refactor: cleaner logic

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

Author: seun-ja

crates/trigger-http/src/server.rs

@@ -47,6 +47,8 @@ use crate::{
     Body, NotFoundRouteKind, TlsConfig, TriggerApp, TriggerInstanceBuilder,
 };
 
+pub const MAX_RETRIES: u16 = 10;
+
 /// An HTTP server which runs Spin apps.
 pub struct HttpServer<F: RuntimeFactors> {
     /// The address the server is listening on.
@@ -148,44 +150,16 @@ impl<F: RuntimeFactors> HttpServer<F> {
 
     /// Serve incoming requests over the provided [`TcpListener`].
     pub async fn serve(self: Arc<Self>) -> anyhow::Result<()> {
-        let listener: TcpListener = match TcpListener::bind(self.listen_addr).await {
-            Ok(listener) => listener,
-            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 {
-                        if addr.port() == u16::MAX {
-                            anyhow::bail!(
-                                "Couldn't find a free port as we've reached the maximum port number. Consider retrying with a lower base port."
-                            );
-                        }
-
-                        addr.set_port(addr.port() + 1);
-
-                        match TcpListener::bind(addr).await {
-                            Ok(listener) => {
-                                found_listener = Some(listener);
-                                break;
-                            }
-                            Err(err) => {
-                                if err.kind() == ErrorKind::AddrInUse {
-                                    continue;
-                                }
-                                anyhow::bail!("Unable to listen on {}", self.listen_addr);
-                            }
-                        }
-                    }
-
-                    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
-                    ))?
+        let listener: TcpListener = if self.find_free_port {
+            self.search_for_free_port().await?
+        } else {
+            TcpListener::bind(self.listen_addr).await.map_err(|err| {
+                if err.kind() == ErrorKind::AddrInUse {
+                    anyhow::anyhow!("Unable to listen on {}. To have Spin search for a free port, use the --find-free-port option.", self.listen_addr)
                 } else {
-                    anyhow::bail!("Unable to listen on {}. To have Spin search for a free port, use the --find-free-port option.", self.listen_addr)
+                    anyhow::anyhow!("Unable to listen on {}", self.listen_addr)
                 }
-            }
+            })?
         };
 
         if let Some(tls_config) = self.tls_config.clone() {
@@ -196,6 +170,36 @@ impl<F: RuntimeFactors> HttpServer<F> {
         Ok(())
     }
 
+    async fn search_for_free_port(&self) -> anyhow::Result<TcpListener> {
+        let mut found_listener = None;
+        let mut addr = self.listen_addr;
+
+        for _ in 1..=MAX_RETRIES {
+            if addr.port() == u16::MAX {
+                anyhow::bail!(
+                    "Couldn't find a free port as we've reached the maximum port number. Consider retrying with a lower base port."
+                );
+            }
+
+            addr.set_port(addr.port() + 1);
+
+            match TcpListener::bind(addr).await {
+                Ok(listener) => {
+                    found_listener = Some(listener);
+                    break;
+                }
+                Err(err) if err.kind() == ErrorKind::AddrInUse => continue,
+                Err(err) => anyhow::bail!("Unable to listen on {addr}: {err:?}",),
+            }
+        }
+
+        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() + MAX_RETRIES
+        ))
+    }
+
     async fn serve_http(self: Arc<Self>, listener: TcpListener) -> anyhow::Result<()> {
         self.print_startup_msgs("http", &listener)?;
         loop {