fix: don't panic on IP address resolution failure (#42)

* don't panic on failure to resolve IP address

* cover additional Error variant in Clone impl

* fmt

Author: cartercanedy

src/client.rs

@@ -202,17 +202,24 @@ impl Client {
             .to_socket_addrs()
             .ctx("converting address to SocketAddr")?
             .next()
-            .expect("at least one SocketAddr");
+            .ok_or(Error::Other("no destination address could be resolved"))?;
+
         let mut socket = if let Some(timeout) = timeouts.connect {
-            TcpStream::connect_timeout(&addr, timeout).ctx("connecting TCP socket with timeout")?
+            TcpStream::connect_timeout(&addr, timeout)
+                .ctx("establishing connetion to remote ADS router (with timeout)")?
         } else {
-            TcpStream::connect(addr).ctx("connecting TCP socket")?
+            TcpStream::connect(addr).ctx("establishing connection to remote ADS router")?
         };
 
         // Disable Nagle to ensure small requests are sent promptly; we're
         // playing ping-pong with request reply, so no pipelining.
-        socket.set_nodelay(true).ctx("setting NODELAY")?;
-        socket.set_write_timeout(timeouts.write).ctx("setting write timeout")?;
+        socket.set_nodelay(true).ctx("setting client socket NODELAY")?;
+        socket
+            .set_write_timeout(timeouts.write)
+            .ctx("setting client socket write timeout")?;
+        socket
+            .set_read_timeout(timeouts.read)
+            .ctx("setting client socket read timeout")?;
 
         // Determine our source AMS address.  If it's not specified, try to use
         // the socket's local IPv4 address, if it's IPv6 (not sure if Beckhoff

src/errors.rs

@@ -25,6 +25,10 @@ pub enum Error {
     /// Error occurred during IO synchronization
     #[error("failed during synchronization of an Ads request/response: {0} ({1})")]
     IoSync(&'static str, &'static str, u32),
+
+    /// An unspecified catch-all error
+    #[error("an error occured: {0}")]
+    Other(&'static str),
 }
 
 impl Clone for Error {
@@ -36,6 +40,7 @@ impl Clone for Error {
             Reply(ctx, e, i) => Reply(ctx, e, *i),
             Overflow(e) => Overflow(*e),
             IoSync(ctx, e, i) => IoSync(ctx, e, *i),
+            Other(ctx) => Other(ctx),
         }
     }
 }