Today we are releasing a set of providers for ASP.NET 4.7.1 that make it easier than ever to deploy your applications to cloud services and take advantage of cloud-scale features.\u00a0 This release includes a new CosmosDb provider for session state and a collection of configuration builders.<\/p>\n
With previous versions of the .NET Framework, new features were provided \u201cin the box\u201d and shipped with Windows and new versions of the entire framework.\u00a0 This means that you can be assured that your providers and capabilities were available on every current version of Windows.\u00a0 It also means that you had to wait until a new version of Windows to get new .NET Framework features.\u00a0 We have adopted a strategy starting with .NET Framework 4.7 to deliver more abstract features with the framework and deploy providers through the NuGet package manager service.\u00a0 There are no concrete ConfigurationBuilder classes in the .NET Framework 4.7.1, and we are now making available several for your use from the NuGet.org repository.\u00a0 In this way, we can update and deploy new ConfigurationBuilders without requiring a fresh install of Windows or the .NET Framework.<\/p>\n
In .NET Framework 4.7.1 we introduced the concept of ConfigurationBuilders.\u00a0 ConfigurationBuilders are objects that allow you to inject application configuration into your .NET Framework 4.7.1 application and continue to use the familiar ConfigurationManager interface to read those values.\u00a0 Sure, you could always write your configuration files to read other config files from disk, but what if you wanted to apply configuration from environment variables?\u00a0 What if you wanted to read configuration from a service, like Azure Key Vault?\u00a0 To work with those configuration sources, you would need to rewrite some non-trivial amount of your application to consume these services.<\/p>\n
With ConfigurationBuilders, no code changes are necessary in your application. \u00a0You simply add references from your web.config or app.config file to the ConfigurationBuilders you want to use and your application will start consuming those sources without updating your configuration files on disk.\u00a0 One form of ConfigurationBuilder is the KeyValueConfigBuilder that matches a key to a value from an external source and adds that pair to your configuration.\u00a0 All of the ConfigurationBuilders we are releasing today support this key-value approach to configuration.\u00a0 Lets take a look at using one of these new ConfigurationBuilders, the EnvironmentConfigBuilder<\/a>.<\/p>\n When you install any of our new ConfigurationBuilders into your application, we automatically allocate the appropriate new configSections in your app.config or web.config file as shown below:<\/p>\n The new \u201cbuilders\u201d section contains information about the ConfigurationBuilders you wish to use in your application.\u00a0 You can declare any number of ConfigurationBuilders, and apply the settings they retrieve to any section of your configuration.\u00a0 Let\u2019s look at applying our environment variables to the appSettings of this configuration.\u00a0 You specify which ConfigurationBuilders to apply to a section by adding the configBuilders attribute to that section, and indicate the name of the defined ConfigurationBuilder to apply, in this case \u201cEnvironment\u201d<\/p>\n The COMPUTERNAME is a common environment variable set by the Windows operating system that we can use to replace the VisualStudio setting defined here.\u00a0 With the below ASPX page in our project, we can run our application and see the following results.<\/p>\n There are several Modes that you can apply to each of the ConfigurationBuilders we are releasing today:<\/p>\n The Greedy and Strict options only apply when operating on AppSettings or ConnectionStrings sections.\u00a0 Expand can perform its string replacement on any section of your config file.<\/p>\n You can also specify prefixes for your settings to be handled by adding the prefix attribute.\u00a0 This allows you to only read settings that start with a known prefix.\u00a0 Perhaps you only want to add environment variables that start with \u201cAPPSETTING_\u201d, you can update your config file like this:<\/p>\n Finally, even though using the APPSETTING_ prefix is a nice catch to only read those settings, you may not want your configuration to actually be called \u201cAPPSETTING_Setting\u201d in code.\u00a0 You can use the stripPrefix attribute (default value is false) to omit the prefix when the value is added to your configuration: Try using the EnvironmentConfigBuilder from inside a Docker container to inject configuration specific to your running instances of your application.\u00a0 We\u2019ve found that this significantly improves the ability to deploy existing applications in containers without having to rewrite your code to read from alternate configuration sources.<\/p>\n We are happy to include a ConfigurationBuilder for Azure Key Vault<\/a> in this initial collection of providers.\u00a0 This ConfigurationBuilder allows you to secure your application using the Azure Key Vault service<\/a>, without any required login information to access the vault.\u00a0 Add this ConfigurationBuilder to your config file and build an add statement like the following:<\/p>\n If your application is running on an Azure service that has <\/a>, this is all you need to read configuration from the vault and add it to your application.\u00a0 Conversely, if you are not running on a service with MSI, you can still use the vault by adding the following attributes: \n* clientId<\/strong> \u2013 the Azure Active Directory application key that has access to your key vault\n* clientSecret<\/strong> \u2013 the Azure Active Directory application secret that corresponds to the clientId<\/p>\n The same mode, prefix, and stripPrefix features described previously are available for use with the AzureKeyVaultConfigBuilder.\u00a0 You can now configure your application to grab that secret database connection string from the keyvault \u201cconn_mydb\u201d setting with a config file that looks like this:<\/p>\n You can use other vaults by using the uri attribute instead of the vaultName attribute, and providing the URI of the vault you wish to connect to.\u00a0 More information about getting started configuring key vault<\/a> is available online.<\/p>\n Today we are introducing five configuration builders as a preview for you to use and extend:<\/p>\n<appSettings configBuilders=\"Environment\">\n <add key=\"COMPUTERNAME\" value=\"VisualStudio\" \/>\n<\/appSettings><\/pre>\n
<add name=\"Environment\" mode=\"Greedy\"\n type=\"Microsoft.Configuration.ConfigurationBuilders.EnvironmentConfigBuilder, Microsoft.Configuration.ConfigurationBuilders.Environment, Version=1.0.0.0, Culture=neutral\" \/><\/pre>\n
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<add name=\"Environment\"\n mode=\"Greedy\" prefix=\"APPSETTING_\" \n type=\"Microsoft.Configuration.ConfigurationBuilders.EnvironmentConfigBuilder, Microsoft.Configuration.ConfigurationBuilders.Environment, Version=1.0.0.0, Culture=neutral\" \/><\/pre>\n
Secure Configuration with Azure Key Vault<\/h2>\n
<add name=\"AzureKeyVault\"\n mode=\"Strict\"\n vaultName=\"MyVaultName\"\n type=\"Microsoft.Configuration.ConfigurationBuilders.AzureKeyVaultConfigBuilder, Microsoft.Configuration.ConfigurationBuilders.Azure\" \/><\/pre>\n
Other Configuration Builders Available<\/h2>\n
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Store SessionState in CosmosDb<\/h2>\n