[Buildroot] [PATCH] support/scripts/cve.py: use fast ijson backend if available on old ijson versions

[Yann E. MORIN]

Peter, All,

On 2021-04-09 13:01 +0200, Peter Korsgaard spake thusly:
> ijson < 2.5 (as available in Debian 10) use the slow python backend by
> default instead of the most efficient one available like modern ijson
> versions, significantly slowing down cve checking. E.G.:
> 
> time ./support/scripts/pkg-stats --nvd-path ~/.nvd -p avahi --html foobar.html
> 
> Goes from
> 174,44s user 2,11s system 99% cpu 2:58,04 total
> 
> To
> 93,53s user 2,00s system 98% cpu 1:36,65 total
> 
> E.G. almost 2x as fast.
> 
> As a workaround, detect when the python backend is used and try to use a
> more efficient one instead.  Use the yajl2_cffi backend as recommended by
> upstream, as it is most likely to work, and print a warning (and continue)
> if we fail to load it.
> 
> The detection is slightly complicated by the fact that ijson.backends used
> to be a reference to a backend module, but is nowadays a string (without the
> ijson.backends prefix).
> 
> Signed-off-by: Peter Korsgaard <peter at korsgaard.com>

Applied to master, thanks.

Regards,
Yann E. MORIN.

> ---
>  support/scripts/cve.py | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/support/scripts/cve.py b/support/scripts/cve.py
> index 6e97ea193f..965fc2a466 100755
> --- a/support/scripts/cve.py
> +++ b/support/scripts/cve.py
> @@ -28,6 +28,12 @@ import operator
>  
>  try:
>      import ijson
> +    # backend is a module in < 2.5, a string in >= 2.5
> +    if 'python' in getattr(ijson.backend, '__name__', ijson.backend):
> +        try:
> +            import ijson.backends.yajl2_cffi as ijson
> +        except ImportError:
> +            sys.stderr.write('Warning: Using slow ijson python backend\n')
>  except ImportError:
>      sys.stderr.write("You need ijson to parse NVD for CVE check\n")
>      exit(1)
> -- 
> 2.20.1
> 
> _______________________________________________
> buildroot mailing list
> buildroot at busybox.net
> http://lists.busybox.net/mailman/listinfo/buildroot

-- 
.-----------------.--------------------.------------------.--------------------.
|  Yann E. MORIN  | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
| +33 662 376 056 | Software  Designer | \ / CAMPAIGN     |  ___               |
| +33 561 099 427 `------------.-------:  X  AGAINST      |  \e/  There is no  |
| http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL    |   v   conspiracy.  |
'------------------------------^-------^------------------^--------------------'