[v2,00/17] iotests: add enhanced debugging info to qemu-io failures

GitLab: https://gitlab.com/jsnow/qemu/-/commits/iotests_qemu_io_diagnostics
CI: https://gitlab.com/jsnow/qemu/-/pipelines/499624472

Howdy,

This series does for qemu_io() what we've done for qemu_img() and makes
it a function that checks the return code by default and raises an
Exception when things do not go according to plan.

This series removes qemu_io_pipe_and_status(), qemu_io_silent(), and
qemu_io_silent_check() in favor of just qemu_io().

V2:

- Fixed 040
- Fixed 245 on tmpfs
- Fixed tests/image-fleecing

- I expect to respin a v3 to:
  (A) Fix the commit message on the 040 fix
  (B) Squash patches 7-12.

001/17:[0004] [FC] 'iotests: replace calls to log(qemu_io(...)) with qemu_io_log()'
  rebased on master, changed imports.
  Kept RB from Eric.

005/17:[down] 'iotests/040: Fix TestCommitWithFilters test'
  New patch, based on feedback from hreitz. Thank you ;_;

006/17:[0013] [FC] 'iotests: create generic qemu_tool() function'
  Quoted return types (Needed for older Python versions)
  Changed phrasing of "args" param docstring (Hanna)
  Removed docstring reflow (It's upstream already)
  Kept RBs.

007/17:[0004] [FC] 'iotests: rebase qemu_io() on top of qemu_tool()'
  Quoted return types (Needed for older Python versions)

011/17:[0019] [FC] 'iotests/245: fixup'
  Rewrite to fix this test on tmpfs (Hanna)

014/17:[down] 'iotests/image-fleecing: switch to qemu_io()'
  New, this test needed to be explicitly migrated away from pipe_and_status.

015/17:[0012] [FC] 'iotests: remove qemu_io_pipe_and_status()'
  This patch is basically empty after the new 014.

016/17:[0006] [FC] 'iotests: remove qemu_io_silent() and qemu_io_silent_check().'
  Reflow some lines (Eric)
  Added RBs.

017/17:[0004] [FC] 'iotests: make qemu_io_log() check return codes by default'
  Changed commit message phrasing (Hanna, IIRC)
  Added RBs.

Notes:

- There are a few remaining uses of qemu-io that don't go through qemu_io;
QemuIoInteractive is a user that is used in 205, 298, 299, and 307. It
... did not appear worth it to morph qemu_tool_popen into something that
could be used by both QemuIoInteractive *and* qemu_io(), so I left it
alone. It's probably fine for now. (But it does bother me, a little.)

- qemu_io_popen itself is used by the nbd-reconnect-on-open test, and it
seems like a legitimate use -- it wants concurrency. Like the above
problem, I couldn't find a way to bring it into the fold, so I
didn't. (Meh.) I eventually plan to add asyncio subprocess management to
machine.py, and I could tackle stuff like this then. It's not worth it
now.

(Maybe I'll bring these in under the fold the next time I get bored, but
I think it's not worth the trouble right now, there are very few
users. I did try, but the benefit to VerboseProcessError is that it
includes stdout/stderr. When using Popen with pipes you lose access to
that information in the management context. Popen does not natively
buffer stdout/stderr, so we'd have to fall back to just using a regular
CalledProcessError. I think I'd have to extend Popen and add
buffering. I think that's something for later. Anyway, that's my
story. How are you today? I hope you are well.)

John Snow (17):
  iotests: replace calls to log(qemu_io(...)) with qemu_io_log()
  iotests/163: Fix broken qemu-io invocation
  iotests: Don't check qemu_io() output for specific error strings
  iotests/040: Don't check image pattern on zero-length image
  iotests/040: Fix TestCommitWithFilters test
  iotests: create generic qemu_tool() function
  iotests: rebase qemu_io() on top of qemu_tool()
  iotests/030: fixup
  iotests/149: fixup
  iotests/205: fixup
  iotests/245: fixup
  iotests/migration-permissions: fixup
  iotests/migration-permissions: use assertRaises() for qemu_io()
    negative test
  iotests/image-fleecing: switch to qemu_io()
  iotests: remove qemu_io_pipe_and_status()
  iotests: remove qemu_io_silent() and qemu_io_silent_check().
  iotests: make qemu_io_log() check return codes by default

 tests/qemu-iotests/030                        | 85 +++++++++++--------
 tests/qemu-iotests/040                        | 53 +++++++-----
 tests/qemu-iotests/056                        |  2 +-
 tests/qemu-iotests/149                        |  6 +-
 tests/qemu-iotests/163                        |  5 +-
 tests/qemu-iotests/205                        |  4 +-
 tests/qemu-iotests/216                        | 12 +--
 tests/qemu-iotests/218                        |  5 +-
 tests/qemu-iotests/224                        |  4 +-
 tests/qemu-iotests/242                        |  6 +-
 tests/qemu-iotests/245                        | 17 ++--
 tests/qemu-iotests/255                        |  4 +-
 tests/qemu-iotests/258                        | 11 ++-
 tests/qemu-iotests/298                        | 15 ++--
 tests/qemu-iotests/303                        |  4 +-
 tests/qemu-iotests/310                        | 22 ++---
 tests/qemu-iotests/iotests.py                 | 69 ++++++++-------
 tests/qemu-iotests/tests/image-fleecing       | 30 ++++---
 .../qemu-iotests/tests/migration-permissions  | 28 +++---
 .../tests/mirror-ready-cancel-error           |  2 +-
 .../qemu-iotests/tests/nbd-reconnect-on-open  |  2 +-
 .../qemu-iotests/tests/stream-error-on-reset  |  4 +-
 22 files changed, 210 insertions(+), 180 deletions(-)