feat: Add SmtpHealthCheck (#396)

examples/full/Cargo.toml

@@ -38,7 +38,7 @@ rusty-sidekiq = { workspace = true, default-features = false }
 serde = { workspace = true, features = ["derive"] }
 
 # Email
-lettre = { workspace = true }
+lettre = { workspace = true, features = ["pool"] }
 
 [build-dependencies]
 tonic-build = { workspace = true }

src/api/core/health.rs

@@ -3,7 +3,7 @@ use crate::error::RoadsterResult;
 use crate::health_check::{CheckResponse, ErrorData, HealthCheck, Status};
 #[cfg(feature = "open-api")]
 use aide::OperationIo;
-#[cfg(feature = "sidekiq")]
+#[cfg(any(feature = "sidekiq", feature = "email-smtp"))]
 use anyhow::anyhow;
 use axum::extract::FromRef;
 use futures::future::join_all;
@@ -135,6 +135,37 @@ async fn ping_db(db: &DatabaseConnection, duration: Option<Duration>) -> Roadste
     Ok(())
 }
 
+#[cfg(feature = "email-smtp")]
+pub(crate) async fn smtp_health(context: &AppContext, duration: Option<Duration>) -> CheckResponse {
+    let timer = Instant::now();
+    let status = match ping_smtp(context.mailer(), duration).await {
+        Ok(_) => Status::Ok,
+        Err(err) => Status::Err(ErrorData::builder().msg(err.to_string()).build()),
+    };
+    let timer = timer.elapsed();
+    CheckResponse::builder()
+        .status(status)
+        .latency(timer)
+        .build()
+}
+
+#[cfg(feature = "email-smtp")]
+async fn ping_smtp(
+    mailer: &lettre::SmtpTransport,
+    duration: Option<Duration>,
+) -> RoadsterResult<()> {
+    let connected = if let Some(duration) = duration {
+        timeout(duration, async { mailer.test_connection() }).await??
+    } else {
+        mailer.test_connection()?
+    };
+    if connected {
+        Ok(())
+    } else {
+        Err(anyhow!("Not connected to the SMTP server").into())
+    }
+}
+
 #[cfg(feature = "sidekiq")]
 #[instrument(skip_all)]
 pub(crate) async fn redis_health(

src/config/health_check/default.toml

@@ -6,3 +6,5 @@ cli = 10000
 [health-check.database]
 
 [health-check.sidekiq]
+
+[health-check.smtp]

src/config/health_check/mod.rs

@@ -30,6 +30,10 @@ pub struct HealthCheck {
     #[validate(nested)]
     pub sidekiq: HealthCheckConfig<()>,
 
+    #[cfg(feature = "email-smtp")]
+    #[validate(nested)]
+    pub smtp: HealthCheckConfig<()>,
+
     /// Allows providing configs for custom health checks. Any configs that aren't pre-defined above
     /// will be collected here.
     ///

src/config/snapshots/roadster__config__tests__test.snap

@@ -26,6 +26,8 @@ cli = 10000
 
 [health-check.sidekiq]
 
+[health-check.smtp]
+
 [service]
 default-enable = true
 

src/health_check/default.rs

@@ -1,6 +1,8 @@
 use crate::app::context::AppContext;
 #[cfg(feature = "db-sql")]
 use crate::health_check::database::DatabaseHealthCheck;
+#[cfg(feature = "email-smtp")]
+use crate::health_check::email::smtp::SmtpHealthCheck;
 #[cfg(feature = "sidekiq")]
 use crate::health_check::sidekiq_enqueue::SidekiqEnqueueHealthCheck;
 #[cfg(feature = "sidekiq")]
@@ -25,6 +27,10 @@ pub fn default_health_checks(
         Arc::new(SidekiqFetchHealthCheck {
             context: context.clone(),
         }),
+        #[cfg(feature = "email-smtp")]
+        Arc::new(SmtpHealthCheck {
+            context: context.clone(),
+        }),
     ];
 
     health_checks
@@ -34,7 +40,7 @@ pub fn default_health_checks(
         .collect()
 }
 
-#[cfg(all(test, feature = "sidekiq", feature = "db-sql",))]
+#[cfg(all(test, feature = "sidekiq", feature = "db-sql", feature = "email-smtp"))]
 mod tests {
     use crate::app::context::AppContext;
     use crate::config::AppConfig;

src/health_check/email/mod.rs

@@ -0,0 +1,2 @@
+#[cfg(feature = "email-smtp")]
+pub mod smtp;

src/health_check/email/smtp.rs

@@ -0,0 +1,57 @@
+use crate::api::core::health::smtp_health;
+use crate::app::context::AppContext;
+use crate::error::RoadsterResult;
+use crate::health_check::{CheckResponse, HealthCheck};
+use async_trait::async_trait;
+use tracing::instrument;
+
+pub struct SmtpHealthCheck {
+    pub(crate) context: AppContext,
+}
+
+#[async_trait]
+impl HealthCheck for SmtpHealthCheck {
+    fn name(&self) -> String {
+        "smtp".to_string()
+    }
+
+    fn enabled(&self) -> bool {
+        enabled(&self.context)
+    }
+
+    #[instrument(skip_all)]
+    async fn check(&self) -> RoadsterResult<CheckResponse> {
+        Ok(smtp_health(&self.context, None).await)
+    }
+}
+
+fn enabled(context: &AppContext) -> bool {
+    context.config().health_check.smtp.common.enabled(context)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::config::AppConfig;
+    use rstest::rstest;
+
+    #[rstest]
+    #[case(false, Some(true), true)]
+    #[case(false, Some(false), false)]
+    #[cfg_attr(coverage_nightly, coverage(off))]
+    fn enabled(
+        #[case] default_enable: bool,
+        #[case] enable: Option<bool>,
+        #[case] expected_enabled: bool,
+    ) {
+        // Arrange
+        let mut config = AppConfig::test(None).unwrap();
+        config.health_check.default_enable = default_enable;
+        config.health_check.smtp.common.enable = enable;
+
+        let context = AppContext::test(Some(config), None, None).unwrap();
+
+        // Act/Assert
+        assert_eq!(super::enabled(&context), expected_enabled);
+    }
+}

src/health_check/mod.rs

@@ -1,6 +1,8 @@
 #[cfg(feature = "db-sql")]
 pub mod database;
 pub mod default;
+#[cfg(feature = "email")]
+pub mod email;
 pub mod registry;
 #[cfg(feature = "sidekiq")]
 pub mod sidekiq_enqueue;

src/health_check/snapshots/roadster__health_check__default__tests__default_middleware@case_2.snap

@@ -6,4 +6,5 @@ expression: health_checks
     'db',
     'sidekiq-enqueue',
     'sidekiq-fetch',
+    'smtp',
 ]