# Exec Wasi

The **exec\_wasi** input plugin, allows to execute WASM program that is WASI target like as external program and collects event logs from there.

## Configuration Parameters

The plugin supports the following configuration parameters:

| Key               | Description                                                                                                                                                              |
| ----------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| WASI\_Path        | The place of a WASM program file.                                                                                                                                        |
| Parser            | Specify the name of a parser to interpret the entry as a structured message.                                                                                             |
| Accessible\_Paths | Specify the whitelist of paths to be able to access paths from WASM programs.                                                                                            |
| Interval\_Sec     | Polling interval (seconds).                                                                                                                                              |
| Interval\_NSec    | Polling interval (nanosecond).                                                                                                                                           |
| Wasm\_Heap\_Size  | Size of the heap size of Wasm execution. Review [unit sizes](https://docs.fluentbit.io/manual/3.2/administration/configuring-fluent-bit/unit-sizes) for allowed values.  |
| Wasm\_Stack\_Size | Size of the stack size of Wasm execution. Review [unit sizes](https://docs.fluentbit.io/manual/3.2/administration/configuring-fluent-bit/unit-sizes) for allowed values. |
| Buf\_Size         | Size of the buffer (check [unit sizes](https://docs.fluentbit.io/manual/3.2/administration/configuring-fluent-bit/unit-sizes) for allowed values)                        |
| Oneshot           | Only run once at startup. This allows collection of data precedent to fluent-bit's startup (bool, default: false)                                                        |
| Threaded          | Indicates whether to run this input in its own [thread](https://docs.fluentbit.io/manual/3.2/administration/multithreading#inputs). Default: `false`.                    |

## Configuration Examples

Here is a configuration example. in\_exec\_wasi can handle parser. To retrieve from structured data from WASM program, you have to create parser.conf:

Note that `Time_Format` should be aligned for the format of your using timestamp. In this documents, we assume that WASM program should write JSON style strings into stdout.

```python
[PARSER]
    Name        wasi
    Format      json
    Time_Key    time
    Time_Format %Y-%m-%dT%H:%M:%S.%L %z
```

Then, you can specify the above parsers.conf in the main fluent-bit configuration:

```python
[SERVICE]
    Flush        1
    Daemon       Off
    Parsers_File parsers.conf
    Log_Level    info
    HTTP_Server  Off
    HTTP_Listen  0.0.0.0
    HTTP_Port    2020

[INPUT]
    Name exec_wasi
    Tag  exec.wasi.local
    WASI_Path /path/to/wasi/program.wasm
    Accessible_Paths .,/path/to/accessible
    Parser wasi

[OUTPUT]
    Name  stdout
    Match *

```