Added SMTP_PORT configuration option.

Cargo.toml

@@ -14,6 +14,7 @@ jsonrpc-core = "8.0.1"
 lazy_static = "1.0.0"
 lettre = "0.8"
 lettre_email = "0.8"
+native-tls = "0.1.5"
 reqwest = "0.8.5"
 serde = "1.0.36"
 serde_derive = "1.0.36"

README.md

@@ -70,6 +70,13 @@ Add a comma-separated list of email address to the "VALIDATORS" config
 option in your .env file. These addresses will be sent emails when `poagov`
 encounters governance events on the POA blockchain.
 
+*Note* `poagov` forces SMTP email notifcations to be sent over an encrypted
+channel, if your SMTP Host does not support TLS or STARTTLS, `poagov` will
+panic. You may notice that we default `SMTP_PORT` to port 587 for STARTTLS,
+but you may use port 465 for TLS, or any other port that your outgoing
+email server is lisening for secure connections. If you require unencrypted
+SMTP, submit an issue and I can add it.
+
 # An Explained Example
 
     $ ./target/release/poagov --sokol --earliest -kt --email

sample.env

@@ -8,6 +8,7 @@ SEND_PUSH_NOTIFICATIONS=false
 
 # Email configuration.
 SMTP_HOST_DOMAIN=
+SMTP_PORT=587
 SMTP_USERNAME=
 SMTP_PASSWORD=
 OUTGOING_EMAIL_ADDRESS=

src/config.rs

@@ -159,6 +159,7 @@ pub struct Config {
     pub validators: Vec<Validator>,
     pub avg_block_time: Duration,
     pub smtp_host_domain: String,
+    pub smtp_port: u16,
     pub smtp_username: String,
     pub smtp_password: String,
     pub outgoing_email: String
@@ -263,17 +264,16 @@ impl Config {
         };
 
         let smtp_host_domain = env::var("SMTP_HOST_DOMAIN").unwrap();
+        let smtp_port = env::var("SMTP_PORT").unwrap().parse().unwrap();
         let smtp_username = env::var("SMTP_USERNAME").unwrap();
         let smtp_password = env::var("SMTP_PASSWORD").unwrap();
         let outgoing_email = env::var("OUTGOING_EMAIL_ADDRESS").unwrap();
 
         Config {
             network, endpoint, contracts, start_block,
-            send_email_notifications,
-            send_push_notifications,
-            validators, avg_block_time,
-            smtp_host_domain, smtp_username,
-            smtp_password, outgoing_email
+            send_email_notifications, send_push_notifications,
+            validators, avg_block_time, smtp_host_domain,
+            smtp_port, smtp_username, smtp_password, outgoing_email
         }
     }
 }

src/logging.rs

@@ -15,7 +15,12 @@ lazy_static! {
 }
 
 pub fn log_notification(notif: &Notification) {
-    info!(LOGGER, "notification"; "data" => format!("{:#?}", notif));
+    let notif_data = match *notif {
+        Notification::Keys(ref inner) => format!("{:#?}", inner),
+        Notification::Threshold(ref inner) => format!("{:#?}", inner),
+        Notification::Proxy(ref inner) => format!("{:#?}", inner)
+    };
+    info!(LOGGER, "notification"; "data" => notif_data);
 }
 
 pub fn log_email_sent(email: &str) {

src/main.rs

@@ -8,6 +8,7 @@ extern crate jsonrpc_core;
 #[macro_use] extern crate lazy_static;
 extern crate lettre;
 extern crate lettre_email;
+extern crate native_tls;
 extern crate reqwest;
 extern crate serde;
 extern crate serde_json;

src/notify.rs

@@ -1,16 +1,18 @@
 use chrono::{DateTime, Utc};
 use ethereum_types::Address;
 use lettre::{EmailTransport, SmtpTransport};
-use lettre::smtp::{self, ConnectionReuseParameters};
+use lettre::smtp::{ClientSecurity, ConnectionReuseParameters, SmtpTransportBuilder};
 use lettre::smtp::authentication::{Credentials, Mechanism};
-use lettre_email::{self, Email, EmailBuilder};
+use lettre::smtp::client::net::{ClientTlsParameters, DEFAULT_TLS_PROTOCOLS};
+use lettre::smtp::error::Error as BuildSmtpError;
+use lettre_email::{Email, EmailBuilder};
+use lettre_email::error::Error as BuildEmailError;
+use native_tls::TlsConnector;
 
 use config::{Config, ContractType, Network, Validator};
 use logging::{log_email_failed, log_email_sent, log_notification};
 use rpc::{BallotCreatedLog, BallotType, KeyType, VotingData};
 
-type BuildEmailResult = Result<Email, lettre_email::error::Error>;
-
 #[derive(Debug)]
 pub enum Notification {
     Keys(KeysNotification),
@@ -119,23 +121,35 @@ pub struct Notifier<'a> {
 }
 
 impl<'a> Notifier<'a> {
-    pub fn new(config: &'a Config) -> Result<Self, smtp::error::Error> {
-        let mailer = if config.send_email_notifications {
-            let creds = Credentials::new(
+    pub fn new(config: &'a Config) -> Result<Self, BuildSmtpError> {        
+        let mut notifier = Notifier { config, mailer: None };
+
+        if config.send_email_notifications {
+            let smtp_addr = (config.smtp_host_domain.as_str(), config.smtp_port);
+            
+            let smtp_tls = {
+                let mut tls_builder = TlsConnector::builder().unwrap();
+                tls_builder.supported_protocols(DEFAULT_TLS_PROTOCOLS).unwrap();
+                let tls = tls_builder.build().unwrap();
+                let tls_params = ClientTlsParameters::new(config.smtp_host_domain.clone(), tls);
+                ClientSecurity::Required(tls_params)
+            };
+
+            let smtp_creds = Credentials::new(
                 config.smtp_username.clone(),
                 config.smtp_password.clone()
             );
-            let mailer = SmtpTransport::simple_builder(&config.smtp_host_domain)?
+
+            let mailer = SmtpTransportBuilder::new(smtp_addr, smtp_tls)?
                 .connection_reuse(ConnectionReuseParameters::ReuseUnlimited)
                 .authentication_mechanism(Mechanism::Plain)
-                .credentials(creds)
+                .credentials(smtp_creds)
                 .build();
-            Some(mailer)
-        } else {
-            None
-        };
 
-        Ok(Notifier { config, mailer })
+            notifier.mailer = Some(mailer);
+        }
+
+        Ok(notifier)
     }
 
     pub fn build_notification(&self, log: &BallotCreatedLog, voting_data: &VotingData) -> Notification {
@@ -161,7 +175,7 @@ impl<'a> Notifier<'a> {
         }
     }
 
-    fn build_email(&self, validator: &Validator, notif: &Notification) -> BuildEmailResult {
+    fn build_email(&self, validator: &Validator, notif: &Notification) -> Result<Email, BuildEmailError> {
         let body = match *notif {
             Notification::Keys(ref inner) => format!("{:#?}\n", inner),
             Notification::Threshold(ref inner) => format!("{:#?}\n", inner),