tracing.md

Tracing

Go-Pilosa supports distributed tracing via the OpenTracing API.

In order to use a tracer with Go-Pilosa, you should:

1. Create the tracer,
2. Pass the OptClientOption(tracer) to NewClient.

In this document, we will be using the Jaeger tracer, but OpenTracing has support for other tracing systems.

Running the Pilosa Server

Let's run a temporary Pilosa container:

$ docker run -it --rm -p 10101:10101 pilosa/pilosa:v1.2.0

Check that you can access Pilosa:

$ curl localhost:10101
Welcome. Pilosa is running. Visit https://www.pilosa.com/docs/ for more information.

Running the Jaeger Server

Let's run a Jaeger Server container:

$ docker run -it --rm -p 5775:5775/udp -p 16686:16686 jaegertracing/all-in-one:latest
...<title>Jaeger UI</title>...

Writing the Sample Code

The sample code depdends on the Jaeger Go client, so let's install it first:

$ go get -u github.com/uber/jaeger-client-go/

Save the following sample code as gopilosa-tracing.go:

package main

import (
	"log"
	"time"

	"github.com/pilosa/go-pilosa"
	"github.com/uber/jaeger-client-go"
	"github.com/uber/jaeger-client-go/config"
)

func main() {
	// Create the tracer.
	cfg := config.Configuration{
		Sampler: &config.SamplerConfig{
			Type:  "const",
			Param: 1,
		},
		Reporter: &config.ReporterConfig{
			LogSpans:            true,
			BufferFlushInterval: 1 * time.Second,
			// Jaeger Server address
			LocalAgentHostPort:  "127.0.0.1:5775",
		},
	}
	tracer, closer, err := cfg.New(
		"go_pilosa_test",
		config.Logger(jaeger.StdLogger),
	)

	// Don't forget to close the tracer.
	defer closer.Close()

	// Create the client, and pass the tracer.
	client, err := pilosa.NewClient(":10101", pilosa.OptClientTracer(tracer))
	if err != nil {
		log.Fatal(err)
	}

	// Read the schema from the server.
	// This should create a trace on the Jaeger server.
	schema, err := client.Schema()
	if err != nil {
		log.Fatal(err)
	}

	// Create and sync the sample schema.
	// This should create a trace on the Jaeger server.
	myIndex := schema.Index("my-index")
	myField := myIndex.Field("my-field")
	err = client.SyncSchema(schema)
	if err != nil {
		log.Fatal(err)
	}

	// Run a query on Pilosa.
	// This should create a trace on the Jaeger server.
	_, err = client.Query(myField.Set(1, 1000))
	if err != nil {
		log.Fatal(err)
	}
}

Checking the Tracing Data

Run the sample code:

$ go run gopilosa-tracing.go

• Open http://localhost:16686 in your web browser to visit Jaeger UI.
• Click on the Search tab and select go_pilosa_test in the Service dropdown on the right.
• Click on Find Traces button at the bottom left.
• You should see a couple of traces, such as: Client.Query, Client.CreateField, Client.Schema, etc.