Creating Amazon SQS queues - AWS SDK for .NET

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Creating Amazon SQS queues

This example shows you how to use the AWS SDK for .NET to create an Amazon SQS queue. The application creates a dead-letter queue if you don't supply the ARN for one. It then creates a standard message queue, which includes a dead-letter queue (the one you supplied or the one that was created).

If you don't supply any command-line arguments, the application simply shows information about all existing queues.

The following sections provide snippets of this example. The complete code for the example is shown after that, and can be built and run as is.

Show existing queues

The following snippet shows a list of the existing queues in the SQS client's region and the attributes of each queue.

The example at the end of this topic shows this snippet in use.

// // Method to show a list of the existing queues private static async Task ShowQueues(IAmazonSQS sqsClient) { ListQueuesResponse responseList = await sqsClient.ListQueuesAsync(""); Console.WriteLine(); foreach(string qUrl in responseList.QueueUrls) { // Get and show all attributes. Could also get a subset. await ShowAllAttributes(sqsClient, qUrl); } } // // Method to show all attributes of a queue private static async Task ShowAllAttributes(IAmazonSQS sqsClient, string qUrl) { var attributes = new List<string>{ QueueAttributeName.All }; GetQueueAttributesResponse responseGetAtt = await sqsClient.GetQueueAttributesAsync(qUrl, attributes); Console.WriteLine($"Queue: {qUrl}"); foreach(var att in responseGetAtt.Attributes) Console.WriteLine($"\t{att.Key}: {att.Value}"); }

Create the queue

The following snippet creates a queue. The snippet includes the use of a dead-letter queue, but a dead-letter queue isn't necessarily required for your queues.

The example at the end of this topic shows this snippet in use.

// // Method to create a queue. Returns the queue URL. private static async Task<string> CreateQueue( IAmazonSQS sqsClient, string qName, string deadLetterQueueUrl=null, string maxReceiveCount=null, string receiveWaitTime=null) { var attrs = new Dictionary<string, string>(); // If a dead-letter queue is given, create a message queue if(!string.IsNullOrEmpty(deadLetterQueueUrl)) { attrs.Add(QueueAttributeName.ReceiveMessageWaitTimeSeconds, receiveWaitTime); attrs.Add(QueueAttributeName.RedrivePolicy, $"{{\"deadLetterTargetArn\":\"{await GetQueueArn(sqsClient, deadLetterQueueUrl)}\"," + $"\"maxReceiveCount\":\"{maxReceiveCount}\"}}"); // Add other attributes for the message queue such as VisibilityTimeout } // If no dead-letter queue is given, create one of those instead //else //{ // // Add attributes for the dead-letter queue as needed // attrs.Add(); //} // Create the queue CreateQueueResponse responseCreate = await sqsClient.CreateQueueAsync( new CreateQueueRequest{QueueName = qName, Attributes = attrs}); return responseCreate.QueueUrl; }

Get a queue's ARN

The following snippet gets the ARN of the queue identified by the given queue URL.

The example at the end of this topic shows this snippet in use.

// // Method to get the ARN of a queue private static async Task<string> GetQueueArn(IAmazonSQS sqsClient, string qUrl) { GetQueueAttributesResponse responseGetAtt = await sqsClient.GetQueueAttributesAsync( qUrl, new List<string>{QueueAttributeName.QueueArn}); return responseGetAtt.QueueARN; }

Complete code

This section shows relevant references and the complete code for this example.

NuGet packages:

Programming elements:

using System; using System.Threading.Tasks; using System.Collections.Generic; using Amazon.SQS; using Amazon.SQS.Model; namespace SQSCreateQueue { // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = // Class to create a queue class Program { private const string MaxReceiveCount = "10"; private const string ReceiveMessageWaitTime = "2"; private const int MaxArgs = 3; static async Task Main(string[] args) { // Parse the command line and show help if necessary var parsedArgs = CommandLine.Parse(args); if(parsedArgs.Count > MaxArgs) CommandLine.ErrorExit( "\nToo many command-line arguments.\nRun the command with no arguments to see help."); // Create the Amazon SQS client var sqsClient = new AmazonSQSClient(); // In the case of no command-line arguments, just show help and the existing queues if(parsedArgs.Count == 0) { PrintHelp(); Console.WriteLine("\nNo arguments specified."); Console.Write("Do you want to see a list of the existing queues? ((y) or n): "); string response = Console.ReadLine(); if((string.IsNullOrEmpty(response)) || (response.ToLower() == "y")) await ShowQueues(sqsClient); return; } // Get the application arguments from the parsed list string queueName = CommandLine.GetArgument(parsedArgs, null, "-q", "--queue-name"); string deadLetterQueueUrl = CommandLine.GetArgument(parsedArgs, null, "-d", "--dead-letter-queue"); string maxReceiveCount = CommandLine.GetArgument(parsedArgs, MaxReceiveCount, "-m", "--max-receive-count"); string receiveWaitTime = CommandLine.GetArgument(parsedArgs, ReceiveMessageWaitTime, "-w", "--wait-time"); if(string.IsNullOrEmpty(queueName)) CommandLine.ErrorExit( "\nYou must supply a queue name.\nRun the command with no arguments to see help."); // If a dead-letter queue wasn't given, create one if(string.IsNullOrEmpty(deadLetterQueueUrl)) { Console.WriteLine("\nNo dead-letter queue was specified. Creating one..."); deadLetterQueueUrl = await CreateQueue(sqsClient, queueName + "__dlq"); Console.WriteLine($"Your new dead-letter queue:"); await ShowAllAttributes(sqsClient, deadLetterQueueUrl); } // Create the message queue string messageQueueUrl = await CreateQueue( sqsClient, queueName, deadLetterQueueUrl, maxReceiveCount, receiveWaitTime); Console.WriteLine($"Your new message queue:"); await ShowAllAttributes(sqsClient, messageQueueUrl); } // // Method to show a list of the existing queues private static async Task ShowQueues(IAmazonSQS sqsClient) { ListQueuesResponse responseList = await sqsClient.ListQueuesAsync(""); Console.WriteLine(); foreach(string qUrl in responseList.QueueUrls) { // Get and show all attributes. Could also get a subset. await ShowAllAttributes(sqsClient, qUrl); } } // // Method to create a queue. Returns the queue URL. private static async Task<string> CreateQueue( IAmazonSQS sqsClient, string qName, string deadLetterQueueUrl=null, string maxReceiveCount=null, string receiveWaitTime=null) { var attrs = new Dictionary<string, string>(); // If a dead-letter queue is given, create a message queue if(!string.IsNullOrEmpty(deadLetterQueueUrl)) { attrs.Add(QueueAttributeName.ReceiveMessageWaitTimeSeconds, receiveWaitTime); attrs.Add(QueueAttributeName.RedrivePolicy, $"{{\"deadLetterTargetArn\":\"{await GetQueueArn(sqsClient, deadLetterQueueUrl)}\"," + $"\"maxReceiveCount\":\"{maxReceiveCount}\"}}"); // Add other attributes for the message queue such as VisibilityTimeout } // If no dead-letter queue is given, create one of those instead //else //{ // // Add attributes for the dead-letter queue as needed // attrs.Add(); //} // Create the queue CreateQueueResponse responseCreate = await sqsClient.CreateQueueAsync( new CreateQueueRequest{QueueName = qName, Attributes = attrs}); return responseCreate.QueueUrl; } // // Method to get the ARN of a queue private static async Task<string> GetQueueArn(IAmazonSQS sqsClient, string qUrl) { GetQueueAttributesResponse responseGetAtt = await sqsClient.GetQueueAttributesAsync( qUrl, new List<string>{QueueAttributeName.QueueArn}); return responseGetAtt.QueueARN; } // // Method to show all attributes of a queue private static async Task ShowAllAttributes(IAmazonSQS sqsClient, string qUrl) { var attributes = new List<string>{ QueueAttributeName.All }; GetQueueAttributesResponse responseGetAtt = await sqsClient.GetQueueAttributesAsync(qUrl, attributes); Console.WriteLine($"Queue: {qUrl}"); foreach(var att in responseGetAtt.Attributes) Console.WriteLine($"\t{att.Key}: {att.Value}"); } // // Command-line help private static void PrintHelp() { Console.WriteLine( "\nUsage: SQSCreateQueue -q <queue-name> [-d <dead-letter-queue>]" + " [-m <max-receive-count>] [-w <wait-time>]" + "\n -q, --queue-name: The name of the queue you want to create." + "\n -d, --dead-letter-queue: The URL of an existing queue to be used as the dead-letter queue."+ "\n If this argument isn't supplied, a new dead-letter queue will be created." + "\n -m, --max-receive-count: The value for maxReceiveCount in the RedrivePolicy of the queue." + $"\n Default is {MaxReceiveCount}." + "\n -w, --wait-time: The value for ReceiveMessageWaitTimeSeconds of the queue for long polling." + $"\n Default is {ReceiveMessageWaitTime}."); } } // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = // Class that represents a command line on the console or terminal. // (This is the same for all examples. When you have seen it once, you can ignore it.) static class CommandLine { // // Method to parse a command line of the form: "--key value" or "-k value". // // Parameters: // - args: The command-line arguments passed into the application by the system. // // Returns: // A Dictionary with string Keys and Values. // // If a key is found without a matching value, Dictionary.Value is set to the key // (including the dashes). // If a value is found without a matching key, Dictionary.Key is set to "--NoKeyN", // where "N" represents sequential numbers. public static Dictionary<string,string> Parse(string[] args) { var parsedArgs = new Dictionary<string,string>(); int i = 0, n = 0; while(i < args.Length) { // If the first argument in this iteration starts with a dash it's an option. if(args[i].StartsWith("-")) { var key = args[i++]; var value = key; // Check to see if there's a value that goes with this option? if((i < args.Length) && (!args[i].StartsWith("-"))) value = args[i++]; parsedArgs.Add(key, value); } // If the first argument in this iteration doesn't start with a dash, it's a value else { parsedArgs.Add("--NoKey" + n.ToString(), args[i++]); n++; } } return parsedArgs; } // // Method to get an argument from the parsed command-line arguments // // Parameters: // - parsedArgs: The Dictionary object returned from the Parse() method (shown above). // - defaultValue: The default string to return if the specified key isn't in parsedArgs. // - keys: An array of keys to look for in parsedArgs. public static string GetArgument( Dictionary<string,string> parsedArgs, string defaultReturn, params string[] keys) { string retval = null; foreach(var key in keys) if(parsedArgs.TryGetValue(key, out retval)) break; return retval ?? defaultReturn; } // // Method to exit the application with an error. public static void ErrorExit(string msg, int code=1) { Console.WriteLine("\nError"); Console.WriteLine(msg); Environment.Exit(code); } } }

Additional considerations

  • Your queue name must be composed of alphanumeric characters, hyphens, and underscores.

  • Queue names and queue URLs are case-sensitive

  • If you need the queue URL but only have the queue name, use one of the AmazonSQSClient.GetQueueUrlAsync methods.

  • This example specifies long polling for all messages on the queue that you create. This is done by using the ReceiveMessageWaitTimeSeconds attribute.

    You can also specify long polling during a call to the ReceiveMessageAsync methods of the AmazonSQSClient class. For more information, see Receiving Amazon SQS messages.

    For information about short polling versus long polling, see Short and long polling in the Amazon Simple Queue Service Developer Guide.

  • A dead letter queue is one that other (source) queues can target for messages that aren't processed successfully. For more information, see Amazon SQS dead-letter queues in the Amazon Simple Queue Service Developer Guide.

  • You can also see the list of queues and the results of this example in the Amazon SQS console.