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tcpkit Build Status

The tcpkit was designed to analyze network packets with lua script, can also be used to observe the request latency of the service with simple protocol, like redis/memcached.

Install

$ git clone https://github.com/git-hulk/tcpkit.git tcpkit
$ cd tcpkit
$ sudo make && make install

Usage

the tcpkit was designed to make network packets programable with LUA by @git-hulk
   -h, Print the tcpkit version strings, print a usage message, and exit
   -i interface, Listen on network card interface
   -r file, Read packets from file (which was created with the -w option or by other tools that write pcap)
   -A Print each packet (minus its link level header) in ASCII.  Handy for capturing web pages
   -B buffer_size, Set the operating system capture buffer size to buffer_size, in units of KiB (1024 bytes)
   -s snaplen, Snarf snaplen bytes of data from each packet rather than the default of 1500 bytes
   -S file, Push packets to lua state if the script was specified
   -t threshold, Print the request lantecy which slower than the threshold, in units of Millisecond
   -w file, Write the raw packets to file
   -p protocol, Parse the packet if the protocol was specified (supports: redis, memcached, http, raw)
   -P stats port, Listen port to fetch the latency stats, default is 33333


For example:

   `tcpkit -i eth0 tcp port 6379 -p redis` was used to monitor the redis reqeust latency

   `tcpkit -i eth0 tcp port 6379 -p redis -w 6379.pcap` would also dump the packets to `6379.pcap`

   `tcpkit -i eth0 tcp port 6379 -p redis -t 10` would only print the request latency slower than 10ms

How To Observe The Latency Of Redis/Memcached

$ tcpkit -i eth0 tcp port 6379 -p redis

tcpkit would listen on NIC eth0 and caputure the tcp port 6379, then parse network packets with Redis protocol. The output was like below:

2020-03-08 19:23:06.253384 127.0.0.1:51137 => 127.0.0.1:6379 | 0.615 ms | COMMAND
2020-03-08 19:23:06.258761 127.0.0.1:51137 => 127.0.0.1:6379 | 0.059 ms | get a

Use the option -t would only show the request which the request latency was slower than threshold(in units of millisecond).

How to Use Lua Script

$ tcpkit -i eth0 tcp port 6379 -p redis -S scripts/example.lua

the callback function function process(packet) in scripts/example.lua would be triggered if new packets reached.

Predefine Scripts

  1. exmaple.lua - example for user defined script
  2. dns.lua - print the dns latency
  3. tcp-connnect.lua - print connection with syn packet retransmit

Request Latency

the stats port listen on 33333 by default, use the -P to change the listen port.

➜  ~ telnet 127.0.0.1 33333
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.

{
	"127.0.0.1:6379":	{
		"requests":	1700,
		"request_bytes":	184100,
		"responses":	1700,
		"response_bytes":	1413764,
		"latency":	[{
				"<0.1ms":	326
			}, {
				"0.1ms~0.2ms":	371
			}, {
				"0.2~0.5ms":	589
			}, {
				"0.5ms~1ms":	291
			}, {
				"1ms~5ms":	123
			}]
	}
}

License

tcpkit is under the MIT license. See the LICENSE file for details.