# Fluent's usage and Commands
###### tags: `By_Ivan`
Some note of things i've read.
**fluent-cat**
The fluent-cat command sends an event to fluentd's in_forward/in_unix plugin. This is particularly useful for debuging.
This can be used for testing between two terminals.
```shell=
$ fluent-cat --none test
HELLOworld
```
```shell=
$ fluentd -c empty.conf
2020-09-11 14:31:53 +0800 [info]: parsing config file is succeeded path="empty.conf"
2020-09-11 14:31:53 +0800 [info]: gem 'fluent-plugin-elasticsearch' version '2.12.5'
2020-09-11 14:31:53 +0800 [info]: gem 'fluent-plugin-formatter_pretty_json' version '1.0.0'
2020-09-11 14:31:53 +0800 [info]: gem 'fluent-plugin-mongo' version '1.4.1'
2020-09-11 14:31:53 +0800 [info]: gem 'fluent-plugin-s3' version '1.4.0'
2020-09-11 14:31:53 +0800 [info]: gem 'fluent-plugin-sql' version '2.0.0'
2020-09-11 14:31:53 +0800 [info]: gem 'fluent-plugin-td' version '1.1.0'
2020-09-11 14:31:53 +0800 [info]: gem 'fluentd' version '1.11.2'
2020-09-11 14:31:53 +0800 [info]: using configuration file: <ROOT>
<source>
@type forward
</source>
<match *>
@type stdout
</match>
</ROOT>
2020-09-11 14:31:53 +0800 [info]: starting fluentd-1.11.2 pid=6111 ruby="2.5.5"
2020-09-11 14:31:53 +0800 [info]: spawn command to main: cmdline=["/usr/bin/ruby", "-Eascii-8bit:ascii-8bit", "/home/ivan/bin/fluentd", "-c", "empty.conf", "--under-supervisor"]
2020-09-11 14:31:53 +0800 [info]: adding match pattern="*" type="stdout"
2020-09-11 14:31:54 +0800 [info]: adding source type="forward"
2020-09-11 14:31:54 +0800 [info]: #0 starting fluentd worker pid=6120 ppid=6111 worker=0
2020-09-11 14:31:54 +0800 [info]: #0 listening port port=24224 bind="0.0.0.0"
2020-09-11 14:31:54 +0800 [info]: #0 fluentd worker is now running worker=0
2020-09-11 14:32:09.417269980 +0800 test: {"message":"HELLOworld"}
```
**none-parser**
Can be used to split multiline input to seperated events
EX: spliting sar result into seperated lines
```r=
<source>
@type exec
command sar | tail -10
tag script
<parse>
@type none
</parse>
</source>
<match script>
@type stdout
</match>
```
### Endpoints and logging
**Endpoints**
Fluentd supports curl endpoint for receiving signal and monitoring plugin instance.
1. instance monitoring
```r=
# add this source plugin to enable this function
<source>
@type monitor_agent
@id in_curl
bind "127.0.0.1"
port 24220
</source>
```
```shell!
$ curl http://127.0.0.1:24220/api/plugins.json
{"plugins":[{"plugin_id":"in_curl","plugin_category":"input","type":"monitor_agent","config":{"@type":"monitor_agent","@id":"in_curl","bind":"127.0.0.1","port":"24220"},"output_plugin":false,"retry_count":null},{"plugin_id":"in_exec","plugin_category":"input","type":"exec","config":{"@type":"exec","@id":"in_exec","command":"echo \"Hello World\"","run_interval":"30s","tag":"test_run"},"output_plugin":false,"retry_count":null},{"plugin_id":"out_std","plugin_category":"output","type":"stdout","config":{"@type":"stdout","@id":"out_std"},"output_plugin":true,"retry_count":0,"emit_records":9,"emit_count":9,"write_count":0,"rollback_count":0,"slow_flush_count":0,"flush_time_count":0,"retry":{}}]}
```
There are several query parameters that can be used. For example, adding "debug" would expose additional internal metrics.
```shell
$ curl http://127.0.0.1:24220/api/plugins.json?debug=1
{
"plugins": [
{
"plugin_id": "in_curl",
"plugin_category": "input",
"type": "monitor_agent",
"config": {
"@type": "monitor_agent",
"@id": "in_curl",
"bind": "127.0.0.1",
"port": "24220"
},
"output_plugin": false,
"retry_count": null,
"instance_variables": {
"log": "#<Fluent::PluginLogger:0x000055f4a86ec5d8>",
"bind": "127.0.0.1",
"port": 24220,
"tag": null,
"emit_interval": 60,
"include_config": true,
"include_retry": true,
"transport_config": "<Fluent::Config::Secti ...
...
```
::: info
When using monitor agent, it is sugested to add @id for each distinct plugin.
This benefits labeling in the query result.
:::
[doc](https://docs.fluentd.org/input/monitor_agent)
2. signal receiving
Originally Fluentd can be controlled by internal signals. For remote server model, RPC can be used to send these signals.
```r=
# add this inside config to enable this function
<system>
rpc_endpoint 127.0.0.1:24444
</system>
```
```shell
$ curl http://127.0.0.1:24444/api/${ENDPOINT}
```
| ENDPOINT | Function |
| -------- | -------- |
|/api/processes.interruptWorkers | Stops the daemon. |
|/api/processes.killWorkers | Stops the daemon. |
|/api/processes.flushBuffersAndKillWorkers |Flushes buffer and stops the daemon. |
|/api/plugins.flushBuffers | Flushes the buffered messages. |
|/api/config.gracefulReload | Reloads configuration. |
|/api/config.reload | Reloads configuration. |
[doc](https://docs.fluentd.org/deployment/rpc)
**Logging**
1. flowcounter
### Multi Process Workers
[doc](https://docs.fluentd.org/deployment/multi-process-workers)
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