context propagation helpers

common/bin-common/src/opentelemetry/context.rs

@@ -0,0 +1,47 @@
+use opentelemetry::propagation::{Injector, Extractor};
+use std::collections::HashMap;
+
+/// Make a Carrier for context propagation
+pub struct ContextCarrier {
+    data: HashMap<String, String>,
+}
+
+impl ContextCarrier {
+    pub fn new() -> Self {
+        ContextCarrier {
+            data: HashMap::new(),
+        }
+    }
+
+    pub fn from_map(data: HashMap<String, String>) -> Self {
+        ContextCarrier { data }
+    }
+
+    pub fn into_map(self) -> HashMap<String, String> {
+        self.data
+    }
+}
+
+impl Injector for ContextCarrier {
+    fn set(&mut self, key: &str, value: String) {
+        self.data.insert(key.to_string(), value);
+    }
+}
+
+impl Extractor for ContextCarrier {
+    fn get(&self, key: &str) -> Option<&str> {
+        self.data.get(key).map(|s| s.as_str())
+    }
+
+    fn keys(&self) -> Vec<&str> {
+        self.data.keys().map(|k| k.as_str()).collect()
+    }
+}
+
+// TODO use generics to extract context from request
+    // fn extract_context_from_request<T>(request: ) -> Context {
+    //     global::get_text_map_propagator(|propagator| {
+    //         propagator.extract(&HeaderExtractor(&request.headers))
+    //     })
+    // }
+

common/bin-common/src/opentelemetry/mod.rs

@@ -1,3 +1,4 @@
+pub mod context;
 pub mod error;
 mod trace_id_format;