How do I view Log analytics data in application insights

Question

How do I view Log analytics data in application insights

charlie curtis 0

I have created a Log analytics workspace and App Insights instance for a Function App (.net 9).

Records are being created from the FA in the workspace. I can see them

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Problem is, nothing is showing in App Insights. I have tried creating a new instance of App Insights, but still blank

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What have i done wrong?

program.cs in FA:

using Microsoft.Azure.Functions.Worker;

using Microsoft.Azure.Functions.Worker.Builder;

using Microsoft.Extensions.Configuration;

using Microsoft.Extensions.DependencyInjection;

using Microsoft.Extensions.Hosting;

using Microsoft.Extensions.Logging;

var builder = FunctionsApplication.CreateBuilder(args);

builder.ConfigureFunctionsWebApplication();

builder.Logging.Services.Configure

Muskan Tomar 555 Reputation points Microsoft Employee

2025-10-30T10:02:24.5866667+00:00

Hey,
The app insights isn't showing anything probably because it is not connected yet. Go to your function App -> Configuration -> Application settings and add the Application insight connection string.

Then try hitting the function and generating the logs
charlie curtis 0 Reputation points

2025-10-30T10:47:31.16+00:00
charlie curtis 0 Reputation points

2025-10-30T10:56:37.1066667+00:00

Was already set, should have mentioned that...
Siva shunmugam Nadessin 3,025 Reputation points Microsoft External Staff Moderator

2025-10-30T15:37:05.9466667+00:00
Hello charlie curtis,

Dump environment at startup (temporarily) to ensure the connection string was injected and see you are able to get value.

Console.WriteLine($"AI CS: {Environment.GetEnvironmentVariable("APPLICATIONINSIGHTS_CONNECTION_STRING")}");
charlie curtis 0 Reputation points

2025-10-30T16:18:41.1333333+00:00

it's there....

Taken direct from the Log anl workspace
Sina Salam 26,661 Reputation points Volunteer Moderator

2025-10-30T21:58:13.91+00:00

Hello charlie curtis,

Welcome to the Microsoft Q&A and thank you for posting your questions here.

I understand that you needed how to view Log analytics data in application insights.

To resolve the issue of telemetry not appearing in Application Insights for a .NET 9 isolated Azure Function App and with all you've done, you need to first confirm that the Application Insights resource is workspace-based and correctly linked to the same Log Analytics workspace where logs are already visible. This can be verified by navigating to Application Insights > Properties. For a reference

Next, instead of relying on the classic Application Insights UI, telemetry should be queried directly from the Logs (Analytics) section using Kusto Query Language (KQL). A basic query like traces | where timestamp > ago(1h) | order by timestamp desc helps confirm if telemetry is being ingested. - https://learn.microsoft.com/en-us/azure/azure-functions/analyze-telemetry-data

For .NET 9 isolated process functions, it’s critical to explicitly configure the Application Insights SDK in Program.cs. This includes adding builder.Services.AddApplicationInsightsTelemetryWorkerService(); and builder.Logging.AddApplicationInsights(); to ensure telemetry is properly captured and sent. For more details.

To validate that telemetry is reaching Application Insights, tools like Fiddler or SDK diagnostic logs can be used to inspect outgoing telemetry and confirm successful HTTP 200 responses from the ingestion endpoint. Check here for a reference

Additionally, if the Application Insights SDK is already configured, it’s advisable to disable Diagnostic Settings on the Function App to avoid redundant or conflicting telemetry streams. This helps prevent duplication and ensures clarity in data sources. Check this reference

Finally, to visualize telemetry effectively in a workspace-based Application Insights setup, you should also leverage Workbooks. These allow for custom dashboards and visualizations using KQL queries, providing a more tailored and insightful view of telemetry data. Check here too for a reference

I hope this is helpful! Do not hesitate to let me know if you have any other questions or clarifications.

Please don't forget to close up the thread here by upvoting and accept it as an answer if it is helpful.
Bharath Y P 2,560 Reputation points Microsoft External Staff Moderator

2025-10-31T05:46:20.14+00:00

Hello charlie curtis, could you confirm whether the solution provided by Sina resolved the issue? If you have any assistance, please let us know. thanks
charlie curtis 0 Reputation points

2025-11-01T10:28:27.7333333+00:00

Hi Bharath

We're working on it.
charlie curtis 0 Reputation points

2025-11-04T09:42:47.2966667+00:00

Hi Siva

Doesn't seem to have made any difference.

Nothing new in the Workspace logs, nothing new in App Insights logs, and nothing in the log stream.

Do you have a project that is working?

Regards

Charlie

Answer recommended by moderator

1 additional answer

Your answer

Muskan Tomar 555 Reputation points Microsoft Employee

2025-10-30T10:02:24.5866667+00:00

Hey,
The app insights isn't showing anything probably because it is not connected yet. Go to your function App -> Configuration -> Application settings and add the Application insight connection string.

Then try hitting the function and generating the logs
charlie curtis 0 Reputation points

2025-10-30T10:47:31.16+00:00
charlie curtis 0 Reputation points

2025-10-30T10:56:37.1066667+00:00

Was already set, should have mentioned that...
Siva shunmugam Nadessin 3,025 Reputation points Microsoft External Staff Moderator

2025-10-30T15:37:05.9466667+00:00

Hello charlie curtis,

Dump environment at startup (temporarily) to ensure the connection string was injected and see you are able to get value.

Console.WriteLine($"AI CS: {Environment.GetEnvironmentVariable("APPLICATIONINSIGHTS_CONNECTION_STRING")}");
charlie curtis 0 Reputation points

2025-10-30T16:18:41.1333333+00:00

it's there....

Taken direct from the Log anl workspace
Bharath Y P 2,560 Reputation points Microsoft External Staff Moderator

2025-10-31T05:46:20.14+00:00

Hello charlie curtis, could you confirm whether the solution provided by Sina resolved the issue? If you have any assistance, please let us know. thanks
charlie curtis 0 Reputation points

2025-11-01T10:28:27.7333333+00:00

Hi Bharath

We're working on it.
charlie curtis 0 Reputation points

2025-11-04T09:42:47.2966667+00:00

Hi Siva

Doesn't seem to have made any difference.

Nothing new in the Workspace logs, nothing new in App Insights logs, and nothing in the log stream.

Do you have a project that is working?

Regards

Charlie

Answer 1

charlie curtis 0

Sorted. partly down to my code, fixed as abouve

and a bad bicep file.

was


resource
	name
	location
	kind
	properties
		Application_Type
		RetentionInDays
		WorkspaceResourceId
		IngestionMode
		publicNetworkAccessForIngestion
		publicNetworkAccessForQuery
		DisableLocalAuth
	}
}

Should have been:

resource components_AppInsight 'microsoft.insights/components@2020-02-02' = {
  name: components_AppInsight_name
  location: rgLocation
  kind: 'web'
  properties: {
    Application_Type: 'web'
    RetentionInDays: 30
    WorkspaceResourceId: workspaces_log.id
    IngestionMode: 'LogAnalytics'
    publicNetworkAccessForIngestion: 'Enabled'
    publicNetworkAccessForQuery: 'Enabled'
    DisableLocalAuth: false
    Flow_Type: 'Redfield'
    Request_Source: 'IbizaAIExtension'
  }
}

charlie curtis 0

Final program.cs looked like this. might not be perfect, but it works

using Microsoft.Azure.Functions.Worker;
using Microsoft.Azure.Functions.Worker.Builder;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
//https://learn.microsoft.com/en-us/azure/azure-functions/dotnet-isolated-process-guide
var builder = FunctionsApplication.CreateBuilder(args);
builder.ConfigureFunctionsWebApplication();
builder.Logging.AddConsole();
builder.Logging.AddApplicationInsights();
builder.Services
    .AddApplicationInsightsTelemetryWorkerService()
    .AddTransient<IRefData>(_ => new RefData(conString))
    .ConfigureFunctionsApplicationInsights()
    .AddLogging(loggingBuilder =>
    {
        loggingBuilder.ClearProviders();
        loggingBuilder.AddApplicationInsights();
        // Set the minimum logging level to Information
        loggingBuilder.SetMinimumLevel(LogLevel.Information);
    });
builder.Logging.Services.Configure<LoggerFilterOptions>(options =>
{
    LoggerFilterRule defaultRule = options.Rules.FirstOrDefault(rule => rule.ProviderName
        == "Microsoft.Extensions.Logging.ApplicationInsights.ApplicationInsightsLoggerProvider");
    if (defaultRule is not null)
    {
        options.Rules.Remove(defaultRule);
    }
});
builder.Build().Run();

Answer 2

Hello charlie curtis,

In .NET 9 Azure Functions (isolated worker model) you need to fully wire logging to Application Insights manually as below code to get the logging pass to traces table.

builder.Services.AddLogging(logging =>
{
logging.ClearProviders(); 
logging.AddApplicationInsights(); 
logging.SetMinimumLevel(LogLevel.Information); 
});

Add the above code before and make sure all the logging comes after this.

builder.Build().Run();

In Host.json file.

Mark isEnabled to false as highlighted below

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What "isEnabled": false Does

Disables sampling entirely.
Ensures every log, request, exception, and dependency is sent to Application Insights.
Useful for debugging, testing, or auditing, where you want full visibility.

After making the changes deploy run your Azure Functions.

Validate Application Insights & Logs Analytics Workspace using below queries to see if logs are flowing as expected.

Application Insights Query

traces
| where timestamp > ago(1h)
| where message contains "<log string to validate>"
| order by timestamp desc

Logs Analytics Workspace Query

AppTraces
| where TimeGenerated > ago(1h)
| where Message contains "<log string to validate>"
| order by TimeGenerated desc

Reference Documents:

https://learn.microsoft.com/en-us/azure/azure-functions/dotnet-isolated-process-guide?tabs=ihostapplicationbuilder%2Cwindows#managing-log-levels

Kindly check and let us know if any questions?

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How do I view Log analytics data in application insights

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