Document need of `opentelemetry::global::shutdown_tracer_provider()`?

[alexpdp7]

Feature Request

Motivation

I was playing with tracing and OpenTelemetry and I was noticing that under some conditions, my test applications were not sending traces at all.

Looking at one of the examples, I saw opentelemetry::global::shutdown_tracer_provider(). Adding this at the end of my program made things work reliably (apparently!).

I think this is related to very short programs that run quickly. Somehow accumulated traces are lost on exit.

Proposal

While this is documented in the opentelemetry crate, and I found it in the examples, I think users of this crate would appreciate some nudging towards this.

Alternatives

Or perhaps, the shutdown can happen automatically? That would be even better.

[jonefeewang]

In my case, it's quite the opposite. This call has had no effect whatsoever. The application exits quickly after receiving a SIGINT, and no span is exported—I can clearly sense it. The program must wait for 10 seconds upon exit to ensure the export of spans.

My initialization method is identical to the one provided in the project's example: opentelemetry-otlp.rs.
My operating environment:

docker run -d -p4317:4317 -p16686:16686 jaegertracing/all-in-one:latest

opentelemetry = { version = "0.25", features = ["trace", "metrics"] }
opentelemetry_sdk = { version = "0.25", default-features = false, features = [
"trace",
"rt-tokio",
] }
opentelemetry-stdout = { version = "0.25", features = ["trace", "metrics"] }
opentelemetry-otlp = { version = "0.25", features = ["metrics"] }
opentelemetry-semantic-conventions = "0.25"
tracing-subscriber = { version = "0.3.0", default-features = false, features = [
"registry",
"std",
"fmt",
"chrono",
"env-filter",
"ansi",
"tracing-log",
] }
tracing-opentelemetry = "=0.26.0"
tracing-core = "0.1.28"

[mladedav]

If you send a SIGINT and don't handle it, shutdown_tracer_provider is never called so it's somewhat expected the spans weren't exported. Or am I misunderstanding what you were trying to say?

[TheButlah]

I also had to call shutdown_tracer_provider in quick programs - for example, with a simple example binary that doesn't block on anything