Create basic opentelemetry example

Cargo.toml

@@ -5,6 +5,7 @@ members = [
     "models/files",
     "models/token",
 
+    "poem/opentelemetry-basic",
     "poem/starwars",
     "poem/subscription",
     "poem/subscription-redis",

poem/opentelemetry-basic/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "poem-opentelemetry-basic"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+async-graphql = { path = "../../..", features = ["opentelemetry"] }
+async-graphql-poem = { path = "../../../integrations/poem" }
+tokio = { version = "1.8", features = ["macros", "rt-multi-thread"] }
+poem = "1.3.42"
+opentelemetry = { version = "0.17.0", features = ["rt-tokio"] }

poem/opentelemetry-basic/src/main.rs

@@ -0,0 +1,42 @@
+use async_graphql::{
+    extensions::OpenTelemetry, EmptyMutation, EmptySubscription, Object, Result, Schema,
+};
+use async_graphql_poem::GraphQL;
+use opentelemetry::sdk::export::trace::stdout;
+use poem::{listener::TcpListener, post, EndpointExt, Route, Server};
+
+struct QueryRoot;
+
+#[Object]
+impl QueryRoot {
+    async fn hello(&self) -> Result<String> {
+        Ok("World".to_string())
+    }
+}
+
+#[tokio::main]
+async fn main() {
+    let tracer = stdout::new_pipeline().install_simple();
+    let opentelemetry_extension = OpenTelemetry::new(tracer);
+
+    let schema = Schema::build(QueryRoot, EmptyMutation, EmptySubscription)
+        .extension(opentelemetry_extension)
+        .finish();
+
+    let app = Route::new()
+        .at("/", post(GraphQL::new(schema.clone())))
+        .data(schema);
+
+    let example_curl = "\
+    curl '0.0.0.0:8000' \
+    -X POST \
+    -H 'content-type: application/json' \
+    --data '{ \"query\": \"{ hello }\" }'";
+
+    println!("Run this curl command from another terminal window to see opentelemetry output in this terminal.\n\n{example_curl}\n\n");
+
+    Server::new(TcpListener::bind("0.0.0.0:8000"))
+        .run(app)
+        .await
+        .unwrap();
+}