Asp.net - Reading Nested Configuration from Azure Function App

TheInquisitiveCoder
July 8, 2023
203 views
0 votes
2 Answers

I’m facing issues in reading Nested configuration values from local.settings.json in my Azure Function(v6) and the values always seem to be coming as null. Below are my code snippets:

local.settings.json:

{
  "IsEncrypted": false,
  "Values": {
    "AzureWebJobsStorage": "UseDevelopmentStorage=true",
    "FUNCTIONS_WORKER_RUNTIME": "dotnet",
    "EndpointDetails": {
      "GetAllTaskDetails": {
        "Url": "https://localhost:7000/api/Task/GetAllTaskDetails",
        "Method": "GET",
        "NotificationRecipients": "[email protected]"
      },
      "GetTaskDetails": {
        "Url": "https://localhost:7000/api/Task/GetTaskDetails",
        "Method": "GET",
        "NotificationRecipients": "[email protected]"
      }
    }
  }
}

Startup.cs:

using Microsoft.Azure.Functions.Extensions.DependencyInjection;
using Microsoft.Extensions.DependencyInjection;

[assembly: FunctionsStartup(typeof(HealthChecker.Startup))]
namespace HealthChecker
{
    public class Startup : FunctionsStartup
    {
        public override void Configure(IFunctionsHostBuilder builder)
        {
            // Getting the IConfiguration instance
            var configuration = builder.GetContext().Configuration;

            // Registering health checks
            builder.Services.AddHealthChecks();

            // Calling the method that defines health checks
            HealthCheckDefinitions.ConfigureHealthChecks(builder.Services.AddHealthChecks(), configuration);
        }
    }
}

HealthCheckDefinitions.cs:

public static class HealthCheckDefinitions
{
 private static Dictionary<string, List<string>> endpointDetails = new Dictionary<string, List<string>>();

 public static void ConfigureHealthChecks(IHealthChecksBuilder builder, IConfiguration configuration){
     private static IConfigurationSection endpointDetailsListConfig;
     private static string getAllTaskDetails;
     private static string getTaskDetails;
     List<string> endpoints = new List<string>();

     InitializeConfigValues(configuration);

     endpoints.AddRange(new List<string>
            {
                 getAllTaskDetails,
                 getTaskDetails
            });

     foreach (var endpoint in endpoints)
            {
                var endpointDetailsConfig 
                  = endpointDetailsListConfig.GetSection(endpoint);
                GetEndpointDetails(endpointDetailsConfig, endpoint);
               
                foreach (var endpointDetail in endpointDetails)
                {
                  builder.AddCheck(endpointDetail.Key, () =>
                  {
                    // lines of code
                    // .....
                  });
                }
            }
   }
 
 private static void InitializeConfigValues(IConfiguration configuration)
    {
        endpointDetailsListConfig = configuration.GetSection("EndpointDetails");
        getAllTaskDetails = endpointDetailsListConfig.GetSection("GetAllTaskDetails").Key;
        getTaskDetails = endpointDetailsListConfig.GetSection("GetTaskDetails").Key;
    }

   private static void GetEndpointDetails(IConfigurationSection endpointDetailsConfig, string endpoint)
    {
        if (!string.IsNullOrEmpty(endpointDetailsConfig["Url"]) && !string.IsNullOrEmpty(endpointDetailsConfig["Method"])
            && !string.IsNullOrEmpty(endpointDetailsConfig["NotificationRecipients"]))
            {
                endpointDetails.Add(endpoint, new List<string>
                {
                    endpointDetailsConfig["Url"],
                    endpointDetailsConfig["Method"],
                    endpointDetailsConfig["NotificationRecipients"]
                });
            }
    }
}

The values of the following are always null. Where am I going wrong here?

                endpointDetailsConfig["Url"],
                endpointDetailsConfig["Method"],
                endpointDetailsConfig["NotificationRecipients"]

Answers

Chosen as BEST ANSWER

So, after spending a day breaking my head on this issue, I finally came to the solution thanks to this post which was an eye-opener for me.

Basically you should not add nested configuration in your local.settings.json file, it creates all sorts of other issues(see below issue) when you do so. Hence, I moved my nested configuration into another file like so:

Missing value for AzureWebJobsStorage in local.settings.json. This is required for all triggers other than httptrigger, kafkatrigger, rabbitmqtrigger, orchestrationTrigger, activityTrigger, entityTrigger. You can run 'func azure functionapp fetch-app-settings ', specify a connection string in local.settings.json, or use managed identity to authenticate.

Configuration.json:

   {
     "EndpointDetails": {
          "GetAllTaskDetails": {
            "Url": "https://localhost:7000/api/Task/GetAllTaskDetails",
            "Method": "GET",
            "NotificationRecipients": "[email protected]"
          },
          "GetTaskDetails": {
            "Url": "https://localhost:7000/api/Task/GetTaskDetails",
            "Method": "GET",
            "NotificationRecipients": "[email protected]"
          }
        }
    }

And my Startup.cs class after necessary changes:

using Microsoft.Azure.Functions.Extensions.DependencyInjection;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;

[assembly: FunctionsStartup(typeof(HealthChecker.Startup))]
namespace HealthChecker
{
    public class Startup : FunctionsStartup
    {
        public override void Configure(IFunctionsHostBuilder builder)
        {
            var context = builder.GetContext();

            // Load configuration from local.settings.json
            var localConfig = new ConfigurationBuilder()
                .SetBasePath(context.ApplicationRootPath)
                .AddJsonFile("local.settings.json", optional: true, reloadOnChange: true)
                .AddEnvironmentVariables()
                .Build();

            // Load configuration from config.json
            var config = new ConfigurationBuilder()
                .SetBasePath(context.ApplicationRootPath)
                .AddJsonFile("configuration.json", optional: true, reloadOnChange: true)
                .AddEnvironmentVariables()
                .Build();

            // Register the configurations
            builder.Services.AddSingleton(localConfig);
            builder.Services.AddSingleton(config);

            // Registering health checks
            builder.Services.AddHealthChecks();

            // Calling the method that defines health checks
            HealthCheckDefinitions.ConfigureHealthChecks(builder.Services.AddHealthChecks(), localConfig, config);
        }
    }
}

And that's pretty much it. You can access these values easily wherever you want to, viz:

HealthCheckDefinitions.cs

public static class HealthCheckDefinitions
    {
     private static Dictionary<string, List<string>> endpointDetails = new Dictionary<string, List<string>>();

     public static void ConfigureHealthChecks(IHealthChecksBuilder builder, IConfiguration configuration){
       private static IConfigurationSection endpointDetailsListConfig;
       private static string getAllTaskDetails;
       private static string getTaskDetails;
       List<string> endpoints = new List<string>();
   
       var x = config["EndpointDetails:GetAllTaskDetails:Url"];
       //lines of code
       //...
 }

 //lines of code
 //...
}

Edit:

One more thing, please make sure that CopyToOutputDirectory is correctly set. Refer this if required. Below is my .csproj file:

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>net6.0</TargetFramework>
    <AzureFunctionsVersion>v4</AzureFunctionsVersion>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="AzureFunctions.Extensions.DependencyInjection" Version="1.1.3" />
    <PackageReference Include="Microsoft.Azure.Functions.Extensions" Version="1.1.0" />
    <PackageReference Include="Microsoft.Extensions.Diagnostics.HealthChecks" Version="6.0.0" />
    <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="6.0.0" />
    <PackageReference Include="Microsoft.NET.Sdk.Functions" Version="4.1.1" />
  </ItemGroup>
  <ItemGroup>
    <None Update="configuration.json">
        <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
        <CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>
    </None>
    <None Update="host.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
    </None>
    <None Update="local.settings.json">
        <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
        <CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>
    </None>
  </ItemGroup>
</Project>

I tried to give all the steps that I followed to fix this issue, hope it helps!

(Edit)

- AstridE
- July 7, 2023 at 7:38 pm
- 0 votes
0
In your local.settings.json file, "GetAllTaskDetails" and "GetTaskDetails" exist here:
```
{
  "Values": {
    "EndpointDetails": {
      "GetAllTaskDetails": {
        ...
      },
      "GetTaskDetails": {
        ...
      }
    }
  }
}
```
I.e. at these paths:

"Values:EndpointDetails:GetAllTaskDetails"
"Values:EndpointDetails:GetTaskDetails"

By setting
```
endpointDetailsListConfig = configuration.GetSection("EndpointDetails");
```
, you try to target a section that is not at the config root level. Hence, the return value of GetSection() should not be an actual configuration section.

As per the .GetSection() documentation:

This method will never return null. If no matching sub-section is found with the specified key, an empty IConfigurationSection will be returned.

Side note:
To verify whether a section (or value) exists or not, call .Exists() on .GetSection()‘s return value.

If you rather target "Values:EndpointDetails", you should be able to traverse the tree correctly from there:
```
endpointDetailsListConfig = configuration.GetSection("Values:EndpointDetails");
```
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Asp.net – Reading Nested Configuration from Azure Function App

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