react-rust-postgres: add connection to postgres with migrations

Signed-off-by: Jérémie Drouet <jeremie.drouet@gmail.com>

react-rust-postgres/backend/src/main.rs

@@ -1,12 +1,32 @@
 #![feature(proc_macro_hygiene, decl_macro)]
 
+#[macro_use]
+extern crate diesel;
+#[macro_use]
+extern crate diesel_migrations;
 #[macro_use]
 extern crate rocket;
 #[macro_use]
 extern crate serde_derive;
+#[macro_use]
 extern crate rocket_contrib;
 
+mod schema;
+mod user;
+
+use rocket::config::{Config, Environment, Value};
+use rocket::fairing::AdHoc;
 use rocket_contrib::json::Json;
+use std::collections::HashMap;
+use std::env;
+
+// This macro from `diesel_migrations` defines an `embedded_migrations` module
+// containing a function named `run`. This allows the example to be run and
+// tested without any outside setup of the database.
+embed_migrations!();
+
+#[database("my_db")]
+struct MyDBConn(diesel::PgConnection);
 
 #[derive(Serialize)]
 struct HelloMessage {
@@ -14,12 +34,63 @@ struct HelloMessage {
 }
 
 #[get("/")]
-fn index() -> Json<HelloMessage> {
+fn index(conn: MyDBConn) -> Json<HelloMessage> {
+    let result = match user::User::all(&*conn) {
+        Ok(res) => res.len(),
+        Err(_) => 0,
+    };
+
     Json(HelloMessage {
-        message: String::from("Hello, world"),
+        message: format!("Hello with {} users", result),
     })
 }
 
-fn main() {
-    rocket::ignite().mount("/", routes![index]).launch();
+fn get_config() -> Config {
+    let mut database_config = HashMap::new();
+    let mut databases = HashMap::new();
+
+    let env_address = env::var("ROCKET_ADDRESS")
+        .or::<String>(Ok(String::from("localhost")))
+        .unwrap();
+
+    let env_mode = env::var("ROCKET_ENV")
+        .or(Ok(String::from("development")))
+        .and_then(|value| value.parse::<Environment>())
+        .unwrap();
+
+    let database_url = match env::var("DATABASE_URL") {
+        Ok(value) => value,
+        Err(_) => String::from("postgres://localhost/postgres"),
+    };
+
+    database_config.insert("url", Value::from(database_url));
+    databases.insert("my_db", Value::from(database_config));
+
+    let config = Config::build(env_mode)
+        .address(env_address)
+        .extra("databases", databases)
+        .finalize()
+        .unwrap();
+
+    config
+}
+
+fn run_db_migrations(r: rocket::Rocket) -> Result<rocket::Rocket, rocket::Rocket> {
+    let conn = MyDBConn::get_one(&r).expect("database connection");
+    match embedded_migrations::run(&*conn) {
+        Ok(()) => Ok(r),
+        Err(e) => {
+            println!("Failed to run database migrations: {:?}", e);
+            Err(r)
+        }
+    }
+}
+
+fn main() {
+    let config = get_config();
+    rocket::custom(config)
+        .attach(MyDBConn::fairing())
+        .attach(AdHoc::on_attach("Database Migrations", run_db_migrations))
+        .mount("/", routes![index])
+        .launch();
 }