Class AsyncQueueProcessor<TQueue, TItem>
Base class for hosted service processing items from an async queue
Inheritance
Inherited Members
Namespace: SuperOffice.Threading
Assembly: SoCore.dll
Syntax
public abstract class AsyncQueueProcessor<TQueue, TItem> : BackgroundService, IDisposable, IHostedService where TQueue : IAsyncQueueBase<TItem>Type Parameters
| Name | Description |
|---|---|
| TQueue | |
| TItem | Item in the queue |
Remarks
The ExecuteAsync(CancellationToken) method is called by the background
service framework, once. It, in turn, delegates to the _queue.ProcessItemsAsync method,
which loops until the cancellation token is triggered; if the queue is empty it waits for items
to arrive.
The ProcessItemAsync(IAsyncQueueProcessItemContext<TItem>, CancellationToken) abstract
method is called for each item in the queue, and must be implemented by derived classes
to perform whatever processing the actual items should receive.
Constructors
AsyncQueueProcessor(TQueue, ILogger<AsyncQueueProcessor<TQueue, TItem>>)
Default Constructor
Declaration
protected AsyncQueueProcessor(TQueue queue, ILogger<AsyncQueueProcessor<TQueue, TItem>> logger)Parameters
| Type | Name | Description |
|---|---|---|
| TQueue | queue | |
| ILogger<AsyncQueueProcessor<TQueue, TItem>> | logger |
Remarks
The ExecuteAsync(CancellationToken) method is called by the background
service framework, once. It, in turn, delegates to the _queue.ProcessItemsAsync method,
which loops until the cancellation token is triggered; if the queue is empty it waits for items
to arrive.
The ProcessItemAsync(IAsyncQueueProcessItemContext<TItem>, CancellationToken) abstract
method is called for each item in the queue, and must be implemented by derived classes
to perform whatever processing the actual items should receive.
Fields
_queue
Base class for hosted service processing items from an async queue
Declaration
protected readonly TQueue _queueField Value
| Type | Description |
|---|---|
| TQueue |
Remarks
The ExecuteAsync(CancellationToken) method is called by the background
service framework, once. It, in turn, delegates to the _queue.ProcessItemsAsync method,
which loops until the cancellation token is triggered; if the queue is empty it waits for items
to arrive.
The ProcessItemAsync(IAsyncQueueProcessItemContext<TItem>, CancellationToken) abstract
method is called for each item in the queue, and must be implemented by derived classes
to perform whatever processing the actual items should receive.
Methods
ExecuteAsync(CancellationToken)
Base class for hosted service processing items from an async queue
Declaration
protected override Task ExecuteAsync(CancellationToken stoppingToken)Parameters
| Type | Name | Description |
|---|---|---|
| CancellationToken | stoppingToken |
Returns
| Type | Description |
|---|---|
| Task |
Overrides
Remarks
The ExecuteAsync(CancellationToken) method is called by the background
service framework, once. It, in turn, delegates to the _queue.ProcessItemsAsync method,
which loops until the cancellation token is triggered; if the queue is empty it waits for items
to arrive.
The ProcessItemAsync(IAsyncQueueProcessItemContext<TItem>, CancellationToken) abstract
method is called for each item in the queue, and must be implemented by derived classes
to perform whatever processing the actual items should receive.
OuterProcessItemAsync(IAsyncQueueProcessItemContext<TItem>, CancellationToken)
Wrapper for ProcessItemAsync(IAsyncQueueProcessItemContext<TItem>, CancellationToken) to catch exceptions and log them.
Declaration
protected Task OuterProcessItemAsync(IAsyncQueueProcessItemContext<TItem> context, CancellationToken cancellationToken)Parameters
| Type | Name | Description |
|---|---|---|
| IAsyncQueueProcessItemContext<TItem> | context | |
| CancellationToken | cancellationToken |
Returns
| Type | Description |
|---|---|
| Task |
Remarks
An unhandled exception in ProcessItemAsync(IAsyncQueueProcessItemContext<TItem>, CancellationToken) will exit from the wait-for-cancellation loop within the ProcessItemsAsync(AsyncQueueProcessItemAsync<TItem>, CancellationToken) method, and this will permanently terminate the background service. As a result, items will no longer be processed and there is no way to restart it... so we try to guard against that.
ProcessItemAsync(IAsyncQueueProcessItemContext<TItem>, CancellationToken)
Process an item from the queue
Declaration
protected abstract Task ProcessItemAsync(IAsyncQueueProcessItemContext<TItem> context, CancellationToken cancellationToken)Parameters
| Type | Name | Description |
|---|---|---|
| IAsyncQueueProcessItemContext<TItem> | context | Context of item to be processed |
| CancellationToken | cancellationToken |
Returns
| Type | Description |
|---|---|
| Task |
Remarks
The ExecuteAsync(CancellationToken) method is called by the background
service framework, once. It, in turn, delegates to the _queue.ProcessItemsAsync method,
which loops until the cancellation token is triggered; if the queue is empty it waits for items
to arrive.
The ProcessItemAsync(IAsyncQueueProcessItemContext<TItem>, CancellationToken) abstract
method is called for each item in the queue, and must be implemented by derived classes
to perform whatever processing the actual items should receive.