Feature/#8

src/Etcd.Microsoft.Extensions.Configuration/Auth/Credentials.cs

@@ -3,30 +3,52 @@
 namespace Etcd.Microsoft.Extensions.Configuration.Auth;
 
 /// <summary>
-/// Provides credentials
+/// Provides credentials.
 /// </summary>
 /// <seealso cref="ICredentials" />
 public class Credentials : ICredentials
 {
+	private const string DefaultUserNameEnvironmentVariableName = "ETCD_CLIENT_USER_NAME";
+	private const string DefaultPasswordEnvironmentVariableName = "ETCD_CLIENT_PASSWORD";
+
 	/// <summary>
 	/// Initializes a new instance of the <see cref="Credentials"/> class.
 	/// </summary>
 	/// <param name="userName">Name of the user.</param>
 	/// <param name="password">The password.</param>
+	/// <param name="userNameSource">The source of the username.</param>
+	/// <param name="passwordSource">The source of the password.</param>
+	/// <param name="information">The information about the credentials.</param>
 	/// <exception cref="ArgumentException">
 	/// Value cannot be null or empty. - userName
 	/// or
 	/// Value cannot be null or empty. - password
 	/// </exception>
-	public Credentials(string userName, string password)
+	public Credentials(string userName, string password,
+		CredentialsSource userNameSource = CredentialsSource.Code,
+		CredentialsSource passwordSource = CredentialsSource.Code,
+		string? information = null)
 	{
 		if (string.IsNullOrEmpty(userName)) throw new ArgumentException("Value cannot be null or empty.", nameof(userName));
 		if (string.IsNullOrEmpty(password)) throw new ArgumentException("Value cannot be null or empty.", nameof(password));
 
 		UserName = userName;
 		Password = password;
+		UserNameSource = userNameSource;
+		PasswordSource = passwordSource;
+		Information = information;
 	}
 
+	/// <summary>
+	/// Gets the source of the user name.
+	/// </summary>
+	public CredentialsSource UserNameSource { get; }
+
+	/// <summary>
+	/// Gets the source of the password.
+	/// </summary>
+	public CredentialsSource PasswordSource { get; }
+
 	/// <summary>
 	/// Gets the name of the user.
 	/// </summary>
@@ -42,4 +64,158 @@ public Credentials(string userName, string password)
 	/// The password.
 	/// </value>
 	public string Password { get; }
+
+	/// <summary>
+	/// Gets the information about the credentials.
+	/// </summary>
+	public string? Information { get; private set; }
+
+	/// <summary>
+	/// Gets the string representation of the credentials.
+	/// </summary>
+	override public string ToString() => Information ?? "etcd code based credentials";
+
+	/// <summary>
+	/// Creates a new credentials instance overriding values from environment variables if they are exists.
+	/// </summary>
+	/// <param name="userName">The user name.</param>
+	/// <param name="password">The password.</param>
+	/// <param name="userNameEnvironmentVariableName">The name of the user name environment variable.</param>
+	/// <param name="passwordEnvironmentVariableName">The name of the password environment variable.</param>
+	/// <exception cref="EtcdException">The etcd user name or password are not provided via code and not found in the environment variable `{userNameEnvironmentVariableName}`.</exception>
+	public static ICredentials WithOverrideFromEnvironmentVariables(
+		string userName,
+		string password,
+		string userNameEnvironmentVariableName = DefaultUserNameEnvironmentVariableName,
+		string passwordEnvironmentVariableName = DefaultPasswordEnvironmentVariableName)
+	{
+		var userNameSource = CredentialsSource.Code;
+		var passwordSource = CredentialsSource.Code;
+
+		var environmentUserName = Environment.GetEnvironmentVariable(userNameEnvironmentVariableName);
+		var environmentPassword = Environment.GetEnvironmentVariable(passwordEnvironmentVariableName);
+
+		if (!string.IsNullOrEmpty(environmentUserName))
+		{
+			userName = environmentUserName;
+
+			userNameSource = CredentialsSource.EnvironmentVariables;
+		}
+
+		if (string.IsNullOrEmpty(userName))
+			throw new EtcdException($"Etcd user name is not provided via code and not found in the environment variable `{userNameEnvironmentVariableName}`.");
+
+		if (!string.IsNullOrEmpty(environmentPassword))
+		{
+			password = environmentPassword;
+
+			passwordSource = CredentialsSource.EnvironmentVariables;
+		}
+
+		if (string.IsNullOrEmpty(password))
+			throw new EtcdException($"Etcd password is not provided via code and not found in the environment variable `{passwordEnvironmentVariableName}`.");
+
+		return new Credentials(userName, password, userNameSource, passwordSource,
+			FormatInformation(
+				userNameSource,
+				passwordSource,
+				userNameEnvironmentVariableName,
+				passwordEnvironmentVariableName));
+	}
+
+	/// <summary>
+	/// Creates a new credentials instance overriding values from environment variables if they are exists.
+	/// </summary>
+	/// <param name="userName">The user name.</param>
+	/// <param name="password">The password.</param>
+	/// <param name="passwordEnvironmentVariableName">The name of the password environment variable.</param>
+	/// <exception cref="EtcdException">The etcd user name or password are not provided via code and not found in the environment variable `{userNameEnvironmentVariableName}`.</exception>
+	public static ICredentials WithOverrideFromEnvironmentVariables(
+		string userName,
+		string password,
+		string passwordEnvironmentVariableName = DefaultPasswordEnvironmentVariableName)
+	{
+		var userNameSource = CredentialsSource.Code;
+		var passwordSource = CredentialsSource.Code;
+
+		var environmentPassword = Environment.GetEnvironmentVariable(passwordEnvironmentVariableName);
+
+		if (string.IsNullOrEmpty(userName))
+			throw new EtcdException($"Etcd user name is not provided.");
+
+		if (!string.IsNullOrEmpty(environmentPassword))
+		{
+			password = environmentPassword;
+
+			passwordSource = CredentialsSource.EnvironmentVariables;
+		}
+
+		if (string.IsNullOrEmpty(password))
+			throw new EtcdException($"Etcd password is not provided via code and not found in the environment variable `{passwordEnvironmentVariableName}`.");
+
+		return new Credentials(userName, password, userNameSource, passwordSource,
+			FormatInformation(
+				userNameSource,
+				passwordSource,
+				null,
+				passwordEnvironmentVariableName));
+	}
+
+
+	/// <summary>
+	/// Creates a new credentials instance from environment variables.
+	/// </summary>
+	/// <param name="userNameEnvironmentVariableName">The name of the user name environment variable.</param>
+	/// <param name="passwordEnvironmentVariableName">The name of the password environment variable.</param>
+	/// <exception cref="EtcdException">The etcd user name or password are not provided via code and not found in the environment variable `{userNameEnvironmentVariableName}`.</exception>
+	public static ICredentials FromEnvironmentVariables(
+		string userNameEnvironmentVariableName = DefaultUserNameEnvironmentVariableName,
+		string passwordEnvironmentVariableName = DefaultPasswordEnvironmentVariableName)
+	{
+		var userNameSource = CredentialsSource.EnvironmentVariables;
+		var passwordSource = CredentialsSource.EnvironmentVariables;
+
+		var userName = Environment.GetEnvironmentVariable(userNameEnvironmentVariableName);
+		var password = Environment.GetEnvironmentVariable(passwordEnvironmentVariableName);
+
+		if (string.IsNullOrEmpty(userName))
+			throw new EtcdException($"Etcd user name is not found in the environment variable `{userNameEnvironmentVariableName}`.");
+
+		if (string.IsNullOrEmpty(password))
+			throw new EtcdException($"Etcd password is not found in the environment variable `{passwordEnvironmentVariableName}`.");
+
+		return new Credentials(userName, password, userNameSource, passwordSource,
+			FormatInformation(
+				userNameSource,
+				passwordSource,
+				userNameEnvironmentVariableName,
+				passwordEnvironmentVariableName));
+	}
+
+	private static string FormatInformation(
+	 	CredentialsSource userNameSource,
+	 	CredentialsSource passwordSource,
+		string? userNameEnvironmentVariableName = null,
+		string? passwordEnvironmentVariableName = null) =>
+			FormatUserNameInformation(userNameSource, userNameEnvironmentVariableName) + ", " + FormatPassword(passwordSource, passwordEnvironmentVariableName);
+
+	private static string FormatUserNameInformation(CredentialsSource userNameSource, string? userNameEnvironmentVariableName = null)
+	{
+		var result = $"etcd user name source: {userNameSource}";
+
+		if (userNameSource == CredentialsSource.EnvironmentVariables)
+			result += $" ({userNameEnvironmentVariableName})";
+
+		return result;
+	}
+
+	private static string FormatPassword(CredentialsSource passwordSource, string? passwordEnvironmentVariableName = null)
+	{
+		var result = $"etcd password source: {passwordSource}";
+
+		if (passwordSource == CredentialsSource.EnvironmentVariables)
+			result += $" ({passwordEnvironmentVariableName})";
+
+		return result;
+	}
 }

src/Etcd.Microsoft.Extensions.Configuration/Auth/CredentialsSource.cs

@@ -0,0 +1,17 @@
+namespace Etcd.Microsoft.Extensions.Configuration.Auth
+{
+	/// <summary>
+	/// Possible sources for credentials.
+	/// </summary>
+	public enum CredentialsSource
+	{
+		/// <summary>
+		/// Credentials provided via code.
+		/// </summary>
+		Code = 0,
+		/// <summary>
+		/// Credentials provided via environment variables.
+		/// </summary>
+		EnvironmentVariables = 1
+	}
+}

src/Etcd.Microsoft.Extensions.Configuration/CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## [3.1.0] - 2025-10-22
+
+### Added
+
+- Possibility to load credentials from environment variables
+
 ## [3.0.0] - 2025-06-26
 
 ### Removed

src/Etcd.Microsoft.Extensions.Configuration/Etcd.Microsoft.Extensions.Configuration.csproj

@@ -8,7 +8,7 @@
 		<SymbolPackageFormat>snupkg</SymbolPackageFormat>
 		<GenerateDocumentationFile>true</GenerateDocumentationFile>
 
-		<Version>3.0</Version>
+		<Version>3.1</Version>
 
 		<Description>Etcd based configuration provider for Microsoft.Extensions.Configuration</Description>
 		<Authors>Simplify community</Authors>

src/Etcd.Microsoft.Extensions.Configuration/EtcdApplicationEnvironment.cs

@@ -20,7 +20,7 @@ public static class EtcdApplicationEnvironment
 	/// <value>
 	/// The connection string.
 	/// </value>
-	/// <exception cref="System.ArgumentNullException">value</exception>
+	/// <exception cref="ArgumentNullException">value</exception>
 	public static string? ConnectionString
 	{
 		get

tests/Integration/Etcd.Microsoft.Extensions.Configuration.IntegrationTests/ConfigurationBuilderTests.cs

@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Linq;
 using Etcd.Microsoft.Extensions.Configuration.Auth;
 using Etcd.Microsoft.Extensions.Configuration.Settings;
@@ -26,7 +27,38 @@ public void Build_WithSettingsFromEtcd_ValuesLoaded()
 			.Build();
 
 		// Act
+		PerformTest(config);
+	}
+
+	[Test]
+	public void Build_WithSettingsFromEtcdAndCredentialsFromEnvironment_ValuesLoaded()
+	{
+		// Arrange
+
+		Environment.SetEnvironmentVariable("ETCD_TEST_USERNAME", "MyUserName");
+		Environment.SetEnvironmentVariable("ETCD_TEST_PASSWORD", "passw");
+
+		var credentials = new Credentials("MyUserName", "passw");
+		var envCredentials = Credentials.WithOverrideFromEnvironmentVariables("foo", "bar", "ETCD_TEST_USERNAME", "ETCD_TEST_PASSWORD");
+		var envCredentials2 = Credentials.WithOverrideFromEnvironmentVariables("MyUserName", "bar", "ETCD_TEST_PASSWORD");
+
+		var etcdSettings = new EtcdSettings("http://localhost:2379");
 
+		var config = new ConfigurationBuilder()
+			.AddEtcd(credentials, etcdSettings)
+			.AddEtcd(envCredentials, etcdSettings, "MyPrefix")
+			.AddEtcd(envCredentials2, etcdSettings, "MYCOMPLEX/prefix", "/")
+			.Build();
+
+		// Act
+		PerformTest(config);
+
+		// Assert
+		Assert.Pass("Credentials info: " + envCredentials.ToString());
+	}
+
+	private static void PerformTest(IConfigurationRoot config)
+	{
 		var testSection = config.GetSection("TestSection");
 		var testSubSection = testSection.GetSection("SubSection");
 		var list = testSection.GetSection("ArraySection").Get<List<string>>();