Class Raindrops::Watcher
In: lib/raindrops/watcher.rb  (CVS)
lib/raindrops/watcher.rb  (CVS)
Parent: Object

Raindrops::Watcher is a stand-alone Rack application for watching any number of TCP and UNIX listeners (all of them by default).

It depends on the Aggregate RubyGem

In your Rack config.ru:

   run Raindrops::Watcher(options = {})

It takes the following options hash:

  • :listeners - an array of listener names, (e.g. %w(0.0.0.0:80 /tmp/sock))
  • :delay - interval between stats updates in seconds (default: 1)

Raindrops::Watcher is compatible any thread-safe/thread-aware Rack middleware. It does not work well with multi-process web servers but can be used to monitor them. It consumes minimal resources with the default :delay.

HTTP endpoints

GET /

Returns an HTML summary listing of all listen interfaces watched on

GET /active/$LISTENER.txt

Returns a plain text summary + histogram with X-* HTTP headers for active connections.

e.g.: curl raindrops-demo.bogomips.org/active/0.0.0.0%3A80.txt

GET /active/$LISTENER.html

Returns an HTML summary + histogram with X-* HTTP headers for active connections.

e.g.: curl raindrops-demo.bogomips.org/active/0.0.0.0%3A80.html

GET /queued/$LISTENER.txt

Returns a plain text summary + histogram with X-* HTTP headers for queued connections.

e.g.: curl raindrops-demo.bogomips.org/queued/0.0.0.0%3A80.txt

GET /queued/$LISTENER.html

Returns an HTML summary + histogram with X-* HTTP headers for queued connections.

e.g.: curl raindrops-demo.bogomips.org/queued/0.0.0.0%3A80.html

POST /reset/$LISTENER

Resets the active and queued statistics for the given listener.

GET /tail/$LISTENER.txt?active_min=1&queued_min=1

Streams chunked a response to the client. Interval is the preconfigured +:delay+ of the application (default 1 second)

The response is plain text in the following format:

  ISO8601_TIMESTAMP LISTENER_NAME ACTIVE_COUNT QUEUED_COUNT LINEFEED

Query parameters:

  • active_min - do not stream a line until this active count is reached
  • queued_min - do not stream a line until this queued count is reached

Response headers (mostly the same names as Raindrops::LastDataRecv)

  • X-Count - number of samples polled
  • X-Last-Reset - date since the last reset

The following headers are only present if X-Count is greater than one.

  • X-Min - lowest number of connections recorded
  • X-Max - highest number of connections recorded
  • X-Mean - mean number of connections recorded
  • X-Std-Dev - standard deviation of connection count
  • X-Outliers-Low - number of low outliers (hopefully many for queued)
  • X-Outliers-High - number of high outliers (hopefully zero for queued)
  • X-Current - current number of connections
  • X-First-Peak-At - date of when X-Max was first reached
  • X-Last-Peak-At - date of when X-Max was last reached

Demo Server

There is a server running this app at raindrops-demo.bogomips.org/ The Raindrops::Middleware demo is also accessible at raindrops-demo.bogomips.org/_raindrops

The demo server is only limited to 30 users, so be sure not to abuse it by using the /tail/ endpoint too much.

[Validate]