From 21f6d7c9c6685202555a181d1606caa665b2e3aa Mon Sep 17 00:00:00 2001
From: Raphael Amorim <rapha850@gmail.com>
Date: Tue, 16 Jan 2024 14:10:34 +0100
Subject: [PATCH] remove generic propagator

---
 src/lib.rs | 106 ++---------------------------------------------------
 1 file changed, 4 insertions(+), 102 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index 885e5a0..9b9dacf 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -3,17 +3,12 @@
 // https://github.com/davidB/tracing-opentelemetry-instrumentation-sdk/blob/d3609ac2cc699d3a24fbf89754053cc8e938e3bf/LICENSE
 
 use opentelemetry_sdk::{
-    propagation::{
-        BaggagePropagator, TextMapCompositePropagator, TraceContextPropagator,
-    },
     resource::{OsResourceDetector, ResourceDetector},
     Resource,
 };
 use std::cmp::max;
 use tracing::Subscriber;
 use tracing_subscriber::fmt::writer::MakeWriterExt;
-
-use opentelemetry::{propagation::TextMapPropagator, trace::TraceError};
 use tracing_subscriber::{
     filter::LevelFilter, fmt::format::FmtSpan, layer::SubscriberExt,
     registry::LookupSpan, Layer,
@@ -144,7 +139,10 @@ pub fn init_tracing_with_fallbacks(
         DetectResource::new(fallback_service_name, fallback_service_version).build();
     let otel_tracer =
         otlp::init_tracer(otel_rsrc, otlp::identity).expect("setup of Tracer");
-    init_propagator().expect("setup of propagator");
+
+    opentelemetry::global::set_text_map_propagator(
+        propagation::TextMapSplitPropagator::default(),
+    );
 
     let level_filter: LevelFilter = max(log_level, tracing::Level::INFO).into();
     let subscriber = tracing_subscriber::registry()
@@ -177,99 +175,3 @@ macro_rules! init_tracing {
 pub fn shutdown_signal() {
     opentelemetry::global::shutdown_tracer_provider();
 }
-
-/// Configure the global propagator based on content of the env variable [OTEL_PROPAGATORS](https://opentelemetry.io/docs/concepts/sdk-configuration/general-sdk-configuration/#otel_propagators)
-/// Specifies Propagators to be used in a comma-separated list.
-/// Default value: `"tracecontext,baggage"`
-/// Example: `export OTEL_PROPAGATORS="b3"`
-/// Accepted values for `OTEL_PROPAGATORS` are:
-///
-/// - "tracecontext": W3C Trace Context
-/// - "baggage": W3C Baggage
-/// - "b3": B3 Single (require feature "zipkin")
-/// - "b3multi": B3 Multi (require feature "zipkin")
-/// - "xray": AWS X-Ray (require feature "xray")
-/// - "ottrace": OT Trace (third party) (not supported)
-/// - "none": No automatically configured propagator.
-///
-/// # Errors
-///
-/// Will return `TraceError` if issue in reading or instanciate propagator.
-pub fn init_propagator() -> Result<(), TraceError> {
-    let value_from_env = std::env::var("OTEL_PROPAGATORS")
-        .unwrap_or_else(|_| "tracecontext,baggage".to_string());
-    let propagators: Vec<(Box<dyn TextMapPropagator + Send + Sync>, String)> =
-        value_from_env
-            .split(',')
-            .map(|s| {
-                let name = s.trim().to_lowercase();
-                propagator_from_string(&name).map(|o| o.map(|b| (b, name)))
-            })
-            .collect::<Result<Vec<_>, _>>()?
-            .into_iter()
-            .flatten()
-            .collect();
-    if !propagators.is_empty() {
-        let (propagators_impl, propagators_name): (Vec<_>, Vec<_>) =
-            propagators.into_iter().unzip();
-        tracing::debug!(target: "otel::setup", OTEL_PROPAGATORS = propagators_name.join(","));
-        let composite_propagator = TextMapCompositePropagator::new(propagators_impl);
-        opentelemetry::global::set_text_map_propagator(composite_propagator);
-    }
-    Ok(())
-}
-
-#[allow(clippy::box_default)]
-fn propagator_from_string(
-    v: &str,
-) -> Result<Option<Box<dyn TextMapPropagator + Send + Sync>>, TraceError> {
-    match v {
-        "tracecontext" => Ok(Some(Box::new(TraceContextPropagator::new()))),
-        "baggage" => Ok(Some(Box::new(BaggagePropagator::new()))),
-        #[cfg(feature = "zipkin")]
-        "b3" => Ok(Some(Box::new(
-            opentelemetry_zipkin::Propagator::with_encoding(
-                opentelemetry_zipkin::B3Encoding::SingleHeader,
-            ),
-        ))),
-        #[cfg(not(feature = "zipkin"))]
-        "b3" => Err(TraceError::from(
-            "unsupported propagators form env OTEL_PROPAGATORS: 'b3', try to enable compile feature 'zipkin'"
-        )),
-        #[cfg(feature = "zipkin")]
-        "b3multi" => Ok(Some(Box::new(
-            opentelemetry_zipkin::Propagator::with_encoding(
-                opentelemetry_zipkin::B3Encoding::MultipleHeader,
-            ),
-        ))),
-        #[cfg(not(feature = "zipkin"))]
-        "b3multi" => Err(TraceError::from(
-            "unsupported propagators form env OTEL_PROPAGATORS: 'b3multi', try to enable compile feature 'zipkin'"
-        )),
-        "jaeger" => Err(TraceError::from(
-            "unsupported propagators form env OTEL_PROPAGATORS: 'jaeger', try to enable compile feature 'jaeger'"
-        )),
-        "xray" => Err(TraceError::from(
-            "unsupported propagators form env OTEL_PROPAGATORS: 'xray', try to enable compile feature 'xray'"
-        )),
-        "none" => Ok(None),
-        unknown => Err(TraceError::from(format!(
-            "unsupported propagators form env OTEL_PROPAGATORS: '{unknown}'"
-        ))),
-    }
-}
-
-#[cfg(test)]
-#[cfg(feature = "tracer")]
-mod tests {
-    use assert2::let_assert;
-
-    #[test]
-    fn init_tracing_failed_on_invalid_propagator() {
-        let_assert!(Err(_) = super::propagator_from_string("xxxxxx"));
-
-        // std::env::set_var("OTEL_PROPAGATORS", "xxxxxx");
-        // dbg!(std::env::var("OTEL_PROPAGATORS"));
-        // let_assert!(Err(_) = init_tracing());
-    }
-}