# Observability - Go SDK > Monitor your Temporal Application state using Metrics, Tracing, Logging, and Visibility features. Emit metrics, configure tracing, customize logging, and use Search Attributes with the Temporal Go SDK for enhanced Workflow Execution insights. This page covers the many ways to view the current state of your [Temporal Application](/temporal#temporal-application)—that is, ways to view which [Workflow Executions](/workflow-execution) are tracked by the [Temporal Platform](/temporal#temporal-platform) and the state of any specified Workflow Execution, either currently or at points of an execution. This section covers features related to viewing the state of the application, including: - [Metrics](#metrics) - [Tracing](#tracing) - [Logging](#logging) - [Visibility](#visibility) ## How to emit metrics **How to emit application metrics using the Temporal Go SDK.** Each Temporal SDK is capable of emitting an optional set of metrics from either the Client or the Worker process. For a complete list of metrics capable of being emitted, see the [SDK metrics reference](/references/sdk-metrics). - For an overview of Prometheus and Grafana integration, refer to the [Monitoring](/self-hosted-guide/monitoring) guide. - For a list of metrics, see the [SDK metrics reference](/references/sdk-metrics). - For an end-to-end example that exposes metrics with the Go SDK, refer to the [samples-go](https://github.com/temporalio/samples-go/tree/main/metrics) repo. To emit metrics from the Temporal Client in Go, create a [metrics handler](https://pkg.go.dev/go.temporal.io/sdk/internal/common/metrics#Handler) from the [Client Options](https://pkg.go.dev/go.temporal.io/sdk@v1.15.0/internal#ClientOptions) and specify a listener address to be used by Prometheus. ```go client.Options{ MetricsHandler: sdktally.NewMetricsHandler(newPrometheusScope(prometheus.Configuration{ ListenAddress: "0.0.0.0:9090", TimerType: "histogram", } ``` The Go SDK currently supports the [Tally](https://pkg.go.dev/go.temporal.io/sdk/contrib/tally) library; however, Tally offers [extensible custom metrics reporting](https://github.com/uber-go/tally#report-your-metrics), which is exposed through the [`WithCustomMetricsReporter`](/references/server-options#withcustommetricsreporter) API. For more information, see the [Go sample for metrics](https://github.com/temporalio/samples-go/tree/main/metrics). ## Tracing Tracing allows you to view the call graph of a Workflow along with its Activities, Nexus Operations, and Child Workflows. The Go SDK provides tracing interceptors for [OpenTelemetry](https://pkg.go.dev/go.temporal.io/sdk/contrib/opentelemetry), [OpenTracing](https://pkg.go.dev/go.temporal.io/sdk/contrib/opentracing), and [Datadog](https://pkg.go.dev/go.temporal.io/sdk/contrib/datadog/tracing). First, create a tracing interceptor for Client instantiation. ```go // OpenTelemetry tracingInterceptor, err := opentelemetry.NewTracingInterceptor(opentelemetry.TracerOptions{}) // OpenTracing tracingInterceptor, err := opentracing.NewInterceptor(opentracing.TracerOptions{}) // Datadog tracingInterceptor, err := tracing.NewTracingInterceptor(tracing.TracerOptions{}) ``` and register it by passing it to [ClientOptions](https://pkg.go.dev/go.temporal.io/sdk/internal#ClientOptions): ```go c, err := client.Dial(client.Options{ Interceptors: []interceptor.ClientInterceptor{tracingInterceptor}, }) ``` You can also register interceptors through a [Plugin](/develop/plugins-guide#interceptors) if you’re building a reusable library. Each tracing interceptor uses its library's native propagation mechanism to serialize trace spans into Temporal headers. For example, OpenTelemetry uses its `TextMapPropagator` with the W3C TraceContext format. The SDK carries these headers across Workflow, Activity, and Child Workflow boundaries, so the tracing library can reconstruct the call graph. For more information, see the documentation for [OpenTelemetry](https://opentelemetry.io/), [OpenTracing](https://opentracing.io), and [Datadog](https://docs.datadoghq.com/tracing/). To build custom context propagation (e.g., tenant IDs, auth tokens), see [Context Propagation](/develop/go/best-practices/context-propagation). ## Log from a Workflow **How to log from a Workflow using the Go SDK.** Send logs and errors to a logging service, so that when things go wrong, you can see what happened. Loggers create an audit trail and capture information about your Workflow's operation. An appropriate logging level depends on your specific needs. During development or troubleshooting, you might use debug or even trace. In production, you might use info or warn to avoid excessive log volume. The logger supports the following logging levels: | Level | Use | | ------- | --------------------------------------------------------------------------------------------------------- | | `TRACE` | The most detailed level of logging, used for very fine-grained information. | | `DEBUG` | Detailed information, typically useful for debugging purposes. | | `INFO` | General information about the application's operation. | | `WARN` | Indicates potentially harmful situations or minor issues that don't prevent the application from working. | | `ERROR` | Indicates error conditions that might still allow the application to continue running. | The Temporal SDK core normally uses `WARN` as its default logging level. In Workflow Definitions you can use [`workflow.GetLogger(ctx)`](https://pkg.go.dev/go.temporal.io/sdk/workflow#GetLogger) to write logs. ```go import ( "context" "time" "go.temporal.io/sdk/activity" "go.temporal.io/sdk/workflow" ) // Workflow is a standard workflow definition. // Note that the Workflow and Activity don't need to care that // their inputs/results are being compressed. func Workflow(ctx workflow.Context, name string) (string, error) { // ... workflow.WithActivityOptions(ctx, ao) // Getting the logger from the context. logger := workflow.GetLogger(ctx) // Logging a message with the key value pair `name` and `name` logger.Info("Compressed Payloads workflow started", "name", name) info := map[string]string{ "name": name, } logger.Info("Compressed Payloads workflow completed.", "result", result) return result, nil } ``` ### Provide a custom logger **How to provide a custom logger to the Temporal Client using the Go SDK.** This field sets a custom Logger that is used for all logging actions of the instance of the Temporal Client. The Go SDK supports custom loggers via `log.NewStructuredLogger()`, which wraps Go's standard [`slog.Logger`](https://pkg.go.dev/log/slog) (Go 1.21+). Because most modern logging libraries (zap, zerolog, logrus, etc.) can back a `slog.Handler`, `slog` serves as the universal bridge to third-party loggers. **Using slog directly:** ```go import ( "log/slog" "os" "go.temporal.io/sdk/client" "go.temporal.io/sdk/log" ) func main() { // ... slogHandler := slog.NewJSONHandler(os.Stdout, &slog.HandlerOptions{Level: slog.LevelInfo}) logger := log.NewStructuredLogger(slog.New(slogHandler)) clientOptions := client.Options{ Logger: logger, } temporalClient, err := client.Dial(clientOptions) // ... } ``` **Bridging a third-party logger through slog (example with zap):** ```go import ( "log/slog" "go.uber.org/zap" "go.uber.org/zap/exp/zapslog" "go.temporal.io/sdk/client" "go.temporal.io/sdk/log" ) func main() { // ... zapLogger, _ := zap.NewProduction() handler := zapslog.NewHandler(zapLogger.Core()) logger := log.NewStructuredLogger(slog.New(handler)) clientOptions := client.Options{ Logger: logger, } temporalClient, err := client.Dial(clientOptions) // ... } ``` As an alternative, you can implement the `log.Logger` interface directly. The Temporal samples repo has a [zap adapter](https://github.com/temporalio/samples-go/blob/main/zapadapter/zap_adapter.go) that can be used as a reference. ## Visibility APIs The term Visibility, within the Temporal Platform, refers to the subsystems and APIs that enable an operator to view Workflow Executions that currently exist within a Temporal Service. ### Search Attributes **How to use Search Attributes using the Go SDK.** The typical method of retrieving a Workflow Execution is by its Workflow Id. However, sometimes you'll want to retrieve one or more Workflow Executions based on another property. For example, imagine you want to get all Workflow Executions of a certain type that have failed within a time range, so that you can start new ones with the same arguments. You can do this with [Search Attributes](/search-attribute). - [Default Search Attributes](/search-attribute#default-search-attribute) like `WorkflowType`, `StartTime` and `ExecutionStatus` are automatically added to Workflow Executions. - [Custom Search Attributes](/search-attribute#custom-search-attribute) can contain their own domain-specific data (like `customerId` or `numItems`). The steps to using custom Search Attributes are: - Create a new Search Attribute in your Temporal Service using `temporal operator search-attribute create` or the Cloud UI. - Set the value of the Search Attribute for a Workflow Execution: - On the Client by including it as an option when starting the Execution. - In the Workflow by calling `UpsertSearchAttributes`. - Read the value of the Search Attribute: - On the Client by calling `DescribeWorkflow`. - In the Workflow by looking at `WorkflowInfo`. - Query Workflow Executions by the Search Attribute using a [List Filter](/list-filter): - [In the Temporal CLI](/cli/command-reference/workflow#list). - In code by calling `ListWorkflowExecutions`. Here is how to query Workflow Executions: The [ListWorkflow()](https://pkg.go.dev/go.temporal.io/sdk/client#Client.ListWorkflow) function retrieves a list of [Workflow Executions](/workflow-execution) that match the [Search Attributes](/search-attribute) of a given [List Filter](/list-filter). The metadata returned from the [Visibility](/temporal-service/visibility) store can be used to get a Workflow Execution's history and details from the [Persistence](/temporal-service/persistence) store. Use a List Filter to define a `request` to pass into `ListWorkflow()`. ```go request := &workflowservice.ListWorkflowExecutionsRequest{ Query: "CloseTime = missing" } ``` This `request` value returns only open Workflows. For more List Filter examples, see the [examples provided for List Filters in the Temporal Visibility guide.](/list-filter#list-filter-examples) ```go resp, err := temporalClient.ListWorkflow(ctx.Background(), request) if err != nil { return err } fmt.Println("First page of results:") for _, exec := range resp.Executions { fmt.Printf("Workflow ID %v\n", exec.Execution.WorkflowId) } ``` ### Set custom Search Attributes **How to set custom Search Attributes using the Go SDK.** After you've created custom Search Attributes in your Temporal Service (using the `temporal operator search-attribute create` command or the Cloud UI), you can set the values of the custom Search Attributes when starting a Workflow. Provide key-value pairs in [`StartWorkflowOptions.SearchAttributes`](https://pkg.go.dev/go.temporal.io/sdk/internal#StartWorkflowOptions). Search Attributes are represented as `map[string]interface{}`. The values in the map must correspond to the [Search Attribute's value type](/search-attribute#supported-types): - Bool = `bool` - Datetime = `time.Time` - Double = `float64` - Int = `int64` - Keyword = `string` - Text = `string` If you had custom Search Attributes `CustomerId` of type Keyword and `MiscData` of type Text, you would provide `string` values: ```go func (c *Client) CallYourWorkflow(ctx context.Context, workflowID string, payload map[string]interface{}) error { // ... searchAttributes := map[string]interface{}{ "CustomerId": payload["customer"], "MiscData": payload["miscData"] } options := client.StartWorkflowOptions{ SearchAttributes: searchAttributes // ... } we, err := c.Client.ExecuteWorkflow(ctx, options, app.YourWorkflow, payload) // ... } ``` ### Upsert Search Attributes **How to upsert Search Attributes using the Go SDK.** You can upsert Search Attributes to add or update Search Attributes from within Workflow code. In advanced cases, you may want to dynamically update these attributes as the Workflow progresses. [UpsertSearchAttributes](https://pkg.go.dev/go.temporal.io/sdk/workflow#UpsertSearchAttributes) is used to add or update Search Attributes from within Workflow code. `UpsertSearchAttributes` will merge attributes to the existing map in the Workflow. Consider this example Workflow code: ```go func YourWorkflow(ctx workflow.Context, input string) error { attr1 := map[string]interface{}{ "CustomIntField": 1, "CustomBoolField": true, } workflow.UpsertSearchAttributes(ctx, attr1) attr2 := map[string]interface{}{ "CustomIntField": 2, "CustomKeywordField": "seattle", } workflow.UpsertSearchAttributes(ctx, attr2) } ``` After the second call to `UpsertSearchAttributes`, the map will contain: ```go map[string]interface{}{ "CustomIntField": 2, // last update wins "CustomBoolField": true, "CustomKeywordField": "seattle", } ``` ### Remove a Search Attribute from a Workflow **How to remove a Search Attribute from a Workflow using the Go SDK.** To remove a Search Attribute that was previously set, set it to an empty array: `[]`. **There is no support for removing a field.** However, to achieve a similar effect, set the field to some placeholder value. For example, you could set `CustomKeywordField` to `impossibleVal`. Then searching `CustomKeywordField != 'impossibleVal'` will match Workflows with `CustomKeywordField` not equal to `impossibleVal`, which includes Workflows without the `CustomKeywordField` set.