Support CosmosDb dependency tracking

[lmolkova]

Cosmos DB SDK (Microsoft.Azure.Cosmos v3.TODO now supports dependency tracking, even when used in Direct (TCP) mode.

You should see DependencyTelemetry reported for all public API calls (that involve network communication with the service). If you use Gateway (HTTP) mode, you would also see dependencies for underlying HTTP calls. For Direct calls, you might see a few nested HTTP dependencies too, but low-level TCP calls are not traced.

Attributes reported by Cosmos SDK can be found here: Azure/azure-cosmos-dotnet-v3#3058. They are populated as custom dimensions.

New dependencies tracing public API calls should have:

• Target following {CosmosDB resource name} | {database name} pattern, e.g. cosmos-tracing-demo | my-store.
• Name follows {container name} | {operation} pattern, e.g. orders | Read
• Type matches Resource Provider namespace (Microsoft.DocumentDB)
• And sdkversion matches rdddsaz.

You can enable distributed tracing for Cosmos with the following API: TODO, add a link to cosmos docs.

In addition to dependency calls, Cosmos DB reports extensive diagnostics when an operation fails or takes too long. You can configure it with the following settings on the Cosmos DB client - TODO.
This diagnostics is sent as a log (TraceTelemetry) with Warning severity having CosmosDiagnostics as JSON in the message. You can identify it using EventName (in custom dimensions) with the RecordDiagnosticsForRequests value.
Such TraceTelemetry should be a child of Cosmos DB dependency telemetry described above.

Changes

CosmosDB direct (TCP mode) dependency tracking (coming in future versions of Cosmos DB v3 SDK).
Uses attributes outlined here and additional cosmos diagnostics is coming from the specific event source and is tracked as TraceTelemetry.

EventSource verbosity is expected to be low - it will be controlled by CosmosDb customers on CosmosDb side. Cosmos would write it when an operation takes longer than a configurable threshold or when an error happens.

Checklist

• CHANGELOG.md updated with one line description of the fix, and a link to the original issue if available.

Notes for reviewers:

• We support comment build triggers
  • /AzurePipelines run will queue all builds
  • /AzurePipelines run <pipeline-name> will queue a specific build

[lmolkova]

/cc @sourabh1007

[sourabh1007]

Why PR headline talk about Cosmos DB "Direct Mode"? is it connection mode specific changes?

[sourabh1007]

Events are loosing diagnostics message while listened by appinsight..below is the log I got

Application Insights Telemetry: {"name":"AppTraces","time":"2022-09-23T17:42:26.1395222Z","iKey":"2fabff39-6a32-42da-9e8f-9fcff7d99c6b","tags":{"ai.application.ver":"1.0.0.0","ai.cloud.roleInstance":"DESKTOP-I8MO142","ai.operation.id":"2239023b88bb44b60eab840e1983cded","ai.operation.parentId":"80155111011166ad","ai.internal.sdkVersion":"dotnetc:2.22.0-14","ai.internal.nodeName":"DESKTOP-I8MO142"},"data":{"baseType":"MessageData","baseData":{"ver":2,"message":"n/a","severityLevel":"Warning","properties":{"EventName":"WriteWarningEvent","EventId":"2","AspNetCoreEnvironment":"Development","DeveloperMode":"true","CategoryName":"Azure.Cosmos"}}}}

Cosmosdb SDK doesn't send n/a.

[lmolkova]

Events are loosing diagnostics message while listened by appinsight..below is the log I got

Fixed, please check

[sourabh1007]

with latest changes, things are looking good except one minor thing i.e. I am seeing cosmosdb text instead of cosmosdb icon (like we were getting previously)

[lmolkova]

with latest changes, things are looking good except one minor thing i.e. I am seeing cosmosdb text instead of cosmosdb icon (like we were getting previously)

for this we need portal team to support Azure CosmosDB (in addition to DocumentDB) - there is nothing I can do on SDK side

[sourabh1007]

with latest changes, things are looking good except one minor thing i.e. I am seeing cosmosdb text instead of cosmosdb icon (like we were getting previously)

for this we need portal team to support Azure CosmosDB (in addition to DocumentDB) - there is nothing I can do on SDK side

but previously this icon was coming. in this latest package only it is not showing up

[sourabh1007]

Looks fine to me. Thanks :)

[reyang]

LGTM.

[cijothomas]

LGTM, left few minor comments.
Given we do not have true e2e tests, would you update the PR description (or a new issue), to act as the documentation for this enhancement? To answer potential customer/support questions like:
What is the min version of CosmosDb package required?
Whether this works for TCP mode as well? Would we see duplicate if Http mode is used?
Also add a note that TraceTelemetry is produced for certain scenarios (this is unusual compared to other dependencies collected automatically)
How are target/name populated?

"rdddsaz" would be the sdkversion I assume..

[lmolkova]

Thank you @reyang and @cijothomas for the review! I believe I addressed all the feedback in the code. PTAL.

As for documentation, I updated the description on this PR, just need to add a few details.

@sourabh1007, can you please help us clarify the following:

• Exact Cosmos DB version that supports tracing
• Is there an example on how to enable and configure tracing? Can you share it or provide a link to existing samples/docs, anything?

Thanks!