cc-metric-collector/internal/ccMetric

ClusterCockpit metrics

As described in the ClusterCockpit specifications, the whole ClusterCockpit stack uses metrics in the InfluxDB line protocol format. This is also the input and output format for the ClusterCockpit Metric Collector but internally it uses an extended format while processing, named CCMetric.

It is basically a copy of the InfluxDB line protocol MutableMetric interface with one extension. Besides the tags and fields, it contains a list of meta information (re-using the Tag structure of the original protocol):

type ccMetric struct {
    name   string            // same as
    tags   []*influx.Tag     // original
    fields []*influx.Field   // Influx
    tm     time.Time         // line-protocol
    meta   []*influx.Tag
}

type CCMetric interface {
    influx.MutableMetric        // the same functions as defined by influx.MutableMetric
    RemoveTag(key string)       // this is not published by the original influx.MutableMetric
    Meta() map[string]string
    MetaList() []*inlux.Tag
    AddMeta(key, value string)
    HasMeta(key string) bool
    GetMeta(key string) (string, bool)
    RemoveMeta(key string)
}

The CCMetric interface provides the same functions as the MutableMetric like {Add, Remove, Has}{Tag, Field} and additionally provides {Add, Remove, Has}Meta.

The InfluxDB protocol creates a new metric with influx.New(name, tags, fields, time) while CCMetric uses ccMetric.New(name, tags, meta, fields, time) where tags and meta are both of type map[string]string.

You can copy a CCMetric with FromMetric(other CCMetric) CCMetric. If you get an influx.Metric from a function, like the line protocol parser, you can use FromInfluxMetric(other influx.Metric) CCMetric to get a CCMetric out of it (see NatsReceiver for an example).