Database locks ensure data consistency in concurrent access. I understand lock types—row, table, advisory. Shared locks allow concurrent reads. Exclusive locks prevent all access. Understanding lock granularity prevents contention. Deadlocks occur whe

ES6 modules organize code into separate files with export and import statements. I use export default for single main export and export { name } for named exports. The import { name } from './module.js' syntax imports specific exports. Using import *

Terraform modules encapsulate related resources into reusable, composable packages. A module is simply a directory with .tf files. The root module calls child modules with the module block. Input variable blocks parameterize modules. output blocks exp

once_cell provides Lazy and OnceCell for safe lazy initialization. Unlike lazy_static!, it doesn't require macros. Lazy<T> is initialized on first access via a closure. I use it for config, regex patterns, or expensive-to-create globals. OnceCel

Custom middleware intercepts all requests and responses. I implement __init__ and __call__ methods. Middleware can modify requests before views, modify responses after views, or short-circuit entirely. Common uses include authentication, logging, CORS

Outlets allow Stimulus controllers to reference and communicate with other controller instances, enabling composition without tight coupling. I define outlets by specifying which controller types to connect to, and Stimulus automatically finds matchin

Session-based apps still need CSRF protection even when the API is ‘JSON’. I like the double-submit cookie approach: set a CSRF token cookie, require the client to echo it in x-csrf-token, and verify they match. The reason I prefer this is that it doe

For gRPC services, GracefulStop is ideal because it allows in-flight RPCs to finish, but it can hang if handlers ignore cancellation or if clients never close streams. I wrap shutdown in a deadline: call GracefulStop in a goroutine, and if it doesn’t

Offset pagination falls apart as soon as rows are inserted or deleted between page fetches—users see duplicates or missing items. Cursor pagination fixes that with stable ordering and ‘seek’ queries. I use a compound cursor that includes both the prim

Query scopes encapsulate common query constraints into reusable methods on models. Local scopes prefix methods with scope and accept a query builder plus additional parameters. I chain scopes fluently—Post::published()->featured()->get(). Global

Multi-tenancy allows multiple clients to share one application with isolated data. I use django-tenant-schemas for PostgreSQL schema-based isolation. Each tenant gets a separate schema (database namespace). The middleware routes requests to correct te

Most of the time I prefer *.turbo_stream.erb templates, but for small one-off responses it can be nice to generate streams directly in the controller using Turbo::Streams::TagBuilder. This keeps the logic close to the action and avoids creating a temp