用C＃編寫Linux守護進程

 若是要在Red Hat Enterprise Linux上將.NET Core進程做爲後臺進程運行，則能夠建立自定義systemd單元。今天我將爲.NET Core編寫兩個自定義系統單元的例子。一個是運行.NET Core控制檯應用程序的一種類型，另外一個是運行ASP.NET Core Web應用程序的簡單類型。 

控制檯應用程序

創建一個應用程序

您能夠用dotnet run在systemd中使用指定項目目錄做爲工做目錄。可是，咱們來構建一個二進制文件並將其用於systemd。用dotnet new 命令建立您的項目後編輯Program.cs以下。

 1 using System;
 2 using System.IO;
 3  
 4 namespace ConsoleApplication
 5 {
 6     public class Program
 7     {
 8         public static void Main(string[] args)
 9         {
10             var path = Path.GetTempFileName();
11             File.WriteAllText(path, "Hello Temp File!");
12             Console.WriteLine($"Wrote temp file: {path}");
13         }
14     }
15 }

而後用dotnet publish命令發佈項目。你會看到bin/<Configuration>/<Framework>目錄下的二進制文件。

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$ dotnet publish -c Release Publishing ConsoleApp for .NETCoreApp,Version=v1.1 Project ConsoleApp (.NETCoreApp,Version=v1.1) was previously compiled. Skipping compilation. publish: Published to /home/tatanaka/Documents/git/tanaka-takayoshi/SystemdExample/1.1/ConsoleApp/bin/Release/netcoreapp1.1/publish Published 1/1 projects successfully

建立一個自定義的systemd

首先，建立一個運行守護進程和工做目錄的用戶。

$ sudo useradd -s /sbin/nologin dotnetuser
$ sudo mkdir /var/SystemdExample
$ sudo cp /home/tatanaka/Documents/git/tanaka-takayoshi/SystemdExample/1.1/ConsoleApp/bin/Release/netcoreapp1.1/publish/* /var/SystemdExample
$ sudo chown -R dotnetuser:dotnetuser /var/SystemdExample

而後在/etc/systemd/system/目錄下建立一個自定義的systemd單元文件。文件名應該是<unit-name>.<unit-type>。我建立的目錄和文件名爲：/etc/systemd/system/netcore-console-example.service。

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[Unit] Description=Example for .NET Core ConsoleApp with systemd DefaultDependencies=no   [Service] Type=oneshot RemainAfterExit=no ExecStart=/opt/rh/rh-dotnetcore11/root/usr/bin/dotnet ConsoleApp.dll WorkingDirectory=/var/SystemdExample User=dotnetuser Group=dotnetuser     [install]

您應該在ExecStart中指定dotnet的完整路徑。以上是紅帽提供的.NET Core 1.1的狀況。而後你能夠用systemctl命令執行守護進程。您可使用systemctl status命令或journalctl命令查看控制檯輸出。

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$ sudo systemctl start netcore-console-example.service $ sudo systemctl status netcore-console-example.service ● netcore-console-example.service - Example for .NET Core ConsoleApp with systemd    Loaded: loaded (/etc/systemd/system/netcore-console-example.service; enabled; vendor preset: disabled)    Active: inactive (dead) since Fri 2017-02-24 00:29:16 JST; 13s ago   Process: 18075 ExecStart=/opt/rh/rh-dotnetcore11/root/usr/bin/dotnet ConsoleApp.dll (code=exited, status=0/SUCCESS)  Main PID: 18075 (code=exited, status=0/SUCCESS)   Feb 24 00:29:16 localhost.localdomain systemd[1]: Starting Example for .NET Core ConsoleApp with systemd... Feb 24 00:29:16 localhost.localdomain dotnet[18075]: Wrote temp file: /tmp/tmph1ok6H.tmp Feb 24 00:29:16 localhost.localdomain systemd[1]: Started Example for .NET Core ConsoleApp with systemd.   $ journalctl -u netcore-console-example.service -e Feb 24 00:29:16 localhost.localdomain systemd[1]: Starting Example for .NET Core ConsoleApp with systemd... Feb 24 00:29:16 localhost.localdomain dotnet[18075]: Wrote temp file: /tmp/tmph1ok6H.tmp Feb 24 00:29:16 localhost.localdomain systemd[1]: Started Example for .NET Core ConsoleApp with systemd. $ sudo cat /tmp/tmph1ok6H.tmp Hello Temp File!

使用PrivateTemp

在上述系統單元中，程序在臨時文件夾下寫入一個文件。你有時想寫一個來自其餘用戶的臨時文件是安全的。您能夠在[Service]section中的指定使用PrivateTemp。

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[Service] Type=oneshot RemainAfterExit=no ExecStart=/opt/rh/rh-dotnetcore11/root/usr/bin/dotnet ConsoleApp.dll WorkingDirectory=/var/SystemdExample User=dotnetuser Group=dotnetuser PrivateTemp=true

 

從新加載單元文件後，程序能夠像前同樣訪問/tmp目錄，但這不是實際的/tmp目錄。

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$ sudo systemctl daemon-reload $ sudo systemctl start netcore-console-example.service $ sudo systemctl status netcore-console-example.service ● netcore-console-example.service - Example for .NET Core ConsoleApp with systemd     Loaded: loaded (/etc/systemd/system/netcore-console-example.service; enabled; vendor preset: disabled)     Active: inactive (dead) since Fri 2017-02-24 00:35:46 JST; 12s ago    Process: 18415 ExecStart=/opt/rh/rh-dotnetcore11/root/usr/bin/dotnet ConsoleApp.dll (code=exited, status=0/SUCCESS)   Main PID: 18415 (code=exited, status=0/SUCCESS)   Feb 24 00:35:46 localhost.localdomain systemd[1]: Starting Example for .NET Core ConsoleApp with systemd... Feb 24 00:35:46 localhost.localdomain dotnet[18415]: Wrote temp file: /tmp/tmpJLWAGC.tmp Feb 24 00:35:46 localhost.localdomain systemd[1]: Started Example for .NET Core ConsoleApp with systemd. $ ls /tmp/tmpJLWAGC.tmp ls: cannot access /tmp/tmpJLWAGC.tmp: No such file or directory

Web應用程序

創建一個應用程序

如今咱們來構建一個ASP.NET Core Web應用程序。今天我使用默認的模板項目。

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$ dotnet new -t web Created new C# project in /home/tatanaka/Documents/git/tanaka-takayoshi/SystemdExample/1.1/WebApp. $ dotnet restore ** snipped** log  : Restore completed in 9721ms. $ dotnet publish -c Release Publishing WebApp for .NETCoreApp,Version=v1.1 ** snipped ** publish: Published to /home/tatanaka/Documents/git/tanaka-takayoshi/SystemdExample/1.1/WebApp/bin/Release/netcoreapp1.1/publish Published 1/1 projects successfully

如今能夠用dotnet命令運行。

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$ dotnet bin/Release/netcoreapp1.1/publish/WebApp.dll info: Microsoft.Extensions.DependencyInjection.DataProtectionServices[0]        User profile is available. Using '/home/tatanaka/.aspnet/DataProtection-Keys' as key repository; keys will not be encrypted at rest. Hosting environment: Production Content root path: /home/tatanaka/Documents/git/tanaka-takayoshi/SystemdExample/1.1/WebApp Now listening on: http://localhost:5000 Application started. Press Ctrl+C to shut down.

建立一個自定義的systemd

爲這個Web應用程序也指定dotnetuser名稱。

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$ sudo mkdir /var/SystemdExample $ sudo cp -R bin/Release/netcoreapp1.1/publish/* /var/SystemdWebExample $ sudo chown -R dotnetuser:dotnetuser /var/SystemdWebExample

而後建立一個自定義的systemd單元文件/etc/systemd/system/netcore-web-example.service。

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[Unit] Description=Example for .NET Core WebApp with systemd DefaultDependencies=no Wants=network.target # network is required After=network.target   [Service] ExecStart=/opt/rh/rh-dotnetcore11/root/usr/bin/dotnet WebApp.dll WorkingDirectory=/var/SystemdWebExample Restart=always RestartSec=10   # Restart service after 10 seconds if dotnet service crashes SyslogIdentifier=dotnet-example User=dotnetuser Group=dotnetuser PrivateTmp=true Environment=ASPNETCORE_ENVIRONMENT=Production # specify environment variable for environment Environment=ASPNETCORE_URLS=http://*:8080 # specify environement variable for listening port   [Install] WantedBy = multi-user.target

最後，您能夠將ASP.NET Core應用程序做爲Linux守護程序運行。請注意，此應用程序偵聽端口8080代替了ASP.NET Core 默認的 5000，由於我在ASPNETCORE_URLS單元文件中指定了環境變量  。

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$ systemctl start netcore-web-example.service [tatanaka@localhost WebApp]$ systemc^C [tatanaka@localhost WebApp]$ sudo systemctl status netcore-web-example.service [sudo] password for tatanaka: ● netcore-web-example.service - Example for .NET Core WebApp with systemd     Loaded: loaded (/etc/systemd/system/netcore-web-example.service; disabled; vendor preset: disabled)     Active: active (running) since Sat 2017-02-25 01:02:12 JST; 11s ago   Main PID: 7041 (dotnet)     CGroup: /system.slice/netcore-web-example.service             └─7041 /opt/rh/rh-dotnetcore11/root/usr/bin/dotnet WebApp.dll   Feb 25 01:02:12 localhost.localdomain systemd[1]: Started Example for .NET Core WebApp with systemd. Feb 25 01:02:12 localhost.localdomain systemd[1]: Starting Example for .NET Core WebApp with systemd... Feb 25 01:02:12 localhost.localdomain dotnet-example[7041]: info: Microsoft.Extensions.DependencyInjection.DataProtectionServices[0] Feb 25 01:02:12 localhost.localdomain dotnet-example[7041]: User profile is available. Using '/home/dotnetuser/.aspnet/DataProtection-Keys' as key repository; keys will not be encrypted at rest. Feb 25 01:02:13 localhost.localdomain dotnet-example[7041]: Hosting environment: Production Feb 25 01:02:13 localhost.localdomain dotnet-example[7041]: Content root path: /var/SystemdWebExample Feb 25 01:02:13 localhost.localdomain dotnet-example[7041]: Now listening on: http://*:8080 Feb 25 01:02:13 localhost.localdomain dotnet-example[7041]: Application started. Press Ctrl+C to shut down.   $ journalctl -u netcore-web-example -xf -- Logs begin at Mon 2017-02-20 11:58:31 JST. -- Feb 25 01:02:36 localhost.localdomain dotnet-example[7041]: info: Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware[2] Feb 25 01:02:36 localhost.localdomain dotnet-example[7041]: Sending file. Request path: '/images/banner4.svg'. Physical path: '/var/SystemdWebExample/wwwroot/images/banner4.svg' Feb 25 01:02:36 localhost.localdomain dotnet-example[7041]: info: Microsoft.AspNetCore.Hosting.Internal.WebHost[2] Feb 25 01:02:36 localhost.localdomain dotnet-example[7041]: Request finished in 0.1973ms 200 image/svg+xml Feb 25 01:02:36 localhost.localdomain dotnet-example[7041]: info: Microsoft.AspNetCore.Hosting.Internal.WebHost[1] Feb 25 01:02:36 localhost.localdomain dotnet-example[7041]: Request starting HTTP/1.1 GET http://localhost:8080/favicon.ico Feb 25 01:02:36 localhost.localdomain dotnet-example[7041]: info: Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware[2] Feb 25 01:02:36 localhost.localdomain dotnet-example[7041]: Sending file. Request path: '/favicon.ico'. Physical path: '/var/SystemdWebExample/wwwroot/favicon.ico' Feb 25 01:02:36 localhost.localdomain dotnet-example[7041]: info: Microsoft.AspNetCore.Hosting.Internal.WebHost[2] Feb 25 01:02:36 localhost.localdomain dotnet-example[7041]: Request finished in 0.5824ms 200 image/x-icon

然而這對於ASP.NET Core的生產使用來講是不夠的。你可能須要設置一個反向代理服務器，好比Jexus,nginx，防火牆等等。

 Writing a Linux daemon in C#