add starting point for flight-client example

Author: andygrove

rust/datafusion/examples/flight-client.rs

@@ -0,0 +1,44 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+use std::pin::Pin;
+
+use futures::Stream;
+use tonic::transport::Server;
+use tonic::{Request, Response, Status, Streaming};
+
+use flight::flight_service_client::FlightServiceClient;
+
+use flight::{
+    FlightData, FlightDescriptor, FlightInfo, Ticket,
+};
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+
+    let mut client = FlightServiceClient::connect("http://localhost:50051").await?;
+
+    let request = tonic::Request::new(Ticket {
+        ticket: "SELECT id FROM alltypes_plain".into(),
+    });
+
+    let response = client.do_get(request).await?;
+
+    println!("RESPONSE={:?}", response);
+
+    Ok(())
+}

rust/datafusion/examples/flight-server.rs

@@ -90,6 +90,8 @@ impl FlightService for FlightServiceImpl {
                     .map(|batch| Ok(FlightData::from(batch)))
                     .collect();
 
+                println!("Returning {} flights", flights.len());
+
                 let output = futures::stream::iter(flights);
 
                 Ok(Response::new(Box::pin(output) as Self::DoGetStream))