Document how to use

Author: renatomefi

README.md

@@ -9,21 +9,96 @@ This POSIX compliant sh script gets php-fpm status page using `cgi-fcgi` tool, p
 ### Download
 
 ```sh
-curl -L -o /usr/local/bin/php-fpm-healthcheck \
-https://raw.githubusercontent.com/renatomefi/php-fpm-healthcheck/master/php-fpm-healthcheck
+wget -O /usr/local/bin/php-fpm-healthcheck \
+https://raw.githubusercontent.com/renatomefi/php-fpm-healthcheck/master/php-fpm-healthcheck \
+&& chmod +x /usr/local/bin/php-fpm-healthcheck
 ```
 
 ### Update
 
 ```sh
-curl -L -o $(which php-fpm-healthcheck) \
-https://raw.githubusercontent.com/renatomefi/php-fpm-healthcheck/master/php-fpm-healthcheck
+wget -O $(which php-fpm-healthcheck) \
+https://raw.githubusercontent.com/renatomefi/php-fpm-healthcheck/master/php-fpm-healthcheck \
+&& chmod +x $(which php-fpm-healthcheck)
 ```
 
 ### Manually
 
 You can always of course manually [download](https://raw.githubusercontent.com/renatomefi/php-fpm-healthcheck/master/php-fpm-healthcheck) and maintain the file, as long as you follow the [MIT License](./LICENSE)
 
+## Usage
+
+### Ping mode
+
+If you're aiming only to make sure php-fpm is alive and answering to requests you can:
+
+```console
+$ php-fpm-healthcheck
+$ echo $?
+0
+```
+
+Or with `verbose` to see php-fpm status output:
+
+```console
+$ php-fpm-healthcheck -v
+Trying to connect to php-fpm via: localhost:9000
+php-fpm status output:
+pool:                 www
+process manager:      dynamic
+start time:           11/Sep/2018:10:47:06 +0000
+start since:          436
+accepted conn:        1
+listen queue:         0
+max listen queue:     0
+listen queue len:     0
+idle processes:       1
+active processes:     1
+total processes:      2
+max active processes: 1
+max children reached: 0
+slow requests:        0
+$ echo $?
+0
+```
+
+### Metric mode
+
+Let's say you want to fail our healthcheck after your fpm has handled more than `3000` requests:
+
+```console
+$ php-fpm-healthcheck --accepted-conn=3000
+$ echo $?
+0
+```
+
+And you can also check if you have more than `10` processes in the queue:
+
+```console
+$ php-fpm-healthcheck --accepted-conn=3000 --listen-queue-len=10
+$ echo $?
+0
+```
+
+#### How a failing metric looks like
+
+```console
+$ php-fpm-healthcheck --accepted-conn=1
+'accepted conn' value '6' is greater than expected '1'
+$ echo $?
+1
+```
+
+### Connection via socket or another host
+
+You can simply specify `FCGI_CONNECT` variable with your connection uri:
+
+```console
+$ FCGI_CONNECT=/var/run/php-fpm.sock php-fpm-healthcheck
+$ echo $?
+0
+```
+
 ## Why POSIX sh
 
 Most of the containers contain limited software installed, using POSIX sh aims to be compatible with most of the OS images around.