chore: move tracing-opentelemetry to its own repo (#2523)

This PR removes tracing-opentelemetry to a dedicated repo located at
https://github.com/tokio-rs/tracing-opentelemetry. (Note that at time of
writing this PR, the new repo has not be made public). We're moving
tracing-opentelemetry to a dedicated repository for the following
reasons:
1. opentelemetry's MSRV is higher than that of `tracing`'s.
2. more importantly, the main `tracing` repo is getting a bit unweildy
   and it feels unreasonable to maintain backports for crates that
   integrate with the larger tracing ecosystem.

(https://github.com/tokio-rs/tracing-opentelemetry does not have the
examples present in this repo; this will occur in a PR that will be
linked from _this_ PR.)

.github/CODEOWNERS

@@ -8,8 +8,5 @@
 # David contributed the Registry implementation.
 /tracing-subscriber/registry    @davidbarsky @hawkw @tokio-rs/tracing
 
-# Julian contributed the OpenTelemetry implementation.
-/tracing-opentelemetry/    @jtescher @tokio-rs/tracing
-
 # Zeki contributed the TracingAppender implementation
 /tracing-appender/              @zekisherif  @tokio-rs/tracing

.github/workflows/CI.yml

@@ -133,17 +133,11 @@ jobs:
         - tracing-macros
         - tracing-serde
         - tracing-tower
-        - tracing-opentelemetry
         - tracing
         - tracing-subscriber
     steps:
     - uses: actions/checkout@v3
-    - uses: actions-rs/toolchain@v1
-      with:
-        toolchain: stable
-        profile: minimal
-        override: true
-
+    - uses: dtolnay/rust-toolchain@stable
     - name: install cargo-hack
       uses: taiki-e/install-action@cargo-hack
     - name: cargo hack check
@@ -194,7 +188,6 @@ jobs:
         - tracing-serde
         - tracing-subscriber
         - tracing-tower
-        - tracing-opentelemetry
         - tracing
         toolchain:
         - 1.49.0
@@ -295,7 +288,6 @@ jobs:
         - tracing-journald
         - tracing-log
         - tracing-macros
-        - tracing-opentelemetry
         - tracing-serde
         - tracing-subscriber
         - tracing-tower

Cargo.toml

@@ -11,7 +11,6 @@ members = [
     "tracing-log",
     "tracing-macros",
     "tracing-mock",
-    "tracing-opentelemetry",
     "tracing-subscriber",
     "tracing-serde",
     "tracing-appender",

README.md

@@ -305,11 +305,6 @@ The crates included as part of Tracing are:
 
 * [`tracing-log`]: Compatibility with the `log` crate (unstable).
 
-* [`tracing-opentelemetry`]: Provides a layer that connects spans from multiple
-  systems into a trace and emits them to [OpenTelemetry]-compatible distributed
-  tracing systems for processing and visualization.
-  ([crates.io][otel-crates]|[docs][otel-docs])
-
 * [`tracing-serde`]: A compatibility layer for serializing trace data with
     `serde` (unstable).
 
@@ -337,7 +332,6 @@ The crates included as part of Tracing are:
 [`tracing-macros`]: tracing-macros
 [`tracing-attributes`]: tracing-attributes
 [`tracing-log`]: tracing-log
-[`tracing-opentelemetry`]: tracing-opentelemetry
 [`tracing-serde`]: tracing-serde
 [`tracing-subscriber`]: tracing-subscriber
 [`tracing-tower`]: tracing-tower

examples/Cargo.toml

@@ -21,9 +21,8 @@ tracing-futures = { version = "0.2.1", path = "../tracing-futures", features = [
 tracing-attributes = { path = "../tracing-attributes", version = "0.1.22" }
 tracing-log = { path = "../tracing-log", version = "0.1.3", features = ["env_logger"] }
 tracing-serde = { path = "../tracing-serde" }
-tracing-opentelemetry = { path = "../tracing-opentelemetry" }
-tracing-journald = { path = "../tracing-journald" }
 tracing-appender = { path = "../tracing-appender", version = "0.2.0" }
+tracing-journald = { path = "../tracing-journald" }
 
 # serde example
 serde_json = "1.0.82"
@@ -51,10 +50,6 @@ log = "0.4.17"
 inferno = "0.11.6"
 tempfile = "3"
 
-# opentelemetry example
-opentelemetry = { version = "0.18.0", default-features = false, features = ["trace"] }
-opentelemetry-jaeger = "0.17.0"
-
 # fmt examples
 snafu = "0.6.10"
 thiserror = "1.0.31"

examples/README.md

@@ -72,12 +72,6 @@ This directory contains a collection of examples that demonstrate the use of the
     unstructured logs from dependencies as `tracing` events, by instrumenting
     [this example][echo] from `hyper`, and using `tracing-log` to record logs
     emitted by `hyper`.
-- **tracing-opentelemetry**:
-  + `opentelemetry`: Demonstrates how `tracing-opentelemetry` can be used to
-    export and visualize `tracing` span data.
-  + `opentelemetry-remote-context`: Demonstrates how `tracing-opentelemetry`
-    can be used to extract and inject remote context when traces span multiple
-    systems.
 
 [tasks]: (https://docs.rs/tokio/0.2.21/tokio/task/index.html)
 [tokio-proxy]: https://github.com/tokio-rs/tokio/blob/v0.1.x/tokio/examples/proxy.rs