bug: init-tracing-opentelemetry >0.26 fails to compile with tls feature

[dpasirst]

I have not had a chance to investigate but wanted to share: upgraded version from 0.26 to 0.28 and it now has this error:

error[E0433]: failed to resolve: use of unresolved module or unlinked crate `tonic`
 --> .cargo/registry/src/index.crates.io-1949cf8c6b5b557f/init-tracing-opentelemetry-0.28.0/src/otlp.rs:4:43
  |
4 | use {opentelemetry_otlp::WithTonicConfig, tonic::transport::ClientTlsConfig};
  |                                           ^^^^^ use of unresolved module or unlinked crate `tonic`
  |

I'm not sure what has changed, but I'm reverting my side to 0.26 for now.

[davidB]

The tonic dependency becomes optional, but tls means grpc+tls, but the tonic dependency was not added to the feature.
I'll try to publish a fix tomorrow.

[davidB]

I'm not able to reproduce. I also used cargo hack to test against several features configuration.
FYI tonic is a transitive dependency of opentelemetry-otlp (it's why the crates doesn't need to explicitly add it for feature)

❯ cargo tree --features tls -i tonic
tonic v0.12.3
├── opentelemetry-otlp v0.29.0
│   └── init-tracing-opentelemetry v0.28.0 (/mnt/nvme0n1p1/david/src/github.com/davidB/tracing-opentelemetry-instrumentation-sdk/init-tracing-opentelemetry)
└── opentelemetry-proto v0.29.0
    └── opentelemetry-otlp v0.29.0 (*)

When you upgrade init-tracing-opentelemetry, did you upgrade opentelemetry accordingly (if you declare it explicitly)?

Reminder: Having multiple versions of opentelemetry generates troubles.
see https://github.com/davidB/tracing-opentelemetry-instrumentation-sdk/tree/main/init-tracing-opentelemetry#troubleshot-why-no-trace

[dpasirst]

I'm not able to reproduce. I also used cargo hack to test against several features configuration. FYI tonic is a transitive dependency of opentelemetry-otlp (it's why the crates doesn't need to explicitly add it for feature)

I will try to reproduce it later today.

[dpasirst]

some findings:
It seems that tls by itself works; however, when combined with other features such as otlp or tracing_subscriber_ext, the issue is triggered. This was not a problem with 0.26.

How to repro:
for reference: rustc 1.87.0 (17067e9ac 2025-05-09) on macOS but when I first reported this, I was on an older version of rustc.

$ cargo init init-tracing-opentelemetry-repro

Cargo.toml

[package]
name = "init-tracing-opentelemetry-repro"
version = "0.1.0"
edition = "2024"

[dependencies]
axum = { version = "0.8.4" }
axum-tracing-opentelemetry = "0.28.0"
tokio = { version = "1.45.0", features = ["full"] }
tracing = { version = "0.1.41", features = ["log"] }
tracing-subscriber = { version = "0.3.19", features = ["env-filter", "std"] }
init-tracing-opentelemetry = { version = "0.28.1", features = [
    "otlp",
    "tracing_subscriber_ext",
    "tls",
] }
tracing-opentelemetry-instrumentation-sdk = { version = "0.28.1", features = [
    "http",
] }
opentelemetry = { version = "0.29.1", features = ["metrics"] }

main.rs

use axum::{response::Html, routing::get, Router};

#[tokio::main]
async fn main() {
    // build our application with a route
    let app = Router::new().route("/", get(handler));

    // run it
    let listener = tokio::net::TcpListener::bind("127.0.0.1:3000")
        .await
        .unwrap();
    println!("listening on {}", listener.local_addr().unwrap());
    axum::serve(listener, app).await.unwrap();
}

async fn handler() -> Html<&'static str> {
    Html("<h1>Hello, World!</h1>")
}

Not sure if this part is helpful:

$ cargo tree -p init-tracing-opentelemetry -i tonic
tonic v0.12.3
├── opentelemetry-otlp v0.29.0
│   └── init-tracing-opentelemetry v0.28.1
│       └── init-tracing-opentelemetry-repro v0.1.0 (./init-tracing-opentelemetry-repro)
└── opentelemetry-proto v0.29.0
    └── opentelemetry-otlp v0.29.0 (*)

$ cargo build
   Compiling init-tracing-opentelemetry v0.28.1
error[E0433]: failed to resolve: use of unresolved module or unlinked crate `tonic`
 --> .cargo/registry/src/index.crates.io-1949cf8c6b5b557f/init-tracing-opentelemetry-0.28.1/src/otlp.rs:4:43
  |
4 | use {opentelemetry_otlp::WithTonicConfig, tonic::transport::ClientTlsConfig};
  |                                           ^^^^^ use of unresolved module or unlinked crate `tonic`
  |
  = help: if you wanted to use a crate named `tonic`, use `cargo add tonic` to add it to your `Cargo.toml`

For more information about this error, try `rustc --explain E0433`.
error: could not compile `init-tracing-opentelemetry` (lib) due to 1 previous error

[davidB]

Thank you for the steps to reproduce.
The fix is released on init-tracing-opentelemetry-0.28.2