/qemu_test/cmd.py
+++ b/tests/functional/qemu_test/cmd.py
@@ -12,6 +12,7 @@
# later. See the COPYING file in the top-level directory.
import logging
+import re
import os
import os.path
import subprocess
@@ -78,6 +79,23 @@ def run_cmd(args):
def is_readable_executable_file(path):
return os.path.isfile(path) and os.access(path, os.R_OK | os.X_OK)
+def _console_read(vm, expect):
+ console_logger = logging.getLogger('console')
+ output = ""
+ while True:
+ data = vm.console_socket.recv(1)
+ if not data:
+ break
+ output += data.decode("latin1")
+ if expect in output:
+ break
+ if "\r" in output or "\n" in output:
+ lines = re.split("[\r\n]", output)
+ if lines[0]:
+ console_logger.debug(lines[0])
+ output = lines.pop()
+ return output
+
def _console_interaction(test, success_message, failure_message,
send_string, keep_sending=False, vm=None):
assert not keep_sending or send_string
@@ -98,12 +116,12 @@ def _console_interaction(test, success_message, failure_message,
continue
try:
- msg = console.readline().decode().strip()
+ msg = _console_read(vm, success_message)
except UnicodeDecodeError:
msg = None
if not msg:
continue
- console_logger.debug(msg)
+ console_logger.debug('found "%s"', msg)
if success_message is None or success_message in msg:
break
if failure_message and failure_message in msg:
--
2.47.0
On Tue, Nov 12, 2024 at 02:02:43PM +0100, Cédric Le Goater wrote:
> Interaction with the console has been a problem in our avocado
> tests. In some cases, the expected string does not match in the
> output, causing the test to fail with a timeout. These were worked
> around by sleeping before reading the console and even with SSH
> connections in some places.
>
> To fix, process the console output char by char and not with
> readline. This routine was largely inspired by console_wait() in
> tests/vm/basevm.py.
>
> Signed-off-by: Cédric Le Goater <clg@redhat.com>
> ---
> tests/functional/qemu_test/cmd.py | 22 ++++++++++++++++++++--
> 1 file changed, 20 insertions(+), 2 deletions(-)
>
> diff --git a/tests/functional/qemu_test/cmd.py b/tests/functional/qemu_test/cmd.py
> index cbabb1ceed3c..5bca29d1d721 100644
> --- a/tests/functional/qemu_test/cmd.py
> +++ b/tests/functional/qemu_test/cmd.py
> @@ -12,6 +12,7 @@
> # later. See the COPYING file in the top-level directory.
>
> import logging
> +import re
> import os
> import os.path
> import subprocess
> @@ -78,6 +79,23 @@ def run_cmd(args):
> def is_readable_executable_file(path):
> return os.path.isfile(path) and os.access(path, os.R_OK | os.X_OK)
>
> +def _console_read(vm, expect):
> + console_logger = logging.getLogger('console')
> + output = ""
> + while True:
> + data = vm.console_socket.recv(1)
> + if not data:
> + break
> + output += data.decode("latin1")
Decoding this as 'latin1' is going to mangle any output
that is not represented by a single-byte UTF-8 codepoint.
You can't simply switch this to 'utf8' though, as in the
socket.recv(1) call you're only reading a single byte,
and you can't guarantee that can be decoded if its part
of a multi-byte sequence.
I think you need to read into a bytearray, instead of
reading into a string. Then convert 'expect' into a
bytearray too, and compare bytes for a match, thus
avoiding problem of partial utf8 sequence decoding
errors.
> + if expect in output:
> + break
> + if "\r" in output or "\n" in output:
> + lines = re.split("[\r\n]", output)
> + if lines[0]:
> + console_logger.debug(lines[0])
> + output = lines.pop()
> + return output
In the commit message you talk about a problem with non-matched
text, and timeouts causing failure.
IIUC, the key difference between this code and the use of readline()
is that this code is checking for a match in the partial line. ie we
don't need to wait for a newline to arrive anymore.
That's an interesting difference, but its not obviously correlated
with the commit message description.
> +
> def _console_interaction(test, success_message, failure_message,
> send_string, keep_sending=False, vm=None):
> assert not keep_sending or send_string
> @@ -98,12 +116,12 @@ def _console_interaction(test, success_message, failure_message,
> continue
>
> try:
> - msg = console.readline().decode().strip()
> + msg = _console_read(vm, success_message)
> except UnicodeDecodeError:
> msg = None
> if not msg:
> continue
> - console_logger.debug(msg)
> + console_logger.debug('found "%s"', msg)
> if success_message is None or success_message in msg:
> break
> if failure_message and failure_message in msg:
> --
> 2.47.0
>
>
With regards,
Daniel
--
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On 12/11/2024 14.02, Cédric Le Goater wrote:
> Interaction with the console has been a problem in our avocado
> tests. In some cases, the expected string does not match in the
> output, causing the test to fail with a timeout. These were worked
> around by sleeping before reading the console and even with SSH
> connections in some places.
>
> To fix, process the console output char by char and not with
> readline. This routine was largely inspired by console_wait() in
> tests/vm/basevm.py.
>
> Signed-off-by: Cédric Le Goater <clg@redhat.com>
> ---
> tests/functional/qemu_test/cmd.py | 22 ++++++++++++++++++++--
> 1 file changed, 20 insertions(+), 2 deletions(-)
>
> diff --git a/tests/functional/qemu_test/cmd.py b/tests/functional/qemu_test/cmd.py
> index cbabb1ceed3c..5bca29d1d721 100644
> --- a/tests/functional/qemu_test/cmd.py
> +++ b/tests/functional/qemu_test/cmd.py
> @@ -12,6 +12,7 @@
> # later. See the COPYING file in the top-level directory.
>
> import logging
> +import re
> import os
> import os.path
> import subprocess
> @@ -78,6 +79,23 @@ def run_cmd(args):
> def is_readable_executable_file(path):
> return os.path.isfile(path) and os.access(path, os.R_OK | os.X_OK)
>
> +def _console_read(vm, expect):
> + console_logger = logging.getLogger('console')
> + output = ""
> + while True:
> + data = vm.console_socket.recv(1)
> + if not data:
> + break
> + output += data.decode("latin1")
> + if expect in output:
> + break
> + if "\r" in output or "\n" in output:
> + lines = re.split("[\r\n]", output)
> + if lines[0]:
> + console_logger.debug(lines[0])
> + output = lines.pop()
> + return output
> +
> def _console_interaction(test, success_message, failure_message,
> send_string, keep_sending=False, vm=None):
> assert not keep_sending or send_string
> @@ -98,12 +116,12 @@ def _console_interaction(test, success_message, failure_message,
> continue
>
> try:
> - msg = console.readline().decode().strip()
> + msg = _console_read(vm, success_message)
> except UnicodeDecodeError:
> msg = None
> if not msg:
> continue
> - console_logger.debug(msg)
> + console_logger.debug('found "%s"', msg)
Sorry for being picky (yay, bike shed painting!), but it's a little bit hard
to distinguish these "found" markers in the console.log from the lines that
just contain the normal output.
Maybe we could use some funky unicode character instead? For example:
console_logger.debug('🔎 %s', msg)
or:
console_logger.debug('✅ %s', msg)
?
Or maybe just indent the normal lines, i.e. in the _console_read() function
you could do this instead:
console_logger.debug(' %s', lines[0])
so that the "found" string is more visually separated?
Or maybe even combine the two approaches?
Thanks,
Thomas
> Maybe we could use some funky unicode character instead? For example:
>
> console_logger.debug('🔎 %s', msg)
>
> or:
>
> console_logger.debug('✅ %s', msg)
How's that ?
https://paste.debian.net/1335303/
Thanks,
C.
On 12/11/2024 14.52, Cédric Le Goater wrote:
>> Maybe we could use some funky unicode character instead? For example:
>>
>> console_logger.debug('🔎 %s', msg)
>>
>> or:
>>
>> console_logger.debug('✅ %s', msg)
>
> How's that ?
>
> https://paste.debian.net/1335303/
Fine for me!
Thanks,
Thomas
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