mon2prom

Documentation

Overview

The mon2prom package supports reading TimeSeries metric values from GCP (Google Cloud Platform) and exporting them as Prometheus metrics.

Index

• Variables
• func MetricFetcher(monClient mon.Client) (chan<- UpdateRequest, func())
• type ForHumans
• type PromVector
  • func NewVec(projectID string, monClient mon.Client, md *sd.MetricDescriptor, ...) *PromVector
  • func (pv *PromVector) Clear()
  • func (pv *PromVector) Collect(ch chan<- prom.Metric)
  • func (pv *PromVector) Describe(ch chan<- *prom.Desc)
  • func (pv *PromVector) ForHumans() (unit string, scale string, count int, bucketType string, buckets interface{})
  • func (pv *PromVector) Populate(ts *sd.TimeSeries, pt *sd.Point) bool
  • func (pv *PromVector) Publish()
  • func (pv *PromVector) ReadOnlyMap() map[label.RuneList]value.Metric
  • func (pv *PromVector) Schedule(ch chan<- UpdateRequest, end string, seq int)
  • func (pv *PromVector) Update(monClient mon.Client, ch chan<- UpdateRequest)
• type UpdateRequest

Variables

var WasScraped = false

Functions

func MetricFetcher

func MetricFetcher(monClient mon.Client) (chan<- UpdateRequest, func())

Returns a runner that updates PromVector values and a channel that each PromVector uses to request an update. Invoke the runner function once all of the PromVectors have been initialized:

ch, runner := mon2prom.MetricFetcher(monClient)
for md := range monClient.StreamMetricDescs(nil, projectID, prefix) {
    mon2prom.NewVec(projectID, monClient, md, ch)
}
go runner()

Types

type ForHumans

type ForHumans struct {
	Unit       string
	Scale      string
	MonCount   int
	BucketType string
	MonBuckets interface{}
}

Descriptive data for a GCP metric that we may want to report at start-up. This structure can be freed after start-up is finished.

type PromVector

type PromVector struct {
	ProjectID  string // GCP Project Name (ID)
	MonDesc    *sd.MetricDescriptor
	PromName   string // Metric name in Prometheus
	PromDesc   *prom.Desc
	MetricKind mon.MetricKind // 'D'elta, 'G'auge, or 'C'ounter
	ValueType  mon.ValueType  // Histogram, Int, Float, or Bool

	BucketOpts   *sd.BucketOptions
	BucketBounds []float64 // Boundaries between hist buckets
	SubBuckets   []int     // Count of SD buckets in each Prom one.
	label.Set              // To build hash keys from label values.
	PrevEnd      string    // Timestamp of prior sample period end.
	PrevWhen     time.Time // When fetched prior period (debug).
	NextWhen     time.Time // When we will fetch next period.
	UpdateStart  time.Time // Used for debugging timing quirks.
	MetricMap    *map[label.RuneList]value.Metric
	ReadOnly     atomic.Value // Read-only metric map to export.
	// contains filtered or unexported fields
}

A vector of Prometheus metrics exported from a GCP metric. Each metric in a vector has a different set of label values.

func NewVec

func NewVec(
	projectID string,
	monClient mon.Client,
	md *sd.MetricDescriptor,
	ch chan<- UpdateRequest,
) *PromVector

Creates a new PromVector, initializes it from recent TimeSeries data, and schedules it to be updated as time goes on. Returns `nil` if the configuration does not specify how this metric should be exported.

func (*PromVector) Clear

func (pv *PromVector) Clear()

Replaces pv.MetricMap with an empty map (not disturbing the map that pv.MetricMap used to point to, which is now the read-only map). If pv refers to a Delta metric kind, then the read-only metrics from the read-only map get (deep) copied into the new map, so that these Counter metrics don't lose their accumulated value.

func (*PromVector) Collect

func (pv *PromVector) Collect(ch chan<- prom.Metric)

Writes out (in protobuf format) each metric in the vector.

func (*PromVector) Describe

func (pv *PromVector) Describe(ch chan<- *prom.Desc)

Just returns the prometheus *Desc for the metric.

func (*PromVector) ForHumans

func (pv *PromVector) ForHumans() (
	unit string,
	scale string,
	count int,
	bucketType string,
	buckets interface{},
)

Returns information that humans might want to know about the metric being exported and then frees up that information to save space. Calling it a second time just gives you zero values for all of the items.

func (*PromVector) Populate

func (pv *PromVector) Populate(ts *sd.TimeSeries, pt *sd.Point) bool

Inserts or updates a single metric value in the metric map based on the latest sample period of the GCP metric.

func (*PromVector) Publish

func (pv *PromVector) Publish()

Converts all of the metrics in pv.MetricMap to be read-only metrics and then atomically replaces the pointer to the old read-only map with the pointer in pv.MetricMap.

func (*PromVector) ReadOnlyMap

func (pv *PromVector) ReadOnlyMap() map[label.RuneList]value.Metric

Atomically fetches the pointer to the read-only map of read-only metrics, usually so that they can be exported by Collect() while updates might be simultaneously applied to the not-read-only map.

func (*PromVector) Schedule

func (pv *PromVector) Schedule(
	ch chan<- UpdateRequest,
	end string,
	seq int,
)

Schedules when to request that the values for this metric next be updated. We compute when the next sample period should be available (plus a few random seconds to reduce "thundering herd") and schedule pv to be sent to the metric runner's channel at that time.

func (*PromVector) Update

func (pv *PromVector) Update(monClient mon.Client, ch chan<- UpdateRequest)

Iterates over all of the TimeSeries values for a single GCP metric and Populates() them into the metric map.

type UpdateRequest

type UpdateRequest struct {
	// contains filtered or unexported fields
}

What gets sent to request a metric be updated.