Add DB migrations table

src/app.rs

@@ -15,6 +15,5 @@ struct IndexTemplate<'a> {
 }
 
 async fn root<'a>(State(database): State<Database>) -> IndexTemplate<'a> {
-    println!("Found {} users", database.log_num_users().await);
     IndexTemplate { title: "LocalHub" }
 }

src/db.rs

@@ -5,27 +5,52 @@ use {
 };
 
 #[derive(Error, Debug)]
-pub enum Error {
+pub enum InitialisationError {
     #[error("Could not initialize DB connection pool.")]
     ConnectionPoolError(#[from] CreatePoolError),
 }
 
+#[derive(Error, Debug)]
+pub enum Error {
+    #[error("")]
+    PoolError(#[from] deadpool_postgres::PoolError),
+    #[error("")]
+    DbError(#[from] tokio_postgres::Error)
+}
+
 #[derive(Clone)]
 pub struct Database {
-    pg_pool: Pool,
+    connection_pool: Pool,
 }
 
 impl Database {
-    pub fn create_pool(connection_url: &str) -> Result<Database, Error> {
+    pub fn create_pool(connection_url: &str) -> Result<Database, InitialisationError> {
         let mut config = deadpool_postgres::Config::new();
         config.url = Some(connection_url.to_string());
         let pg_pool = config.create_pool(Some(Runtime::Tokio1), NoTls)?;
-        Ok(Database { pg_pool })
+        Ok(Database { connection_pool: pg_pool })
     }
 
-    pub async fn log_num_users(&self) -> usize {
-        let client = self.pg_pool.get().await.unwrap();
-        let results = client.query("SELECT * FROM users;", &[]).await.unwrap();
-        results.len()
+    pub async fn get_db_version(&self) -> Result<i32, Error> {
+        let client = self.connection_pool.get().await?;
+        client.execute(r#"
+            DO $$BEGIN
+              IF NOT EXISTS 
+                ( SELECT 1
+                    FROM  information_schema.tables
+                    WHERE table_schema = 'public'
+                    AND   table_name = 'migration_info'
+                )
+              THEN
+                  CREATE TABLE migration_info (
+                     onerow_id bool PRIMARY KEY DEFAULT true,
+                     migration_version INTEGER,
+                     CONSTRAINT onerow_unique CHECK (onerow_id));
+                  INSERT
+                    INTO migration_info (migration_version)
+                    VALUES (-1);
+              END IF;
+            END$$;"#, &[]).await?;
+        Ok(client.query_one(r#"SELECT migration_version FROM migration_info;"#, &[]).await?.get(0))
     }
 }

src/main.rs

@@ -13,7 +13,7 @@ pub enum Error {
     MissingConfigError(#[from] config::Error),
 
     #[error("Database error: {0}")]
-    DatabaseError(#[from] db::Error),
+    DatabaseError(#[from] db::InitialisationError),
 
     #[error("{0}")]
     IOError(#[from] std::io::Error),
@@ -35,6 +35,8 @@ async fn localhub_main() -> Result<(), Error> {
 
     let db_pool = Database::create_pool(&config.database_url)?;
 
+    dbg!(db_pool.get_db_version().await.unwrap());
+
     let app = app::routes()
         .with_state(db_pool)
         .nest_service("/static", ServeDir::new(&config.static_file_path));