commands.py: live output logging + result.error encoding fix

Tests that use bitbake("my-test-image") can run for a long time
without any indication to the user of oe-selftest about what's going
on. The test author has to log the bitbake output explicitly,
otherwise it is lost in case of test failures.

Now it is possible to use bitbake("my-test-image",
output_log=self.logger) to get more output both on the console and in
the XML output (when xmlrunner is installed). Example output:

2017-06-23 12:23:14,144 - oe-selftest - INFO - Running tests...
2017-06-23 12:23:14,145 - oe-selftest - INFO - ----------------------------------------------------------------------
2017-06-23 12:23:14,151 - oe-selftest - INFO - Running: bitbake my-test-image
2017-06-23 12:23:16,363 - oe-selftest - INFO - Loading cache...done.
2017-06-23 12:23:17,575 - oe-selftest - INFO - Loaded 3529 entries from dependency cache.
2017-06-23 12:23:18,811 - oe-selftest - INFO - Parsing recipes...done.
2017-06-23 12:23:19,659 - oe-selftest - INFO - Parsing of 2617 .bb files complete (2612 cached, 5 parsed). 3533 targets, 460 skipped, 0 masked, 0 errors.
2017-06-23 12:23:19,659 - oe-selftest - INFO - NOTE: Resolving any missing task queue dependencies

Because the implementation was already using threading, the same is
done to decouple reading and writing the different pipes instead of
trying to multiplex IO in a single thread. Previously the helper
thread waited for command completion, now that is done in the main
thread.

The most common case (no input data, joined stdout/stderr) still uses
one extra thread and a single read(), so performance should be roughly
the same as before.

Probably unintentionally, result.error was left as byte string when
migrating to Python3. OE-core doesn't seem to use runCmd() with split
output at the moment, so changing result.error to be treated the same
as result.output (i.e. decoded to a normal strings) seems like a
relatively safe API change (or rather, implementation fix).

Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>

merge: wait()
Signed-off-by: Ross Burton <ross.burton@intel.com>

0 files changed, 0 insertions, 0 deletions