v0.5.0

Add the appmetrics package (#182)

The appmetrics package provides utilities to define and create metrics struct. A metrics struct contains all the metric instances (counters, gauges, histograms, etc.) for a package or application and defines how those metrics appear in a registry. For example:

type Metrics struct {
    Requests       metrics.Counter `metric:"requests"`
    FailedRequests metrics.Counter `metric:"requests.error"`
}

Applications usually define a single global instance of their metrics struct, which they reference in all other packages that report metrics. See the package documentation for more details and examples.

Add ability to ignore requests in logs and metrics (#185)

Calling baseapp.Ignore(*http.Request, baseapp.IgnoreRule) from a request handler can disable logging or metrics for a particular request. This may be useful if there are certain common requests, like health checks, that are uninteresting or distracting. Custom middleware can check for ignored requests using the baseapp.IsIgnored(*http.Request, baseapp.IgnoreRule) bool function.

Other Changes

• Report request rates and latencies by status code in the default metrics (#181)
• Add the ability to change metrics.Timer units when exporting metrics to Datadog (#184)
• Move the baseapp/datadog package to appmetrics/emitter/datadog and deprecate the old package (#183)
• Minor dependency and build tool upgrades