A Heroku app to measure latency from client to the server
Deploy and open the top page of the app.
Click the Deloy to Heroku button, then migrate the database,
and scale the worker:
$ heroku run rake db:migrate
$ heroku ps:scale worker=1
Schedule a task, say hourly, on Heroku Scheduler to sweep database for delayed execution of geocoding locations and measuring distances
rake locations:geocode ping_results:measure_distance
Alternatively, create an app on Heroku (or somewhere else), push, and provision add-ons:
$ heroku create <app-name>
$ heroku addons:create heroku-postgresql
$ heroku addons:create heroku-redis
$ heroku addons:create scheduler
$ git push heroku master
Migrate the database, and scale - one or more web and worker are needed:
$ heroku run rake db:migrate
$ heroku ps:scale web=1 worker=1
Schedule a task, say hourly, on Heroku Scheduler to sweep database for delayed execution of geocoding locations and measuring distances
rake locations:geocode ping_results:measure_distance
Set APP_STATUS config var to staging for database access through the app.
This program measures time needed to receive response for a HEAD request
to one of its static assets.
See the Javascript code for details.
The time measured should be for a round trip of packets between
the client and the server.
A tcpudmp shows something like below for each ping.
08:11:30.340923 IP misoan.51404 > ec2-54-243-156-39.compute-1.amazonaws.com.http: Flags [P.], seq 2347:3100, ack 2835, win 296, length 753
08:11:30.477844 IP ec2-54-243-156-39.compute-1.amazonaws.com.http > misoan.51404: Flags [P.], seq 2835:3052, ack 3100, win 96, length 217
08:11:30.477929 IP misoan.51404 > ec2-54-243-156-39.compute-1.amazonaws.com.http: Flags [.], ack 3052, win 314, length 0