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重新啟動後 Systemctl 無法啟動使用 ttyACM0 連接埠的服務

tag-icon • tag-icon systemd services udev
重新啟動後 Systemctl 無法啟動使用 ttyACM0 連接埠的服務

在 ttyACM0 連接埠可用後，我需要啟動用 C# (.NET6) 編寫的自己的服務（SignalR 用戶端）。該服務應在其他服務之後啟動（SignalR 伺服器）。

重啟後伺服器服務正常啟動（沒有任何問題）。客戶端服務狀態給予資訊：

● RfidHwSigRClient.service
Loaded: loaded (/etc/systemd/system/RfidHwSigRClient.service;
disabled; vendor preset: enabled)    Active: inactive (dead) since Mon
2023-03-06 22:20:58 CET; 2min 17s ago   Process: 1583
ExecStart=/usr/bin/dotnet
/home/predator/Projects/VSLinuxDbg/RfidHwSigRClient/RfidHwSigRClient.dll
(code=exited, status=0/SUCCESS)   Process: 767 ExecStartPre=/bin/sleep
10 (code=exited, status=0/SUCCESS)  Main PID: 1583 (code=exited,
status=0/SUCCESS)

Mar 06 22:20:46 PredatorClient systemd[1]: Starting
RfidHwSigRClient.service... Mar 06 22:20:57 PredatorClient
dotnet[1583]: Microsoft.Hosting.Lifetime[0] Application started.
Hosting environment: Production; Content root path: / Mar 06 22:20:57
PredatorClient systemd[1]: Started RfidHwSigRClient.service. Mar 06
22:20:58 PredatorClient dotnet[1583]:
Microsoft.Extensions.Hosting.Internal.Host[9] BackgroundService failed
System.UnauthorizedAccessException: Access to the port '/dev/usb_rfid'
is denied.  ---> System.IO.IOException: Device or resource busy    ---
End of inner exception stack trace ---    at
System.IO.Ports.SafeSerialDeviceHandle.Open(String portName)    at
System.IO.Ports.SerialStream..ctor(String portName, Int32 baudRate,
Parity parity, Int32 dataBits, StopBits stopBits, Int32 readTimeout,
Int32 writeTimeout, Handshake handshake, Boolean dtrEnable, Boolean
rtsEnable, Boolean discardNull, Byte parityReplace)    at
System.IO.Ports.SerialPort.Open()    at
Predator.Hardware.RfIDCard.RfId.Connect() in
D:\Projects\PredatorDotNet\Source\PredatorClientDotNet\Hardware\RFIDCard\RfId.cs:line
159    at
Predator.SignalRComm.RfidHwSigRClient.RfidBroker.ConnectAsync() in
D:\Projects\PredatorDotNet\Source\PredatorClientDotNet\SignalRComm\Derived\RfidHwSigRClient\RfidHwSigRClient\RfidBroker.cs:line
95    at
Predator.SignalRComm.RfidHwSigRClient.RfidBroker.ExecuteAsync(CancellationToken
stoppingToken) in
D:\Projects\PredatorDotNet\Source\PredatorClientDotNet\SignalRComm\Derived\RfidHwSigRClient\RfidHwSigRClient\RfidBroker.cs:line
77    at
Microsoft.Extensions.Hosting.Internal.Host.TryExecuteBackgroundServiceAsync(BackgroundService
backgroundService) Mar 06 22:20:58 PredatorClient dotnet[1583]:
Microsoft.Extensions.Hosting.Internal.Host[10] The
HostOptions.BackgroundServiceExceptionBehavior is configured to
StopHost. A BackgroundService has thrown an unhandled exception, and
the IHost instance is stopping. To avoid this behavior, configure this
to Ignore; however the BackgroundService will not be restarted.
System.UnauthorizedAccessException: Access to the port '/dev/usb_rfid'
is denied.  ---> System.IO.IOException: Device or resource busy    ---
End of inner exception stack trace ---    at
System.IO.Ports.SafeSerialDeviceHandle.Open(String portName)    at
System.IO.Ports.SerialStream..ctor(String portName, Int32 baudRate,
Parity parity, Int32 dataBits, StopBits stopBits, Int32 readTimeout,
Int32 writeTimeout, Handshake handshake, Boolean dtrEnable, Boolean
rtsEnable, Boolean discardNull, Byte parityReplace)    at
System.IO.Ports.SerialPort.Open()    at
Predator.Hardware.RfIDCard.RfId.Connect() in
D:\Projects\PredatorDotNet\Source\PredatorClientDotNet\Hardware\RFIDCard\RfId.cs:line
159    at
Predator.SignalRComm.RfidHwSigRClient.RfidBroker.ConnectAsync() in
D:\Projects\PredatorDotNet\Source\PredatorClientDotNet\SignalRComm\Derived\RfidHwSigRClient\RfidHwSigRClient\RfidBroker.cs:line
95    at
Predator.SignalRComm.RfidHwSigRClient.RfidBroker.ExecuteAsync(CancellationToken
stoppingToken) in
D:\Projects\PredatorDotNet\Source\PredatorClientDotNet\SignalRComm\Derived\RfidHwSigRClient\RfidHwSigRClient\RfidBroker.cs:line
77    at
Microsoft.Extensions.Hosting.Internal.Host.TryExecuteBackgroundServiceAsync(BackgroundService
backgroundService) Mar 06 22:20:58 PredatorClient dotnet[1583]:
Microsoft.Hosting.Lifetime[0] Application is shutting down...

問題是連接埠不可用。

Ubuntu一啟動，我就可以systemctl restart service_name從命令列重新啟動客戶端服務( )，並且服務可以正常工作(端口已準備好）。

我讀過幾個有關如何啟動服務的論壇。不幸的是，沒有任何成功。

我的 udev 規則如下所示：

KERNEL=="ttyACM*", ATTRS{manufacturer}=="MOD elektronik*", ATTRS{product}=="MOD RFID reader", MODE="0666", SYMLINK+="usb_rfid", ENV{SYSTEMD_WANTS}+="RfidHwSigRClient.service"

我的 RfidHwSigRClient.service 如下：

[unit]
Description=RFId Card Reader SignalR Client Service
BindsTo=dev-usb_rfid.device
Requires=MainSigRServer.service
After=dev-usb_rfid.device MainSigRserver.service
StartLimitIntervalSec=300
StartLimitBurst=30

[Service]
User=predator
Group=predator
Type=notify
ExecStartPre=/bin/sleep 10
ExecStart=/usr/bin/dotnet /home/predator/Projects/VSLinuxDbg/RfidHwSigRClient/RfidHwSigRClient.dll
TimeoutStartSec=30s
Restart=on-failure
RestartSec=5s

[Install]
WantedBy=multi-use

我還檢查過 10 秒後啟動服務 ( ExecStartPre=/bin/sleep 10)，但沒有成功。使用者 predator 屬於群組 dialout。 Ubuntu 是 18.04 LTS。

請問，有人知道我做錯了什麼嗎？謝謝。 R。

答案1

我不得不使用 sleep aprox。 15秒後開始客戶服務。如果睡眠時間是10s。連接埠未準備好（存取被拒絕）。但是，我仍然不知道連接埠和伺服器服務都準備好後立即啟動客戶端服務。

我的體溫。 RfidHwSigRClient.service的設定如下：

[Unit]
Description=RFId Card Reader SignalR Client Service
BindsTo=dev-usb_rfid.device
After=dev-usb_rfid.device MainSigRServer.service
StartLimitIntervalSec=300
StartLimitBurst=30

[Service]
Type=notify
ExecStartPre=/bin/sleep 15
ExecStart=/usr/bin/dotnet /home/predator/Projects/VSLinuxDbg/RfidHwSigRClient/RfidHwSigRClient.dll
Restart=on-failure
RestartSec=5s
User=predator
Group=predator

[Install]
WantedBy=dev-usb_rfid.device

Udev 規則 99-usb-serial.rules 是：

KERNEL=="ttyACM*", ATTRS{manufacturer}=="MOD elektronik*", ATTRS{product}=="MOD RFID reader", SYMLINK+="usb_rfid", MODE="0666", ACTION=="add", RUN+="/home/predator/Projects/Scripts/rfid_plugged.sh", TAG+="systemd" ENV{SYSTEMD_WANTS}+="MainSigRServer.service"

謝謝..

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