[PATCH proxmox 3/7] notify (smtp): Factor out transport building logic into own function

[Arthur Bied-Charreton <a.bied-charreton@proxmox.com>]

XOAUTH2 support will make the transport building logic a lot more
complex, having a separate function for it will make it more manageable.

Signed-off-by: Arthur Bied-Charreton <a.bied-charreton@proxmox.com>
---
 proxmox-notify/src/endpoints/smtp.rs | 44 ++++++++++++++++------------
 1 file changed, 25 insertions(+), 19 deletions(-)

diff --git a/proxmox-notify/src/endpoints/smtp.rs b/proxmox-notify/src/endpoints/smtp.rs
index 699ed1c6..1340d8ea 100644
--- a/proxmox-notify/src/endpoints/smtp.rs
+++ b/proxmox-notify/src/endpoints/smtp.rs
@@ -162,6 +162,30 @@ pub struct SmtpEndpoint {
     pub private_config: SmtpPrivateConfig,
 }
 
+impl SmtpEndpoint {
+    fn build_transport(&self, tls: Tls, port: u16) -> Result<SmtpTransport, Error> {
+        let mut transport_builder = SmtpTransport::builder_dangerous(&self.config.server)
+            .tls(tls)
+            .port(port)
+            .timeout(Some(Duration::from_secs(SMTP_TIMEOUT.into())));
+
+        if let Some(username) = self.config.username.as_deref() {
+            if let Some(password) = self.private_config.password.as_deref() {
+                transport_builder = transport_builder.credentials((username, password).into());
+            } else {
+                return Err(Error::NotifyFailed(
+                    self.name().into(),
+                    Box::new(Error::Generic(
+                        "username is set but no password was provided".to_owned(),
+                    )),
+                ));
+            }
+        };
+
+        Ok(transport_builder.build())
+    }
+}
+
 impl Endpoint for SmtpEndpoint {
     fn send(&self, notification: &Notification) -> Result<(), Error> {
         let tls_parameters = TlsParameters::new(self.config.server.clone())
@@ -182,25 +206,7 @@ impl Endpoint for SmtpEndpoint {
             }
         };
 
-        let mut transport_builder = SmtpTransport::builder_dangerous(&self.config.server)
-            .tls(tls)
-            .port(port)
-            .timeout(Some(Duration::from_secs(SMTP_TIMEOUT.into())));
-
-        if let Some(username) = self.config.username.as_deref() {
-            if let Some(password) = self.private_config.password.as_deref() {
-                transport_builder = transport_builder.credentials((username, password).into());
-            } else {
-                return Err(Error::NotifyFailed(
-                    self.name().into(),
-                    Box::new(Error::Generic(
-                        "username is set but no password was provided".to_owned(),
-                    )),
-                ));
-            }
-        }
-
-        let transport = transport_builder.build();
+        let transport = self.build_transport(tls, port)?;
 
         let recipients = mail::get_recipients(
             self.config.mailto.as_slice(),
-- 
2.47.3