This adds an Exception that extends the Python stdlib
subprocess.CalledProcessError.
The difference is that the str() method of this exception also adds the
stdout/stderr logs. In effect, if this exception goes unhandled, Python
will print the output in a visually distinct wrapper to the terminal so
that it's easy to spot in a sea of traceback information.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
python/qemu/utils/__init__.py | 36 +++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/python/qemu/utils/__init__.py b/python/qemu/utils/__init__.py
index 5babf40df2..355ac550bc 100644
--- a/python/qemu/utils/__init__.py
+++ b/python/qemu/utils/__init__.py
@@ -18,6 +18,7 @@
import os
import re
import shutil
+from subprocess import CalledProcessError
import textwrap
from typing import Optional
@@ -26,6 +27,7 @@
__all__ = (
+ 'VerboseProcessError',
'add_visual_margin',
'get_info_usernet_hostfwd_port',
'kvm_available',
@@ -121,3 +123,37 @@ def _wrap(line: str) -> str:
os.linesep.join(_wrap(line) for line in content.splitlines()),
_bar(None, top=False),
))
+
+
+class VerboseProcessError(CalledProcessError):
+ """
+ The same as CalledProcessError, but more verbose.
+
+ This is useful for debugging failed calls during test executions.
+ The return code, signal (if any), and terminal output will be displayed
+ on unhandled exceptions.
+ """
+ def summary(self) -> str:
+ """Return the normal CalledProcessError str() output."""
+ return super().__str__()
+
+ def __str__(self) -> str:
+ lmargin = ' '
+ width = -len(lmargin)
+ sections = []
+
+ name = 'output' if self.stderr is None else 'stdout'
+ if self.stdout:
+ sections.append(add_visual_margin(self.stdout, width, name))
+ else:
+ sections.append(f"{name}: N/A")
+
+ if self.stderr:
+ sections.append(add_visual_margin(self.stderr, width, 'stderr'))
+ elif self.stderr is not None: