Make application dockerised

Update mail_app to also have different forms of configuration outside of a single base yaml file. Allows local or production configurations to be established.

.Dockerignore

@@ -0,0 +1,2 @@
+/target
+.vscode

.gitignore

@@ -1,2 +1,3 @@
 /target
-.vscode
+.vscode
+.env

Cargo.lock

@@ -547,6 +547,9 @@ name = "either"
 version = "1.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e78d4f1cc4ae33bbfc157ed5d5a5ef3bc29227303d595861deb238fcec4e9457"
+dependencies = [
+ "serde 1.0.130",
+]
 
 [[package]]
 name = "encoding_rs"
@@ -1631,6 +1634,7 @@ version = "1.0.68"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0f690853975602e1bfe1ccbf50504d67174e3bcf340f23b5ea9992e0587a52d8"
 dependencies = [
+ "indexmap",
  "itoa",
  "ryu",
  "serde 1.0.130",
@@ -1810,9 +1814,12 @@ dependencies = [
  "dotenv",
  "either",
  "heck",
+ "hex",
  "once_cell",
  "proc-macro2",
  "quote",
+ "serde 1.0.130",
+ "serde_json",
  "sha2",
  "sqlx-core",
  "sqlx-rt",

Cargo.toml

@@ -29,7 +29,8 @@ features = [
     "postgres",
     "uuid",
     "chrono",
-    "migrate"
+    "migrate",
+    "offline"
 ]
 
 [dev-dependencies]

Dockerfile

@@ -0,0 +1,11 @@
+FROM rust:1.56
+
+WORKDIR /app
+
+COPY . .
+ENV SQLX_OFFLINE true
+RUN CARGO BUILD --release
+
+ENV APP_ENVIRONMENT production
+
+ENTRYPOINT ["./target/release/mail_app"]

configuration/base.yaml

@@ -1,4 +1,5 @@
-application_port: 8000
+application:
+  port: 8000
 database:
   host: "localhost"
   port: 5432

configuration/local.yaml

@@ -0,0 +1,2 @@
+application:
+  host: 127.0.0.1

configuration/production.yaml

@@ -0,0 +1,2 @@
+application:
+  host: 0.0.0.0

sqlx-data.json

@@ -0,0 +1,18 @@
+{
+  "db": "PostgreSQL",
+  "5db1f9dfcdee685b02851f144e29d3e2726127d5a1d614880a0be89d8fa6904b": {
+    "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

@@ -1,7 +1,15 @@
+use std::convert::{TryFrom, TryInto};
+
 #[derive(serde::Deserialize)]
 pub struct Settings {
     pub database: DatabaseSettings,
-    pub application_port: u16
+    pub application: ApplicationSettings,
+}
+
+#[derive(serde::Deserialize)]
+pub struct ApplicationSettings {
+    pub port: u16,
+    pub host: String,
 }
 
 #[derive(serde::Deserialize)]
@@ -16,14 +24,55 @@ pub struct DatabaseSettings {
 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");
 
-    // Add config from `configuration` file (yaml, json, etc.)
-    settings.merge(config::File::with_name("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,
+}
+
+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(Self::Local),
+            "production" => Ok(Self::Production),
+            other => Err(format!(
+                "{} is nto a supported environment. Use either `local` or `production`.", other
+            )),
+        }
+    }
+}
+
 impl DatabaseSettings {
     pub fn connection_string(&self) -> String {
         format!(

src/main.rs

@@ -13,12 +13,11 @@ async fn main() -> std::io::Result<()> {
     let configuration = get_configuration().expect("Failed to read configuration data.");
 
     // Configure connection to database for our startup
-    let connection_pool = PgPool::connect(&configuration.database.connection_string())
-        .await
+    let connection_pool = PgPool::connect_lazy(&configuration.database.connection_string())
         .expect("Failed to connect to Postgres.");
 
     // Take port from settings file
-    let address = format!("127.0.0.1:{}", configuration.application_port);
+    let address = format!("{}:{}", configuration.application.host, configuration.application.port);
     let listener = TcpListener::bind(address)?;
     run(listener, connection_pool)?.await?;
     Ok(())