NEWS.md
In atheriel/openmetrics: A 'Prometheus' Client for R Using the 'OpenMetrics' Format

openmetrics 0.3.0.9000

push_to_gateway() now has retry_times and httr_config parameters to enable more fine-grained control over the underlying HTTP request -- for example, to set timeouts or control SSL behaviour.
register_shiny_metrics() will no longer generate a cryptic error if called more than once in a session (#9).
Counters now have their creation time reset when the total is reset, as required by the OpenMetrics standard (#10).
Minor performance improvements and better error messages.

Label names should now be passed as the labels parameter when creating a metric, instead of being inferred from the remaining named arguments. For consistency with other clients, there is no longer a notion of a "default" label value. This also makes it possible to have labels like name, help, type, and so on that conflict with existing parameter names.
Relatedly, all labels must now be specified when calling methods on a metric (such as inc() or set()), since there is no default to fall back on.

The package now has its own hex logo.
Only generate the OpenMetrics format when the (preliminary) OpenMetrics content-type is passed in the Accept header. Otherwise, fall back on the Prometheus format and content-type (#3).
Pushgateway functions will now stop() for HTTP errors instead of merely issuing a warning. Clients that can tolerate these errors will likely tryCatch() them anyway, since httr::RETRY() can fail for other reasons.
Requests made to Shiny apps that return HTTP 401 will no longer include the rendered metrics anyway.
The ", \n, and \ characters are now escaped in labels and help text, as in the OpenMetrics reference implementation (#1).
Counter metrics can now be incremented by zero.
Counter, Gauge, and Histogram metrics can now take an optional unit parameter. The provided unit must match the one in the name of the metric itself -- e.g. a received_bytes metric must have unit "bytes" (#2).
Counters and Histograms now have a _created child metric, as per the OpenMetrics draft specification (#2).

Add push_to_gateway() and delete_from_gateway() for manually pushing metrics to a Prometheus Pushgateway instance.
Histogram metrics now have a built-in time() method for collecting observations on the duration of an expression.
The built-in process_cpu_seconds_total metric is now correctly reported as a Counter instead of a Gauge. This fixes an inconsistency with other Prometheus clients that would prevent metrics being used with Pushgateway.

Fixes inaccurate CPU usage when using register_default_metrics(). Previously, this would include the total elapsed time for the process (as opposed to the CPU time that was actually used).

Initial release. openmetrics is an opinionated Prometheus and OpenMetrics client for R.
Automatically instrument Plumber apps with register_plumber_metrics() and Shiny apps with register_shiny_metrics().
Collect default metrics with register_default_metrics().
Create custom metrics with counter_metric(), gauge_metric(), and histogram_metric() and custom registries with registry().
Write metrics in the OpenMetrics/Prometheus text format to any location with render_metrics().