tcpkit 
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 10msHow To Observe The Latency Of Redis/Memcached
$ tcpkit -i eth0 tcp port 6379 -p redistcpkit 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
- exmaple.lua - example for user defined script
- dns.lua - print the dns latency
- 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.