Creating IAM managed policies from JSON - AWS SDK for .NET

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Creating IAM managed policies from JSON

This example shows you how to use the AWS SDK for .NET to create an IAM managed policy from a given policy document in JSON. The application creates an IAM client object, reads the policy document from a file, and then creates the policy.

Note

For an example policy document in JSON, see the additional considerations at the end of this topic.

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.

Create the policy

The following snippet creates an IAM managed policy with the given name and policy document.

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

// // Method to create an IAM policy from a JSON file private static async Task<CreatePolicyResponse> CreateManagedPolicy( IAmazonIdentityManagementService iamClient, string policyName, string jsonFilename) { return await iamClient.CreatePolicyAsync(new CreatePolicyRequest{ PolicyName = policyName, PolicyDocument = File.ReadAllText(jsonFilename)}); }

Complete code

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

using System; using System.Collections.Generic; using System.IO; using System.Threading.Tasks; using Amazon.IdentityManagement; using Amazon.IdentityManagement.Model; namespace IamCreatePolicyFromJson { // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = // Class to create an IAM policy with a given policy document class Program { private const int MaxArgs = 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) || (parsedArgs.Count > MaxArgs)) { PrintHelp(); return; } // Get the application arguments from the parsed list string policyName = CommandLine.GetArgument(parsedArgs, null, "-p", "--policy-name"); string policyFilename = CommandLine.GetArgument(parsedArgs, null, "-j", "--json-filename"); if( string.IsNullOrEmpty(policyName) || (string.IsNullOrEmpty(policyFilename) || !policyFilename.EndsWith(".json"))) CommandLine.ErrorExit( "\nOne or more of the required arguments is missing or incorrect." + "\nRun the command with no arguments to see help."); // Create an IAM service client var iamClient = new AmazonIdentityManagementServiceClient(); // Create the new policy var response = await CreateManagedPolicy(iamClient, policyName, policyFilename); Console.WriteLine($"\nPolicy {response.Policy.PolicyName} has been created."); Console.WriteLine($" Arn: {response.Policy.Arn}"); } // // Method to create an IAM policy from a JSON file private static async Task<CreatePolicyResponse> CreateManagedPolicy( IAmazonIdentityManagementService iamClient, string policyName, string jsonFilename) { return await iamClient.CreatePolicyAsync(new CreatePolicyRequest{ PolicyName = policyName, PolicyDocument = File.ReadAllText(jsonFilename)}); } // // Command-line help private static void PrintHelp() { Console.WriteLine( "\nUsage: IamCreatePolicyFromJson -p <policy-name> -j <json-filename>" + "\n -p, --policy-name: The name you want the new policy to have." + "\n -j, --json-filename: The name of the JSON file with the policy document."); } } // = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = // 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

  • The following is an example policy document that you can copy into a JSON file and use as input for this application:

    { "Version" : "2012-10-17", "Id" : "DotnetTutorialPolicy", "Statement" : [ { "Sid" : "DotnetTutorialPolicyS3", "Effect" : "Allow", "Action" : [ "s3:Get*", "s3:List*" ], "Resource" : "*" }, { "Sid" : "DotnetTutorialPolicyPolly", "Effect": "Allow", "Action": [ "polly:DescribeVoices", "polly:SynthesizeSpeech" ], "Resource": "*" } ] }
  • You can verify that the policy was created by looking in the IAM console. In the Filter policies drop-down list, select Customer managed. Delete the policy when you no longer need it.