dcensus

Documentation

Overview

Package dcensus provides functionality for debug instrumentation.

Index

• Variables
• func DebugHandler() (http.Handler, error)
• func Init(cfg *config.Config, views ...*view.View) error
• func MDur(m *stats.Float64Measure, d time.Duration) stats.Measurement
• func NewViewExporter(cfg *config.Config) (_ *stackdriver.Exporter, err error)
• func RecordWithTag(ctx context.Context, key tag.Key, val string, m stats.Measurement)
• type RouteTagger
• type Router
  • func NewRouter(tagger RouteTagger) *Router
  • func (r *Router) Handle(route string, handler http.Handler)
  • func (r *Router) HandleFunc(route string, handler http.HandlerFunc)

Variables

var (
	ServerRequestCount = &view.View{
		Name:        "go-discovery/http/server/request_count",
		Description: "Count of HTTP requests started by Method",
		TagKeys:     []tag.Key{ochttp.Method},
		Measure:     ochttp.ServerRequestCount,
		Aggregation: view.Count(),
	}
	ServerResponseCount = &view.View{
		Name:        "go-discovery/http/server/response_count",
		Description: "Server response count by status code and route",
		TagKeys:     []tag.Key{ochttp.StatusCode, ochttp.KeyServerRoute},
		Measure:     ochttp.ServerLatency,
		Aggregation: view.Count(),
	}
	ServerLatency = &view.View{
		Name:        "go-discovery/http/server/response_latency",
		Description: "Server response distribution by status code and route",
		TagKeys:     []tag.Key{ochttp.KeyServerRoute},
		Measure:     ochttp.ServerLatency,
		Aggregation: ochttp.DefaultLatencyDistribution,
	}
	ServerResponseBytes = &view.View{
		Name:        "go-discovery/http/server/response_bytes",
		Description: "Size distribution of HTTP response body",
		TagKeys:     []tag.Key{ochttp.KeyServerRoute},
		Measure:     ochttp.ServerResponseBytes,
		Aggregation: ochttp.DefaultSizeDistribution,
	}
	ServerViews = []*view.View{
		ServerRequestCount,
		ServerResponseCount,
		ServerLatency,
		ServerResponseBytes,
	}
)

Customizations of ochttp views. Views are updated as follows:

• ClientHost and ServerRoute are added to resp. client and server metrics. Since these are bounded cardinality in our metrics, they are useful to add additional context.
• Method tags are removed. We don't have any routes that accept more than one HTTP method.

var KeyStatus = tag.MustNewKey("status")

KeyStatus is a tag key named "status".

Functions

func DebugHandler

func DebugHandler() (http.Handler, error)

DebugHandler creates a new http.Handler for serving debug information.

func Init

func Init(cfg *config.Config, views ...*view.View) error

Init configures tracing and aggregation according to the given Views. If running on GCP, Init also configures exporting to StackDriver.

func MDur

func MDur(m *stats.Float64Measure, d time.Duration) stats.Measurement

MDur returns the latency value used for recording a measurement with opencensus.

func NewViewExporter

func NewViewExporter(cfg *config.Config) (_ *stackdriver.Exporter, err error)

NewViewExporter creates a StackDriver exporter for stats.

func RecordWithTag

func RecordWithTag(ctx context.Context, key tag.Key, val string, m stats.Measurement)

RecordWithTag is a convenience function for recording a single measurement with a single tag.

Types

type RouteTagger

type RouteTagger func(route string, r *http.Request) string

RouteTagger is a func that can be used to derive a dynamic route tag for an incoming request.

type Router

type Router struct {
	http.Handler
	// contains filtered or unexported fields
}

Router is an http multiplexer that instruments per-handler debugging information and census instrumentation.

func NewRouter

func NewRouter(tagger RouteTagger) *Router

NewRouter creates a new Router, using tagger to tag incoming requests in monitoring. If tagger is nil, a default route tagger is used.

func (*Router) Handle

func (r *Router) Handle(route string, handler http.Handler)

Handle registers handler with the given route. It has the same routing semantics as http.ServeMux.

func (*Router) HandleFunc

func (r *Router) HandleFunc(route string, handler http.HandlerFunc)

HandleFunc is a wrapper around Handle for http.HandlerFuncs.