feat: set up Mailpit SMTP server as part of our Docker Compose file (#4151)

* feat(labrinth): support STMP servers with no auth credentials

* feat: set up Mailpit SMTP server as part of our Docker Compose services swarm

* chore(docker-compose): fix healthcheck for mail service

* feat(docker-compose): enable SpamAssassin integration through Postmark

Unlike spinning up yet another container, this requires no
configuration, and is good and simple enough for a funny little feature
developers may occassionally use with non-confidential messages.

apps/docs/src/content/docs/contributing/labrinth.md

@@ -5,7 +5,7 @@ description: Guide for contributing to Modrinth's backend
 
 This project is part of our [monorepo](https://github.com/modrinth/code). You can find it in the `apps/labrinth` directory. The instructions below assume that you have switched your working directory to the `apps/labrinth` subdirectory.
 
-[labrinth] is the Rust-based backend serving Modrinth's API with the help of the [Actix](https://actix.rs) framework. To get started with a labrinth instance, install docker, docker-compose (which comes with Docker), and [Rust]. The initial startup can be done simply with the command `docker-compose up`, or with `docker compose up` (Compose V2 and later). That will deploy a PostgreSQL database on port 5432 and a MeiliSearch instance on port 7700. To run the API itself, you'll need to use the `cargo run` command, this will deploy the API on port 8000.
+[labrinth] is the Rust-based backend serving Modrinth's API with the help of the [Actix](https://actix.rs) framework. To get started with a labrinth instance, install docker, docker-compose (which comes with Docker), and [Rust]. The initial startup can be done simply with the command `docker-compose up`, or with `docker compose up` (Compose V2 and later). That will deploy a PostgreSQL database on port 5432, a MeiliSearch instance on port 7700, and a [Mailpit](https://mailpit.axllent.org/) SMTP server on port 1025, with a web UI to inspect sent emails on port 8025. To run the API itself, you'll need to use the `cargo run` command, this will deploy the API on port 8000.
 
 To get a basic configuration, copy the `.env.local` file to `.env`. Now, you'll have to install the sqlx CLI, which can be done with cargo:
 

apps/labrinth/.env.local

@@ -87,11 +87,11 @@ HCAPTCHA_SECRET=none
 
 SMTP_FROM_NAME=Modrinth
 SMTP_FROM_ADDRESS=no-reply@mail.modrinth.com
-SMTP_USERNAME=none
-SMTP_PASSWORD=none
-SMTP_HOST=none
-SMTP_PORT=465
-SMTP_TLS=tls
+SMTP_USERNAME=
+SMTP_PASSWORD=
+SMTP_HOST=localhost
+SMTP_PORT=1025
+SMTP_TLS=none
 
 SITE_VERIFY_EMAIL_PATH=auth/verify-email
 SITE_RESET_PASSWORD_PATH=auth/reset-password

apps/labrinth/src/auth/email/mod.rs

@@ -39,7 +39,8 @@ pub fn send_email_raw(
     let password = dotenvy::var("SMTP_PASSWORD")?;
     let host = dotenvy::var("SMTP_HOST")?;
     let port = dotenvy::var("SMTP_PORT")?.parse::<u16>().unwrap_or(465);
-    let creds = Credentials::new(username, password);
+    let creds =
+        (!username.is_empty()).then(|| Credentials::new(username, password));
     let tls_setting = match dotenvy::var("SMTP_TLS")?.as_str() {
         "none" => Tls::None,
         "opportunistic_start_tls" => {
@@ -55,13 +56,12 @@ pub fn send_email_raw(
         }
     };
 
-    let mailer = SmtpTransport::relay(&host)?
-        .port(port)
-        .tls(tls_setting)
-        .credentials(creds)
-        .build();
+    let mut mailer = SmtpTransport::relay(&host)?.port(port).tls(tls_setting);
+    if let Some(creds) = creds {
+        mailer = mailer.credentials(creds);
+    }
 
-    mailer.send(&email)?;
+    mailer.build().send(&email)?;
 
     Ok(())
 }

docker-compose.yml

@@ -58,6 +58,19 @@ services:
       interval: 3s
       timeout: 5s
       retries: 3
+  mail:
+    image: axllent/mailpit:v1.27
+    container_name: labrinth-mail
+    ports:
+      - '1025:1025'
+      - '8025:8025'
+    environment:
+      MP_ENABLE_SPAMASSASSIN: postmark
+    healthcheck:
+      test: ['CMD', 'wget', '-q', '-O/dev/null', 'http://localhost:8025/api/v1/info']
+      interval: 3s
+      timeout: 5s
+      retries: 3
   labrinth:
     profiles:
       - with-labrinth