improvement: readability and refactor

Signed-off-by: Aminu 'Seun Joshua <[email protected]>

Author: seun-ja

crates/trigger-http/src/server.rs

@@ -153,10 +153,16 @@ impl<F: RuntimeFactors> HttpServer<F> {
             Err(err) => {
                 if self.find_free_port && err.kind() == ErrorKind::AddrInUse {
                     let mut found_listener = None;
+                    let mut addr = self.listen_addr;
                     for _ in 1..=9 {
-                        let mut addr = self.listen_addr;
                         addr.set_port(addr.port() + 1);
 
+                        if !addr.port() == u16::MAX {
+                            return Err(anyhow::anyhow!(
+                                "Couldn't find a free port as we've reached the maximum port number. Consider retrying with a lower base port."
+                            ));
+                        }
+
                         match TcpListener::bind(addr).await {
                             Ok(listener) => {
                                 found_listener = Some(listener);
@@ -166,21 +172,21 @@ impl<F: RuntimeFactors> HttpServer<F> {
                                 if err.kind() == ErrorKind::AddrInUse {
                                     continue;
                                 }
-                                return Err(anyhow::anyhow!("Unable to listen on {}", addr));
+                                return Err(anyhow::anyhow!(
+                                    "Unable to listen on {}",
+                                    self.listen_addr
+                                ));
                             }
                         }
                     }
 
-                    match found_listener {
-                        Some(listener) => listener,
-                        None => {
-                            return Err(anyhow::anyhow!(
-                                "All retries failed. Unable to bind to a free port"
-                            ));
-                        }
-                    }
+                    found_listener.ok_or_else(|| anyhow::anyhow!(
+                        "Couldn't find a free port in the range {}-{}. Consider retrying with a different base port.",
+                        self.listen_addr.port(),
+                        self.listen_addr.port() + 9
+                    ))?
                 } else {
-                    return Err(anyhow::anyhow!("Unable to listen on {}", self.listen_addr));
+                    return Err(anyhow::anyhow!("Unable to listen on {}. To have Spin search for a free port, use the --find-free-port option.", self.listen_addr));
                 }
             }
         };

tests/testing-framework/src/runtimes/in_process_spin.rs

@@ -104,7 +104,7 @@ async fn initialize_trigger(
     .await?;
 
     let app = spin_app::App::new("my-app", locked_app);
-    let trigger = HttpTrigger::new(&app, "127.0.0.1:80".parse().unwrap(), None, true)?;
+    let trigger = HttpTrigger::new(&app, "127.0.0.1:80".parse().unwrap(), None, false)?;
     let mut builder = TriggerAppBuilder::<_, FactorsBuilder>::new(trigger);
     let trigger_app = builder
         .build(