Documented Background-Jobs-RabbitMq

docs/en/Background-Jobs-RabbitMq.md

@@ -1,3 +1,129 @@
 # RabbitMQ Background Job Manager
 
-TODO
+RabbitMQ is an industry standard message broker. While it is typically used for inter-process communication (messaging / distributed events), it is pretty useful to store and execute background jobs in FIFO (First In First Out) order.
+
+ABP Framework provides the [Volo.Abp.BackgroundJobs.RabbitMQ](https://www.nuget.org/packages/Volo.Abp.BackgroundJobs.RabbitMQ) NuGet package to use the RabbitMQ for background job execution.
+
+> See the [background jobs document](Background-Jobs.md) to learn how to use the background job system. This document only shows how to install and configure the RabbitMQ integration.
+
+## Installation
+
+Use the ABP CLI to add [Volo.Abp.BackgroundJobs.RabbitMQ](https://www.nuget.org/packages/Volo.Abp.BackgroundJobs.RabbitMQ) NuGet package to your project:
+
+* Install the [ABP CLI](https://docs.abp.io/en/abp/latest/CLI) if you haven't installed before.
+* Open a command line (terminal) in the directory of the `.csproj` file you want to add the `Volo.Abp.BackgroundJobs.RabbitMQ` package.
+* Run `abp add-package Volo.Abp.BackgroundJobs.RabbitMQ` command.
+
+If you want to do it manually, install the [Volo.Abp.BackgroundJobs.RabbitMQ](https://www.nuget.org/packages/Volo.Abp.BackgroundJobs.RabbitMQ) NuGet package to your project and add `[DependsOn(typeof(AbpBackgroundJobsRabbitMqModule))]` to the [ABP module](Module-Development-Basics.md) class inside your project.
+
+## Configuration
+
+### Default Configuration
+
+The default configuration automatically connects to the local RabbitMQ server (localhost) with the standard port. **In this case, no configuration needed.**
+
+### RabbitMQ Connection(s)
+
+You can configure the RabbitMQ connections using the standard [configuration system](Configuration.md), like using the `appsettings.json` file, or using the [options](Options.md) classes.
+
+#### `appsettings.json` file configuration
+
+This is the simplest way to configure the RabbitMQ connections. It is also very strong since you can use any other configuration source (like environment variables) that is [supported by the AspNet Core](https://docs.microsoft.com/en-us/aspnet/core/fundamentals/configuration/).
+
+**Example:  Configuring the Default RabbitMQ Connection**
+
+````json
+{
+  "RabbitMQ": {
+    "Connections": {
+      "Default": {
+        "HostName": "123.123.123.123",
+        "Port": "5672"
+      }
+    }
+  }
+}
+````
+
+You can use any of the [ConnectionFactry](http://rabbitmq.github.io/rabbitmq-dotnet-client/api/RabbitMQ.Client.ConnectionFactory.html#properties) properties as the connection properties. See [the RabbitMQ document](https://www.rabbitmq.com/dotnet-api-guide.html#exchanges-and-queues) to understand these options better.
+
+Defining multiple connections is allowed. In this case, you can use different connections for different background job types (see the `AbpRabbitMqBackgroundJobOptions` section below).
+
+**Example: Declare two connections**
+
+````json
+{
+  "RabbitMQ": {
+    "Connections": {
+      "Default": {
+        "HostName": "123.123.123.123"
+      },
+      "SecondConnection": {
+        "HostName": "321.321.321.321"
+      }
+    }
+  }
+}
+````
+
+#### AbpRabbitMqOptions
+
+`AbpRabbitMqOptions` class can be used to configure the connection strings for the RabbitMQ. You can configure this options inside the `ConfigureServices` of your [module](Module-Development-Basics.md).
+
+**Example: Configure the connection**
+
+````csharp
+Configure<AbpRabbitMqOptions>(options =>
+{
+    options.Connections.Default.UserName = "user";
+    options.Connections.Default.Password = "pass";
+    options.Connections.Default.HostName = "123.123.123.123";
+    options.Connections.Default.Port = 5672;
+});
+````
+
+Using these options classes can be combined with the `appsettings.json` way. Configuring an option property in the code overrides the value in the configuration file.
+
+### AbpRabbitMqBackgroundJobOptions
+
+#### Job Queue Names
+
+By default, each job type uses a separate queue. Queue names are calculated by combining a standard prefix and the job name. Default prefix is `AbpBackgroundJobs.` So, if the job name is `EmailSending` then the queue name in the RabbitMQ becomes `AbpBackgroundJobs.EmailSending`
+
+> Use `BackgroundJobName` attribute on the background job class to specify the job name. Otherwise, the job name will be the full name (with namespace) of the job class.
+
+#### Job Connections
+
+By default, all the job types use the `Default` RabbitMQ connection.
+
+#### Customization
+
+`AbpRabbitMqBackgroundJobOptions` can be used to customize the queue names and the connections used by the jobs.
+
+**Example:**
+
+````csharp
+Configure<AbpRabbitMqBackgroundJobOptions>(options =>
+{
+    options.DefaultQueueNamePrefix = "my_app_jobs.";
+    options.JobQueues[typeof(EmailSendingJob)] =
+        new JobQueueConfiguration(
+            typeof(EmailSendingJob),
+            queueName: "my_app_jobs.emails",
+            connectionName: "SecondConnection"
+        );
+});
+````
+
+* This example sets the default queue name prefix to `my_app_jobs.`. If different applications use the same RabbitMQ server, it would be important to use different prefixes for each application to not consume jobs of each other.
+* Also specifies a different connection string for the `EmailSendingJob`.
+
+`JobQueueConfiguration` class has some additional options in its constructor;
+
+* `queueName`: The queue name that is used for this job. The prefix is not added, so you need to specify the full name of the queue.
+* `connectionName`: The RabbitMQ connection name (see the connection configuration above). This is optional and the default value is `Default`.
+* `durable` (optional, default: `true`).
+* `exclusive` (optional, default: `false`).
+* `autoDelete` (optional, default: `false`)
+
+See the RabbitMQ documentation if you want to understand the `durable`, `exclusive` and `autoDelete` options better, while most of the times the default configuration is what you want. 

docs/en/Background-Jobs.md

@@ -40,7 +40,8 @@ using Volo.Abp.Emailing;
 
 namespace MyProject
 {
-    public class EmailSendingJob : BackgroundJob<EmailSendingArgs>, ITransientDependency
+    public class EmailSendingJob
+        : AsyncBackgroundJob<EmailSendingArgs>, ITransientDependency
     {
         private readonly IEmailSender _emailSender;
 
@@ -49,9 +50,9 @@ namespace MyProject
             _emailSender = emailSender;
         }
 
-        public override void Execute(EmailSendingArgs args)
+        public override async Task ExecuteAsync(EmailSendingArgs args)
         {
-            _emailSender.Send(
+            await _emailSender.SendAsync(
                 args.EmailAddress,
                 args.Subject,
                 args.Body
@@ -63,6 +64,8 @@ namespace MyProject
 
 This job simply uses `IEmailSender` to send emails (see [email sending document](Emailing.md)).
 
+> `AsyncBackgroundJob` is used to create a job needs to perform async calls. You can inherit from `BackgroundJob<TJob>` and override the `Execute` method if the method doesn't need to perform any async call.
+
 #### Exception Handling
 
 A background job should not hide exceptions. If it throws an exception, the background job is automatically re-tried after a calculated waiting time. Hide exceptions only if you don't want to re-run the background job for the current argument.