34 KiB

Raw Blame History

title

author

description

monikerRange

ms.author

ms.custom

ms.date

no-loc

uid

Use multiple environments in ASP.NET Core

rick-anderson

Learn how to control app behavior across multiple environments in ASP.NET Core apps.

>= aspnetcore-2.1

riande

mvc

7/1/2020

Kestrel

appsettings.json

ASP.NET Core Identity

Blazor

Blazor Server

Blazor WebAssembly

Identity

Let's Encrypt

Razor

SignalR

fundamentals/environments

Use multiple environments in ASP.NET Core

::: moniker range=">= aspnetcore-3.0"

By Rick Anderson and Kirk Larkin

ASP.NET Core configures app behavior based on the runtime environment using an environment variable.

View or download sample code (how to download)

Environments

To determine the runtime environment, ASP.NET Core reads from the following environment variables:

DOTNET_ENVIRONMENT
ASPNETCORE_ENVIRONMENT when xref:Microsoft.Extensions.Hosting.GenericHostBuilderExtensions.ConfigureWebHostDefaults* is called. The default ASP.NET Core web app templates call ConfigureWebHostDefaults. The ASPNETCORE_ENVIRONMENT value overrides DOTNET_ENVIRONMENT.

IHostEnvironment.EnvironmentName can be set to any value, but the following values are provided by the framework:

xref:Microsoft.Extensions.Hosting.Environments.Development : The launchSettings.json file sets ASPNETCORE_ENVIRONMENT to Development on the local machine.
xref:Microsoft.Extensions.Hosting.Environments.Staging
xref:Microsoft.Extensions.Hosting.Environments.Production : The default if DOTNET_ENVIRONMENT and ASPNETCORE_ENVIRONMENT have not been set.

The following code:

Calls UseDeveloperExceptionPage when ASPNETCORE_ENVIRONMENT is set to Development.
Calls UseExceptionHandler when the value of ASPNETCORE_ENVIRONMENT is set to Staging, Production, or Staging_2.
Injects xref:Microsoft.AspNetCore.Hosting.IWebHostEnvironment into Startup.Configure. This approach is useful when the app only requires adjusting Startup.Configure for a few environments with minimal code differences per environment.
Is similar to the code generated by the ASP.NET Core templates.

[!code-csharp]

The Environment Tag Helper uses the value of IHostEnvironment.EnvironmentName to include or exclude markup in the element:

[!code-cshtml]

The About page from the sample code includes the preceding markup and displays the value of IWebHostEnvironment.EnvironmentName.

On Windows and macOS, environment variables and values aren't case-sensitive. Linux environment variables and values are case-sensitive by default.

Create EnvironmentsSample

The sample code used in this document is based on a Razor Pages project named EnvironmentsSample.

The following code creates and runs a web app named EnvironmentsSample:

dotnet new webapp -o EnvironmentsSample
cd EnvironmentsSample
dotnet run --verbosity normal

When the app runs, it displays some of the following output:

Using launch settings from c:\tmp\EnvironmentsSample\Properties\launchSettings.json
info: Microsoft.Hosting.Lifetime[0]
      Now listening on: https://localhost:5001
info: Microsoft.Hosting.Lifetime[0]
      Application started. Press Ctrl+C to shut down.
info: Microsoft.Hosting.Lifetime[0]
      Hosting environment: Development
info: Microsoft.Hosting.Lifetime[0]
      Content root path: c:\tmp\EnvironmentsSample

Development and launchSettings.json

The development environment can enable features that shouldn't be exposed in production. For example, the ASP.NET Core templates enable the Developer Exception Page in the development environment.

The environment for local machine development can be set in the Properties\launchSettings.json file of the project. Environment values set in launchSettings.json override values set in the system environment.

The launchSettings.json file:

Is only used on the local development machine.
Is not deployed.
contains profile settings.

The following JSON shows the launchSettings.json file for an ASP.NET Core web project named EnvironmentsSample created with Visual Studio or dotnet new:

[!code-json]

The preceding markup contains two profiles:

IIS Express: The default profile used when launching the app from Visual Studio. The "commandName" key has the value "IISExpress", therefore, IISExpress is the web server. You can set the launch profile to the project or any other profile included. For example, in the image below, selecting the project name launches the Kestrel web server.
EnvironmentsSample: The profile name is the project name. This profile is used by default when launching the app with dotnet run. The "commandName" key has the value "Project", therefore, the Kestrel web server is launched.

The value of commandName can specify the web server to launch. commandName can be any one of the following:

IISExpress : Launches IIS Express.
IIS : No web server launched. IIS is expected to be available.
Project : Launches Kestrel.

The Visual Studio project properties Debug tab provides a GUI to edit the launchSettings.json file. Changes made to project profiles may not take effect until the web server is restarted. Kestrel must be restarted before it can detect changes made to its environment.

The following launchSettings.json file contains multiple profiles:

[!code-json]

Profiles can be selected:

From the Visual Studio UI.
Using the dotnet run command in a command shell with the --launch-profile option set to the profile's name. This approach only supports Kestrel profiles.
```
dotnet run --launch-profile "SampleApp"
```

[!WARNING] launchSettings.json shouldn't store secrets. The Secret Manager tool can be used to store secrets for local development.

When using Visual Studio Code, environment variables can be set in the .vscode/launch.json file. The following example sets several Host configuration values environment variables:

[!code-json]

The .vscode/launch.json file is only used by Visual Studio Code.

Production

The production environment should be configured to maximize security, performance, and application robustness. Some common settings that differ from development include:

Caching.
Client-side resources are bundled, minified, and potentially served from a CDN.
Diagnostic error pages disabled.
Friendly error pages enabled.
Production logging and monitoring enabled. For example, using Application Insights.

Set the environment

It's often useful to set a specific environment for testing with an environment variable or platform setting. If the environment isn't set, it defaults to Production, which disables most debugging features. The method for setting the environment depends on the operating system.

When the host is built, the last environment setting read by the app determines the app's environment. The app's environment can't be changed while the app is running.

The About page from the sample code displays the value of IWebHostEnvironment.EnvironmentName.

Azure App Service

To set the environment in Azure App Service, perform the following steps:

Select the app from the App Services blade.
In the Settings group, select the Configuration blade.
In the Application settings tab, select New application setting.
In the Add/Edit application setting window, provide ASPNETCORE_ENVIRONMENT for the Name. For Value, provide the environment (for example, Staging).
Select the Deployment slot setting checkbox if you wish the environment setting to remain with the current slot when deployment slots are swapped. For more information, see Set up staging environments in Azure App Service in the Azure documentation.
Select OK to close the Add/Edit application setting window.
Select Save at the top of the Configuration blade.

Azure App Service automatically restarts the app after an app setting is added, changed, or deleted in the Azure portal.

Windows

Environment values in launchSettings.json override values set in the system environment.

To set the ASPNETCORE_ENVIRONMENT for the current session when the app is started using dotnet run, the following commands are used:

Command prompt

set ASPNETCORE_ENVIRONMENT=Staging
dotnet run --no-launch-profile

PowerShell

$Env:ASPNETCORE_ENVIRONMENT = "Staging"
dotnet run --no-launch-profile

The preceding command sets ASPNETCORE_ENVIRONMENT only for processes launched from that command window.

To set the value globally in Windows, use either of the following approaches:

Open the Control Panel > System > Advanced system settings and add or edit the ASPNETCORE_ENVIRONMENT value:
Open an administrative command prompt and use the setx command or open an administrative PowerShell command prompt and use [Environment]::SetEnvironmentVariable:

Command prompt
```
setx ASPNETCORE_ENVIRONMENT Staging /M
```
The /M switch indicates to set the environment variable at the system level. If the /M switch isn't used, the environment variable is set for the user account.

PowerShell
```
[Environment]::SetEnvironmentVariable("ASPNETCORE_ENVIRONMENT", "Staging", "Machine")
```
The Machine option value indicates to set the environment variable at the system level. If the option value is changed to User, the environment variable is set for the user account.

When the ASPNETCORE_ENVIRONMENT environment variable is set globally, it takes effect for dotnet run in any command window opened after the value is set. Environment values in launchSettings.json override values set in the system environment.

web.config

To set the ASPNETCORE_ENVIRONMENT environment variable with web.config, see the Setting environment variables section of xref:host-and-deploy/aspnet-core-module#setting-environment-variables.

Project file or publish profile

For Windows IIS deployments: Include the <EnvironmentName> property in the publish profile (.pubxml) or project file. This approach sets the environment in web.config when the project is published:

<PropertyGroup>
  <EnvironmentName>Development</EnvironmentName>
</PropertyGroup>

Per IIS Application Pool

To set the ASPNETCORE_ENVIRONMENT environment variable for an app running in an isolated Application Pool (supported on IIS 10.0 or later), see the AppCmd.exe command section of the Environment Variables <environmentVariables> topic. When the ASPNETCORE_ENVIRONMENT environment variable is set for an app pool, its value overrides a setting at the system level.

When hosting an app in IIS and adding or changing the ASPNETCORE_ENVIRONMENT environment variable, use any one of the following approaches to have the new value picked up by apps:

Execute net stop was /y followed by net start w3svc from a command prompt.
Restart the server.

macOS

Setting the current environment for macOS can be performed in-line when running the app:

ASPNETCORE_ENVIRONMENT=Staging dotnet run

Alternatively, set the environment with export prior to running the app:

export ASPNETCORE_ENVIRONMENT=Staging

Machine-level environment variables are set in the .bashrc or .bash_profile file. Edit the file using any text editor. Add the following statement:

export ASPNETCORE_ENVIRONMENT=Staging

Linux

For Linux distributions, use the export command at a command prompt for session-based variable settings and bash_profile file for machine-level environment settings.

Set the environment in code

Call xref:Microsoft.Extensions.Hosting.HostingHostBuilderExtensions.UseEnvironment* when building the host. See xref:fundamentals/host/generic-host#environmentname.

Configuration by environment

To load configuration by environment, see xref:fundamentals/configuration/index#json-configuration-provider.

Environment-based Startup class and methods

Inject IWebHostEnvironment into the Startup class

Inject xref:Microsoft.AspNetCore.Hosting.IWebHostEnvironment into the Startup constructor. This approach is useful when the app requires configuring Startup for only a few environments with minimal code differences per environment.

In the following example:

The environment is held in the _env field.
_env is used in ConfigureServices and Configure to apply startup configuration based on the app's environment.

[!code-csharp]

Startup class conventions

When an ASP.NET Core app starts, the Startup class bootstraps the app. The app can define multiple Startup classes for different environments. The appropriate Startup class is selected at runtime. The class whose name suffix matches the current environment is prioritized. If a matching Startup{EnvironmentName} class isn't found, the Startup class is used. This approach is useful when the app requires configuring startup for several environments with many code differences per environment. Typical apps will not need this approach.

To implement environment-based Startup classes, create a Startup{EnvironmentName} classes and a fallback Startup class:

[!code-csharp]

Use the UseStartup(IWebHostBuilder, String) overload that accepts an assembly name:

[!code-csharp]

Startup method conventions

Configure and ConfigureServices support environment-specific versions of the form Configure<EnvironmentName> and Configure<EnvironmentName>Services. If a matching Configure<EnvironmentName>Services or Configure<EnvironmentName> method isn't found, the ConfigureServices or Configure method is used, respectively. This approach is useful when the app requires configuring startup for several environments with many code differences per environment:

[!code-csharp]

Additional resources

::: moniker-end

::: moniker range="< aspnetcore-3.0"

By Rick Anderson

ASP.NET Core configures app behavior based on the runtime environment using an environment variable.

View or download sample code (how to download)

Environments

ASP.NET Core reads the environment variable ASPNETCORE_ENVIRONMENT at app startup and stores the value in IHostingEnvironment.EnvironmentName. ASPNETCORE_ENVIRONMENT can be set to any value, but three values are provided by the framework:

[!code-csharp]

The preceding code:

Calls UseDeveloperExceptionPage when ASPNETCORE_ENVIRONMENT is set to Development.
Calls UseExceptionHandler when the value of ASPNETCORE_ENVIRONMENT is set one of the following:
- Staging
- Production
- Staging_2

The Environment Tag Helper uses the value of IHostingEnvironment.EnvironmentName to include or exclude markup in the element:

[!code-cshtml]

On Windows and macOS, environment variables and values aren't case-sensitive. Linux environment variables and values are case-sensitive by default.

Development

The development environment can enable features that shouldn't be exposed in production. For example, the ASP.NET Core templates enable the Developer Exception Page in the development environment.

The following JSON shows three profiles from a launchSettings.json file:

{
  "iisSettings": {
    "windowsAuthentication": false,
    "anonymousAuthentication": true,
    "iisExpress": {
      "applicationUrl": "http://localhost:54339/",
      "sslPort": 0
    }
  },
  "profiles": {
    "IIS Express": {
      "commandName": "IISExpress",
      "launchBrowser": true,
      "environmentVariables": {
        "ASPNETCORE_My_Environment": "1",
        "ASPNETCORE_DETAILEDERRORS": "1",
        "ASPNETCORE_ENVIRONMENT": "Staging"
      }
    },
    "EnvironmentsSample": {
      "commandName": "Project",
      "launchBrowser": true,
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Staging"
      },
      "applicationUrl": "http://localhost:54340/"
    },
    "Kestrel Staging": {
      "commandName": "Project",
      "launchBrowser": true,
      "environmentVariables": {
        "ASPNETCORE_My_Environment": "1",
        "ASPNETCORE_DETAILEDERRORS": "1",
        "ASPNETCORE_ENVIRONMENT": "Staging"
      },
      "applicationUrl": "http://localhost:51997/"
    }
  }
}

[!NOTE] The applicationUrl property in launchSettings.json can specify a list of server URLs. Use a semicolon between the URLs in the list:
"EnvironmentsSample": {
   "commandName": "Project",
   "launchBrowser": true,
   "applicationUrl": "https://localhost:5001;http://localhost:5000",
   "environmentVariables": {
     "ASPNETCORE_ENVIRONMENT": "Development"
   }
}

When the app is launched with dotnet run, the first profile with "commandName": "Project" is used. The value of commandName specifies the web server to launch. commandName can be any one of the following:

IISExpress
IIS
Project (which launches Kestrel)

When an app is launched with dotnet run:

launchSettings.json is read if available. environmentVariables settings in launchSettings.json override environment variables.
The hosting environment is displayed.

The following output shows an app started with dotnet run:

PS C:\Websites\EnvironmentsSample> dotnet run
Using launch settings from C:\Websites\EnvironmentsSample\Properties\launchSettings.json...
Hosting environment: Staging
Content root path: C:\Websites\EnvironmentsSample
Now listening on: http://localhost:54340
Application started. Press Ctrl+C to shut down.

The Visual Studio project properties Debug tab provides a GUI to edit the launchSettings.json file:

Changes made to project profiles may not take effect until the web server is restarted. Kestrel must be restarted before it can detect changes made to its environment.

[!WARNING] launchSettings.json shouldn't store secrets. The Secret Manager tool can be used to store secrets for local development.

When using Visual Studio Code, environment variables can be set in the .vscode/launch.json file. The following example sets the environment to Development:

{
   "version": "0.2.0",
   "configurations": [
        {
            "name": ".NET Core Launch (web)",

            ... additional VS Code configuration settings ...

            "env": {
                "ASPNETCORE_ENVIRONMENT": "Development"
            }
        }
    ]
}

A .vscode/launch.json file in the project isn't read when starting the app with dotnet run in the same way as Properties/launchSettings.json. When launching an app in development that doesn't have a launchSettings.json file, either set the environment with an environment variable or a command-line argument to the dotnet run command.

Production

The production environment should be configured to maximize security, performance, and app robustness. Some common settings that differ from development include:

Caching.
Client-side resources are bundled, minified, and potentially served from a CDN.
Diagnostic error pages disabled.
Friendly error pages enabled.
Production logging and monitoring enabled. For example, Application Insights.

Set the environment

When the host is built, the last environment setting read by the app determines the app's environment. The app's environment can't be changed while the app is running.

Environment variable or platform setting

Azure App Service

To set the environment in Azure App Service, perform the following steps:

Select the app from the App Services blade.
In the Settings group, select the Configuration blade.
In the Application settings tab, select New application setting.
In the Add/Edit application setting window, provide ASPNETCORE_ENVIRONMENT for the Name. For Value, provide the environment (for example, Staging).
Select the Deployment slot setting checkbox if you wish the environment setting to remain with the current slot when deployment slots are swapped. For more information, see Set up staging environments in Azure App Service in the Azure documentation.
Select OK to close the Add/Edit application setting window.
Select Save at the top of the Configuration blade.

Azure App Service automatically restarts the app after an app setting (environment variable) is added, changed, or deleted in the Azure portal.

Windows

To set the ASPNETCORE_ENVIRONMENT for the current session when the app is started using dotnet run, the following commands are used:

Command prompt

set ASPNETCORE_ENVIRONMENT=Development

PowerShell

$Env:ASPNETCORE_ENVIRONMENT = "Development"

These commands only take effect for the current window. When the window is closed, the ASPNETCORE_ENVIRONMENT setting reverts to the default setting or machine value.

To set the value globally in Windows, use either of the following approaches:

Open the Control Panel > System > Advanced system settings and add or edit the ASPNETCORE_ENVIRONMENT value:
Open an administrative command prompt and use the setx command or open an administrative PowerShell command prompt and use [Environment]::SetEnvironmentVariable:

Command prompt
```
setx ASPNETCORE_ENVIRONMENT Development /M
```
The /M switch indicates to set the environment variable at the system level. If the /M switch isn't used, the environment variable is set for the user account.

PowerShell
```
[Environment]::SetEnvironmentVariable("ASPNETCORE_ENVIRONMENT", "Development", "Machine")
```
The Machine option value indicates to set the environment variable at the system level. If the option value is changed to User, the environment variable is set for the user account.

When the ASPNETCORE_ENVIRONMENT environment variable is set globally, it takes effect for dotnet run in any command window opened after the value is set.

web.config

To set the ASPNETCORE_ENVIRONMENT environment variable with web.config, see the Setting environment variables section of xref:host-and-deploy/aspnet-core-module#setting-environment-variables.

Project file or publish profile

<PropertyGroup>
  <EnvironmentName>Development</EnvironmentName>
</PropertyGroup>

Per IIS Application Pool

[!IMPORTANT] When hosting an app in IIS and adding or changing the ASPNETCORE_ENVIRONMENT environment variable, use any one of the following approaches to have the new value picked up by apps:

Execute net stop was /y followed by net start w3svc from a command prompt.

Restart the server.

macOS

Setting the current environment for macOS can be performed in-line when running the app:

ASPNETCORE_ENVIRONMENT=Development dotnet run

Alternatively, set the environment with export prior to running the app:

export ASPNETCORE_ENVIRONMENT=Development

Machine-level environment variables are set in the .bashrc or .bash_profile file. Edit the file using any text editor. Add the following statement:

export ASPNETCORE_ENVIRONMENT=Development

Linux

For Linux distributions, use the export command at a command prompt for session-based variable settings and bash_profile file for machine-level environment settings.

Set the environment in code

Call xref:Microsoft.AspNetCore.Hosting.HostingAbstractionsWebHostBuilderExtensions.UseEnvironment* when building the host. See xref:fundamentals/host/web-host#environment.

Configuration by environment

To load configuration by environment, we recommend:

appsettings files (appsettings.{Environment}.json). See xref:fundamentals/configuration/index#json-configuration-provider.
Environment variables (set on each system where the app is hosted). See xref:fundamentals/host/web-host#environment and xref:security/app-secrets#environment-variables.
User secrets (in the Development environment only). See xref:security/app-secrets.

Environment-based Startup class and methods

Inject IHostingEnvironment into Startup.Configure

Inject xref:Microsoft.AspNetCore.Hosting.IHostingEnvironment into Startup.Configure. This approach is useful when the app only requires configuring Startup.Configure for only a few environments with minimal code differences per environment.

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
    if (env.IsDevelopment())
    {
        // Development environment code
    }
    else
    {
        // Code for all other environments
    }
}

Inject IHostingEnvironment into the Startup class

Inject xref:Microsoft.AspNetCore.Hosting.IHostingEnvironment into the Startup constructor and assign the service to a field for use throughout the Startup class. This approach is useful when the app requires configuring startup for only a few environments with minimal code differences per environment.

In the following example:

The environment is held in the _env field.
_env is used in ConfigureServices and Configure to apply startup configuration based on the app's environment.

public class Startup
{
    private readonly IHostingEnvironment _env;

    public Startup(IHostingEnvironment env)
    {
        _env = env;
    }

    public void ConfigureServices(IServiceCollection services)
    {
        if (_env.IsDevelopment())
        {
            // Development environment code
        }
        else if (_env.IsStaging())
        {
            // Staging environment code
        }
        else
        {
            // Code for all other environments
        }
    }

    public void Configure(IApplicationBuilder app)
    {
        if (_env.IsDevelopment())
        {
            // Development environment code
        }
        else
        {
            // Code for all other environments
        }
    }
}

Startup class conventions

When an ASP.NET Core app starts, the Startup class bootstraps the app. The app can define separate Startup classes for different environments (for example, StartupDevelopment). The appropriate Startup class is selected at runtime. The class whose name suffix matches the current environment is prioritized. If a matching Startup{EnvironmentName} class isn't found, the Startup class is used. This approach is useful when the app requires configuring startup for several environments with many code differences per environment.

To implement environment-based Startup classes, create a Startup{EnvironmentName} class for each environment in use and a fallback Startup class:

// Startup class to use in the Development environment
public class StartupDevelopment
{
    public void ConfigureServices(IServiceCollection services)
    {
    }

    public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
    }
}

// Startup class to use in the Production environment
public class StartupProduction
{
    public void ConfigureServices(IServiceCollection services)
    {
    }

    public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
    }
}

// Fallback Startup class
// Selected if the environment doesn't match a Startup{EnvironmentName} class
public class Startup
{
    public void ConfigureServices(IServiceCollection services)
    {
    }

    public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
    }
}

Use the UseStartup(IWebHostBuilder, String) overload that accepts an assembly name:

public static void Main(string[] args)
{
    CreateWebHostBuilder(args).Build().Run();
}

public static IWebHostBuilder CreateWebHostBuilder(string[] args)
{
    var assemblyName = typeof(Startup).GetTypeInfo().Assembly.FullName;

    return WebHost.CreateDefaultBuilder(args)
        .UseStartup(assemblyName);
}

Startup method conventions

[!code-csharp]

Additional resources

::: moniker-end

34 KiB Raw Blame History

Use multiple environments in ASP.NET Core

Environments

Create EnvironmentsSample

Development and launchSettings.json

Production

Set the environment

Azure App Service

Windows

macOS

Linux

Set the environment in code

Configuration by environment

Environment-based Startup class and methods

Inject IWebHostEnvironment into the Startup class

Startup class conventions

Startup method conventions

Additional resources

Environments

Development

Production

Set the environment

Environment variable or platform setting

Azure App Service

Windows

macOS

Linux

Set the environment in code

Configuration by environment

Environment-based Startup class and methods

Inject IHostingEnvironment into Startup.Configure

Inject IHostingEnvironment into the Startup class

Startup class conventions

Startup method conventions

Additional resources

34 KiB

Raw Blame History