Support Activity.Tags

[lmolkova]

Activity.Tags is a property bag with string key value pairs. Tags only belong to current activity and does not flow to the child activities (internal or external).

ApplicationInsights should copy them to telemetry properties

Note that Tags should be copied only to the operation that is represented by current Activity and not to the nested telemetries tracked in scope of this operation.

[lmolkova]

If it will be decided to tag telemetry with all parents Activities tags, similar to

var activity = Activity.Current;
while (activity != null) {
   // set all tags on telemetry
  activity = activity.Parent;
}

such code may introduce endless loop if the stack of activities is broken (contains a cycle). Here https://github.com/aspnet/Microsoft.AspNet.TelemetryCorrelation/pull/23 we have introduced a hard limit on nested Activities (128) to protect from this hypothetical issue.

While it does not seem to be possible now, it's likely that Activity.Current setter will become public and we should expect any kinds of weird stacks in future.

[TimothyMothra]

@lmolkova Do you want to address this within 2.7 milestone or assign to "Future" ?

[Expecho]

@lmolkova , @TimothyMothra I just noticed that inside a .Net Core 3.1 based Azure Function this is already happening. Given the code below a custom property is added to the request telemetry.

        [FunctionName("HttpTriggered")]
        public IActionResult Run(
            [HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest req)
        {
            Activity.Current.AddTag("aTag", "aValue");
            return new OkResult();
        }

when I tried the same inside a web api controller hosted in an azure web app it does not work. What is the status of this issue?

[cijothomas]

This is supported in Azure Functions, but not in the main ApplicationInsights SDK shipped from this repo. At this stage the recommendation is to write own TelemetryInitializer to populate Activity.Tags into ITelemetry.Properties.

There will be tighter integration between Activity and ApplicationInsights (via OpenTelemetry), I believe this would be addressed in the future, but not planned for 2020.

[cijothomas]

@Expecho Did you use Activity.Current.AddTag("aTag", "aValue"); as a way to add custom properties to an auto-collected telemetry in codeless attach? (There might be support for this coming in a future version of codeless attach, though there is no timeline to this yet)

[Expecho]

@Expecho Did you use Activity.Current.AddTag("aTag", "aValue"); as a way to add custom properties to an auto-collected telemetry in codeless attach? (There might be support for this coming in a future version of codeless attach, though there is no timeline to this yet)

I use it to add custom properties with values that are not accessible inside a TelemetryInitializer.

[cijothomas]

Got it... Can you give example of such values.. Where are you retrieving it?

[cijothomas]

Since you are using SDK, the following can also work.

var telemetry = httpContext?.Features.Get<RequestTelemetry>();
if (telemetry != null)
{
   telemetry.Properties.Add("key", "value");
}
                

[Expecho]

Since you are using SDK, the following can also work.

var telemetry = httpContext?.Features.Get<RequestTelemetry>();
if (telemetry != null)
{
   telemetry.Properties.Add("key", "value");
}
                

Yes, I know. But this does not work in an EventGrid event triggered Azure Function for example, because there is no http context/request we can access.

I am about to give a demo to some collegues about how to enrich telemetry and copied some code from an azure function and realized it did not work based on Activity.Current. Then I tried to find out where this difference of behavior comes from. Now I know :-)

For azure functions we will stick to Activity when we have no request/context available and for all other cases we use ttpContext?.Features.

Sometimes we want to have those properties attached to all telemetry so it easier to query. For example, say we have an exception in some eventgrid triggered azure function. It is easies to know which event caused it by looking at the eventid custom property than to first have to find the request that triggered the processing.

[cijothomas]

Just listing down current state:

1. For SDK usage in non-Functions - have to write own initializer, and copy things from Activity.Tags manually to Property.
2. Azure Functions does Tags -> Properties automatically.
3. Codeless - no option to add additional property exists today.

I totally understand the use case :) Not planning to make any changes to SDK now to handle this, but this would be covered when we do OpenTelemetry integration, when Activity will be used for representing every operation.

[SeanFeldman]

Just listing down current state:

1. For SDK usage in non-Functions - have to write own initializer, and copy things from Activity.Tags manually to Property.
2. Azure Functions does Tags -> Properties automatically.
3. Codeless - no option to add additional property exists today.

I'm using Azure Functions (v3, netcoreapp3.1, Microsoft.Azure.WebJobs.Logging.ApplicationInsights 3.0.18), adding Tag and Baggage and it doesn't work, @cijothomas. Despite the second item in the list, saying it should work. Do I need to follow the suggestion of writing my own TelemetryInitializer?

[cijothomas]

@SeanFeldman If you are facing issues with Functions integration with ApplicationInsihgts, please open an issue in the Functions repo. https://github.com/Azure/azure-webjobs-sdk

[Expecho]

@SeanFeldman are you sure it does not work? Because I confirmed this to be working some time ago, see https://github.com/Ibis-Software/AppInsightsDemo/blob/master/src/FunctionApp/HttpTriggered.cs

[SeanFeldman]

@Expecho I'm not tracking custom events. In my Service Bus triggered Function, I'm logging and expect to see those tags to be added to the custom dictionary entries on the log statement captured with traces. At some point in time, it was working just fine (Tags and Baggage) but then it stopped.

I'll create a stand-alone repro to see if I can repeat it in a fresh project and raise an issue in https://github.com/Azure/azure-webjobs-sdk, just like @cijothomas has recommended.

[simonness]

Just to echo what @SeanFeldman said, I recently added a reference to Microsoft.ApplicationInsights 3.0.18 to a Azure Functions v3 project and Activity Tags added in HTTP Trigger Functions that were ending up in the Custom Properties of Requests in application insights are no longer.

I notice in @Expecho's example, Microsoft.Azure.WebJobs.Logging.ApplicationInsights 3.0.18 is being referenced, which depends on Microsoft.ApplicationInsights 3.0.14. Indeed when I downgrade Microsoft.ApplicationInsights to 3.0.14 things start working again.

It therefore feels like there's been a breaking change somewhere between 3.0.14 and 3.0.18 of Microsoft.ApplicationInsights?

[Zenuka]

I'm also having troubles with using Activity.Current in an Azure function. I've created a bug here: https://github.com/Azure/azure-webjobs-sdk/issues/2761

[kosperera]

How does this work with the Azure Functions v4 net6 isolated approach? Especially in the Middleware? I get a Null Reference Exception when I tried context.Features.Get<RequestTelemetry>() or Activity.Current.AddTag() or Activity.Current.AddBaggage().

[cijothomas]

How does this work with the Azure Functions v4 net6 isolated approach? Especially in the Middleware? I get a Null Reference Exception when I tried context.Features.Get<RequestTelemetry>() or Activity.Current.AddTag() or Activity.Current.AddBaggage().

If you are facing issues with Functions integration with ApplicationInsihgts, please open an issue in the Functions repo. https://github.com/Azure/azure-webjobs-sdk

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