Internals

This gives some details on the internals of titan that may be of use when using the package.

Principle

Titan aims not to make your service go down, the irony that would be… Therefore titan makes very little use of stop and instead uses warning starting in [IGNORING] and skips the action.

Tip

Warnings starting in [IGNORING] indicate actions being ignored, e.g.: metric not being set to given value.

E.g.: One cannot decrease the value of Counters, if you try to do so Titan will return a warning and ignore the action but will not stop.

Storage

When titan is loaded in your environment with library(titan) it creates an environment in which it stores all metrics.

This is useful when, for instance, you setup a shiny application with titan, run it locally with titanApp, test it, then stop the app to make changes; when you run it again the metrics from the previous run will remain.

Info

You can run cleanRegistry to clean the environment.

Serving

As mentioned Prometheus pulls the metrics from your service, therefore those metrics have to be made available. These are exposed in the form of a plain text (text/plain) endpoint called /metrics where titan will serve the metrics that Prometheus can then read, store, and analyse.

With shiny you can use the function titanApp where you would normally use shinyApp, with plumber you can use prTitan where you would normally use pr, with Ambiorix, and other services you can use renderMetrics.

There are more details and many examples on how to use this on this site.