正在更新 Amazon SQS 队列 - 适用于 .NET 的 AWS 开发工具包
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正在更新 Amazon SQS 队列

此示例向您展示如何使用 适用于 .NET 的 AWS 开发工具包 更新 Amazon SQS 队列。检查后,应用程序使用给定的值更新给定的属性,然后显示队列的所有属性。

如果命令行引数中只包含队列URL,应用程序将仅显示队列的所有实体。

以下部分提供了此示例的片段。的 示例的完整代码 之后显示,并且可以按原样构建和运行。

显示队列实体

以下代码段显示由给定队列URL标识的队列的属性。

示例 在本主题结束时 显示此片段正在使用。

// // Method to show all attributes of a queue private static async Task ShowAllAttributes(IAmazonSQS sqsClient, string qUrl) { GetQueueAttributesResponse responseGetAtt = await sqsClient.GetQueueAttributesAsync(qUrl, new List<string>{ QueueAttributeName.All }); Console.WriteLine($"Queue: {qUrl}"); foreach(var att in responseGetAtt.Attributes) Console.WriteLine($"\t{att.Key}: {att.Value}"); }

验证属性名称

以下代码段验证正在更新的属性的名称。

示例 在本主题结束时 显示此片段正在使用。

// // Method to check the name of the attribute private static bool ValidAttribute(string attribute) { var attOk = false; var qAttNameType = typeof(QueueAttributeName); List<string> qAttNamefields = new List<string>(); foreach(var field in qAttNameType.GetFields()) qAttNamefields.Add(field.Name); foreach(var name in qAttNamefields) if(attribute == name) { attOk = true; break; } return attOk; }

更新队列属性

以下代码段更新由给定队列URL标识的队列属性。

示例 在本主题结束时 显示此片段正在使用。

// // Method to update a queue attribute private static async Task UpdateAttribute( IAmazonSQS sqsClient, string qUrl, string attribute, string value) { await sqsClient.SetQueueAttributesAsync(qUrl, new Dictionary<string, string>{{attribute, value}}); }

完整代码

本节显示此示例的相关参考和完整代码。

NuGet 程序包:

编程元素:

using System; using System.Collections.Generic; using System.Threading.Tasks; using Amazon.SQS; using Amazon.SQS.Model; namespace SQSUpdateQueue { // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = // Class to update a queue class Program { private const int MaxArgs = 3; private const int InvalidArgCount = 2; static async Task Main(string[] args) { // Parse the command line and show help if necessary var parsedArgs = CommandLine.Parse(args); if(parsedArgs.Count == 0) { PrintHelp(); return; } if((parsedArgs.Count > MaxArgs) || (parsedArgs.Count == InvalidArgCount)) CommandLine.ErrorExit("\nThe number of command-line arguments is incorrect." + "\nRun the command with no arguments to see help."); // Get the application parameters from the parsed arguments var qUrl = CommandLine.GetParameter(parsedArgs, null, "-q"); var attribute = CommandLine.GetParameter(parsedArgs, null, "-a"); var value = CommandLine.GetParameter(parsedArgs, null, "-v", "--value"); if(string.IsNullOrEmpty(qUrl)) CommandLine.ErrorExit("\nYou must supply at least a queue URL." + "\nRun the command with no arguments to see help."); // Create the Amazon SQS client var sqsClient = new AmazonSQSClient(); // In the case of one command-line argument, just show the attributes for the queue if(parsedArgs.Count == 1) await ShowAllAttributes(sqsClient, qUrl); // Otherwise, attempt to update the given queue attribute with the given value else { // Check to see if the attribute is valid if(ValidAttribute(attribute)) { // Perform the update and then show all the attributes of the queue await UpdateAttribute(sqsClient, qUrl, attribute, value); await ShowAllAttributes(sqsClient, qUrl); } else { Console.WriteLine($"\nThe given attribute name, {attribute}, isn't valid."); } } } // // Method to show all attributes of a queue private static async Task ShowAllAttributes(IAmazonSQS sqsClient, string qUrl) { GetQueueAttributesResponse responseGetAtt = await sqsClient.GetQueueAttributesAsync(qUrl, new List<string>{ QueueAttributeName.All }); Console.WriteLine($"Queue: {qUrl}"); foreach(var att in responseGetAtt.Attributes) Console.WriteLine($"\t{att.Key}: {att.Value}"); } // // Method to check the name of the attribute private static bool ValidAttribute(string attribute) { var attOk = false; var qAttNameType = typeof(QueueAttributeName); List<string> qAttNamefields = new List<string>(); foreach(var field in qAttNameType.GetFields()) qAttNamefields.Add(field.Name); foreach(var name in qAttNamefields) if(attribute == name) { attOk = true; break; } return attOk; } // // Method to update a queue attribute private static async Task UpdateAttribute( IAmazonSQS sqsClient, string qUrl, string attribute, string value) { await sqsClient.SetQueueAttributesAsync(qUrl, new Dictionary<string, string>{{attribute, value}}); } // // Command-line help private static void PrintHelp() { Console.WriteLine("\nUsage: SQSUpdateQueue -q queue_url [-a attribute -v value]"); Console.WriteLine(" -q: The URL of the queue you want to update."); Console.WriteLine(" -a: The name of the attribute to update."); Console.WriteLine(" -v, --value: The value to assign to the attribute."); } } // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = // 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: "--param value" or "-p value". // If "param" is found without a matching "value", Dictionary.Value is an empty string. // If "value" is found without a matching "param", Dictionary.Key is "--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 = string.Empty; // Is there 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 a parameter from the parsed command-line arguments public static string GetParameter( Dictionary<string,string> parsedArgs, string def, params string[] keys) { string retval = null; foreach(var key in keys) if(parsedArgs.TryGetValue(key, out retval)) break; return retval ?? def; } // // Exit with an error. public static void ErrorExit(string msg, int code=1) { Console.WriteLine("\nError"); Console.WriteLine(msg); Environment.Exit(code); } } }

其他注意事项

  • 要更新 RedrivePolicy 实体,您必须为整个值报价,并避开密钥/值对的报价(适合您的操作系统)。

    例如,在Windows上,该值的构建方式类似于以下内容:

    "{\"deadLetterTargetArn\":\"DEAD_LETTER-QUEUE-ARN\",\"maxReceiveCount\":\"10\"}"