> ## Documentation Index
> Fetch the complete documentation index at: https://docs.trulayer.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Go SDK configuration

> Every option you can pass to trulayer.NewClient().

## Options

Pass `ClientOption` functions as variadic arguments to `NewClient`. All options are optional — the defaults are production-safe for most services.

| Option                               | Type            | Default                       | Description                                                                 |
| ------------------------------------ | --------------- | ----------------------------- | --------------------------------------------------------------------------- |
| `WithBaseURL(u string)`              | `string`        | `https://api.trulayer.ai`     | Override the API base URL. Use for self-hosted deployments or test mocks.   |
| `WithBatchSize(n int)`               | `int`           | `50`                          | Flush when this many traces are buffered. Values ≤ 0 are ignored.           |
| `WithFlushInterval(d time.Duration)` | `time.Duration` | `2s`                          | Flush after this interval, whichever comes first. Values ≤ 0 are ignored.   |
| `WithHTTPClient(h *http.Client)`     | `*http.Client`  | stdlib default (10 s timeout) | Override the HTTP client. Useful for custom transports, proxies, and tests. |

### Environment variable — `TRULAYER_DRY_RUN`

Set `TRULAYER_DRY_RUN` to `1`, `true`, or `yes` (case-insensitive) to disable all network calls. The SDK constructs traces and spans normally, but nothing is sent to the ingest API.

```bash theme={null}
TRULAYER_DRY_RUN=true go run ./main.go
```

When dry-run mode is active, `SubmitFeedback` is also a no-op and returns `nil`.

If you call `NewClient` with an empty API key and `TRULAYER_DRY_RUN` is **not** set, the SDK logs a warning via `log.Printf` and no traces will be sent. Always set the env var explicitly in CI and local development to silence the warning.

## Example — production

```go theme={null}
package main

import (
    "context"
    "net/http"
    "os"
    "time"

    "github.com/trulayer/client-go/trulayer"
)

func main() {
    tl := trulayer.NewClient(
        os.Getenv("TRULAYER_API_KEY"),
        trulayer.WithBatchSize(100),
        trulayer.WithFlushInterval(5*time.Second),
        trulayer.WithHTTPClient(&http.Client{
            Timeout: 15 * time.Second,
        }),
    )
    defer func() {
        shutdownCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
        defer cancel()
        if err := tl.Shutdown(shutdownCtx); err != nil {
            // log or alert — buffered traces may have been lost
        }
    }()

    // your application logic here
}
```

## Example — local / offline

For CI pipelines, local development without a TruLayer API key, or any context where you want zero network activity:

```go theme={null}
// Option 1 — environment variable (no code changes required)
// TRULAYER_DRY_RUN=true go run ./main.go

// Option 2 — point at a local mock server
tl := trulayer.NewClient(
    "tl_local",
    trulayer.WithBaseURL("http://localhost:4010"),
)
```

Use `WithBaseURL` when you want to assert on the captured payloads in tests rather than silently discarding them. See [Testing](/sdks/go/testing) for the recommended `net/http/httptest` pattern.

## Flush control

`Flush` blocks until all enqueued traces have been attempted. Pass a context to set a deadline:

```go theme={null}
ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
defer cancel()
if err := tl.Flush(ctx); err != nil {
    log.Printf("flush: %v", err)
}
```

`Shutdown` performs a final flush and stops the background goroutine. In long-lived servers, wire it into your graceful-shutdown hook:

```go theme={null}
shutdownCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
defer cancel()
if err := tl.Shutdown(shutdownCtx); err != nil {
    log.Printf("shutdown: %v", err)
}
```

Subsequent `NewTrace` calls after `Shutdown` still succeed, but the resulting traces will not be sent.