Design (LLD) Ride sharing service - Machine CodingSubhahu Jain·Dec 30, 2022·9 min readTable of contentsCodeIssues in Above Design1️⃣ No Ride Lifecycle / State Machine (Major LLD Issue)ProblemMissing StatesWhy This MattersInterview ExpectationSolution2️⃣ Driver Assignment Is Race-Prone (Critical Concurrency Bug)ProblemConcurrency IssueReal-World FailureInterview Red Flag 🚨Solution3️⃣ No Driver Availability / LockingMissing ConceptsRequired InvariantSolution4️⃣ Observer Pattern Is Not Thread-SafeProblemConcurrency IssuesWorseImpactSolution5️⃣ Notifications Are Coupled to Core Flow (LLD Issue)ProblemDesign IssueInterview InsightSolution6️⃣ Ride Acceptance Is Not IdempotentProblemConcurrency IssueReal-World EffectSolution7️⃣ Pricing Strategy Is Too Naive (LLD Issue)ProblemMissing FactorsInterview ExpectationSolution8️⃣ Payment Is Not TransactionalProblemMissingConcurrency RiskSolution9️⃣ Ratings System Can Be CorruptedProblemMissing GuardsConcurrency IssueSolution🔟 Databases Are Not Thread-SafeProblemConcurrency IssueInterview ExpectationSolution11️⃣ No Matching Strategy AbstractionProblemMissing StrategiesLLD GapSolution12️⃣ No Cancellation Rules or DeadlinesMissing EntirelyReal-World RequirementSolutionJavaScriptProgramming BlogsPythonGeneral Programmingalgorithms
