ParkSquare.ConfigDump.AspNetCore 8.0.3

.Net Core Configuration Debug Dump

Background

Configuration in modern .Net frameworks is based on key-value pairs, and configuration providers. These providers read data from various places, combine them all together and then present them to your application.

Here are some of the more popular configuration providers:

• JSON file (appsettings.json)
• Environment variables
• Command line arguments
• In-memory Dictionary

If a key/value pair appears in more than one provider, the one registered last will take precedence. Usually, your app will have values set in appsettings.json. When deploying to your test and live environments, some of these may be transformed - for example by Octopus Deploy or some other similar mechanism. Furthermore, especically when deploying to Microsoft Azure or using Docker containers, you may additionally override values using environment variables.

It can be troublesome to work out if the final view of your config being presented to the app is as you expect. That's where this library comes in!

Once added, on startup (or at a time of your choosing) you will see all key/value pairs listed, similar to the example log output below, depending on which ILogger you have configured. If the configuration provider has a file source, as the JsonConfigurationProvider does, then the filename will also be shown, e.g. appsettings.json and appsettings.development.json.

15:03:18 DBG   applicationName=ParkSquare.Demo [ChainedConfigurationProvider]
15:03:18 DBG   AUTO_RELOAD_WS_ENDPOINT=ws://localhost:58484/ParkSquare.Demo/ [ChainedConfigurationProvider]
15:03:18 DBG   HTTPS_PORT=5001 [ChainedConfigurationProvider]
15:03:18 DBG   AllowedHosts=* [JsonConfigurationProvider/appsettings.json]
15:03:18 DBG   Serilog:Enrich:0=FromLogContext [JsonConfigurationProvider/appsettings.json]
15:03:18 DBG   Serilog:Enrich:1=WithMachineName [JsonConfigurationProvider/appsettings.json]
15:03:18 DBG   Serilog:Enrich:2=WithThreadId [JsonConfigurationProvider/appsettings.json]
15:03:18 DBG   Smtp:Port=25 [JsonConfigurationProvider/appsettings.json]
15:03:18 DBG   Smtp:ServerName=localhost [JsonConfigurationProvider/appsettings.json]
15:03:18 DBG   :ASPNETCORE_BROWSER_TOOLS=true [EnvironmentVariablesConfigurationProvider]
15:03:18 DBG   ALLUSERSPROFILE=C:\ProgramData [EnvironmentVariablesConfigurationProvider]
15:03:18 DBG   APPDATA=C:\Users\Jon\AppData\Roaming [EnvironmentVariablesConfigurationProvider]

Getting Started

A simple line added to Startup.cs will cause a list of all config key/value pairs to be dumped out, complete with the config provider they came from. It will use whichever ILogger implementation(s) you are using, so works great with things such as Serilog, console or file logging.

Console Apps

Install the ParkSquare.ConfigDump package using the command above, or using Visual Studio's package manager. Now add a new JSON file to your project, and call it appsettings.json.

Build you configuration object:

var config = new ConfigurationBuilder()
    .AddJsonFile("appsettings.json", true, true)
    .Build();

Now register the required dependencies. This includes adding a logging provider, the config itself, and the config dump implementation:

var services = new ServiceCollection()
    .AddLogging(builder => builder.AddConsole())
    .AddSingleton<IConfiguration>(config)
    .AddConfigDump()    // Enables config dump
    .BuildServiceProvider()

Log configured values at startup

At this point, you can either call .DumpConfig() on your service collection to log out the config key/value pairs:

// Complete example: log config values on startup

static void Main(string[] args)
{
    var config = new ConfigurationBuilder()
        .AddJsonFile("appsettings.json", true, true)
        .Build();

    using (var services = new ServiceCollection()
        .AddLogging(builder => builder.AddConsole())
        .AddSingleton<IConfiguration>(config)
        .AddConfigDump()
        .BuildServiceProvider())
        {
            services.DumpConfig();
        }
}

Log configured values inside your own code

Alternatively, you can inject IConfigurationDumper into your own classes and call Dump() whenever suits you:

// Example of injecting into your own class
// Call .AddConfigDump() to register dependencies, or register them manually

public class DemoClass
{
    private readonly IConfigurationDumper _configurationDumper;

    public DemoClass(IConfigurationDumper configurationDumper)
    {
        _configurationDumper = configurationDumper;
    }

    public void DoSomething()
    {
        // ....other code....

        _configurationDumper.Dump();
    }
}

Asp.Net API & Web Apps

To use with Asp.Net Core, add the ParkSquare.ConfigDump.AspNetCore package.

Open Startup.cs and add the following to the ConfigureServices() method. Make sure you use the extension method from ParkSquare.ConfigDump.AspNetCore and not the one in ParkSquare.ConfigDump, as it sets up additional dependencies specific to Asp.Net Core. The call to AddConfigDump() should be just before AddMvc():

using ParkSquare.ConfigDump.AspNetCore;

// ....other code....

public void ConfigureServices(IServiceCollection services)
{
    // ....other registrations....

    // Add this just before AddMvc()
    services.AddConfigDump();

    services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
}

When your app starts up, your config will be logged out before it starts accepting requests.

Changing Log Level

By default, your config will be logged using a log level of 'information'. If you want to change this to some other log level, such as 'debug', simply pass the required level to the .AddConfigDump() call:

services.AddConfigDump(LogLevel.Debug);