Update README for more info on logging & update opentracing deps

Cargo.toml

@@ -18,8 +18,8 @@ derive_more = "0.99"
 futures = "0.3"
 itertools = "0.10"
 once_cell = "1.5"
-opentelemetry-jaeger = "0.11"
-opentelemetry = "0.12"
+opentelemetry-jaeger = "0.12"
+opentelemetry = { version = "0.13", features = ["rt-tokio"] }
 parking_lot = "0.11"
 prost = "0.7"
 prost-types = "0.7"
@@ -28,7 +28,7 @@ thiserror = "1.0"
 tokio = { version = "1.1", features = ["rt", "rt-multi-thread", "parking_lot"] }
 tracing = { version = "0.1", features = ["log"] }
 tracing-futures = "0.2"
-tracing-opentelemetry = "0.11"
+tracing-opentelemetry = "0.12"
 tracing-subscriber = "0.2"
 url = "2.2"
 rand = "0.8.3"

README.md

@@ -32,16 +32,6 @@ We are using [clippy](https://github.com/rust-lang/rust-clippy) for linting.
 You can run it using:
 `cargo clippy --all -- -D warnings`
 
-## Style Guidelines
-
-### Error handling
-Any error which is returned from a public interface should be well-typed, and we use 
-[thiserror](https://github.com/dtolnay/thiserror) for that purpose.
-
-Errors returned from things only used in testing are free to use 
-[anyhow](https://github.com/dtolnay/anyhow) for less verbosity.
-
-
 ## Debugging
 The crate uses [tracing](https://github.com/tokio-rs/tracing) to help with debugging. To enable
 it for a test, insert the below snippet at the start of the test. By default, tracing data is output
@@ -54,4 +44,22 @@ let _enter = s.enter();
 ```
 
 To run the Jaeger instance:
-`docker run --rm -p6831:6831/udp -p6832:6832/udp -p16686:16686 jaegertracing/all-in-one:latest`
+`docker run --rm -p6831:6831/udp -p6832:6832/udp -p16686:16686 jaegertracing/all-in-one:latest`
+
+To show logs in the console, set the `RUST_LOG` environment variable to `temporal_sdk_core=DEBUG`
+or whatever level you desire. The env var is parsed according to tracing's 
+[EnvFilter](https://docs.rs/tracing-subscriber/latest/tracing_subscriber/struct.EnvFilter.html)
+rules.
+
+If you are working on a language SDK, you are expected to initialize tracing early in your `main`
+equivalent.
+
+## Style Guidelines
+
+### Error handling
+Any error which is returned from a public interface should be well-typed, and we use 
+[thiserror](https://github.com/dtolnay/thiserror) for that purpose.
+
+Errors returned from things only used in testing are free to use 
+[anyhow](https://github.com/dtolnay/anyhow) for less verbosity.
+

src/core_tracing.rs

@@ -1,18 +1,17 @@
 use itertools::Itertools;
-use once_cell::sync::OnceCell;
-use opentelemetry_jaeger::Uninstall;
-use std::collections::VecDeque;
-use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt, EnvFilter};
+use std::{collections::VecDeque, sync::Once};
+use tracing_subscriber::util::SubscriberInitExt;
+use tracing_subscriber::{layer::SubscriberExt, EnvFilter};
 
-static TRACING_INIT: OnceCell<Uninstall> = OnceCell::new();
+static TRACING_INIT: Once = Once::new();
 
 /// Initialize tracing subscribers and output. Core will not call this itself, it exists here so
 /// that consumers and tests have an easy way to initialize tracing.
 pub fn tracing_init() {
-    TRACING_INIT.get_or_init(|| {
-        let (tracer, uninstall) = opentelemetry_jaeger::new_pipeline()
+    TRACING_INIT.call_once(|| {
+        let tracer = opentelemetry_jaeger::new_pipeline()
             .with_service_name("coresdk")
-            .install()
+            .install_batch(opentelemetry::runtime::Tokio)
             .unwrap();
         let opentelemetry = tracing_opentelemetry::layer().with_tracer(tracer);
         let filter_layer = EnvFilter::try_from_default_env()
@@ -26,7 +25,6 @@ pub fn tracing_init() {
             .with(fmt_layer)
             .try_init()
             .unwrap();
-        uninstall
     });
 }