opencensus-jaeger-go

Opencensus Jaeger Exporter for Go

This is a simple example using the Jaeger exporter from Opencensus to send spans to SignalFx. The code is in main.go

Setup and Usage

Dependencies

Import the following packages:

import (
    "go.opencensus.io/exporter/jaeger"
    "go.opencensus.io/trace"
)

Creating an exporter

exporter, err := jaeger.NewExporter(jaeger.Options{
    CollectorEndpoint: ingestUrl,
    Process: jaeger.Process{
        ServiceName: serviceName,
    },
    Username: "auth",
    Password: accessToken,
})
defer exporter.Flush()

Afterwards, register and configure the exporter

trace.RegisterExporter(exporter)
trace.ApplyConfig(trace.Config{DefaultSampler: trace.AlwaysSample()})

Creating spans

First, we need a context. If this is a parent span, get a empty context.

ctx := context.Background()

If this is a child span being created, we can take a context returned from the parent span and use that.

Using the context, start the span.

ctx, span := trace.StartSpan(ctx, "span-name")
defer span.End()

This creates a span as well as the context for the new span. This context can be used to associate child spans with this as its parent.

Span.End() is used to close a span. Using defer simplifies handling it, unless the span crosses multiple methods.

Tags and annotations

Spans can be tagged with useful and interesting values before being exported. The three currently supported types are bool, int64, and string.

span.AddAttributes(
    trace.BoolAttribute("has_error", error),
    trace.Int64Attribute("error_count", count),
    trace.StringAttribute("error_message", message),
)

Another useful way to attach information with a span is an annotation. Annotations are a list of attributes that have a timestamp relative to the start of the span.

attributes := []trace.Attribute{
	trace.Int64Attribute("count", int64(count)),
	trace.StringAttribute("full_timestamp", time.Now().String()),
}

span.Annotate(attributes, "annotation")

Running the example

export GOPATH=`pwd`
go get ./...
go run main.go

This will start a server listening to port 8080. Navigate to http://localhost:8080/test.

Each request will have a span, during which the app will generate a random number. It will then increment by 1 up to that number, generating a child span for each increment.

Resources

• https://godoc.org/go.opencensus.io/exporter/jaeger