> ## Documentation Index
> Fetch the complete documentation index at: https://private-7c7dfe99-mintlify-8c05c8a2.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

> Golang SDK for ClickStack - The ClickHouse Observability Stack

# Golang

ClickStack uses the OpenTelemetry standard for collecting telemetry data (logs and
traces). Traces are auto-generated with automatic instrumentation, so manual
instrumentation isn't required to get value out of tracing.

**This Guide Integrates:**

<table>
  <tbody>
    <tr>
      <td className="pe-2">✅ Logs</td>
      <td className="pe-2">✅ Metrics</td>
      <td className="pe-2">✅ Traces</td>
    </tr>
  </tbody>
</table>

<h2 id="getting-started">
  Getting started
</h2>

<h3 id="install-opentelemetry">
  Install OpenTelemetry instrumentation packages
</h3>

To install the OpenTelemetry and HyperDX Go packages, use the command below. It is recommended to check out the [current instrumentation packages](https://github.com/open-telemetry/opentelemetry-go-contrib/tree/v1.4.0/instrumentation#instrumentation-packages) and install the necessary packages to ensure that the trace information is attached correctly.

```shell theme={null}
go get -u go.opentelemetry.io/otel
go get -u github.com/hyperdxio/otel-config-go
go get -u github.com/hyperdxio/opentelemetry-go
go get -u github.com/hyperdxio/opentelemetry-logs-go
```

<h3 id="native-http-server-example">
  Native HTTP server example (net/http)
</h3>

For this example, we will be using `net/http/otelhttp`.

```shell theme={null}
go get -u go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp
```

Refer to the commented sections to learn how to instrument your Go application.

```go theme={null}

package main

import (
  "context"
  "io"
  "log"
  "net/http"
  "os"

  "github.com/hyperdxio/opentelemetry-go/otelzap"
  "github.com/hyperdxio/opentelemetry-logs-go/exporters/otlp/otlplogs"
  "github.com/hyperdxio/otel-config-go/otelconfig"
  "go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
  "go.opentelemetry.io/otel/trace"
  "go.uber.org/zap"
  sdk "github.com/hyperdxio/opentelemetry-logs-go/sdk/logs"
  semconv "go.opentelemetry.io/otel/semconv/v1.21.0"
  "go.opentelemetry.io/otel/sdk/resource"
)

// configure common attributes for all logs
func newResource() *resource.Resource {
  hostName, _ := os.Hostname()
  return resource.NewWithAttributes(
    semconv.SchemaURL,
    semconv.ServiceVersion("1.0.0"),
    semconv.HostName(hostName),
  )
}

// attach trace id to the log
func WithTraceMetadata(ctx context.Context, logger *zap.Logger) *zap.Logger {
  spanContext := trace.SpanContextFromContext(ctx)
  if !spanContext.IsValid() {
    // ctx does not contain a valid span.
    // There is no trace metadata to add.
    return logger
  }
  return logger.With(
    zap.String("trace_id", spanContext.TraceID().String()),
    zap.String("span_id", spanContext.SpanID().String()),
  )
}

func main() {
  // Initialize otel config and use it across the entire app
  otelShutdown, err := otelconfig.ConfigureOpenTelemetry()
  if err != nil {
    log.Fatalf("error setting up OTel SDK - %e", err)
  }
  defer otelShutdown()

  ctx := context.Background()

  // configure opentelemetry logger provider
  logExporter, _ := otlplogs.NewExporter(ctx)
  loggerProvider := sdk.NewLoggerProvider(
    sdk.WithBatcher(logExporter),
  )
  // gracefully shutdown logger to flush accumulated signals before program finish
  defer loggerProvider.Shutdown(ctx)

  // create new logger with opentelemetry zap core and set it globally
  logger := zap.New(otelzap.NewOtelCore(loggerProvider))
  zap.ReplaceGlobals(logger)
  logger.Warn("hello world", zap.String("foo", "bar"))

  http.Handle("/", otelhttp.NewHandler(wrapHandler(logger, ExampleHandler), "example-service"))

  port := os.Getenv("PORT")
  if port == "" {
    port = "7777"
  }

  logger.Info("** Service Started on Port " + port + " **")
  if err := http.ListenAndServe(":"+port, nil); err != nil {
    logger.Fatal(err.Error())
  }
}

// Use this to wrap all handlers to add trace metadata to the logger
func wrapHandler(logger *zap.Logger, handler http.HandlerFunc) http.HandlerFunc {
  return func(w http.ResponseWriter, r *http.Request) {
    logger := WithTraceMetadata(r.Context(), logger)
    logger.Info("request received", zap.String("url", r.URL.Path), zap.String("method", r.Method))
    handler(w, r)
    logger.Info("request completed", zap.String("path", r.URL.Path), zap.String("method", r.Method))
  }
}

func ExampleHandler(w http.ResponseWriter, r *http.Request) {
  w.Header().Add("Content-Type", "application/json")
  io.WriteString(w, `{"status":"ok"}`)
}
```

<h3 id="gin-application-example">
  Gin application example
</h3>

For this example, we will be using `gin-gonic/gin`.

```shell theme={null}
go get -u go.opentelemetry.io/contrib/instrumentation/github.com/gin-gonic/gin/otelgin
```

Refer to the commented sections to learn how to instrument your Go application.

```go theme={null}

package main

import (
  "context"
  "log"
  "net/http"

  "github.com/gin-gonic/gin"
  "github.com/hyperdxio/opentelemetry-go/otelzap"
  "github.com/hyperdxio/opentelemetry-logs-go/exporters/otlp/otlplogs"
  sdk "github.com/hyperdxio/opentelemetry-logs-go/sdk/logs"
  "github.com/hyperdxio/otel-config-go/otelconfig"
  "go.opentelemetry.io/contrib/instrumentation/github.com/gin-gonic/gin/otelgin"
  "go.opentelemetry.io/otel/trace"
  "go.uber.org/zap"
)

// attach trace id to the log
func WithTraceMetadata(ctx context.Context, logger *zap.Logger) *zap.Logger {
  spanContext := trace.SpanContextFromContext(ctx)
  if !spanContext.IsValid() {
    // ctx does not contain a valid span.
    // There is no trace metadata to add.
    return logger
  }
  return logger.With(
    zap.String("trace_id", spanContext.TraceID().String()),
    zap.String("span_id", spanContext.SpanID().String()),
  )
}

func main() {
  // Initialize otel config and use it across the entire app
  otelShutdown, err := otelconfig.ConfigureOpenTelemetry()
  if err != nil {
    log.Fatalf("error setting up OTel SDK - %e", err)
  }

  defer otelShutdown()

  ctx := context.Background()

  // configure opentelemetry logger provider
  logExporter, _ := otlplogs.NewExporter(ctx)
  loggerProvider := sdk.NewLoggerProvider(
    sdk.WithBatcher(logExporter),
  )

  // gracefully shutdown logger to flush accumulated signals before program finish
  defer loggerProvider.Shutdown(ctx)

  // create new logger with opentelemetry zap core and set it globally
  logger := zap.New(otelzap.NewOtelCore(loggerProvider))
  zap.ReplaceGlobals(logger)

  // Create a new Gin router
  router := gin.Default()

  router.Use(otelgin.Middleware("service-name"))

  // Define a route that responds to GET requests on the root URL
  router.GET("/", func(c *gin.Context) {
    _logger := WithTraceMetadata(c.Request.Context(), logger)
    _logger.Info("Hello World!")
    c.String(http.StatusOK, "Hello World!")
  })

  // Run the server on port 7777
  router.Run(":7777")
}
```

<h3 id="configure-environment-variables">
  Configure environment variables
</h3>

Afterwards you'll need to configure the following environment variables in your shell to ship telemetry to ClickStack via the OpenTelemetry collector:

<Tabs>
  <Tab title="Managed ClickStack">
    ```shell theme={null}
    export OTEL_EXPORTER_OTLP_ENDPOINT=https://your-otel-collector:4318 \
    OTEL_EXPORTER_OTLP_PROTOCOL=http/protobuf \
    OTEL_SERVICE_NAME='<NAME_OF_YOUR_APP_OR_SERVICE>' \
    ```
  </Tab>

  <Tab title="ClickStack Open Source">
    ```shell theme={null}
    export OTEL_EXPORTER_OTLP_ENDPOINT=https://your-otel-collector:4318 \
    OTEL_EXPORTER_OTLP_PROTOCOL=http/protobuf \
    OTEL_SERVICE_NAME='<NAME_OF_YOUR_APP_OR_SERVICE>' \
    OTEL_EXPORTER_OTLP_HEADERS='authorization=<YOUR_INGESTION_API_KEY>'
    ```
  </Tab>
</Tabs>

The `OTEL_EXPORTER_OTLP_HEADERS` environment variable contains the API Key available via HyperDX app in `Team Settings → API Keys`.