mirror of
https://github.com/coredns/coredns.io.git
synced 2024-04-21 12:32:00 +00:00
Miek Gieben
9d3c78f16f
Make notes in coredns' repo to make it authoritative there. Signed-off-by: Miek Gieben <miek@miek.nl>
52 lines
1.3 KiB
Markdown
52 lines
1.3 KiB
Markdown
+++
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title = "debug"
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description = "*debug* disables the automatic recovery upon a crash so that you'll get a nice stack trace."
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weight = 6
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tags = [ "plugin", "debug" ]
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categories = [ "plugin" ]
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date = "2019-03-03T14:11:50.601808"
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## Description
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Normally CoreDNS will recover from panics, using *debug* inhibits this. The main use of *debug* is
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to help testing. A side effect of using *debug* is that `log.Debug` and `log.Debugf` will be printed
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to standard output.
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Note that the *errors* plugin (if loaded) will also set a `recover` negating this setting.
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## Syntax
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~~~ txt
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debug
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~~~
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Some plugin will debug log DNS messages. This is done in the following format:
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~~~
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debug: 000000 00 0a 01 00 00 01 00 00 00 00 00 01 07 65 78 61
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debug: 000010 6d 70 6c 65 05 6c 6f 63 61 6c 00 00 01 00 01 00
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debug: 000020 00 29 10 00 00 00 80 00 00 00
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debug: 00002a
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~~~
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Using `text2pcap` (part of Wireshark) this can be converted back to binary, with the following
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command line: `text2pcap -i 17 -u 53,53`. Where 17 is the protocol (UDP) and 53 are the ports. These
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ports allow wireshark to detect these packets as DNS messages.
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Each plugin can decide to dump messages to aid in debugging.
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## Examples
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Disable the ability to recover from crashes and show debug logging:
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~~~ corefile
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. {
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debug
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}
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~~~
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## Also See
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https://www.wireshark.org/docs/man-pages/text2pcap.html.
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