# Logger

The Logger capability provides WASM functions with the ability to log arbitrary data. Much like a traditional logger framework, this capability offers multiple log levels.

By default Debug and Trace level logs are disabled. To enable these log levels to consult the configuration options for Tarmac.

## Error

Critical errors within the system.

```golang
_, err := wapc.HostCall("tarmac", "logger", "error", []byte("This is the data that should be logged"))
```

### Interface Details

| Namespace | Capability | Function | Input       | Output |
| --------- | ---------- | -------- | ----------- | ------ |
| `tarmac`  | `logger`   | `error`  | Log Message | `nil`  |

## Warn

Non-critical errors within the system.

```golang
_, err := wapc.HostCall("tarmac", "logger", "warn", []byte("This is the data that should be logged"))
```

### Interface Details

| Namespace | Capability | Function | Input       | Output |
| --------- | ---------- | -------- | ----------- | ------ |
| `tarmac`  | `logger`   | `warn`   | Log Message | `nil`  |

## Info

Informational logs.

```golang
_, err := wapc.HostCall("tarmac", "logger", "info", []byte("This is the data that should be logged"))
```

### Interface Details

| Namespace | Capability | Function | Input       | Output |
| --------- | ---------- | -------- | ----------- | ------ |
| `tarmac`  | `logger`   | `info`   | Log Message | `nil`  |

## Debug

Request level errors & informational logs. Disabled by default, calls to Debug logging are ignored unless `debug` is enabled for the Tarmac host.

```golang
_, err := wapc.HostCall("tarmac", "logger", "debug", []byte("This is the data that should be logged"))
```

### Interface Details

| Namespace | Capability | Function | Input       | Output |
| --------- | ---------- | -------- | ----------- | ------ |
| `tarmac`  | `logger`   | `debug`  | Log Message | `nil`  |

## Trace

Low-level details of execution. Disabled by default, calls to Trace logging are ignored unless `trace` is enabled for the Tarmac host.

```golang
_, err := wapc.HostCall("tarmac", "logger", "trace", []byte("This is the data that should be logged"))
```

### Interface Details

| Namespace | Capability | Function | Input       | Output |
| --------- | ---------- | -------- | ----------- | ------ |
| `tarmac`  | `logger`   | `trace`  | Log Message | `nil`  |