OpenCost plugins make extending OpenCost’s coverage into new external cost sources (e.g. monitoring, data platforms, cloud services, and other SaaS solutions) available to the open source community. They allow for the ingestion of arbitrary cost data into OpenCost through conformance to the FOCUS spec.
Any plugin released within this repository can be deployed alongside OpenCost. When deployed, OpenCost will query all installed plugins with a request for the following:
The plugins are expected to return a response that conforms to the aforementioned FOCUS spec for the given window and resolution. OpenCost will then store the response, and continue to request data for further time ranges.
The FOCUS spec is broken up into two parts:
CustomCost
CustomCostExtendedAttributes
Plugin development only necessitates the implementation of the CustomCost
response. Extended attributes are an optional response object. However, we high encourage the use of extended attributes, as doing so will assist us in developing the UX of said attributes within OpenCost.See this ExcaliDraw diagram for a more details overview of the plugin system
At the most basic level, all a plugin needs to do is gather cost data given a time window and resolution. The logistics of this are straightforward, but the complexity of the implementation will depend on the data source in question.
<repo>/<plugin>/cmd/main/
<repo>/<plugin>/<plugin>plugin/
<repo>/<plugin>/tests/
<repo>/<plugin>/
, run go mod init github.com/opencost/opencost-plugins/<plugin>
and go get github.com/hashicorp/go-plugin
.All plugins require a configuration. For example, the Datadog plugin configuration takes in some information required to authenticate with the Datadog API. This configuration will be defined by a struct inside <repo>/<plugin>/<plugin>plugin/
.
Once the configuration is designed, it's time to write the plugin. Within <repo>/<plugin>/cmd/main/>
, create main.go
:
<plugin>Source
struct (Datadog reference).CustomCostSource
interface for your plugin source (Datadog reference). At the time of the writing of this guide, the only required function is GetCustomCosts
, which takes in a CustomCostRequest
object and returns a list of CustomCostResponse
objects. Let's step through the Datadog reference implementation:
GetWindows
).main
function:
Write some unit tests to validate the functionality of your new plugin. See the Datadog unit tests for reference.
Add a new line to the opencost-plugins
manifest containing the name of your new plugin. This manifest is used to automatically retrieve the list of available OpenCost plugins.
Now that your plugin is implemented and tested, all that's left is to get it submitted for review. Create a PR based off your branch and submit it, and an OpenCost developer will review it for you.