A tool to capture tcp packets and analyze the packets with LUA.
TCPKIT is a tool to capture tcp packets and analyze the packets with lua.
-s which server ip to monitor, must specify when runing in client side. e.g. 192.168.1.2,192.168.1.3
-p which n_latency to monitor, e.g. 6379,6380
-P stats listen port, default is 33333
-i network card interface, e.g. bond0, lo, em0... see 'ifconfig'
-d daemonize, run process in background
-r set offline file captured by tcpdump or tcpkit
-t request latency threshold, unit is millisecond
-m protocol mode, raw,redis,memcached,http
-w dump packets to 'savefile'
-S lua script path, default is ../scripts/example.lua
-B operating system capture buffer size, in units of KiB (1024 bytes)
-o log output file
-u udp
-v version
-h help
$ git clone https://github.com/git-hulk/tcpkit.git tcpkit
$ cd tcpkit
$ sudo make && make install
Supports Redis/Memcached/Http protocol now, we take Redis as example here:
$ sudo tcpkit -i em1 -s 192.168.1.2 -p 6379,6380,6381 -t 10 -m redis
and the request latency more than 10ms would be printed, like below:
2018-11-16 18:38:36.873067 172.20.64.106:53499 => 192.168.1.2:6379 | 11 ms | set foo bar
2018-11-16 18:38:55.051167 172.20.64.106:53499 => 192.168.1.2:6379 | 14 ms | get foo
Tcpkit would print all requests if the -t
option wasn't set.
If tcpkit was deployed client-side, use the -s
option to specify the server host/ip.
Caution:
-s
option should be specified when tcpkit is running in client side or decode packets from offline pcap.
If the protocol wasn't supported by tcpkit or to inspect the tcp stream data, we can use raw mode.
The tcp packet would be passed to lua VM
, and we can analyze the packet with lua script. e.g.
$ sudo tcpkit -i em1 -p 6379 -m raw -S ../scripts/example.lua
- exmaple.lua - example for user defined script
- dns.lua - print the dns latency
- tcp-connnect.lua - print connection with syn packet retransmit
Tcpkit also exports latency stats to the user by tcp port (default is 33333), use the -P
option to change it.
The output is a json string, like below:
[{"6379":{"total_reqs": 7,"total_costs":76785, "slow_reqs":7,"latencies":[0,0,0,0,0,3,3,1,0,0,0,0,0,0,0,0,0,0]}},
{"6380":{"total_reqs": 0,"total_costs":0, "slow_reqs":0,"latencies":[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]}}]
This means that the port 6379
received 7
total requests, and that total costs is 76785
us, with 7
slow requests (slow threshold is 5ms
):
5ms-10ms
: 3 requests
10ms-20ms
: 3 requests
20ms-50ms
: 1 request
The latencies
arrays above correspond to the following latency buckets:
0.1ms
, 0.2ms
, 0.5ms
, 1ms
, 5ms
, 10ms
, 20ms
, 50ms
, 100ms
, 200ms
, 500ms
, 1s
, 2s
, 3s
, 5s
, 10s
, 20s
, >20s