register with optional role in the post request

server/src/auth/docs/role_added.txt

@@ -0,0 +1,37 @@
+❯ grpcurl -plaintext -d '{
+  "username": "testuser_default_role",
+  "email": "default@example.com",
+  "password": "password",
+  "password_confirmation": "password"
+}' localhost:50051 multieko2.auth.AuthService/Register
+{
+  "id": "73017288-af41-49d8-b4cb-2ac2109b38a1",
+  "username": "testuser_default_role",
+  "email": "default@example.com",
+  "role": "accountant"
+}
+❯ grpcurl -plaintext -d '{
+  "username": "testuser_admin_role",
+  "email": "admin@example.com",
+  "password": "password",
+  "password_confirmation": "password",
+  "role": "admin"
+}' localhost:50051 multieko2.auth.AuthService/Register
+{
+  "id": "9437e318-818b-4c34-822d-c2d6601b835e",
+  "username": "testuser_admin_role",
+  "email": "admin@example.com",
+  "role": "admin"
+}
+❯ grpcurl -plaintext -d '{
+  "username": "testuser_invalid_role",
+  "email": "invalid@example.com",
+  "password": "password",
+  "password_confirmation": "password",
+  "role": "invalid_role_name"
+}' localhost:50051 multieko2.auth.AuthService/Register
+ERROR:
+  Code: InvalidArgument
+  Message: Invalid role specified: 'invalid_role_name'
+╭─     ~/Doc/pr/multieko2/server     main +3 !1 
+╰─

server/src/auth/handlers/register.rs

@@ -5,6 +5,8 @@ use common::proto::multieko2::auth::{RegisterRequest, AuthResponse};
 use crate::db::PgPool;
 use crate::auth::models::AuthError;
 
+const DEFAULT_ROLE: &str = "accountant";
+
 pub async fn register(
     pool: &PgPool,
     payload: RegisterRequest,
@@ -18,20 +20,28 @@ pub async fn register(
     let password_hash = hash(payload.password, DEFAULT_COST)
         .map_err(|e| Status::internal(AuthError::HashingError(e.to_string()).to_string()))?;
 
+    let role_to_insert = if payload.role.is_empty() { DEFAULT_ROLE } else { &payload.role };
+
     // Insert user
     let user = sqlx::query!(
         r#"
         INSERT INTO users (username, email, password_hash, role)
-        VALUES ($1, $2, $3, 'accountant')
+        VALUES ($1, $2, $3, $4)
         RETURNING id, username, email, role
         "#,
         payload.username,
         payload.email,
-        password_hash
+        password_hash,
+        role_to_insert
     )
     .fetch_one(pool)
     .await
     .map_err(|e| {
+        if let Some(db_err) = e.as_database_error() {
+            if db_err.constraint() == Some("valid_roles") {
+                return Status::invalid_argument(format!("Invalid role specified: '{}'", role_to_insert));
+            }
+        }
         if e.to_string().contains("duplicate key") {
             Status::already_exists(AuthError::UserExists.to_string())
         } else {