Fix memory_used OID parsing for Mikrotik devices

Handle OctetString values returned as bytes by converting them to int
using little-endian byte order (4 bytes) for Mikrotik devices.

SYSTEMD.md

@@ -0,0 +1,39 @@
+# Service systemd pour snmp2mqtt
+
+## Installation
+
+Copiez le fichier dans `/etc/systemd/system/` :
+
+```bash
+sudo cp snmp2mqtt.service /etc/systemd/system/
+sudo cp snmp-discover.service /etc/systemd/system/
+```
+
+Créez un utilisateur dédié :
+
+```bash
+sudo useradd -r -s /bin/false snmp2mqtt
+sudo chown -R snmp2mqtt:snmp2mqtt /home/snmp2mqtt/snmp2mqtt
+```
+
+Rechargez systemd et activez le service :
+
+```bash
+sudo systemctl daemon-reload
+sudo systemctl enable snmp2mqtt
+sudo systemctl start snmp2mqtt
+```
+
+## Journalisation
+
+```bash
+journalctl -u snmp2mqtt -f
+```
+
+## Pour snmp-discover
+
+Le service `snmp-discover.service` est de type `oneshot` et ne doit pas être activé automatiquement. Il est destiné à être lancé manuellement pour configurer les appareils :
+
+```bash
+sudo systemctl start snmp-discover
+```

snmp-discover.service

@@ -0,0 +1,15 @@
+[Unit]
+Description=SNMP Discovery Tool for snmp2mqtt
+Documentation=https://git.antoineve.me/AntoineVe/snmp2mqtt
+
+[Service]
+Type=oneshot
+User=snmp2mqtt
+Group=snmp2mqtt
+WorkingDirectory=/home/snmp2mqtt/snmp2mqtt
+ExecStart=/home/snmp2mqtt/snmp2mqtt/.venv/bin/python /home/snmp2mqtt/snmp2mqtt/snmp-discover.py --config /home/snmp2mqtt/snmp2mqtt/config.yaml
+StandardOutput=journal
+StandardError=journal
+
+[Install]
+WantedBy=multi-user.target

snmp2mqtt.py

@@ -278,10 +278,29 @@ async def get_snmp(req):
                 continue
             else:
                 for varBind in varBinds:
-                    logging.debug(f"{req['device_name']} {oid['name']} => {oid['type'](varBind[1])}")
+                    raw_value = varBind[1]
+                    
+                    # Handle different SNMP value types
+                    if oid['type'] == int and hasattr(raw_value, '__bytes__'):
+                        # Convert OctetString/bytes to int
+                        # For Mikrotik devices, memory values might be in the first 4 bytes
+                        raw_bytes = bytes(raw_value)
+                        # Try to interpret as integer, handling different byte orders
+                        try:
+                            if len(raw_bytes) >= 4:
+                                # Try little-endian first (common for Mikrotik)
+                                value = int.from_bytes(raw_bytes[:4], byteorder='little', signed=False)
+                            else:
+                                value = int.from_bytes(raw_bytes, byteorder='big', signed=False)
+                        except (ValueError, TypeError):
+                            value = raw_value
+                    else:
+                        value = raw_value
+                    
+                    logging.debug(f"{req['device_name']} {oid['name']} => {oid['type'](value)}")
                     
                     # Cast to the right type
-                    value = oid['type'](varBind[1])
+                    value = oid['type'](value)
                     
                     # Apply operation if defined
                     if 'operation' in oid:

snmp2mqtt.service

@@ -0,0 +1,19 @@
+[Unit]
+Description=SNMP to MQTT bridge for Home Assistant
+Documentation=https://git.antoineve.me/AntoineVe/snmp2mqtt
+After=network.target
+Wants=network.target
+
+[Service]
+Type=simple
+User=snmp2mqtt
+Group=snmp2mqtt
+WorkingDirectory=/home/snmp2mqtt/snmp2mqtt
+ExecStart=/home/snmp2mqtt/snmp2mqtt/.venv/bin/python /home/snmp2mqtt/snmp2mqtt/snmp2mqtt.py --config /home/snmp2mqtt/snmp2mqtt/config.yaml
+Restart=on-failure
+RestartSec=10
+StandardOutput=journal
+StandardError=journal
+
+[Install]
+WantedBy=multi-user.target