ocagent

README

OpenCensus Agent Go Exporter

This repository contains the Go implementation of the OpenCensus Agent (OC-Agent) Exporter. OC-Agent is a deamon process running in a VM that can retrieve spans/stats/metrics from OpenCensus Library, export them to other backends and possibly push configurations back to Library. See more details on OC-Agent Readme.

Note: This is an experimental repository and is likely to get backwards-incompatible changes. Ultimately we may want to move the OC-Agent Go Exporter to OpenCensus Go core library.

Installation

$ go get -u contrib.go.opencensus.io/exporter/ocagent

Usage

import (
	"context"
	"fmt"
	"log"
	"time"

	"contrib.go.opencensus.io/exporter/ocagent"
	"go.opencensus.io/trace"
)

func Example() {
	exp, err := ocagent.NewExporter(ocagent.WithInsecure(), ocagent.WithServiceName("your-service-name"))
	if err != nil {
		log.Fatalf("Failed to create the agent exporter: %v", err)
	}
	defer exp.Stop()

	// Now register it as a trace exporter.
	trace.RegisterExporter(exp)

	// Then use the OpenCensus tracing library, like we normally would.
	ctx, span := trace.StartSpan(context.Background(), "AgentExporter-Example")
	defer span.End()

	for i := 0; i < 10; i++ {
		_, iSpan := trace.StartSpan(ctx, fmt.Sprintf("Sample-%d", i))
		<-time.After(6 * time.Millisecond)
		iSpan.End()
	}
}

Documentation

Overview

Example (Insecure)

package main

import (
	"context"
	"fmt"
	"log"
	"time"

	"contrib.go.opencensus.io/exporter/ocagent"
	"go.opencensus.io/trace"
)

func main() {
	exp, err := ocagent.NewExporter(ocagent.WithInsecure(), ocagent.WithServiceName("engine"))
	if err != nil {
		log.Fatalf("Failed to create the agent exporter: %v", err)
	}
	defer exp.Stop()

	// Now register it as a trace exporter.
	trace.RegisterExporter(exp)

	// Then use the OpenCensus tracing library, like we normally would.
	ctx, span := trace.StartSpan(context.Background(), "AgentExporter-Example")
	defer span.End()

	for i := 0; i < 10; i++ {
		_, iSpan := trace.StartSpan(ctx, fmt.Sprintf("Sample-%d", i))
		<-time.After(6 * time.Millisecond)
		iSpan.End()
	}
}

Example (WithTLS)

package main

import (
	"context"
	"fmt"
	"log"
	"time"

	"google.golang.org/grpc/credentials"

	"contrib.go.opencensus.io/exporter/ocagent"
	"go.opencensus.io/trace"
)

func main() {
	// Please take at look at https://godoc.org/google.golang.org/grpc/credentials#TransportCredentials
	// for ways on how to initialize gRPC TransportCredentials.
	creds, err := credentials.NewClientTLSFromFile("my-cert.pem", "")
	if err != nil {
		log.Fatalf("Failed to create gRPC client TLS credentials: %v", err)
	}

	exp, err := ocagent.NewExporter(ocagent.WithTLSCredentials(creds), ocagent.WithServiceName("engine"))
	if err != nil {
		log.Fatalf("Failed to create the agent exporter: %v", err)
	}
	defer exp.Stop()

	// Now register it as a trace exporter.
	trace.RegisterExporter(exp)

	// Then use the OpenCensus tracing library, like we normally would.
	ctx, span := trace.StartSpan(context.Background(), "Securely-Talking-To-Agent-Span")
	defer span.End()

	for i := 0; i < 10; i++ {
		_, iSpan := trace.StartSpan(ctx, fmt.Sprintf("Sample-%d", i))
		<-time.After(6 * time.Millisecond)
		iSpan.End()
	}
}

Index

• Constants
• func NodeWithStartTime(nodeName string) *commonpb.Node
• type Exporter
  • func NewExporter(opts ...ExporterOption) (*Exporter, error)
  • func NewUnstartedExporter(opts ...ExporterOption) (*Exporter, error)
  • func (ae *Exporter) ExportSpan(sd *trace.SpanData)
  • func (ae *Exporter) ExportTraceServiceRequest(batch *agenttracepb.ExportTraceServiceRequest) error
  • func (ae *Exporter) ExportView(vd *view.Data)
  • func (ae *Exporter) Flush()
  • func (ae *Exporter) Start() error
  • func (ae *Exporter) Stop() error
• type ExporterOption
  • func UseCompressor(compressorName string) ExporterOption
  • func WithAddress(addr string) ExporterOption
  • func WithHeaders(headers map[string]string) ExporterOption
  • func WithInsecure() ExporterOption
  • func WithReconnectionPeriod(rp time.Duration) ExporterOption
  • func WithServiceName(serviceName string) ExporterOption
  • func WithTLSCredentials(creds credentials.TransportCredentials) ExporterOption

Examples

• Package (Insecure)
• Package (WithTLS)

Constants

const (
	DefaultAgentPort uint16 = 55678
	DefaultAgentHost string = "localhost"
)

const Version = "0.0.1"

Functions

func NodeWithStartTime

func NodeWithStartTime(nodeName string) *commonpb.Node

NodeWithStartTime creates a node using nodeName and derives:

Hostname from the environment
Pid from the current process
StartTimestamp from the start time of this process
Language and library information.

Types

type Exporter

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

func NewExporter

func NewExporter(opts ...ExporterOption) (*Exporter, error)

func NewUnstartedExporter

func NewUnstartedExporter(opts ...ExporterOption) (*Exporter, error)

func (*Exporter) ExportSpan

func (ae *Exporter) ExportSpan(sd *trace.SpanData)

func (*Exporter) ExportTraceServiceRequest

func (ae *Exporter) ExportTraceServiceRequest(batch *agenttracepb.ExportTraceServiceRequest) error

func (*Exporter) ExportView

func (ae *Exporter) ExportView(vd *view.Data)

func (*Exporter) Flush

func (ae *Exporter) Flush()

func (*Exporter) Start

func (ae *Exporter) Start() error

Start dials to the agent, establishing a connection to it. It also initiates the Config and Trace services by sending over the initial messages that consist of the node identifier. Start invokes a background connector that will reattempt connections to the agent periodically if the connection dies.

func (*Exporter) Stop

func (ae *Exporter) Stop() error

Stop shuts down all the connections and resources related to the exporter.

type ExporterOption

type ExporterOption interface {
	// contains filtered or unexported methods
}

func UseCompressor

func UseCompressor(compressorName string) ExporterOption

UseCompressor will set the compressor for the gRPC client to use when sending requests. It is the responsibility of the caller to ensure that the compressor set has been registered with google.golang.org/grpc/encoding. This can be done by encoding.RegisterCompressor. Some compressors auto-register on import, such as gzip, which can be registered by calling `import _ "google.golang.org/grpc/encoding/gzip"`

func WithAddress

func WithAddress(addr string) ExporterOption

WithAddress allows one to set the address that the exporter will connect to the agent on. If unset, it will instead try to use connect to DefaultAgentHost:DefaultAgentPort

func WithHeaders

func WithHeaders(headers map[string]string) ExporterOption

WithHeaders will send the provided headers when the gRPC stream connection is instantiated

func WithInsecure

func WithInsecure() ExporterOption

WithInsecure disables client transport security for the exporter's gRPC connection just like grpc.WithInsecure() https://godoc.org/google.golang.org/grpc#WithInsecure does. Note, by default, client security is required unless WithInsecure is used.

func WithReconnectionPeriod

func WithReconnectionPeriod(rp time.Duration) ExporterOption

func WithServiceName

func WithServiceName(serviceName string) ExporterOption

WithServiceName allows one to set/override the service name that the exporter will report to the agent.

func WithTLSCredentials

func WithTLSCredentials(creds credentials.TransportCredentials) ExporterOption

WithTLSCredentials allows the connection to use TLS credentials when talking to the server. It takes in grpc.TransportCredentials instead of say a Certificate file or a tls.Certificate, because the retrieving these credentials can be done in many ways e.g. plain file, in code tls.Config or by certificate rotation, so it is up to the caller to decide what to use.