OpenTelemetry Go distro for Uptrace

This document explains how to configure OpenTelemetry Go SDK to export spans and metrics to Uptrace using OTLP/gRPC.

To learn about OpenTelemetry API, see OpenTelemetry Go Tracing API and OpenTelemetry Go Metrics API.

Uptrace Go

uptrace-go is a thin wrapper over opentelemetry-go that configures OpenTelemetry SDK to export data to Uptrace. It does not add any new functionality and is provided only for your convenience.

To install uptrace-go:

shell

go get github.com/uptrace/uptrace-go

Configuration

You can configure Uptrace client using a DSN (Data Source Name) from the project settings page.

import "github.com/uptrace/uptrace-go/uptrace"

uptrace.ConfigureOpentelemetry(
    // copy your project DSN here or use UPTRACE_DSN env var
    //uptrace.WithDSN("<FIXME>"),

    uptrace.WithServiceName("myservice"),
    uptrace.WithServiceVersion("v1.0.0"),
    uptrace.WithDeploymentEnvironment("production"),
)

You can find the full list of available options at pkg.go.dev.

Option	Description
`WithDSN`	A data source that specifies Uptrace project credentials. For example, `https://<token>@api.uptrace.dev?grpc=4317`.
`WithServiceName`	`service.name` resource attribute. For example, `myservice`.
`WithServiceVersion`	`service.version` resource attribute. For example, `1.0.0`.
`WithDeploymentEnvironment`	`deployment.environment` resource attribute. For example, `production`.
`WithResourceAttributes`	Any other resource attributes.
`WithResourceDetectors`	Configures additional resource detectors, for example, EC2 detector or GCE detector.
`WithResource`	Resource contains attributes representing an entity that produces telemetry. Resource attributes are copied to all spans and events.

You can also use environment variables to configure the client:

Env var	Description
`UPTRACE_DSN`	A data source that is used to connect to uptrace.dev. For example, `https://<token>@uptrace.dev/<project_id>`.
`OTEL_RESOURCE_ATTRIBUTES`	Key-value pairs to be used as resource attributes. For example, `service.name=myservice,service.version=1.0.0`.
`OTEL_SERVICE_NAME=myservice`	Sets the value of the service.name resource attribute. Takes precedence over `OTEL_RESOURCE_ATTRIBUTES`.
`OTEL_PROPAGATORS`	Propagators to be used as a comma separated list. The default is `tracecontext,baggage`.

See OpenTelemetry documentation for details.

Quickstart

Spend 5 minutes to install OpenTelemetry distro, generate your first trace, and click the link in your terminal to view the trace.

Step 0. Create an Uptrace project to obtain a DSN (connection string), for example, https://<token>@api.uptrace.dev?grpc=4317.
Step 1. Install uptrace-go:

shell

go get github.com/uptrace/uptrace-go

Step 2. Copy the code to main.go replacing the DSN:

package main

import (
    "context"
    "errors"
    "fmt"

    "go.opentelemetry.io/otel"
    "go.opentelemetry.io/otel/attribute"
    "go.opentelemetry.io/otel/codes"
    "go.opentelemetry.io/otel/trace"

    "github.com/uptrace/uptrace-go/uptrace"
)

func main() {
    ctx := context.Background()

    // Configure OpenTelemetry with sensible defaults.
    uptrace.ConfigureOpentelemetry(
        // copy your project DSN here or use UPTRACE_DSN env var
        // uptrace.WithDSN("<FIXME>"),

        uptrace.WithServiceName("myservice"),
        uptrace.WithServiceVersion("1.0.0"),
    )
    // Send buffered spans and free resources.
    defer uptrace.Shutdown(ctx)

    // Create a tracer. Usually, tracer is a global variable.
    tracer := otel.Tracer("app_or_package_name")

    // Create a root span (a trace) to measure some operation.
    ctx, main := tracer.Start(ctx, "main-operation")
    // End the span when the operation we are measuring is done.
    defer main.End()

    // The passed ctx carries the parent span (main).
    // That is how OpenTelemetry manages span relations.
    _, child1 := tracer.Start(ctx, "GET /posts/:id")
    child1.SetAttributes(
        attribute.String("http.method", "GET"),
        attribute.String("http.route", "/posts/:id"),
        attribute.String("http.url", "http://localhost:8080/posts/123"),
        attribute.Int("http.status_code", 200),
    )
    if err := errors.New("dummy error"); err != nil {
        child1.RecordError(err, trace.WithStackTrace(true))
        child1.SetStatus(codes.Error, err.Error())
        child1.End()
    }

    _, child2 := tracer.Start(ctx, "SELECT")
    child2.SetAttributes(
        attribute.String("db.system", "mysql"),
        attribute.String("db.statement", "SELECT * FROM posts LIMIT 100"),
    )
    child2.End()

    fmt.Printf("trace: %s\n", uptrace.TraceURL(main))
}

Step 3. Run the code to get a link for the generated trace:

shell

go run main.go
trace: https://app.uptrace.dev/traces/<trace_id>

Step 4. Follow the link to view the trace:

Already using OTLP exporter?

If you are already using OTLP exporter, you can continue to use it with Uptrace by changing some configuration options.

To maximize performance and efficiency, consider the following recommendations when configuring OpenTelemetry SDK.

Recommendation	Signals	Significance
Use `BatchSpanProcessor` to export multiple spans in a single request.	All	Essential
Enable `gzip` compression to compress the data before sending and reduce the traffic cost.	All	Essential
Prefer `delta` metrics temporality, because such metrics are smaller and Uptrace must convert `cumulative` metrics to `delta` anyway.	Metrics	Recommended
Prefer Protobuf encoding over JSON.	All	Recommended
Use AWS X-Ray ID generator for OpenTelemetry.	Traces, Logs	Optional

To configure OpenTelemetry to send data to Uptrace, use the provided endpoint and pass the DSN via uptrace-dsn header:

Transport	Endpoint	Port
gRPC	https://api.uptrace.dev:4317	4317
HTTPS	https://api.uptrace.dev	443

Most languages allow to configure OTLP exporter using environment variables:

shell

# Uncomment the appropriate protocol for your programming language.
# Only for OTLP/gRPC
#export OTEL_EXPORTER_OTLP_ENDPOINT="https://api.uptrace.dev:4317"
# Only for OTLP/HTTP
#export OTEL_EXPORTER_OTLP_ENDPOINT="https://api.uptrace.dev"

# Pass Uptrace DSN in gRPC/HTTP headers.
export OTEL_EXPORTER_OTLP_HEADERS="uptrace-dsn=<FIXME>"

# Enable gzip compression.
export OTEL_EXPORTER_OTLP_COMPRESSION=gzip

# Enable exponential histograms.
export OTEL_EXPORTER_OTLP_METRICS_DEFAULT_HISTOGRAM_AGGREGATION=BASE2_EXPONENTIAL_BUCKET_HISTOGRAM

# Prefer delta temporality.
export OTEL_EXPORTER_OTLP_METRICS_TEMPORALITY_PREFERENCE=DELTA

When configuring BatchSpanProcessor, use the following settings:

shell

# Maximum allowed time to export data in milliseconds.
export OTEL_BSP_EXPORT_TIMEOUT=10000

# Maximum batch size.
# Using larger batch sizes can be problematic,
# because Uptrace rejects requests larger than 20MB.
export OTEL_BSP_MAX_EXPORT_BATCH_SIZE=10000

# Maximum queue size.
# Increase queue size if you have lots of RAM, for example,
# `10000 * number_of_gigabytes`.
export OTEL_BSP_MAX_QUEUE_SIZE=30000

# Max concurrent exports.
# Setting this to the number of available CPUs might be a good idea.
export OTEL_BSP_MAX_CONCURRENT_EXPORTS=2

Exporting traces

Here is how you can export traces to Uptrace following the recommendations above:

package main

import (
    "context"
    "fmt"
    "os"

    "go.opentelemetry.io/contrib/propagators/aws/xray"
    "go.opentelemetry.io/otel"
    "go.opentelemetry.io/otel/attribute"
    "go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
    "go.opentelemetry.io/otel/sdk/resource"
    sdktrace "go.opentelemetry.io/otel/sdk/trace"
)

func main() {
    ctx := context.Background()

    dsn := os.Getenv("UPTRACE_DSN")
    if dsn == "" {
        panic("UPTRACE_DSN environment variable is required")
    }
    fmt.Println("using DSN:", dsn)

    exporter, err := otlptracehttp.New(
        ctx,
        otlptracehttp.WithEndpoint("api.uptrace.dev"),
        otlptracehttp.WithHeaders(map[string]string{
            // Set the Uptrace DSN here or use UPTRACE_DSN env var.
            "uptrace-dsn": dsn,
        }),
        otlptracehttp.WithCompression(otlptracehttp.GzipCompression),
    )
    if err != nil {
        panic(err)
    }

    bsp := sdktrace.NewBatchSpanProcessor(exporter,
        sdktrace.WithMaxQueueSize(10_000),
        sdktrace.WithMaxExportBatchSize(10_000))
    // Call shutdown to flush the buffers when program exits.
    defer bsp.Shutdown(ctx)

    resource, err := resource.New(ctx,
        resource.WithFromEnv(),
        resource.WithTelemetrySDK(),
        resource.WithHost(),
        resource.WithAttributes(
            attribute.String("service.name", "myservice"),
            attribute.String("service.version", "1.0.0"),
        ))
    if err != nil {
        panic(err)
    }

    tracerProvider := sdktrace.NewTracerProvider(
        sdktrace.WithResource(resource),
        sdktrace.WithIDGenerator(xray.NewIDGenerator()),
    )
    tracerProvider.RegisterSpanProcessor(bsp)

    // Install our tracer provider and we are done.
    otel.SetTracerProvider(tracerProvider)

    tracer := otel.Tracer("app_or_package_name")
    ctx, span := tracer.Start(ctx, "main")
    defer span.End()

    fmt.Printf("trace: https://app.uptrace.dev/traces/%s\n", span.SpanContext().TraceID())
}

Exporting metrics

Here is how you can export metrics to Uptrace following the recommendations above:

package main

import (
    "context"
    "fmt"
    "os"
    "time"

    "go.opentelemetry.io/otel"
    "go.opentelemetry.io/otel/attribute"
    "go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc"
    "go.opentelemetry.io/otel/metric"
    sdkmetric "go.opentelemetry.io/otel/sdk/metric"
    "go.opentelemetry.io/otel/sdk/metric/metricdata"
    "go.opentelemetry.io/otel/sdk/resource"
    "google.golang.org/grpc/encoding/gzip"
)

func main() {
    ctx := context.Background()

    dsn := os.Getenv("UPTRACE_DSN")
    if dsn == "" {
        panic("UPTRACE_DSN environment variable is required")
    }
    fmt.Println("using DSN:", dsn)

    exporter, err := otlpmetricgrpc.New(ctx,
        otlpmetricgrpc.WithEndpoint("api.uptrace.dev:4317"),
        otlpmetricgrpc.WithHeaders(map[string]string{
            // Set the Uptrace DSN here or use UPTRACE_DSN env var.
            "uptrace-dsn": dsn,
        }),
        otlpmetricgrpc.WithCompressor(gzip.Name),
        otlpmetricgrpc.WithTemporalitySelector(preferDeltaTemporalitySelector),
    )
    if err != nil {
        panic(err)
    }

    reader := sdkmetric.NewPeriodicReader(
        exporter,
        sdkmetric.WithInterval(15*time.Second),
    )

    resource, err := resource.New(ctx,
        resource.WithFromEnv(),
        resource.WithTelemetrySDK(),
        resource.WithHost(),
        resource.WithAttributes(
            attribute.String("service.name", "myservice"),
            attribute.String("service.version", "1.0.0"),
        ))
    if err != nil {
        panic(err)
    }

    provider := sdkmetric.NewMeterProvider(
        sdkmetric.WithReader(reader),
        sdkmetric.WithResource(resource),
    )
    otel.SetMeterProvider(provider)

    meter := provider.Meter("app_or_package_name")
    counter, _ := meter.Int64Counter(
        "uptrace.demo.counter_name",
        metric.WithUnit("1"),
        metric.WithDescription("counter description"),
    )

    fmt.Println("exporting data to Uptrace...")
    for {
        counter.Add(ctx, 1)
        time.Sleep(time.Millisecond)
    }
}

func preferDeltaTemporalitySelector(kind sdkmetric.InstrumentKind) metricdata.Temporality {
    switch kind {
    case sdkmetric.InstrumentKindCounter,
        sdkmetric.InstrumentKindObservableCounter,
        sdkmetric.InstrumentKindHistogram:
        return metricdata.DeltaTemporality
    default:
        return metricdata.CumulativeTemporality
    }
}

Exporting logs

Here is how you can export logs to Uptrace following the recommendations above:

package main

import (
    "context"
    "fmt"
    "log/slog"
    "os"
    "time"

    "go.opentelemetry.io/contrib/bridges/otelslog"
    "go.opentelemetry.io/contrib/propagators/aws/xray"
    "go.opentelemetry.io/otel"
    "go.opentelemetry.io/otel/attribute"
    "go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp"
    "go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
    "go.opentelemetry.io/otel/log/global"
    sdklog "go.opentelemetry.io/otel/sdk/log"
    "go.opentelemetry.io/otel/sdk/resource"
    sdktrace "go.opentelemetry.io/otel/sdk/trace"
    "go.opentelemetry.io/otel/trace"
)

func main() {
    ctx := context.Background()

    dsn := os.Getenv("UPTRACE_DSN")
    if dsn == "" {
        panic("UPTRACE_DSN environment variable is required")
    }
    fmt.Println("using DSN:", dsn)

    resource, err := resource.New(ctx,
        resource.WithFromEnv(),
        resource.WithTelemetrySDK(),
        resource.WithHost(),
        resource.WithAttributes(
            attribute.String("service.name", "myservice"),
            attribute.String("service.version", "1.0.0"),
        ))
    if err != nil {
        panic(err)
    }

    shutdownTracing := configureTracing(ctx, dsn, resource)
    defer shutdownTracing()

    shutdownLogging := configureLogging(ctx, dsn, resource)
    defer shutdownLogging()

    tracer := otel.Tracer("app_or_package_name")
    logger := otelslog.NewLogger("app_or_package_name")

    ctx, main := tracer.Start(ctx, "main-operation", trace.WithSpanKind(trace.SpanKindServer))
    defer main.End()

    logger.ErrorContext(ctx, "hello world", slog.String("error", "error message"))

    fmt.Printf("trace: https://app.uptrace.dev/traces/%s\n", main.SpanContext().TraceID())
}

func configureLogging(ctx context.Context, dsn string, resource *resource.Resource) func() {
    exp, err := otlploghttp.New(ctx,
        otlploghttp.WithEndpoint("api.uptrace.dev"),
        otlploghttp.WithHeaders(map[string]string{
            "uptrace-dsn": dsn,
        }),
        otlploghttp.WithCompression(otlploghttp.GzipCompression),
    )
    if err != nil {
        panic(err)
    }

    bsp := sdklog.NewBatchProcessor(exp,
        sdklog.WithMaxQueueSize(10_000),
        sdklog.WithExportMaxBatchSize(10_000),
        sdklog.WithExportInterval(10*time.Second),
        sdklog.WithExportTimeout(10*time.Second),
    )

    provider := sdklog.NewLoggerProvider(
        sdklog.WithProcessor(bsp),
        sdklog.WithResource(resource),
    )

    global.SetLoggerProvider(provider)

    return func() {
        provider.Shutdown(ctx)
    }
}

func configureTracing(ctx context.Context, dsn string, resource *resource.Resource) func() {
    exporter, err := otlptracehttp.New(
        ctx,
        otlptracehttp.WithEndpoint("api.uptrace.dev"),
        otlptracehttp.WithHeaders(map[string]string{
            "uptrace-dsn": dsn,
        }),
        otlptracehttp.WithCompression(otlptracehttp.GzipCompression),
    )
    if err != nil {
        panic(err)
    }

    bsp := sdktrace.NewBatchSpanProcessor(exporter,
        sdktrace.WithMaxQueueSize(10_000),
        sdktrace.WithMaxExportBatchSize(10_000),
    )

    tracerProvider := sdktrace.NewTracerProvider(
        sdktrace.WithResource(resource),
        sdktrace.WithIDGenerator(xray.NewIDGenerator()),
    )
    tracerProvider.RegisterSpanProcessor(bsp)

    otel.SetTracerProvider(tracerProvider)

    return func() {
        tracerProvider.Shutdown(ctx)
    }
}

Serverless

AWS Lambda

See OpenTelemetry Go Lambda.

Vercel

On Vercel, you need to configure OpenTelemetry in the init function and ForceFlush spans when the Vercel handler exits.

package handler

import (
    "fmt"
    "net/http"

    "go.opentelemetry.io/otel"
    "github.com/uptrace/uptrace-go/uptrace"
)

var tracer = otel.Tracer("app_or_package_name")

func init() {
    uptrace.ConfigureOpentelemetry(...)
}

func Handler(w http.ResponseWriter, req *http.Request) {
    ctx := req.Context()

    // Flush buffered spans.
    defer uptrace.ForceFlush(ctx)

    ctx, span := tracer.Start(ctx, "handler-name")
    defer span.End()

    fmt.Fprintf(w, "<h1>Hello from Go!</h1>")
}

Sampling

You can reduce the number of created (sampled) spans by configuring head-based sampling:

import "go.opentelemetry.io/contrib/samplers/probability/consistent"

sampler := consistent.ParentProbabilityBased(
    consistent.ProbabilityBased(0.5), // sample 50% of traces
)

uptrace.ConfigureOpentelemetry(
    uptrace.WithTraceSampler(sampler),

    // Other options
)

By default, uptrace-go samples all spans.

Errors monitoring

To monitor errors with a stack trace, use the RecordError API:

import (
    "go.opentelemetry.io/otel/codes"
    "go.opentelemetry.io/otel/trace"
)

ctx, span := tracer.Start(ctx, "operation-name")
defer span.End()

span.RecordError(errors.New("oh my"), trace.WithStackTrace(true))
span.SetStatus(codes.Error, err.Error())

See OpenTelemetry Go Tracing API for details.

Logs monitoring

To monitor logs, use OpenTelemetry instrumentations for popular logging libraries:

If that is not possible, see Monitoring Logs for more options such as Vector or FluentBit.

SDK logging

By default, OpenTelemetry Go SDK logs error messages to stderr. You can discard or redirect those logs by providing an error handler:

import "go.opentelemetry.io/otel"

otel.SetErrorHandler(otel.ErrorHandlerFunc(func(err error) {
    // ignore the error
}))

Baggage

You can use package baggagecopy to read key/values stored in baggage in the starting span's parent context and add them as attributes to the span.

import "go.opentelemetry.io/contrib/processors/baggagecopy"

uptrace.ConfigureOpentelemetry(
    WithSpanProcessor(
        baggagecopy.NewSpanProcessor(nil),
    ),
)

What's next?

Next, instrument more operations to get a more detailed picture. Try to prioritize network calls, disk operations, database queries, errors, and logs.

You can also create your own instrumentations using OpenTelemetry Go Tracing API.

Get startedLearn how to monitor your Erlang/Elixir applications with OpenTelemetry and Uptrace.

Tracing API