Therry

Purpose

Provide a web service that caches Graphite metrics and exposes an endpoint for dumping or searching them.

Usage

Dumping all of the known metrics:

$ curl -s -H 'Accept: application/json' http://127.0.0.1:5001/ | jsonpp
[
  "carbon.agents.li520-115-a.avgUpdateTime",
  "carbon.agents.li520-115-a.cache.overflow",
  "carbon.agents.li520-115-a.cache.queries",
  "carbon.agents.li520-115-a.cache.queues",
...
  "foo-obfuscurity-com.swap.swap-used.value",
  "foo-obfuscurity-com.swap.swap_io-in.value",
  "foo-obfuscurity-com.swap.swap_io-out.value",
  "foo-obfuscurity-com.users.users.users"
]

Searching for a specific string across all metrics:

$ curl -s -H 'Accept: application/json' -d 'pattern=gorsuch' -X GET http://127.0.0.1:5001/search/ | jsonpp
[
  "github.backstop.refs.heads.master.michael-gorsuch-gmail-com.120a181c62d0f595b4a262251cfada192aef0189",
  "github.backstop.refs.heads.master.michael-gorsuch-gmail-com.92d45166b37d6310d5501f7a4541ded643e09280",
  "github.backstop.refs.heads.master.michael-gorsuch-gmail-com.dd17953f3e1152bbe4a499e7d5929e301247c6c4",
  "github.backstop.refs.heads.travis-ci.michael-gorsuch-gmail-com.922bb15fb593763865cd5d4c9b8f4d14cc364ef3",
  "gorsuch.a",
  "gorsuch.b",
  "gorsuch.c",
  "gorsuch.foo"
]

Checking the health of the service:

$ curl -s -H 'Accept: application/json' GET http://127.0.0.1:5001/health/ | jsonpp
{
  "status": "OK",
  "count": 356
}

Deployment

Therry is a very basic Sinatra application. It uses rufus-scheduler to gather routine updates to the Graphite metrics store before caching them in memory.

Service Dependencies

None.

Configuration Vars

• METRICS_UPDATE_INTERVAL - How frequently to update the list of known metrics from the remote Graphite server. The more often you add new metrics, the lower this value should be. A reasonable default for most installations would be 1h (time strings as understood by Rufus scheduler). If users complain that they don't see new metrics, it means that it hasn't synced since a new metric has been added. You can simply restart Therry, and optionally lower this value to suit your users' patience threshold, to manually update the metrics list.

• GRAPHITE_URL - Base URL for the Graphite server (e.g. http://graphite.example.com).

• GRAPHITE_USER - Basic Authentication username for the Graphite server (optional).

• GRAPHITE_PASS - Basic Authentication password for the Graphite server (optional).

Local

Therry uses the Sinatra web framework under Ruby 1.9. Anyone wishing to run Therry as a local service should be familiar with common Ruby packaging and dependency management utilities such as RVM and Bundler. If you are installing a new Ruby version with RVM, make sure that you have the appropriate OpenSSL development libraries installed before compiling Ruby.

All environment variables can be set from the command-line, although it's suggested to use .env instead. This file will automatically be picked up by foreman, which is also helpful when debugging (e.g. foreman run pry). This file will not be committed (unless you remove or modify .gitignore) so you shouldn't have to worry about accidentally leaking credentials.

$ rvm use 1.9.2
$ bundle install
$ foreman start

Heroku

$ export DEPLOY=production/staging/you
$ heroku create -r $DEPLOY -s cedar
$ heroku config:set -r $DEPLOY GRAPHITE_URL=...
$ heroku config:set -r $DEPLOY METRICS_UPDATE_INTERVAL=1h
$ heroku config:set -r $DEPLOY RAKE_ENV=production
$ git push $DEPLOY master
$ heroku scale -r $DEPLOY web=1

LICENSE

Therry is distributed under the MIT license. Third-party software libraries included with this project are distributed under their respective licenses.