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# Logging

> Structured logging with Logger class and global configuration functions.

[env-vars]: /docs/server-sdks/reference/typescript/agents/configuration/environment-variables

The SDK provides a structured logging system with configurable log levels, formats,
colors, and output streams. Configuration is driven by environment variables (see
[Environment Variables][env-vars]) and can be overridden programmatically.

```typescript {1}
import { Logger, getLogger, setGlobalLogLevel } from '@signalwire/sdk';
```

---

## **Logger**

Structured logger that respects global level, format, and color settings. Each
Logger has a name and optional bound context data included in every entry.

### **Parameters**

**`name`** `string` — required

Logger name shown in log output (e.g., `"AgentBase"`, `"SessionManager"`).

---

**`context`** `Record<string, unknown>`

Optional key-value pairs included in every log entry from this logger.

---

### **debug** / **info** / **warn** / **error**

Log a message at the given severity level.

**`msg`** `string` — required

The log message.

---

**`data`** `Record<string, unknown>`

Optional structured data to include in the log entry.

---

### **bind**

Create a child logger with additional bound context fields merged into the
parent's context.

**`context`** `Record<string, unknown>` — required

Key-value pairs to merge into the child logger's context.

---

**Returns:** `Logger` -- A new Logger instance with the merged context.

---

## **getLogger**

Create or retrieve a cached Logger instance by name.

## **Parameters**

**`name`** `string` — required

Logger name. Instances are cached — calling `getLogger('foo')` twice returns the same Logger.

---

## **Returns**

`Logger`

## **Example**

```typescript {3}
import { getLogger } from '@signalwire/sdk';

const log = getLogger('MyAgent');
log.info('Agent started', { port: 3000 });
log.debug('Processing request', { callId: 'abc-123' });
```

---

## **setGlobalLogLevel**

Set the minimum log level for all loggers. Messages below this level are suppressed.

## **Parameters**

**`level`** `"debug" | "info" | "warn" | "error"` — required

The minimum severity level to emit.

---

## **Returns**

`void`

## **Example**

```typescript {3}
import { setGlobalLogLevel } from '@signalwire/sdk';

setGlobalLogLevel('debug'); // Show all messages including debug
```

---

## **suppressAllLogs**

Suppress or restore all log output globally.

## **Parameters**

**`suppress`** `boolean` — default: true

`true` to suppress all output, `false` to restore.

---

## **Returns**

`void`

## **Example**

```typescript {3}
import { suppressAllLogs } from '@signalwire/sdk';

suppressAllLogs(true); // Silence all logging
```

---

## **setGlobalLogFormat**

Set the output format for all loggers.

## **Parameters**

**`format`** `"text" | "json"` — required

`"text"` for human-readable output with colors, `"json"` for structured JSON entries.

---

## **Returns**

`void`

## **Example**

```typescript {3}
import { setGlobalLogFormat } from '@signalwire/sdk';

setGlobalLogFormat('json'); // Structured JSON output for log aggregators
```

---

## **setGlobalLogColor**

Enable or disable ANSI color codes in text-format output.

## **Parameters**

**`enabled`** `boolean` — required

`true` to enable colors, `false` to disable.

---

## **Returns**

`void`

## **Example**

```typescript {3}
import { setGlobalLogColor } from '@signalwire/sdk';

setGlobalLogColor(false); // Disable colors for CI/CD pipelines
```

---

## **setGlobalLogStream**

Set the output stream for all loggers.

## **Parameters**

**`stream`** `"stdout" | "stderr"` — required

The output stream to use.

---

## **Returns**

`void`

## **Example**

```typescript {3}
import { setGlobalLogStream } from '@signalwire/sdk';

setGlobalLogStream('stderr'); // Route all logs to stderr
```

---

## **resetLoggingConfiguration**

Reset all logging settings to their environment-variable-based defaults and clear
the logger cache.

## **Parameters**

None.

## **Returns**

`void`

## **Example**

```typescript {3}
import { resetLoggingConfiguration } from '@signalwire/sdk';

resetLoggingConfiguration();
```

---

## **getExecutionMode**

Detect the execution environment by inspecting well-known environment variables.

## **Parameters**

None.

## **Returns**

`string` -- The detected environment name. The SDK derives the log mode from
it internally.

| Environment            | Detection                                                   | Log Mode  |
| ---------------------- | ----------------------------------------------------------- | --------- |
| CGI                    | `GATEWAY_INTERFACE`                                         | `off`     |
| AWS Lambda             | `AWS_LAMBDA_FUNCTION_NAME` or `LAMBDA_TASK_ROOT`            | `stderr`  |
| Google Cloud Functions | `FUNCTION_TARGET` or `K_SERVICE`                            | `default` |
| Azure Functions        | `AZURE_FUNCTIONS_ENVIRONMENT` or `FUNCTIONS_WORKER_RUNTIME` | `default` |
| Server (default)       | No match                                                    | `default` |

## **Example**

```typescript {3}
import { getExecutionMode } from '@signalwire/sdk';

const env = getExecutionMode();
console.log(`Running in ${env} environment`);
```

> Structured logging with Logger class and global configuration functions.