It receives certain JSON events as HTTP POSTs, parses them, and writes received JSON with along with some extra metadata to stdout using console.log(). POST-ed data does not usually exceed ~800 bytes per request.
It runs with node 0.10.15 engine on Heroku with just one web dyno. Also it uses Express 3.3.4 web service library.
I've subjected the app to some traffic by means of blitz.io:
$ blitz curl -T 100 -p 1-300:25,300-300:35 -v:foo number[100,999] \
-X POST -d '{"a": "blob of well-formed JSON, several hundred bytes long... using #{foo} variable for extra points"}' \
-H 'Content-Type:application/json' \
http://super-secret-app-yeah.herokuapp.com/event
This command initiates a rush of POST requests from a group of clients that ramp from 1 to 300 over 25 seconds, and it continues to hammer the app with 300 concurrent clients for another 35 seconds.
rushing from virginia...
Time Users Response Hits Timeouts Errors Hits/s Mbps
2.5s 29 0.024s 22 0 0
5.0s 60 0.017s 116 1 0 37.44 0.02
7.5s 90 0.017s 290 1 0 69.43 0.05
10.0s 121 0.018s 533 1 0 96.88 0.06
12.5s 151 0.019s 848 1 0 125.59 0.08
15.1s 180 0.019s 1240 1 1 154.96 0.10
17.6s 211 0.023s 1695 15 1 180.01 0.12
20.1s 241 0.024s 2213 39 1 206.51 0.14
22.6s 271 0.023s 2817 46 1 240.81 0.16
25.1s 300 0.023s 3492 60 1 269.16 0.18
27.6s 300 0.020s 4184 96 1 276.00 0.19
30.1s 300 0.017s 4918 101 1 292.65 0.19
32.8s 300 0.020s 5688 117 1 289.28 0.19
35.3s 300 0.018s 6420 121 1 292.13 0.19
37.8s 300 0.019s 7148 130 1 288.51 0.19
40.3s 300 0.020s 7875 143 1 289.88 0.19
42.8s 300 0.019s 8593 164 1 286.47 0.19
45.3s 300 0.020s 9303 187 1 283.20 0.19
47.9s 300 0.019s 10032 200 1 288.14 0.19
50.4s 300 0.020s 10758 213 1 289.44 0.19
52.9s 300 0.019s 11491 215 1 291.11 0.19
55.4s 300 0.021s 12239 215 1 298.23 0.19
57.9s 300 0.019s 12954 223 1 283.72 0.19
I took a screen shot of what log2viz was showing during the performance peak:
