Merge pull request #17686 from abpframework/liangshiwei/community-article

Add Moving Background Job Execution To A Separate Application article

docs/en/Community-Articles/2023-09-20-Moving-Background-Job-Execution-To-A-Separate-Application/POST.md

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+# Moving Background Job Execution To A Separate Application
+
+In this article, I will show you how to move the background job execution to a separate application.
+
+Here are some benefits of doing this:
+
+* If your background jobs consume high system resources (CPU, RAM or Disk), then you can deploy that background application to a dedicated server  so it won't affect your application's performance.
+* You can scale your background job application independently from your web application. For example, you can deploy multiple instances of your background job application to a Kubernetes cluster and scale it easily.
+
+Here are some disadvantages of doing this:
+ 
+* You need to deploy and maintain at least two applications instead of one.
+* You need to implement a mechanism to share the common code between your applications. For example, you can create a shared project and add it to your applications as a project reference.
+
+## Source code
+
+You can find the source code of the application at [abpframework/abp-samples](https://github.com/abpframework/abp-samples/tree/master/SeparateBackgroundJob).
+
+You can check the PR to see the changes step by step: [abpframework/abp-samples#250](https://github.com/abpframework/abp-samples/pull/250)
+
+## Creating the Web Application
+
+First, we need to create a new web application using the ABP CLI:
+
+```bash
+abp new SeparateBackgroundJob -t app
+```
+
+* Create a shared project named `SeparateBackgroundJob.Common.Shared` to share the `BackgroundJob` and `BackgroundJobArgs` classes between the web and job executor applications.
+* Install the `Volo.Abp.BackgroundJobs.Abstractions` package to the `SeparateBackgroundJob.Common.Shared` project.
+
+Add the `SeparateBackgroundJobCommonSharedModule` class to the `SeparateBackgroundJob.Common.Shared` project:
+
+```csharp
+[DependsOn(typeof(AbpBackgroundJobsAbstractionsModule))]
+public class SeparateBackgroundJobCommonSharedModule : AbpModule
+{
+}
+```
+
+Add the `MyReportJob` and `MyReportJobArgs` classes to the `SeparateBackgroundJob.Common.Shared` project:
+
+```csharp
+public class MyReportJob : AsyncBackgroundJob<MyReportJobArgs>, ITransientDependency
+{
+    public override Task ExecuteAsync(MyReportJobArgs args)
+    {
+        Logger.LogInformation("Executing MyReportJob with args: {0}", args.Content);
+        return Task.CompletedTask;
+    }
+}
+
+public class MyReportJobArgs
+{
+    public string? Content { get; set; }
+}
+```
+
+Add the `SeparateBackgroundJob.Common.Shared` project reference to the `SeparateBackgroundJob.Domain` project and add `SeparateBackgroundJobCommonSharedModule` to the `DependsOn` attribute of the `SeparateBackgroundJobDomainModule` class:
+
+```csharp
+[DependsOn(
+    typeof(SeparateBackgroundJobDomainSharedModule),
+    typeof(AbpAuditLoggingDomainModule),
+    typeof(AbpBackgroundJobsDomainModule),
+    typeof(AbpFeatureManagementDomainModule),
+    typeof(AbpIdentityDomainModule),
+    typeof(AbpOpenIddictDomainModule),
+    typeof(AbpPermissionManagementDomainOpenIddictModule),
+    typeof(AbpPermissionManagementDomainIdentityModule),
+    typeof(AbpSettingManagementDomainModule),
+    typeof(AbpTenantManagementDomainModule),
+    typeof(AbpEmailingModule),
+    typeof(SeparateBackgroundJobCommonSharedModule) //Add this line
+)]
+public class SeparateBackgroundJobDomainModule : AbpModule
+```
+
+Open the `Index.cshtml` and replace the content with the following code:
+
+```csharp
+@page
+@using Microsoft.AspNetCore.Mvc.Localization
+@using SeparateBackgroundJob.Localization
+@using Volo.Abp.Users
+@model SeparateBackgroundJob.Web.Pages.IndexModel
+@inject IHtmlLocalizer<SeparateBackgroundJobResource> L
+@inject ICurrentUser CurrentUser
+
+@section styles {
+    <abp-style src="/Pages/Index.css"/>
+}
+
+@section scripts {
+    <abp-script src="/Pages/Index.js"/>
+}
+
+<div class="container">
+    <abp-card>
+        <abp-card-header>
+            <abp-card-title>
+                Add NEW BACKGROUND JOB
+            </abp-card-title>
+        </abp-card-header>
+        <abp-card-body>
+            <form id="NewItemForm" method="post" class="row row-cols-lg-auto g-3 align-items-center">
+                <div class="col-12">
+                    <div class="input-group">
+                        <input id="ReportContent" required name="ReportContent" type="text" class="form-control" placeholder="enter text...">
+                    </div>
+                </div>
+                <div class="col-12">
+                    <button type="submit" class="btn btn-primary">Add</button>
+                </div>
+            </form>
+        </abp-card-body>
+    </abp-card>
+</div>
+```
+
+Open the `Index.cshtml.cs` and replace the content with the following code:
+
+```csharp
+public class IndexModel : SeparateBackgroundJobPageModel
+{
+    private readonly IBackgroundJobManager _backgroundJobManager;
+
+    [BindProperty(SupportsGet = true)]
+    public string? ReportContent { get; set; }
+
+    public IndexModel(IBackgroundJobManager backgroundJobManager)
+    {
+        _backgroundJobManager = backgroundJobManager;
+    }
+
+    public void OnGet()
+    {
+
+    }
+    
+    public async Task OnPostAsync()
+    {
+        await _backgroundJobManager.EnqueueAsync(new MyReportJobArgs
+        {
+            Content = ReportContent
+        });
+        
+        Alerts.Success("Job is queued!");
+    }
+}
+```
+
+Run the application and navigate to the home page. You should see the following page:
+
+![1](images/1.png)
+
+When you enter some text and click the **Add** button, the job will be queued and executed in the web application:
+
+## Creating the Console Application
+
+Now we split the background job execution to a separate console application.
+
+Open the `SeparateBackgroundJobWebModule` class to disable the background job execution in the web application:
+
+```csharp
+public class SeparateBackgroundJobWebModule : AbpModule
+{
+    ....
+        
+    public override void ConfigureServices(ServiceConfigurationContext context)
+    {
+        ...
+            
+        //Disable background job execution in the web application
+        Configure<AbpBackgroundJobOptions>(options =>
+        {
+            options.IsJobExecutionEnabled = false;
+        });
+    }
+    
+    ...
+}
+```
+
+* Create a new console application using the ABP CLI:
+
+```bash
+abp new BackgroundJobExecutor -t console
+```
+
+* Add the `BackgroundJobExecutor` project to the solution of the web application.
+* Add the `SeparateBackgroundJob.Common.Shared` project reference to the `BackgroundJobExecutor` project.
+* Install the `Volo.Abp.BackgroundJobs.EntityFrameworkCore` and `Volo.Abp.EntityFrameworkCore.SqlServer` packages to the `BackgroundJobExecutor` project.
+
+Update the `BackgroundJobExecutorModule` class as follows:
+
+```csharp
+[DependsOn(
+    typeof(AbpAutofacModule),
+    typeof(AbpBackgroundJobsEntityFrameworkCoreModule),
+    typeof(AbpEntityFrameworkCoreSqlServerModule),
+    typeof(SeparateBackgroundJobCommonSharedModule)
+)]
+public class BackgroundJobExecutorModule : AbpModule
+{
+    public override void ConfigureServices(ServiceConfigurationContext context)
+    {
+        Configure<AbpDbContextOptions>(options =>
+        {
+            options.UseSqlServer();
+        });
+    }
+    
+    ....
+}
+```
+
+Open the `appsettings.json` file to configure the [connection string](https://docs.abp.io/en/abp/latest/Connection-Strings#configure-the-connection-strings):
+
+```json
+{
+  "ConnectionStrings": {
+    "AbpBackgroundJobs": "Server=(LocalDb)\\MSSQLLocalDB;Database=SeparateBackgroundJob;Trusted_Connection=True"
+  }
+}
+```
+
+> You must use the same connection string for the web application, `AbpBackgroundJobs` is the default connection string name for the background job module.
+
+The solution structure should look like this:
+
+![solution](images/solution.png)
+
+Now, run the web and console application. When you enter some text and click the **Add** button, the job will be queued and executed in the console application:
+
+![2](images/2.png)