[SVLS-6337] Shut down trace agent if resource group can't be determined

[kathiehuang]

What does this PR do?

Adds a check to see if we are in an Azure function that is on the flex consumption plan and doesn't have the DD_AZURE_RESOURCE_GROUP env var set. If so, shut down the trace agent.

• We updated the libdatadog Azure metadata detection logic to check for the env var similarly
• We also plan to update the serverless-compat layers to check for these env vars too for defense in depth.

Motivation

• Currently the aas.resource.group span attribute for functions on flex consumption plans is set incorrectly in Datadog - they're all set to "flex"
  • This is important to fix because aas.resource.id is built using aas.resource.group, and the resource id is used in billing, which needs to be accurate
  • We had to figure out what to do if a customer who is using Datadog to monitor their Azure function on a flex consumption plan doesn't set the DD_AZURE_RESOURCE_GROUP env var. Rather than handling that in libdatadog, we decided to do it at a higher level in the trace agent to inform the customer of the error while shutting down the trace agent gracefully and preventing any traces from being sent to Datadog

Jira Ticket

Describe how to test/QA your changes

1. Update the commit hash in datadog-trace-agent/Cargo.toml
   everywhere that libdatadog is used to the most recent commit hash of the PR in libdatadog (currently d1b35ef21fff3c4588073504905081c8923bbc4b)
2. Follow the instructions in the Serverless Compatability Layer docs to build the Rust binary
3. Deploy an Azure function on flex consumption plan using the terraform tool, setting use_serverless_compat_local_path to true and making sure the built binary is in your python folder
4. Hit an endpoint in your function or wait a minute for the invoker to invoke your function and check the Datadog traces for your function. Without the DD_AZURE_RESOURCE_GROUP env var, you should see no traces. Check the logs in Azure Portal - you should see an error log with the message "ERROR: Resource group not found. If you are using Azure Functions on Flex Consumption plan, please add your resource group name as an environment variable called DD_AZURE_RESOURCE_GROUP in Azure app settings."
5. Go to Settings > Environment Variables in the Azure Portal for your function and add DD_AZURE_RESOURCE_GROUP as an environment variable with your resource group. Repeat step 4, you should see the correct resource group in the resource.group span attribute!

Expected error without DD_AZURE_RESOURCE_GROUP, no traces sent to DD:

With DD_AZURE_RESOURCE_GROUP - traces sent to DD with the correct resource group/id.

[lucaspimentel]

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. More of your lovely PRs please.

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[kathiehuang]

@codex review

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[kathiehuang]

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Keep it up!

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[apiarian-datadog]

what log level does this use? what amount of logging would it cause?

[kathiehuang]

I was following the pattern of how other parts of this file handles errors, but I'm a little confused because in the Azure logs, the error is being mapped to a severityLevel of 1, but Azure docs says errors should be severity level 3.

For amount of logging, it seems like it logs this error whenever the Azure Function app instance starts (happens a couple logs after "Initializing Warm up Extension"). But it seems like the trace agent keeps trying to restart so a lot of logs get outputted that look like these:

I'm a little bit confused but happy to call about this!

[duncanpharvey]

LGTM!