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Subject: Re: [BPF v1] tools: bpftool: Fix JSON output when lookup fails
To:     Krzesimir Nowak <krzesimir@kinvolk.io>, bpf@vger.kernel.org
Cc:     Alban Crequy <alban@kinvolk.io>,
        =?UTF-8?Q?Iago_L=c3=b3pez_Galeiras?= <iago@kinvolk.io>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        Jakub Kicinski <jakub.kicinski@netronome.com>,
        Stanislav Fomichev <sdf@google.com>,
        Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp>,
        Okash Khawaja <osk@fb.com>,
        David Calavera <david.calavera@gmail.com>,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20190605191707.24429-1-krzesimir@kinvolk.io>
From:   Quentin Monnet <quentin.monnet@netronome.com>
Message-ID: <3b26789b-3b51-8c47-b710-8df09b63ce73@netronome.com>
Date:   Thu, 6 Jun 2019 09:35:03 +0100
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2019-06-05 21:17 UTC+0200 ~ Krzesimir Nowak <krzesimir@kinvolk.io>
> In commit 9a5ab8bf1d6d ("tools: bpftool: turn err() and info() macros
> into functions") one case of error reporting was special cased, so it
> could report a lookup error for a specific key when dumping the map
> element. What the code forgot to do is to wrap the key and value keys
> into a JSON object, so an example output of pretty JSON dump of a
> sockhash map (which does not support looking up its values) is:
> 
> [
>     "key": ["0x0a","0x41","0x00","0x02","0x1f","0x78","0x00","0x00"
>     ],
>     "value": {
>         "error": "Operation not supported"
>     },
>     "key": ["0x0a","0x41","0x00","0x02","0x1f","0x78","0x00","0x01"
>     ],
>     "value": {
>         "error": "Operation not supported"
>     }
> ]
> 
> Note the key-value pairs inside the toplevel array. They should be
> wrapped inside a JSON object, otherwise it is an invalid JSON. This
> commit fixes this, so the output now is:
> 
> [{
>         "key": ["0x0a","0x41","0x00","0x02","0x1f","0x78","0x00","0x00"
>         ],
>         "value": {
>             "error": "Operation not supported"
>         }
>     },{
>         "key": ["0x0a","0x41","0x00","0x02","0x1f","0x78","0x00","0x01"
>         ],
>         "value": {
>             "error": "Operation not supported"
>         }
>     }
> ]
> 
> Fixes: 9a5ab8bf1d6d ("tools: bpftool: turn err() and info() macros into functions")
> Cc: Quentin Monnet <quentin.monnet@netronome.com>
> Signed-off-by: Krzesimir Nowak <krzesimir@kinvolk.io>

Thanks for the fix!

Quentin