feat: allow specifying the maximum number of messages to fetch

Author: endor

examples/long_lived.rs

@@ -26,7 +26,7 @@ impl FromPubSubMessage for UpdatePacket {
 fn schedule_pubsub_pull(subscription: Arc<Subscription>) {
     task::spawn(async move {
         while subscription.client().is_running() {
-            match subscription.get_messages::<UpdatePacket>().await {
+            match subscription.get_messages::<UpdatePacket>(100).await {
                 Ok(messages) => {
                     for (result, ack_id) in messages {
                         match result {

examples/serde.rs

@@ -40,7 +40,7 @@ async fn main() {
     };
 
     let order_sub = Arc::new(pubsub.subscribe(config.pubsub_subscription));
-    match order_sub.clone().get_messages::<UpdatePacket>().await {
+    match order_sub.clone().get_messages::<UpdatePacket>(100).await {
         Ok(packets) => {
             for packet in &packets {
                 println!("Received: {:?}", packet);

examples/singleshot.rs

@@ -37,7 +37,7 @@ async fn main() {
     };
 
     let subscription = Arc::new(pubsub.subscribe(config.pubsub_subscription));
-    match subscription.get_messages::<UpdatePacket>().await {
+    match subscription.get_messages::<UpdatePacket>(100).await {
         Ok(messages) => {
             for (result, ack_id) in messages {
                 match result {

examples/subscribe_to_topic.rs

@@ -35,7 +35,7 @@ async fn main() {
     println!("Subscribed to topic with: {}", sub.name);
     let packets = sub
         .clone()
-        .get_messages::<UpdatePacket>()
+        .get_messages::<UpdatePacket>(100)
         .await
         .expect("Error Checking PubSub");
 

src/subscription.rs

@@ -59,6 +59,7 @@ impl Subscription {
 
     pub async fn get_messages<T: FromPubSubMessage>(
         &self,
+        max_messages: i32,
     ) -> Result<Vec<(Result<T, error::Error>, String)>, error::Error> {
         let client = self
             .client
@@ -69,7 +70,7 @@ impl Subscription {
             .parse()
             .unwrap();
 
-        let json = r#"{"maxMessages": 100}"#;
+        let json = format!("{{\"maxMessages\": {}}}", max_messages);
 
         let mut req = client.request(Method::POST, json);
         *req.uri_mut() = uri.clone();