go-checkit

(Go) check it

checkit is a command line tool (written in Go, obviously), that runs a sequence of HTTP GET against a given HTTP(S) endpoint, for a configurable duration and frequency. It supports HTTP/1.x and /2, over IPv4 and IPv6, because Go net/http does.

How does it "check"

For every HTTP GET we currently measure:

• time to establish the connection
• time to send request, wait, receive the response
• round trip time from the moment the request is submitted to the moment it comes back
• the "total" HTTP GET execution as seen by the application

NOTE: The word currently above stands to signify that we could evolve this to instrument the net/http library further, and gather more precise metrics (like DNS resolution time or separating send,wait,receive times). Those are currently left as TODOs.

Connection reuse?

All HTTP connection reuse is disabled. On purpose. The aim of this tool is not to optimize for speed nor efficiency: is to collect accurate data. And so connection reuse would definitely skew the results if left in place.

For details, take a look at the KeepAlive options in transport.go module.

How do we measure

We track the time measurements using the Histogram implementation by the go-metrics project. This allows to produce as final result:

• Min, Mean and Max
• 75 and 99 Percentiles

Allowing to spot outliers and ensure that the final numbers are not skewed in any way.

Usage

Just use -h flag to print it out:

$ checkit -h

Usage of ./bin/checkit:
  -duration float
    	How long to run the check for (in minutes) (default 5)
  -frequency int
    	Frequency at which to run the checks (in milliseconds (default 500)
  -h	Print usage
  -url string
    	URL to check (default "https://gitlab.com")

Example output

Launch against the default URL, run for 1 minute at a 500 milliseconds frequency:

$ checkit -duration=1 -frequency=500

2017/04/28 12:18:28 Checking URL 'https://gitlab.com'
2017/04/28 12:18:28 Running for 1.0 minute(s) at a 500 millisecond(s) frequency
2017/04/28 12:18:28 
2017/04/28 12:18:28 Beginning checks at 2017-04-28 12:18:28.511723766 +0100 BST
..........................................
2017/04/28 12:19:29 Ending checks at 2017-04-28 12:19:29.662597002 +0100 BST
2017/04/28 12:19:29 
2017/04/28 12:19:29 *** RESULTS (in milliseconds) ***
2017/04/28 12:19:29 Performed 42 checks
2017/04/28 12:19:29 Establish connection  	 Min 88 	 Mean 90.05 	 Max 103 	 P75 91.00 	 P99 103.00 (ms)
2017/04/28 12:19:29 Send, wait, receive   	 Min 444 	 Mean 451.74 	 Max 516 	 P75 452.00 	 P99 516.00 (ms)
2017/04/28 12:19:29 Round trip            	 Min 533 	 Mean 542.38 	 Max 605 	 P75 544.00 	 P99 605.00 (ms)
2017/04/28 12:19:29 HTTP GET (i.e. total) 	 Min 921 	 Mean 952.00 	 Max 1123 	 P75 952.75 	 P99 1123.00 (ms)

Launch against https://youtube.com, run for 2 minutes at a 300 milliseconds frequency:

$ checkit -url https://youtube.com -duration 2 -frequency 300

2017/04/28 13:12:50 Checking URL 'https://youtube.com'
2017/04/28 13:12:50 Running for 2.0 minute(s) at a 300 millisecond(s) frequency
2017/04/28 13:12:50 
2017/04/28 13:12:50 Beginning checks at 2017-04-28 13:12:50.108452272 +0100 BST
....................................................................................................................................................................................................................................................................................
2017/04/28 13:14:50 Ending checks at 2017-04-28 13:14:50.430113974 +0100 BST
2017/04/28 13:14:50 
2017/04/28 13:14:50 *** RESULTS (in milliseconds) ***
2017/04/28 13:14:50 Performed 276 checks
2017/04/28 13:14:50 Establish connection  	 Min 10 	 Mean 12.52 	 Max 23 	 P75 13.00 	 P99 22.23 (ms)
2017/04/28 13:14:50 Send, wait, receive   	 Min 51 	 Mean 61.44 	 Max 85 	 P75 64.00 	 P99 81.92 (ms)
2017/04/28 13:14:50 Round trip            	 Min 63 	 Mean 74.58 	 Max 100 	 P75 78.00 	 P99 93.69 (ms)
2017/04/28 13:14:50 HTTP GET (i.e. total) 	 Min 115 	 Mean 132.41 	 Max 244 	 P75 136.00 	 P99 156.46 (ms)

License

MIT. Please see LICENSE file on top of the repository.