The RPM Contrib Gem
rpm_contrib gem contains instrumentation for the New Relic RPM agent
contributed by the community of RPM users. It requires the RPM Agent to run.
To use the contrib gem, install the
rpm_contrib gem from gemcutter. It will
also install the required version of the
newrelic_rpm gem if it's not already
For Rails 2.1 and later, add this dependency to your in your environment.rb:
For other frameworks, make sure you load rubygems if it isn't already, then just require the contrib gem:
require 'rubygems' require 'rpm_contrib'
When you load the rpm_contrib gem, the
newrelic_rpm gem will also be
initialized. No need for a separate require statement for
rpm_contrib gem must be loaded before the
newrelic_rpm gem initializes.
A number of frameworks are supported in the contrib gem. They are all turned on by default but you can add settings to your newrelic.yml to disable any of them.
The gem will detect a Camping app but you need to manually add the instrumentation to your configuration file. See RPMContrib::Instrumentation::Camping for more information.
No special configuration required for Paperclip visibility. You can disable
it by setting
disable_paperclip to true in the newrelic.yml file.
The MongoMapper object mapper is the only currently supported mapper for RPM visibility using this gem. Feel free to add others and let us know.
No special configuration required. You can disable it by setting
disable_mongodb to true in the newrelic.yml file.
To disable resque, add this to your newrelic.yml:
Redis instrumentation will record operations as well as
summary metrics under the
Database/Redis metric namespace.
To disable Redis instrumentation, add this to your newrelic.yml:
How to Add Custom Instrumentation
We encourage contributions to this project and will provide whatever assistance we can to those wishing to develop instrumentation for other open source Ruby libraries.
There are several extension points in the agent you can take advantage of with this gem.
- Custom tracers which measure methods and give visibility to otherwise unmeasured libraries.
- Samplers which sample some value about once a minute.
- Dispatcher support for web request handlers which would otherwise be undetected. In order for the agent to turn on in 'auto' mode it needs to discover a web dispatcher, or be started manually.
- Framework support, for alternatives to Rails like Camping or Ramaze
Custom tracers for frameworks should be added to the
directory. These files are loaded at the time the Agent starts. They will not
be loaded if the Agent does not start up.
It is important that you wrap any instrumentation with the checks necessary to determine if the code being instrumented is loaded. You can't add code to the contrib gem that will break when run in any other context besides yours.
For details on how to define custom tracers, refer to the support documentation on adding custom tracers. You can also get detailed information on the API from the Agent method tracing rdocs, especially the add_method_tracer docs.
A good example can be found in
You can add samplers which will record metrics approximately once a minute. Samplers are useful for capturing generic instrumentation for display in custom views.
Samplers should extend the
class. They should be placed in the
Refer to examples in the RPM agent to see how to get started.
Supporting New Dispatchers
If you want to add support for a new dispatcher which is not being recognized by
default by the RPM agent, add code to the
This code needs to define a module in the
This module will be accessed at the time environment detection takes place, when
the agent is initialized.
This module should define the method
discover_dispatcher and return the name
of the dispatcher if detected, or defer to super. See
rpm_contrib/detection/camping.rb for a good example.
Supporting New Frameworks
Supporting new frameworks can be pretty involved and generally involves both adding custom instrumentation as well as framework and dispatcher detection.
In addition it will be necessary to define a new control class with the same
name as the framework. This control class must go in
Refer to the camping example in this gem to see how this is done in general.
If you decide to tackle any new frameworks, contact firstname.lastname@example.org and we'll be happy to help you work through it.
Note on Patches/Pull Requests
- Fork the http://www.github.com/newrelic/rpm_contrib project.
- Add instrumentation files to
lib/rpm_contrib/instrumentation. These files will be loaded when the RPM agent is initialized.
- Add samplers to
lib/rpm_contrib/samplers. These classes are installed automatically when the RPM agent is initialized.
- Add tests.
- Commit, do not mess with the Rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)
- Send me a pull request. Bonus points for topic branches.
Refer to the Agent API Documentation at http://newrelic.github.com/rpm
See the support site faqs at http://support.newrelic.com/faqs for additional tips and documentation.
Contact email@example.com for help.
Copyright (c) 2009-2010 New Relic. See LICENSE for details.