Allow cloning the transport with different credentials

Author: swallez

elasticsearch/src/http/transport.rs

@@ -711,6 +711,20 @@ impl Transport {
     pub fn set_auth(&self, credentials: Credentials) {
         *self.credentials.write() = Some(credentials);
     }
+
+    /// Creates a new `Transport` that is a clone of this one, except for authentication
+    /// credentials. This is the opposite of [`Transport::set_auth()`]. Typically used
+    /// when working in multi-tenant environments where credentials can vary with every
+    /// request.
+    pub fn clone_with_auth(&self, credentials: Option<Credentials>) -> Self {
+        Self {
+            client: self.client.clone(),
+            credentials: Arc::new(RwLock::new(credentials)),
+            conn_pool: self.conn_pool.clone(),
+            request_body_compression: self.request_body_compression,
+            send_meta: self.send_meta,
+        }
+    }
 }
 
 impl Default for Transport {
@@ -1298,4 +1312,28 @@ pub mod tests {
 
         Ok(())
     }
+
+    #[test]
+    fn clone_with_credentials() -> anyhow::Result<()> {
+        let t1: Transport = TransportBuilder::new(SingleNodeConnectionPool::default())
+            .auth(Credentials::Basic("foo".to_string(), "bar".to_string()))
+            .build()?;
+
+        let t2 = t1.clone_with_auth(Some(Credentials::Bearer("The bear".to_string())));
+
+        if let Some(Credentials::Basic(login, password)) = t1.credentials.read().as_ref() {
+            assert_eq!(login, "foo");
+            assert_eq!(password, "bar");
+        } else {
+            panic!("Expected Basic credentials");
+        }
+
+        if let Some(Credentials::Bearer(token)) = t2.credentials.read().as_ref() {
+            assert_eq!(token, "The bear");
+        } else {
+            panic!("Expected Bearer credentials");
+        }
+
+        Ok(())
+    }
 }