[OE-core] [PATCH 27/43] utils/multiprocess_launch: Improve failing subprocess output

[Armin Kuster]

From: Richard Purdie <richard.purdie at linuxfoundation.org>

Output before this patch:

ERROR: bash-4.4.18-r0 do_package_write_ipk: Fatal errors occurred in subprocesses:
Command 'PATH="X" opkg-build -Z xz -a "--memlimit=50% --threads=88" Foobar /media/build1/poky/build/nodistro-glibc/work/core2-64-oe-linux/bash/4.4.18-r0/deploy-ipks/core2-64' returned non-zero exit status 1.: Traceback (most recent call last):
  File "/media/build1/poky/meta/lib/oe/utils.py", line 272, in run
    ret = self._target(*self._args, **self._kwargs)
  File "/media/build1/poky/meta/classes/package_ipk.bbclass", line 230, in ipk_write_pkg
    shell=True)
  File "/usr/lib/python3.6/subprocess.py", line 336, in check_output
    **kwargs).stdout
  File "/usr/lib/python3.6/subprocess.py", line 418, in run
    output=stdout, stderr=stderr)
subprocess.CalledProcessError: Command 'PATH="X" opkg-build -Z xz -a "--memlimit=50% --threads=88" Foobar /media/build1/poky/build/nodistro-glibc/work/core2-64-oe-linux/bash/4.4.18-r0/deploy-ipks/core2-64' returned non-zero exit status 1.

Note how stdout/stderr from the failing command isn't shown.

After this patch:

ERROR: bash-4.4.18-r0 do_package_write_ipk: Fatal errors occurred in subprocesses:
Command 'PATH="X" opkg-build -Z xz -a "--memlimit=50% --threads=88" Foobar /media/build1/poky/build/nodistro-glibc/work/core2-64-oe-linux/bash/4.4.18-r0/deploy-ipks/core2-64' returned non-zero exit status 1.
Subprocess output:Foobar
*** Error: Package name Foobar contains illegal characters, (other than [a-z0-9.+-])

opkg-build: Please fix the above errors and try again.

We suddenly get a much more usable error message. The traceback is supressed
as its distracting from the real problem in this case.

Ideally python itself would handle this but it doesn't so we have to
wrap the exception. We already do this in bitbake itself for the same reason.

Signed-off-by: Richard Purdie <richard.purdie at linuxfoundation.org>
Signed-off-by: Armin Kuster <akuster808 at gmail.com>
---
 meta/lib/oe/utils.py | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/meta/lib/oe/utils.py b/meta/lib/oe/utils.py
index a4fd79c..5925181 100644
--- a/meta/lib/oe/utils.py
+++ b/meta/lib/oe/utils.py
@@ -324,7 +324,12 @@ def multiprocess_launch(target, items, d, extraargs=None):
     if errors:
         msg = ""
         for (e, tb) in errors:
-            msg = msg + str(e) + ": " + str(tb) + "\n"
+            if isinstance(e, subprocess.CalledProcessError) and e.output:
+                msg = msg + str(e) + "\n"
+                msg = msg + "Subprocess output:"
+                msg = msg + e.output.decode("utf-8", errors="ignore")
+            else:
+                msg = msg + str(e) + ": " + str(tb) + "\n"
         bb.fatal("Fatal errors occurred in subprocesses:\n%s" % msg)
     return results
 
-- 
2.7.4