Pull traces from the application

[Pragmateek]

The OT ecosystem is essentially push based: the apps/services are responsible for sending their telemetry signals to the OT infrastructure (a collector or directly a tool like Jaeger).

I have ASP.NET Core applications that are running in an isolated infrastructure (isolated database and network file-system) and above all no initiated egress (only response to HTTP requests) so no way to push telemetry data.
And no way to run Docker containers on the host or another one.

For metrics hopefully Prometheus is pull based, it is only a matter of binding a "metrics" endpoint.
But for traces I've not seen any pull based solution, but maybe I've missed some tools.

I've though of developping my own "push/pull inverter":

• collect the traces in the application,
• expose an endpoint (restricted to the dev team thanks to Windows Authentication),
• let a small forwarder run on our dev machines which would pull from it and push to Jaeger.

But I've not found any "clean" integration point:

• there is an in-memory exporter but it works at a high level with Activity objects, which I would need to process, especially serialize myself, and then I'm not sure if they can be easily reinjected in the forwarder local OT stack, to be pushed further down to Jaeger,
• I could intercept at the exit of the OT pipeline, with a custom HttpMessageHandler, but it looks quite hacky.

As a degraded solution I've looked for an ASP.NET Core integrated OT stack collecting telemetry data in memory and rendering them in an integrated dashboard, so all is done locally in the app.
Like Hangfire which is an integrated job runner with a management dashboard, no need for additional infrastructure, you just reference a NuGet package (not perfect of course as you must ensure the app is up when it's time to run the jobs).
But I've not found anything, maybe I've missed it, so if you have any package that could do the job please share.
I don't need a full fledged OT infrastructure, so I should be happy with a basic tool, though I prefer to rely on the "standard" tools like Jaeger.

Any input is welcome. 🙂

[Kielek]

I am not aware about any official protocol to handle this, but you could consider writing/exporting to the disk file? If so, there is a technical possibility to implement it based on this specification: https://opentelemetry.io/docs/specs/otel/protocol/file-exporter/

We do not have it yet and I am not aware that anybody is working on this.
Tracking issue: #5920

[Pragmateek]

Thanks for your response.
Unfortunately network file-systems are isolated, so we can't get the files from our dev machines.
I'll see what I can implement myself, and maybe ask to the Jaeger project itself.
Discussion on the Jaeger repository: Pull traces from an application.