.Dockerignore

@@ -0,0 +1,8 @@
+target/
+.vscode
+tests/
+.git
+.gitignore
+.env
+Dockerfile
+migrations/

.cargo/config.toml

@@ -1,25 +0,0 @@
-# On Windows
-# ```
-# cargo install -f cargo-binutils
-# rustup component add llvm-tools-preview
-# ```
-[target.x86_64-pc-windows-msvc]
-rustflags = ["-C", "link-arg=-fuse-ld=lld"]
-[target.x86_64-pc-windows-gnu]
-rustflags = ["-C", "link-arg=-fuse-ld=lld"]
-
-# On Linux:
-# - Ubuntu, `sudo apt-get install lld clang`
-# - Arch, `sudo pacman -S lld clang`
-[target.x86_64-unknown-linux-gnu]
-rustflags = ["-C", "linker=clang", "-C", "link-arg=-fuse-ld=lld"]
-
-# On MacOS, `brew install michaeleisel/zld/zld`
-# [target.x86_64-apple-darwin]
-# rustflags = ["-C", "link-arg=-fuse-ld=/usr/local/bin/zld"]
-
-[target.aarch64-apple-darwin]
-rustflags = [
-    "-C",
-    "link-arg=-fuse-ld=/opt/homebrew/Cellar/llvm/17.0.6_1/bin/ld64.lld",
-]

.dockerignore

@@ -1,6 +0,0 @@
-.env
-target/
-tests/
-Dockerfile
-scripts/
-migrations/

.drone.yml

@@ -0,0 +1,48 @@
+kind: pipeline
+type: docker
+name: mailApp
+
+trigger:
+  branch:
+    - master
+  event:
+    - push
+
+steps:
+  - name: postgresDBTest # Test that the service is ready to be acted upon for cargo tests
+    image: postgres:12
+    environment:
+      PGPASSWORD: password
+      DATABASE_URL: postgres://postgres:password@postgres:5432/newsletter
+    commands:
+      - sleep 35
+      - "psql -U postgres -d newsletter -h postgres"
+
+  - name: sqlxMigrate
+    image: rust:1.57
+    environment: 
+      DATABASE_URL: postgres://postgres:password@postgres:5432/newsletter
+      SKIP_DOCKER: 
+        from_secret: SKIP_DOCKER
+    commands:
+      - apt update && apt install -y build-essential pkg-config libssl-dev # Dependancies for sqlx
+      - cargo install --version=0.5.7 sqlx-cli --no-default-features --features postgres # Install sqlx
+      - sqlx database create
+      - sqlx migrate run
+
+  - name: test
+    image: rust:1.57
+    environment:
+      APP_ENVIRONMENT: drone
+    commands:
+      - apt update && apt install -y build-essential pkg-config libssl-dev # Dependancies for tarpaulin
+      - cargo install cargo-tarpaulin
+      - cargo tarpaulin -v --all-features --timeout 120 --color always # RUN THOSE TESTS
+
+services:
+  - name: postgres
+    image: postgres:12
+    environment:
+      POSTGRES_USER: postgres
+      POSTGRES_PASSWORD: password
+      POSTGRES_DB: newsletter

.gitignore

@@ -1,11 +1,3 @@
 /target
 .vscode
-#.env
-.gitlab-ci-local
-.DS_Store
-
-# Added by cargo
-#
-# already existing elements were commented out
-
-#/target
+.env

.gitlab-ci-local-env

@@ -1 +0,0 @@
-PRIVILEGED=true

.gitlab-ci.yml

@@ -1,57 +1,30 @@
 image: "rust:latest"
 
-services:
-  - postgres:latest
-
-variables:
-  POSTGRES_DB: newsletter
-  POSTGRES_USER: postgres
-  POSTGRES_PASSWORD: password
-  POSTGRES_HOST: postgres
-  DB_PORT: 5432
-  DATABASE_URL: "postgres://$POSTGRES_USER:$POSTGRES_PASSWORD@$POSTGRES_HOST:$DB_PORT/$POSTGRES_DB"
-  APP_DATABASE__HOST: $POSTGRES_HOST
-
-cache: # Caches build artifacts so we don't build from scratch in both build and test
-  key: ${CI_COMMIT_REF_SLUG}
-  paths:
-    - .cargo/bin
-    - .cargo/registry/index
-    - .cargo/registry/cache
-    - target/debug/deps
-    - target/debug/build
-  policy: pull-push
-
 default:
   before_script:
-    - export CARGO_HOME="$CI_PROJECT_DIR/.cargo"
-    - export PATH="$CARGO_HOME/bin:$PATH"
     - rustc --version 
     - cargo --version
-    - apt update -yq && apt-get install -yq postgresql-client lld clang
-    - if ! [ -x "$(command -v cargo-sqlx)" ]; then cargo install --version='~0.7' sqlx-cli --no-default-features --features rustls,postgres; fi
-    - SKIP_DOCKER=true ./scripts/init_db.sh
-    # This is to ensure that the database is reachable and give it some time to initialize.
-    - until psql "dbname=$POSTGRES_DB user=$POSTGRES_USER password=$POSTGRES_PASSWORD host=postgres" -c '\l'; do sleep 3; done
 
 stages:
-  - build
   - test
 
-build:
-  stage: build
-  script:
-    - cargo build
-
 test-code:
   stage: test
   script:
     - cargo test
-    - if ! [ -x "$(command -v cargo-tarpaulin)" ]; then cargo install cargo-tarpaulin; fi
+    - cargo install cargo-tarpaulin
     - cargo tarpaulin --ignore-tests
 
 lint-code:
   stage: test
   script:
+    - rustup component add rustfmt
+    - cargo fmt -- --check
     - rustup component add clippy
     - cargo clippy -- -D warnings
+
+audit-code:
+  stage: test
+  script:
+    - cargo install cargo-audit
+    - cargo audit

.sqlx/query-bcfcfebc6f5e8ffbf97d97c5a209be78b46d703924482cf8b43842705fcb7714.json

@@ -1,17 +0,0 @@
-{
-  "db_name": "PostgreSQL",
-  "query": "\n        INSERT INTO subscriptions (id, email, name, subscribed_at)\n        VALUES ($1, $2, $3, $4)\n        ",
-  "describe": {
-    "columns": [],
-    "parameters": {
-      "Left": [
-        "Uuid",
-        "Text",
-        "Text",
-        "Timestamptz"
-      ]
-    },
-    "nullable": []
-  },
-  "hash": "bcfcfebc6f5e8ffbf97d97c5a209be78b46d703924482cf8b43842705fcb7714"
-}

Cargo.toml

@@ -1,6 +1,7 @@
 [package]
 name = "mail_app"
 version = "0.1.0"
+authors = ["NickBland <nick.bland@nickbland.dev>"]
 edition = "2021"
 
 [lib]
@@ -11,32 +12,27 @@ path = "src/main.rs"
 name = "mail_app"
 
 [dependencies]
-actix-web = "4"
+actix-web = "=4.0.0-beta.16"
 tokio = { version = "1", features = ["macros", "rt-multi-thread"] }
-serde = { version = "1", features = ["derive"] }
-serde-aux = "4"
-config = { version = "0.13", default-features = false, features = ["yaml"] }
-uuid = { version = "1", features = ["v4"] }
-chrono = { version = "0.4.22", default-features = false, features = ["clock"] }
-tracing = { version = "0.1", features = ["log"] }
+serde = "1.0.115"
+config = { version = "0.11", default-features = false, features = ["yaml"] }
+sqlx = { version = "0.5.5", default-features = false, features = [ "runtime-actix-rustls", "macros", "postgres", "uuid", "chrono", "migrate", "offline"] }
+uuid = { version = "0.8.1", features = ["v4"] }
+chrono = "0.4.15"
+tracing = "0.1.19"
 tracing-subscriber = { version = "0.3", features = ["registry", "env-filter"] }
-tracing-bunyan-formatter = "0.3"
-tracing-actix-web = "0.7"
-tracing-log = "0.1"
+tracing-bunyan-formatter = "0.3.1"
+tracing-log = "0.1.1"
+serde-aux = "3"
+tracing-actix-web = "0.5.0-beta.7"
 secrecy = { version = "0.8", features = ["serde"] }
-
-[dependencies.sqlx]
-version = "0.7"
-default-features = false
-features = [
-    "runtime-tokio-rustls",
-    "macros",
-    "postgres",
-    "uuid",
-    "chrono",
-    "migrate",
-]
+unicode-segmentation = "1"
+validator = "0.14"
 
 [dev-dependencies]
 reqwest = { version = "0.11", features = ["json"] }
-once_cell = "1"
+once_cell = "1.7.2"
+claim = "0.5"
+fake = "~2.3"
+quickcheck = "0.9.2"
+quickcheck_macros = "0.9.1"

Dockerfile

@@ -1,32 +1,30 @@
-##### Chef
-FROM lukemathwalker/cargo-chef:latest-rust-1.76.0 as chef
+FROM lukemathwalker/cargo-chef:latest-rust-1.57.0 AS chef
 WORKDIR /app
-RUN apt update && apt install lld clang -y
 
-##### Planner
-FROM chef as planner
+# Create lock file for project to be used in builder
+FROM chef AS planner
 COPY . .
 RUN cargo chef prepare --recipe-path recipe.json
 
-##### Builder
-# Builder prepares project dependancies, not the application.
+# Build dependancies
 FROM chef as builder
 COPY --from=planner /app/recipe.json recipe.json
 RUN cargo chef cook --release --recipe-path recipe.json
+
 COPY . .
 ENV SQLX_OFFLINE true
-# Now build the application itself.
-RUN cargo build --release --bin mail_app
+RUN cargo build --release
 
-##### Runtime
-FROM debian:bookworm-slim as runtime
+FROM debian:bullseye-slim AS runtime
 
 WORKDIR /app
-RUN apt update && apt install -y --no-install-recommends openssl ca-certificates \
-    && apt autoremove -y \
-    && apt clean -y \
-    && rm -rf /var/lib/apt/lists/*
+
+# Install dependancies required
+RUN apt update -y && apt install -y --no-install-recommends openssl && apt autoremove -y && apt clean -y && rm -rf /var/lib/apt/lists/*
+
+# Copy the fully built binary and configuration to the image
 COPY --from=builder /app/target/release/mail_app mail_app
 COPY configuration configuration 
 ENV APP_ENVIRONMENT production
+
 ENTRYPOINT ["./mail_app"]

configuration/drone.yaml

@@ -0,0 +1,5 @@
+application:
+  host: 0.0.0.0
+database:
+  host: "postgres"
+  require_ssl: false

migrations/20211105005738_create_subscriptions_table.sql

@@ -1,6 +1,5 @@
--- migrations/{timestamp}_create_subscriptions_table.sql
 -- Create Subscriptions Table
-CREATE TABLE subscriptions(
+CREATE TABLE Subscriptions(
     id uuid NOT NULL,
     PRIMARY KEY (id),
     email TEXT NOT NULL UNIQUE,

scripts/init_db.sh

@@ -3,49 +3,50 @@ set -x
 set -eo pipefail
 
 if ! [ -x "$(command -v psql)" ]; then
-    echo >&2 "Error: psql is not installed."
+	echo >&2 "Error: `psql` is not installed."
+	echo >&2 "Use:"
+	echo >&2 "		sudo apt update && sudo apt install postgresql-client"
+	echo >&2 "to install it."
 	exit 1
 fi
 
 if ! [ -x "$(command -v sqlx)" ]; then
-    echo >&2 "Error: sqlx is not installed."
+	echo >&2 "Error: `sqlx` is not installed."
 	echo >&2 "Use:"
-    echo >&2 "  cargo install --version="~0.6" sqlx-cli"
-    echo >&2 "  --no-default-features --feature rustls,postgres"
-    echo >&2 "to install."
+	echo >&2 "		sudo apt install build-essential pkg-config libssl-dev"
+	echo >&2 "		cargo install --version=0.5.7 sqlx-cli --no-default-features --features postgres"
+	echo >&2 "to install it."
 	exit 1
 fi
 
-DB_USER="${POSTGRES_USER:=postgres}"
+DB_USER=${POSTGRES_USER:=postgres}
 DB_PASSWORD="${POSTGRES_PASSWORD:=password}"
 DB_NAME="${POSTGRES_DB:=newsletter}"
 DB_PORT="${POSTGRES_PORT:=5432}"
-DB_HOST="${POSTGRES_HOST:=localhost}"
 
+# Allow to skip Docker installation if Postgres is already running
 if [[ -z "${SKIP_DOCKER}" ]]
 then
 	docker run \
+		--name postgres-db \
 		-e POSTGRES_USER=${DB_USER} \
 		-e POSTGRES_PASSWORD=${DB_PASSWORD} \
 		-e POSTGRES_DB=${DB_NAME} \
 		-p "${DB_PORT}":5432 \
-        --name "mailAppDB" \
-        -d postgres:alpine \
+		-d postgres \
 		postgres -N 1000
 fi
 
-# Ping until ready to accept commands
 export PGPASSWORD="${DB_PASSWORD}"
-until psql -h "${DB_HOST}" -U "${DB_USER}" -p "${DB_PORT}" -d "postgres" -c '\q'; do
+until psql -h "localhost" -U "${DB_USER}" -p "${DB_PORT}" -d "postgres" -c '\q'; do
 	>&2 echo "Postgres is still unavailable - sleeping"
 	sleep 1
 done
 
->&2 echo "Postgres is running on port ${DB_PORT}, and ready to accept commands!"
+>&2 echo "Postgres is up and running on port ${DB_PORT} - running migrations."
 
-DATABASE_URL=postgres://${DB_USER}:${DB_PASSWORD}@${DB_HOST}:${DB_PORT}/${DB_NAME}
-export DATABASE_URL
+export DATABASE_URL=postgres://${DB_USER}:${DB_PASSWORD}@localhost:${DB_PORT}/${DB_NAME}
 sqlx database create
 sqlx migrate run
 
->&2 echo "Postgres has been migrated, ready for queries!"
+>&2 echo "Postgres has been migrated. Jobs Complete."

scripts/remove_test_dbs.sh

@@ -1,14 +0,0 @@
-#!/usr/bin/env bash
-set -x
-set -eo pipefail
-
-DB_USER="${POSTGRES_USER:=postgres}"
-DB_PASSWORD="${POSTGRES_PASSWORD:=password}"
-DB_NAME="${POSTGRES_DB:=newsletter}"
-DB_PORT="${POSTGRES_PORT:=5432}"
-DB_HOST="${POSTGRES_HOST:=localhost}"
-
-for dbname in $(psql -h "$DB_HOST" -p "$DB_PORT" -U "$DB_USER" -d "$DB_NAME" -c "copy (select datname from pg_database where datname like '%-%-%-%-%') to stdout") ; do
-    echo "dropping database $dbname"
-    dropdb -h "$DB_HOST" -p "$DB_PORT" -U "$DB_USER" "$dbname"
-done

spec.yaml

@@ -0,0 +1,41 @@
+#! spec.yaml
+name: rust-project
+
+region: sgp1
+services:
+  - name: rust-project
+    dockerfile_path: Dockerfile
+    source_dir: .
+    github:
+      repo: NickBland/mailApp
+      branch: master
+      deploy_on_push: true
+    health_check:
+      http_path: /health_check
+    http_port: 8000
+    instance_count: 1
+    instance_size_slug: basic-xxs
+    routes:
+      - path: /
+    envs:
+      - key: APP_DATABASE__USERNAME
+        scope: RUN_TIME
+        value: ${newsletter.USERNAME}
+      - key: APP_DATABASE__PASSWORD
+        scope: RUN_TIME
+        value: ${newsletter.PASSWORD}
+      - key: APP_DATABASE__HOST
+        scope: RUN_TIME
+        value: ${newsletter.HOSTNAME}
+      - key: APP_DATABASE__PORT
+        scope: RUN_TIME
+        value: ${newsletter.PORT}
+      - key: APP_DATABASE__DATABASE_NAME
+        scope: RUN_TIME
+        value: ${newsletter.DATABASE}
+databases:
+  - engine: PG
+    name: newsletter
+    num_nodes: 1
+    size: deb-s-dev-database
+    version: "12"

sqlx-data.json

@@ -0,0 +1,18 @@
+{
+  "db": "PostgreSQL",
+  "793f0df728d217c204123f12e4eafd6439db2d49d0cb506618ae9e780c7e0558": {
+    "query": "\n    INSERT INTO subscriptions (id, email, name, subscribed_at)\n    VALUES ($1, $2, $3, $4)\n            ",
+    "describe": {
+      "columns": [],
+      "parameters": {
+        "Left": [
+          "Uuid",
+          "Text",
+          "Text",
+          "Timestamptz"
+        ]
+      },
+      "nullable": []
+    }
+  }
+}

src/configuration.rs

@@ -1,6 +1,8 @@
-use secrecy::{ExposeSecret, Secret};
+use std::convert::{TryFrom, TryInto};
+
 use serde_aux::field_attributes::deserialize_number_from_string;
 use sqlx::postgres::{PgConnectOptions, PgSslMode};
+use sqlx::ConnectOptions;
 
 #[derive(serde::Deserialize)]
 pub struct Settings {
@@ -8,17 +10,6 @@ pub struct Settings {
     pub application: ApplicationSettings,
 }
 
-#[derive(serde::Deserialize)]
-pub struct DatabaseSettings {
-    pub username: String,
-    pub password: Secret<String>,
-    #[serde(deserialize_with = "deserialize_number_from_string")]
-    pub port: u16,
-    pub host: String,
-    pub database_name: String,
-    pub require_ssl: bool,
-}
-
 #[derive(serde::Deserialize)]
 pub struct ApplicationSettings {
     #[serde(deserialize_with = "deserialize_number_from_string")]
@@ -26,62 +17,15 @@ pub struct ApplicationSettings {
     pub host: String,
 }
 
-pub enum Environment {
-    Local,
-    Production,
-}
-
-impl Environment {
-    pub fn as_str(&self) -> &'static str {
-        match self {
-            Environment::Local => "local",
-            Environment::Production => "production",
-        }
-    }
-}
-
-impl TryFrom<String> for Environment {
-    type Error = String;
-
-    fn try_from(s: String) -> Result<Self, Self::Error> {
-        match s.to_lowercase().as_str() {
-            "local" => Ok(Environment::Local),
-            "production" => Ok(Environment::Production),
-            e => Err(format!(
-                "{} is not a supported environment. Use `local` or `production`",
-                e
-            )),
-        }
-    }
-}
-
-pub fn get_configuration() -> Result<Settings, config::ConfigError> {
-    let base_path = std::env::current_dir().expect("Failed to determine the current directory");
-    let configuration_directory = base_path.join("configuration");
-
-    // Detect current environment, default to LOCAL
-    let environment: Environment = std::env::var("APP_ENVIRONMENT")
-        .unwrap_or_else(|_| "local".into())
-        .try_into()
-        .expect("Failed to parse APP_ENVIRONMENT");
-    let environment_filename = format!("{}.yaml", environment.as_str());
-
-    // initialise config reader
-    let settings = config::Config::builder()
-        .add_source(config::File::from(
-            configuration_directory.join("base.yaml"),
-        ))
-        .add_source(config::File::from(
-            configuration_directory.join(environment_filename),
-        ))
-        .add_source(
-            config::Environment::with_prefix("APP")
-                .prefix_separator("_")
-                .separator("__"),
-        )
-        .build()?;
-
-    settings.try_deserialize::<Settings>()
+#[derive(serde::Deserialize)]
+pub struct DatabaseSettings {
+    pub username: String,
+    pub password: String,
+    #[serde(deserialize_with = "deserialize_number_from_string")]
+    pub port: u16,
+    pub host: String,
+    pub database_name: String,
+    pub require_ssl: bool,
 }
 
 impl DatabaseSettings {
@@ -92,14 +36,71 @@ impl DatabaseSettings {
             PgSslMode::Prefer
         };
         PgConnectOptions::new()
-            .username(&self.username)
-            .password(self.password.expose_secret())
             .host(&self.host)
+            .username(&self.username)
+            .password(&self.password)
             .port(self.port)
             .ssl_mode(ssl_mode)
     }
 
     pub fn with_db(&self) -> PgConnectOptions {
-        self.without_db().database(&self.database_name)
+        let mut options = self.without_db().database(&self.database_name);
+        options.log_statements(tracing::log::LevelFilter::Trace);
+        options
+    }
+}
+
+pub fn get_configuration() -> Result<Settings, config::ConfigError> {
+    // Initialise configuration reader
+    let mut settings = config::Config::default();
+    let base_path = std::env::current_dir().expect("Failed to determine the current directory");
+    let configuration_directory = base_path.join("configuration");
+
+    // Read default config file
+    settings.merge(config::File::from(configuration_directory.join("base")).required(true))?;
+
+    let environment: Environment = std::env::var("APP_ENVIRONMENT")
+        .unwrap_or_else(|_| "local".into())
+        .try_into()
+        .expect("Failed to parse APP_ENVIRONMENT.");
+
+    settings.merge(
+        config::File::from(configuration_directory.join(environment.as_str())).required(true),
+    )?;
+
+    settings.merge(config::Environment::with_prefix("app").separator("__"))?;
+
+    // Try convert into Settings type
+    settings.try_into()
+}
+
+pub enum Environment {
+    Local,
+    Production,
+    Drone
+}
+
+impl Environment {
+    pub fn as_str(&self) -> &'static str {
+        match self {
+            Environment::Local => "local",
+            Environment::Production => "production",
+            Environment::Drone => "drone",
+        }
+    }
+}
+
+impl TryFrom<String> for Environment {
+    type Error = String;
+
+    fn try_from(s: String) -> Result<Self, Self::Error> {
+        match s.to_lowercase().as_str() {
+            "local" => Ok(Self::Local),
+            "production" => Ok(Self::Production),
+            "drone" => Ok(Self::Drone),
+            other => Err(format!(
+                "{} is nto a supported environment. Use either `local`, `production` or `drone`.", other
+            )),
+        }
     }
 }

src/domain/mod.rs

@@ -0,0 +1,7 @@
+mod subscriber_name;
+mod subscriber_email;
+mod new_subscriber;
+
+pub use subscriber_name::SubscriberName;
+pub use new_subscriber::NewSubscriber;
+pub use subscriber_email::SubscriberEmail;

src/domain/new_subscriber.rs

@@ -0,0 +1,7 @@
+use crate::domain::SubscriberName;
+use crate::domain::SubscriberEmail;
+
+pub struct NewSubscriber {
+    pub email: SubscriberEmail,
+    pub name: SubscriberName,
+}

src/domain/subscriber_email.rs

@@ -0,0 +1,61 @@
+use validator::validate_email;
+
+#[derive(Debug)]
+pub struct SubscriberEmail(String);
+
+impl SubscriberEmail {
+    pub fn parse(s: String) -> Result<SubscriberEmail, String> {
+        if validate_email(&s) {
+            Ok(Self(s))
+        } else {
+            Err(format!("{} is not a valid email address", s))
+        }
+    }
+}
+
+impl AsRef<str> for SubscriberEmail {
+    fn as_ref(&self) -> &str {
+        &self.0
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::SubscriberEmail;
+    use claim::assert_err;
+    use fake::faker::internet::en::SafeEmail;
+    use fake::Fake;
+
+    #[test]
+    fn empty_string_is_rejected() {
+        let email = "".to_string();
+        assert_err!(SubscriberEmail::parse(email));
+    }
+
+    #[test]
+    fn email_missing_at_symbol_is_rejected() {
+        let email = "ursuladomain.com".to_string();
+        assert_err!(SubscriberEmail::parse(email));
+    }
+
+    #[test]
+    fn email_missing_subject_is_rejected() {
+        let email = "@domain.com".to_string();
+        assert_err!(SubscriberEmail::parse(email));
+    }
+
+    #[derive(Debug, Clone)]
+    struct ValidEmailFixture(pub String);
+
+    impl quickcheck::Arbitrary for ValidEmailFixture {
+        fn arbitrary<G: quickcheck::Gen>(g: &mut G) -> Self {
+            let email = SafeEmail().fake_with_rng(g);
+            Self(email)
+        }
+    }
+
+    #[quickcheck_macros::quickcheck]
+    fn valid_emails_are_parsed_successfully(valid_email: ValidEmailFixture) -> bool {
+        SubscriberEmail::parse(valid_email.0).is_ok()
+    }
+}

src/domain/subscriber_name.rs

@@ -0,0 +1,64 @@
+use unicode_segmentation::UnicodeSegmentation;
+
+#[derive(Debug)]
+pub struct SubscriberName(String);
+
+impl SubscriberName {
+    pub fn parse(s: String) -> Result<SubscriberName, String> {
+        let is_empty_or_whitespace = s.trim().is_empty(); // Remove trailing whitespaces and check if containsd any characters
+        let is_too_long = s.graphemes(true).count() > 256;
+        let forbidden_characters = ['/', '(', ')', '"', '<', '>', '\\', '{', '}'];
+        let contains_forbidden_characters = s.chars().any(|g| forbidden_characters.contains(&g)); // Iterate to check if name contains any of the forbidden characters
+    
+        // Return `false` if any conditions are violated
+        if is_empty_or_whitespace || is_too_long || contains_forbidden_characters {
+            Err(format!("{} is not a valid subscriber name", s))
+        } else {
+            Ok(Self(s))
+        }
+    }
+}
+
+impl AsRef<str> for SubscriberName {
+    fn as_ref(&self) -> &str {
+        &self.0
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::domain::SubscriberName;
+    use claim::{assert_err, assert_ok};
+
+    #[test]
+    fn a_name_longer_than_256_graphemes_is_rejected() {
+        let name = "a".repeat(257);
+        assert_err!(SubscriberName::parse(name));
+    }
+
+    #[test]
+    fn whitespace_only_names_are_rejected() {
+        let name = " ".to_string();
+        assert_err!(SubscriberName::parse(name));
+    }
+
+    #[test]
+    fn empty_string_is_rejected() {
+        let name = "".to_string();
+        assert_err!(SubscriberName::parse(name));
+    }
+
+    #[test]
+    fn names_containing_invalid_characters_are_rejected() {
+        for name in &['/', '(', ')', '"', '<', '>', '\\', '{', '}'] {
+            let name = name.to_string();
+            assert_err!(SubscriberName::parse(name));
+        }
+    }
+
+    #[test]
+    fn a_valid_name_is_parsed_successfully() {
+        let name = "Ursula Le Guin".to_string();
+        assert_ok!(SubscriberName::parse(name));
+    }
+}

src/lib.rs

@@ -1,4 +1,6 @@
+#![allow(clippy::toplevel_ref_arg)]
 pub mod configuration;
 pub mod routes;
 pub mod startup;
 pub mod telemetry;
+pub mod domain;

src/main.rs

@@ -1,20 +1,26 @@
-use mail_app::configuration::get_configuration;
-use mail_app::startup::run;
-use mail_app::telemetry::{get_subscriber, init_subscriber};
-use sqlx::postgres::PgPoolOptions;
 use std::net::TcpListener;
+use sqlx::postgres::PgPoolOptions;
+
+use mail_app::startup::run;
+use mail_app::configuration::get_configuration;
+use mail_app::telemetry::{get_subscriber, init_subscriber};
 
 #[tokio::main]
-async fn main() -> Result<(), std::io::Error> {
+async fn main() -> std::io::Result<()> {
     let subscriber = get_subscriber("mail_app".into(), "info".into(), std::io::stdout);
     init_subscriber(subscriber);
 
-    let configuration = get_configuration().expect("Failed to read configuration");
-    let connection_pool = PgPoolOptions::new().connect_lazy_with(configuration.database.with_db());
-    let address = format!(
-        "{}:{}",
-        configuration.application.host, configuration.application.port
-    );
+    // Attempt to read from config
+    let configuration = get_configuration().expect("Failed to read configuration data.");
+
+    // Configure connection to database for our startup
+    let connection_pool = PgPoolOptions::new()
+        .connect_timeout(std::time::Duration::from_secs(2))
+        .connect_lazy_with(configuration.database.with_db());
+
+    // Take port from settings file
+    let address = format!("{}:{}", configuration.application.host, configuration.application.port);
     let listener = TcpListener::bind(address)?;
-    run(listener, connection_pool)?.await
+    run(listener, connection_pool)?.await?;
+    Ok(())
 }

src/routes/subscriptions.rs

@@ -1,14 +1,27 @@
 use actix_web::{web, HttpResponse};
-use chrono::Utc;
 use sqlx::PgPool;
+use chrono::Utc;
 use uuid::Uuid;
 
+use crate::domain::{NewSubscriber, SubscriberName, SubscriberEmail};
+
 #[derive(serde::Deserialize)]
 pub struct FormData {
     email: String,
-    name: String,
+    name: String
 }
 
+impl TryFrom<FormData> for NewSubscriber {
+    type Error = String;
+
+    fn try_from(value: FormData) -> Result<Self, Self::Error> {
+        let name = SubscriberName::parse(value.name)?;
+        let email = SubscriberEmail::parse(value.email)?;
+        Ok(Self { email, name })
+    }
+}
+
+#[allow(clippy::async_yields_async)]
 #[tracing::instrument(
     name = "Adding a new subscriber",
     skip(form, pool),
@@ -17,9 +30,12 @@ pub struct FormData {
         subscriber_name = %form.name
     )
 )]
-
-pub async fn subscribe(form: web::Form<FormData>, pool: web::Data<PgPool>) -> HttpResponse {
-    match insert_subscriber(&pool, &form).await {
+pub async fn subscribe(form: web::Form<FormData>, pool: web::Data<PgPool>,) -> HttpResponse {
+    let new_subscriber = match form.0.try_into() {
+        Ok(form) => form,
+        Err(_) => return HttpResponse::BadRequest().finish(),
+    };
+    match insert_subscriber(&pool, &new_subscriber).await {
         Ok(_) => HttpResponse::Ok().finish(),
         Err(_) => HttpResponse::InternalServerError().finish(),
     }
@@ -27,18 +43,17 @@ pub async fn subscribe(form: web::Form<FormData>, pool: web::Data<PgPool>) -> Ht
 
 #[tracing::instrument(
     name = "Saving new subscriber details in the database",
-    skip(form, pool)
+    skip(new_subscriber, pool)
 )]
-
-pub async fn insert_subscriber(pool: &PgPool, form: &FormData) -> Result<(), sqlx::Error> {
+pub async fn insert_subscriber(pool: &PgPool, new_subscriber: &NewSubscriber) -> Result<(), sqlx::Error> {
     sqlx::query!(
         r#"
     INSERT INTO subscriptions (id, email, name, subscribed_at)
     VALUES ($1, $2, $3, $4)
             "#,
         Uuid::new_v4(),
-        form.email,
-        form.name,
+        new_subscriber.email.as_ref(),
+        new_subscriber.name.as_ref(),
         Utc::now()
     )
     .execute(pool)

src/startup.rs

@@ -1,10 +1,12 @@
-use crate::routes::{health_check, subscribe};
+use actix_web::{web, App, HttpServer};
 use actix_web::dev::Server;
-use actix_web::{web, web::Data, App, HttpServer};
-use sqlx::PgPool;
+use actix_web::web::Data;
 use std::net::TcpListener;
+use sqlx::PgPool;
 use tracing_actix_web::TracingLogger;
 
+use crate::routes::{health_check, subscribe};
+
 pub fn run(listener: TcpListener, db_pool: PgPool) -> Result<Server, std::io::Error> {
     let db_pool = Data::new(db_pool);
     let server = HttpServer::new(move || {

src/telemetry.rs

@@ -1,18 +1,18 @@
-use tracing::{subscriber::set_global_default, Subscriber};
+use tracing::{Subscriber, subscriber::set_global_default};
 use tracing_bunyan_formatter::{BunyanFormattingLayer, JsonStorageLayer};
 use tracing_log::LogTracer;
-use tracing_subscriber::{fmt::MakeWriter, layer::SubscriberExt, EnvFilter, Registry};
+use tracing_subscriber::{layer::SubscriberExt, EnvFilter, Registry, fmt::MakeWriter};
 
+/// Compose multiple layers into a tracing compatible subscriber
 pub fn get_subscriber<Sink>(
     name: String,
     env_filter: String,
     sink: Sink,
-) -> impl Subscriber + Send + Sync
+) -> impl Subscriber + Sync + Send
 where
     Sink: for<'a> MakeWriter<'a> + Send + Sync + 'static,
 {
-    let env_filter =
-        EnvFilter::try_from_default_env().unwrap_or_else(|_| EnvFilter::new(env_filter));
+    let env_filter = EnvFilter::try_from_default_env().unwrap_or_else(|_| EnvFilter::new(env_filter));
     let formatting_layer = BunyanFormattingLayer::new(name, sink);
     Registry::default()
         .with(env_filter)
@@ -20,7 +20,8 @@ where
         .with(formatting_layer)
 }
 
-pub fn init_subscriber(subscriber: impl Subscriber + Send + Sync) {
-    LogTracer::init().expect("Failed to set logger.");
-    set_global_default(subscriber).expect("Failed to set subscriber.");
+/// Register a subscriber as global default to process span data.
+pub fn init_subscriber(subscriber: impl Subscriber + Sync + Send) {
+    LogTracer::init().expect("Failed to set logger");
+    set_global_default(subscriber).expect("Failed to set subscriber");
 }

tests/health_check.rs

@@ -1,10 +1,16 @@
-use mail_app::configuration::{get_configuration, DatabaseSettings};
-use mail_app::startup::run;
-use mail_app::telemetry::{get_subscriber, init_subscriber};
-use once_cell::sync::Lazy;
-use sqlx::{Connection, Executor, PgConnection, PgPool};
 use std::net::TcpListener;
+use sqlx::{Connection, Executor, PgConnection, PgPool};
 use uuid::Uuid;
+use once_cell::sync::Lazy;
+
+use mail_app::startup::run;
+use mail_app::configuration::{get_configuration, DatabaseSettings};
+use mail_app::telemetry::{get_subscriber, init_subscriber};
+
+pub struct TestApp {
+    pub address: String,
+    pub db_pool: PgPool,
+}
 
 static TRACING: Lazy<()> = Lazy::new(|| {
     let default_filter_level = "info".to_string();
@@ -18,26 +24,23 @@ static TRACING: Lazy<()> = Lazy::new(|| {
     };
 });
 
-pub struct TestApp {
-    pub address: String,
-    pub db_pool: PgPool,
-}
-
+// Create new instance of the application on a random port and return address [`http://localhost:XXXX`]
 async fn spawn_app() -> TestApp {
     Lazy::force(&TRACING);
 
-    let listener = TcpListener::bind("127.0.0.1:0").expect("Failed to bind to random port.");
+    let listener = TcpListener::bind("127.0.0.1:0")
+        .expect("Failed to bind to random port");
     let port = listener.local_addr().unwrap().port();
     let address = format!("http://127.0.0.1:{}", port);
 
-    let mut configuration = get_configuration().expect("Failed to read configuration");
-    configuration.database.database_name = Uuid::new_v4().to_string();
+    let mut configuration = get_configuration()
+        .expect("Failed to read configuration.");
+    configuration.database.database_name = Uuid::new_v4().to_string(); // Adjust database string to be random!
     let connection_pool = configure_database(&configuration.database).await;
 
-    let server = run(listener, connection_pool.clone()).expect("Failed to bind address");
-    // Launch in background
+    let server = run(listener, connection_pool.clone())
+        .expect("Failed to bind address");
     let _ = tokio::spawn(server);
-
     TestApp {
         address,
         db_pool: connection_pool,
@@ -45,25 +48,24 @@ async fn spawn_app() -> TestApp {
 }
 
 pub async fn configure_database(config: &DatabaseSettings) -> PgPool {
-    // Create Database
+    // Create database
     let mut connection = PgConnection::connect_with(&config.without_db())
         .await
-        .expect("Failed to connect to Postgres.");
+        .expect("Failed to connect to Postgres");
     connection
-        .execute(format!(r#"CREATE DATABASE "{}";"#, config.database_name).as_str())
+        .execute(&*format!(r#"CREATE DATABASE "{}";"#, config.database_name))
         .await
         .expect("Failed to create database.");
 
-    // Migrate Database
+    // Migrate database
     let connection_pool = PgPool::connect_with(config.with_db())
         .await
         .expect("Failed to connect to Postgres.");
     sqlx::migrate!("./migrations")
         .run(&connection_pool)
         .await
-        .expect("Failed to migrate the database.");
+        .expect("Failed to migrate the database");
 
-    // Return connection pool
     connection_pool
 }
 
@@ -78,21 +80,21 @@ async fn health_check_works() {
         .get(&format!("{}/health_check", &app.address))
         .send()
         .await
-        .expect("Failed to execute request");
+        .expect("Failed to execute request.");
 
-    // Assert
+    // Assert our test
     assert!(response.status().is_success());
     assert_eq!(Some(0), response.content_length());
 }
 
 #[tokio::test]
-async fn subscribe_returns_a_200_for_valid_form_data() {
+async fn subscribe_returns_200_for_valid_form_data() {
     // Arrange
     let app = spawn_app().await;
     let client = reqwest::Client::new();
+    let body = "name=le%20guin&email=ursula_le_guin%40gmail.com";
 
     // Act
-    let body = "name=le%20guin&email=ursula_le_guin%40gmail.com";
     let response = client
         .post(&format!("{}/subscriptions", &app.address))
         .header("Content-Type", "application/x-www-form-urlencoded")
@@ -101,7 +103,7 @@ async fn subscribe_returns_a_200_for_valid_form_data() {
         .await
         .expect("Failed to execute request.");
 
-    // Assert
+    // Assert test
     assert_eq!(200, response.status().as_u16());
 
     let saved = sqlx::query!("SELECT email, name FROM subscriptions",)
@@ -114,14 +116,14 @@ async fn subscribe_returns_a_200_for_valid_form_data() {
 }
 
 #[tokio::test]
-async fn subscribe_returns_a_400_when_data_is_missing() {
+async fn subscribe_returns_400_for_missing_form_data() {
     //Arrange
     let app = spawn_app().await;
     let client = reqwest::Client::new();
     let test_cases = vec![
-        ("name=le%20guin", "missing email"),
-        ("email=ursula_le_guin%40gmail.com", "missing name"),
-        ("", "missing both name and email"),
+        ("name=le%20guin", "missing the email"),
+        ("email=ursula_le_guin%40gmail.com", "missing the name"),
+        ("", "missing both name and email")
     ];
 
     for (invalid_body, error_message) in test_cases {
@@ -138,8 +140,37 @@ async fn subscribe_returns_a_400_when_data_is_missing() {
         assert_eq!(
             400,
             response.status().as_u16(),
-            "The API id not fail wth 400 Bad Request when the payload was {}.",
-            error_message
+            // Customised error message on test failure
+            "The API did not fail with 400 Bad Request when the payload was {}.", error_message
+        );
+    }
+}
+
+#[tokio::test]
+async fn subscribe_returns_a_400_when_fields_are_present_but_empty() {
+    // Arrange
+    let app = spawn_app().await;
+    let client = reqwest::Client::new();
+    let test_cases = vec![
+        ("name=&email=ursula_le_guin%40gmail.com", "empty name"),
+        ("name=Ursula&email=", "empty email"),
+        ("name=Ursula&email=definitely-not-an-email", "invalid email"),
+    ];
+
+    for (body, description) in test_cases {
+        // Act
+        let response = client
+            .post(&format!("{}/subscriptions", &app.address))
+            .header("Content-Type", "application/x-www-form-urlencoded")
+            .body(body)
+            .send()
+            .await
+            .expect("Failed to execute request.");
+
+        // Assert
+        assert_eq!(400,
+            response.status().as_u16(),
+            "The API did not return a 400 Bad Request when the payload was {}.", description
         );
     }
 }