backend

Documentation

Overview

Package backend defines an interface and RPC methods for communication with Graphite backends.

Example use:

var b Backend
metrics, err := Render(ctx, b, from, until, targets)

The package will transparently handle concurrent requests to multiple backends:

var bs []Backend
metrics, err := Renders(ctx, bs, from, until, targets)

Index

• func Finds(ctx context.Context, backends []Backend, request types.FindRequest) (types.Matches, []error)
• func Infos(ctx context.Context, backends []Backend, request types.InfoRequest) ([]types.Info, []error)
• func Renders(ctx context.Context, backends []Backend, request types.RenderRequest, ...) ([]types.Metric, types.MetricRenderStats, []error)
• type Backend
  • func Filter(backends []Backend, targets []string) []Backend

Functions

func Finds

func Finds(ctx context.Context, backends []Backend, request types.FindRequest) (types.Matches, []error)

Finds makes Find calls to multiple backends.

func Infos

func Infos(ctx context.Context, backends []Backend, request types.InfoRequest) ([]types.Info, []error)

Infos makes Info calls to multiple backends.

func Renders

func Renders(
	ctx context.Context,
	backends []Backend,
	request types.RenderRequest,
	replicaMismatchConfig cfg.RenderReplicaMismatchConfig,
	logger *zap.Logger) ([]types.Metric, types.MetricRenderStats, []error)

Renders makes Render calls to multiple backends. replicaMatchMode indicates how data points of the metrics fetched from replicas will be checked and applied on the final metrics. replicaMismatchReportLimit limits the number of mismatched metrics reported in log for each render request.

Types

type Backend

type Backend interface {
	Find(context.Context, types.FindRequest) (types.Matches, error)
	Info(context.Context, types.InfoRequest) ([]types.Info, error)
	Render(context.Context, types.RenderRequest) ([]types.Metric, error)

	Contains([]string) bool // Reports whether a backend contains any of the given targets.
	Logger() *zap.Logger    // A logger used to communicate non-fatal warnings.
	GetServerAddress() string
}

Backend codifies the RPC calls a Graphite backend responds to.

func Filter

func Filter(backends []Backend, targets []string) []Backend

Filter filters the given backends by whether they Contain() the given targets.