update readme

README.md

@@ -1,7 +1,71 @@
-# Log buffer
+# Fog Willow
 
-This app listens on a UDP port. Parses packets with a specific signature. Buffers the packet payloads and writes them to disk.
+## Log Buffer
 
-Allows us to efficiently transport logs out of the PHP app and directly to the system with the hard disk where we store log files.
+This app listens on a UDP port. Parses packets with a specific format. Buffers the packet payloads and writes them to disk.
 
-See [config file example](https://github.com/Notifiarr/fogwillow/blob/main/fog.conf).
+Allows us to efficiently transport logs out of the PHP app and
+directly to the system with the hard disk where we store log files.
+We use this because NFS was too slow, and we can trade a bit of reliability for faster log exfiltration.
+
+
+## Packet Format
+
+The first line of the packet is an integer that signals how many settings to expect.
+A minimum of 1 settings is required: `filepath=/path`
+Other recognized [settings](https://github.com/Notifiarr/fogwillow/blob/main/pkg/fog/set.go#L8) are:
+`flush=true`, `truncate=true`, `delete=true`, `password=p4ssw0rd`
+
+### Example Packets
+
+```text
+1
+filepath=/path/to/file.log
+[INFO] this is a log line
+```
+
+```text
+2
+filepath=/path/to/file.log
+password=option4lPassw0rd
+[INFO] this is a log line
+```
+
+Create a packet with `echo` and `netcat`:
+```bash
+echo -n "1\nfilepath=/tmp/filename.txt\nfile content goes here\nline 2 in the file" | nc -uw0 127.0.0.1 9000
+```
+
+## Metrics
+
+Has a Prometheus exporter built in with juicy [metrics](https://github.com/Notifiarr/fogwillow/blob/main/pkg/metrics/metrics.go)!<br/>
+[![grafana](https://github.com/Notifiarr/fogwillow/wiki/images/grafana-thumb.png "grafana images")](https://github.com/Notifiarr/fogwillow/wiki/images/grafana-thumb.png)
+
+## PHP Client
+
+Very simple procedure we use for testing.
+
+```php
+$socket = socket_create(AF_INET, SOCK_DGRAM, SOL_UDP);
+
+function socket_put_contents($socket, $outputfile, $line, $host, $length = 8000)
+{
+    if (strlen($line) > $length) {
+        foreach (str_split($line, $length) as $piece) {
+            $loggerPayload = "1\nfilepath=".$outputfile."\n".$piece;
+            usleep(1);
+            socket_sendto($socket, $loggerPayload, strlen($loggerPayload), 0, $host, 9000);
+        }
+    } else {
+        $loggerPayload = "1\nfilepath=" . $outputfile . "\n" . $line;
+        socket_sendto($socket, $loggerPayload, strlen($loggerPayload), 0, $host, 9000);
+    }
+}
+```
+
+# Usage
+
+We run this from a Docker container directly on a Synology NAS. Using this image:<br/>
+`ghcr.io/Notifiarr/fogwillow:main`
+
+Mount `/config` and give it a `/config/fog.conf` file that looks like the [example](https://github.com/Notifiarr/fogwillow/blob/main/fog.conf). You also want to mount a place to store files, and set that to `output_path` in the config file.