exec_wasi: wasm: Add documents for Wasm based plugins (#881)

* pipelines: inputs: exec_wasi: Add document for in_exec_wasi plugin

Signed-off-by: Hiroshi Hatake <[email protected]>

* summary: Add Exec Wasi section

Signed-off-by: Hiroshi Hatake <[email protected]>

* pipelines: filters: wasm: Add document for filter_wasm plugin

Signed-off-by: Hiroshi Hatake <[email protected]>

* summary: Add wasm section

Signed-off-by: Hiroshi Hatake <[email protected]>

Signed-off-by: Hiroshi Hatake <[email protected]>

Author: cosmo0920

SUMMARY.md

@@ -85,6 +85,7 @@
   * [Docker Events](pipeline/inputs/docker-events.md)
   * [Dummy](pipeline/inputs/dummy.md)
   * [Exec](pipeline/inputs/exec.md)
+  * [Exec Wasi](pipeline/inputs/exec_wasi.md)
   * [Fluent Bit Metrics](pipeline/inputs/fluentbit-metrics.md)
   * [Forward](pipeline/inputs/forward.md)
   * [Head](pipeline/inputs/head.md)
@@ -134,6 +135,7 @@
   * [Standard Output](pipeline/filters/standard-output.md)
   * [Throttle](pipeline/filters/throttle.md)
   * [Tensorflow](pipeline/filters/tensorflow.md)
+  * [Wasm](pipeline/filters/wasm.md)
 * [Outputs](pipeline/outputs/README.md)
   * [Amazon CloudWatch](pipeline/outputs/cloudwatch.md)
   * [Amazon Kinesis Data Firehose](pipeline/outputs/firehose.md)

pipeline/filters/wasm.md

@@ -0,0 +1,44 @@
+---
+description: Use Wasm programs as a filter
+---
+
+# Wasm Filter
+
+Wasm Filter allows you to modify the incoming records using [Wasm](https://webassembly.org/) technology.
+
+Due to the necessity to have a flexible filtering mechanism, it is now possible to extend Fluent Bit capabilities by writing custom filters using built Wasm programs and its runtime. A Wasm-based filter takes two steps:
+
+0. (Optional) Compiled as AOT (Ahead Of Time) objects to optimize Wasm execution pipeline
+1. Configure the Filter in the main configuration
+2. Prepare a Wasm program that will be used by the Filter
+
+## Configuration Parameters <a id="config"></a>
+
+The plugin supports the following configuration parameters:
+
+| Key | Description |
+| :--- | :--- |
+| Wasm\_Path | Path to the built Wasm program that will be used. This can be a relative path against the main configuration file. |
+| Function\_Name | Wasm function name that will be triggered to do filtering. It's assumed that the function is built inside the Wasm program specified above. |
+| Accessible\_Paths | Specify the whilelist of paths to be able to access paths from WASM programs. |
+
+## Configuration Examples <a id="config_example"></a>
+
+Here is a configuration example.
+
+```python
+[INPUT]
+    Name   dummy
+    Tag    dummy.local
+
+[FILTER]
+    Name wasm
+    Match dummy.*
+    WASM_Path /path/to/wasm_program.wasm
+    Function_Name filter_function_name
+    Accessible_Paths .,/path/to/accessible
+
+[OUTPUT]
+    Name   stdout
+    Match  *
+```

pipeline/inputs/exec_wasi.md

@@ -0,0 +1,60 @@
+# 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 whilelist of paths to be able to access paths from WASM programs. |
+| Interval\_Sec | Polling interval \(seconds\). |
+| Interval\_NSec | Polling interval \(nanosecond\). |
+| Buf\_Size | Size of the buffer \(check [unit sizes](https://docs.fluentbit.io/manual/configuration/unit_sizes) for allowed values\) |
+| Oneshot | Only run once at startup. This allows collection of data precedent to fluent-bit's startup (bool, default: false) |
+
+## 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 *
+
+```