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Lessons (25)

• Dependencies, Data Sources, and Resource Lifecycle

  Understand the dependency graph, read existing infrastructure, and reason about replacements and lifecycle safeguards. References create a graph …

• NestJS Core Concepts

  … modules, controllers, providers and dependency injection, then the request lifecycle of middleware, guards, interceptors, pipes and exception filters …

• S3: Store Files Safely

  … upload file directly Cost control Use lifecycle rules: move old files to a cheaper storage class or delete …

• Testing, Preconditions, and Policy Checks

  Use validation, lifecycle conditions, Terraform tests, and policy checks to catch different classes of errors. Different checks answer …

• Storage, Search and Location Queries

  … suitable read systems while preserving one authoritative listing lifecycle and bounded stale exposure. Practical response 1. Store photo …

• Production Capstone and Interview Practice

  … Keep backend lifecycle and production destruction controls separate from routine lab cleanup. Interview practice Why is state needed …

• Microkernel (Plugin) Architecture

  … registry + lifecycle ts // core/processor.ts export class MarkdownProcessor { private plugins: MarkdownPlugin[] = []; use(plugin: MarkdownPlugin): this { if (this …

• Internals, Upgrades, Resilience and Interview Questions

  … What is an Operator? A CRD plus a controller that automates the lifecycle of an application using a …

• Product-Scale Frontend Patterns

  … when it is only queued. Feature flags need lifecycle ownership Flags decouple deployment from release, but old flags …

• Containers at Scale: ECS Deep Dive and EKS

  … Option Notes --- --- Managed node groups AWS manages EC2 lifecycle and rolling upgrades Karpenter Provisions the right instance for …

• Count, for_each, Functions, and Stable Identities

  … It does not create separate resource instances and cannot generate lifecycle meta-arguments. Prefer ordinary resource for each …

• Cost Optimization and the Well-Architected Framework

  … instance types and capacity-optimized allocation. S3 - Use Lifecycle rules and Intelligent-Tiering when access patterns are unknown …

• Reusable Modules and Clear Interfaces

  … This is a useful abstraction because it bundles a policy and lifecycle boundary. Avoid modules that simply rename …

• Behavioral Patterns II: Chain, Template, Iterator, Mediator, Memento, Visitor

  … used it: React class lifecycle methods, test frameworks ( beforeEach → test → afterEach ), NestJS lifecycle hooks. 💡 Modern alternative: pass the …

• Design a Logging and Monitoring Platform

  … Measure ingestion lag, dropped samples, query latency, cardinality and storage cost. Design the data lifecycle Collect structured events …

• Imports, Moved Blocks, and Safe Refactoring

  … use: hcl removed { from = aws s3 bucket.assets lifecycle { destroy = false } } The object remains in AWS but leaves …

• Practical Lab: S3 File Upload and CloudFront Delivery with NestJS

  … 7 } } ] } EOF aws s3api put-bucket-lifecycle-configuration --bucket $BUCKET \ --lifecycle-configuration file://lifecycle.json Verify: bash aws …

• Design a File Storage Service

  … A reconciler checks the object/session and retries finalization; a lifecycle policy removes abandoned parts. Already-issued signed …

• Database Relations & Foreign Keys

  … Do not split tables merely because two columns look related; a profile with the same lifecycle can live …

• Proxies, APIs and Real-Time Protocols

  … Repeated connections Live two-way chat WebSocket Connection lifecycle/fan-out Ordered reliable bytes TCP More overhead Loss …

• Scalable Frontend Architecture

  … and mutation queries.ts cache keys and data lifecycle components/ui/ Button, Dialog, Input: no order rules lib …

• Drift, Troubleshooting, and Disaster Recovery

  … broad depends on Remove the cycle or separate lifecycle stages Resource already exists Import ownership, wrong state key …

• EC2, Storage and Auto Scaling

  … disk RDS Relational application records Separate managed database lifecycle Many EC2 filesystems are on EBS, so “on the …

• 500 Users Upload Documents at Once: Design the Background Job Pipeline

  … job, you have an orphan file that a lifecycle rule can clean up. If it died after inserting …

• Practical Project: Deploy a Real CRM App on EKS

  … CMD ["node", "dist/main.js"] Add an ECR lifecycle policy to delete untagged images and keep only the …