{ "policy": { "version": 5, "patterns": { "version": 1, "method": "CURATED_PRACTICE_TOPIC", "notice": "Pattern topics identify design choices to practice. Read the ticket's acceptance criteria and justify the simplest suitable approach. Tags are not capability or ownership evidence; an untagged ticket has no curated pattern topic assigned." }, "fieldMix": { "version": 1, "method": "CURATED_ESTIMATE", "notice": "Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence." }, "contentStatus": "PRACTICE_BRIEF", "assessmentStatus": "NOT_QUALIFIED", "evidenceUse": "NONE", "aiPolicy": "AI tools are welcome during implementation. Record assumptions, review the result, and verify its behavior.", "notice": "Fictional engineering practice briefs. Starter repositories, fixtures, automated grading, and verified ownership are not included.", "outcomeEvidence": "Tests, patches, and runbooks are requested deliverables. They become Outcome Evidence only through a qualified Mission and immutable Evidence IDs.", "ownershipEvidence": "Independent adaptation must be observed under a declared verification policy and cite immutable Evidence IDs. Completing a planning ticket establishes no Ownership Evidence." }, "patternTopics": [ { "id": "factory-method", "label": "Factory Method", "group": "Creational" }, { "id": "abstract-factory", "label": "Abstract Factory", "group": "Creational" }, { "id": "builder", "label": "Builder", "group": "Creational" }, { "id": "prototype", "label": "Prototype", "group": "Creational" }, { "id": "singleton", "label": "Singleton", "group": "Creational" }, { "id": "adapter", "label": "Adapter", "group": "Structural" }, { "id": "bridge", "label": "Bridge", "group": "Structural" }, { "id": "composite", "label": "Composite", "group": "Structural" }, { "id": "decorator", "label": "Decorator", "group": "Structural" }, { "id": "facade", "label": "Facade", "group": "Structural" }, { "id": "flyweight", "label": "Flyweight", "group": "Structural" }, { "id": "proxy", "label": "Proxy", "group": "Structural" }, { "id": "chain-of-responsibility", "label": "Chain of Responsibility", "group": "Behavioral" }, { "id": "command", "label": "Command", "group": "Behavioral" }, { "id": "interpreter", "label": "Interpreter", "group": "Behavioral" }, { "id": "iterator", "label": "Iterator", "group": "Behavioral" }, { "id": "mediator", "label": "Mediator", "group": "Behavioral" }, { "id": "memento", "label": "Memento", "group": "Behavioral" }, { "id": "observer", "label": "Observer", "group": "Behavioral" }, { "id": "state", "label": "State", "group": "Behavioral" }, { "id": "strategy", "label": "Strategy", "group": "Behavioral" }, { "id": "template-method", "label": "Template Method", "group": "Behavioral" }, { "id": "visitor", "label": "Visitor", "group": "Behavioral" }, { "id": "ports-and-adapters", "label": "Ports and Adapters", "group": "Architectural" }, { "id": "cqrs", "label": "CQRS", "group": "Architectural" }, { "id": "strangler-fig", "label": "Strangler Fig", "group": "Architectural" }, { "id": "saga", "label": "Saga", "group": "Distributed and reliability" }, { "id": "transactional-outbox", "label": "Transactional Outbox", "group": "Distributed and reliability" }, { "id": "circuit-breaker", "label": "Circuit Breaker", "group": "Distributed and reliability" }, { "id": "bulkhead", "label": "Bulkhead", "group": "Distributed and reliability" } ], "projects": [ { "id": "558c0723-d030-4cd2-8b38-a2485f2edfa4", "key": "CUPDATE", "title": "A recoverable edge software-update simulator", "field": "Embedded and edge", "summary": "Stage, validate and switch synthetic software images in an A/B slot emulator.", "context": "Fictional information kiosks receive small generated image blobs through a local update adapter. Simulate slots and boot outcomes in software; do not flash hardware or execute image contents.", "stack": [ "TypeScript", "Slot emulator", "Filesystem adapter", "Vitest" ], "prerequisites": [ "Generate inert byte images with manifests and development-only signing fixtures.", "Implement simulated boot success failure and power-cut points." ], "developerValue": "Practice update state machines and recoverable activation.", "companyValue": "Inspect whether an engineer can prevent partial rollout from stranding devices under declared conditions.", "delivery": "Use local emulator evidence only; signing fixtures never authorize production devices.", "phases": [ { "id": "images", "title": "Validate update candidates", "goal": "Define version and image integrity." }, { "id": "slots", "title": "Stage and activate", "goal": "Keep a recoverable known-good slot." }, { "id": "fleet", "title": "Handle local rollout outcomes", "goal": "Bound retries and explain simulator status." } ], "tickets": [ { "id": "359fe059-9a6c-465c-959e-f3708510044d", "key": "CUPDATE-101", "title": "Parse edge-update manifests with explicit supported versions", "type": "TASK", "priority": "MEDIUM", "difficulty": "FOUNDATIONAL", "estimateMinutes": 75, "phaseId": "images", "dependsOn": [], "scenario": "Unknown manifest fields are treated as executable update instructions. Replace loose parsing with a bounded schema.", "acceptanceCriteria": [ "Known schema parses", "Unsupported version rejects", "Oversized fields reject before allocation" ], "implementationNotes": [ "Manifests are data and never scripts." ], "verification": [ "Parse valid inert image manifest", "Reject unsupported version" ], "deliverables": [ "Manifest parser and cases" ], "rollout": "Reject new updates when schema identity is uncertain.", "skills": [ "Validation", "Update systems" ], "fieldMix": [ { "field": "Embedded and edge", "percentage": 60 }, { "field": "Security", "percentage": 40 } ], "patterns": [] }, { "id": "66424d07-03b4-4a60-a91e-8f37959ecb60", "key": "CUPDATE-102", "title": "Verify edge-update image size and digest before staging", "type": "BUG", "priority": "HIGH", "difficulty": "FOUNDATIONAL", "estimateMinutes": 90, "phaseId": "images", "dependsOn": [ "CUPDATE-101" ], "scenario": "A truncated synthetic image is marked downloaded. Gate staging on complete integrity verification.", "acceptanceCriteria": [ "Size and digest both match", "Mismatch blocks staging", "Current active slot stays untouched" ], "implementationNotes": [ "Stream verification under an explicit memory bound." ], "verification": [ "Verify generated image", "Truncate or flip a byte" ], "deliverables": [ "Image verifier and corruption cases" ], "rollout": "Keep failed images quarantined from slot activation.", "skills": [ "Hashing", "Integrity" ], "fieldMix": [ { "field": "Storage systems", "percentage": 50 }, { "field": "Embedded and edge", "percentage": 50 } ], "patterns": [] }, { "id": "e5875246-81b1-4ab5-8797-fe8532060fda", "key": "CUPDATE-103", "title": "Validate edge-update manifests using local trust fixtures", "type": "TASK", "priority": "HIGH", "difficulty": "INTERMEDIATE", "estimateMinutes": 150, "phaseId": "images", "dependsOn": [ "CUPDATE-101", "CUPDATE-102" ], "scenario": "The simulator accepts any manifest signature. Add a trust adapter using ephemeral development keys.", "acceptanceCriteria": [ "Trusted fixture signature passes", "Unknown signer fails", "Tampered manifest fails" ], "implementationNotes": [ "No private keys enter source control or production configuration." ], "verification": [ "Verify local signed fixture", "Change signed manifest field" ], "deliverables": [ "Trust adapter and negative cases" ], "rollout": "Disable update acceptance if trusted verification is unavailable.", "skills": [ "Cryptography", "Provider interfaces" ], "fieldMix": [ { "field": "Security", "percentage": 70 }, { "field": "Embedded and edge", "percentage": 30 } ], "patterns": [] }, { "id": "5a14f69e-5424-42e9-8366-c2295100fd31", "key": "CUPDATE-104", "title": "Write edge-update images only into the inactive simulated slot", "type": "TASK", "priority": "HIGH", "difficulty": "ADVANCED", "estimateMinutes": 180, "phaseId": "slots", "dependsOn": [ "CUPDATE-102", "CUPDATE-103" ], "scenario": "Update copying overwrites the currently selected image before validation finishes. Restrict staging to the inactive slot.", "acceptanceCriteria": [ "Active slot remains byte-identical", "Inactive slot gets candidate bytes", "Failed write leaves active selection unchanged" ], "implementationNotes": [ "Slot paths must stay inside the fixture root." ], "verification": [ "Stage valid image", "Fail copy midway" ], "deliverables": [ "Slot writer and isolation cases" ], "rollout": "Abandon inactive candidate and retain active slot.", "skills": [ "Isolation", "Filesystem" ], "fieldMix": [ { "field": "Embedded and edge", "percentage": 50 }, { "field": "Storage systems", "percentage": 50 } ], "patterns": [] }, { "id": "b610907f-ad7e-41ea-abc1-7cd489aa6466", "key": "CUPDATE-105", "title": "Record edge-update activation intent before changing the boot selector", "type": "BUG", "priority": "HIGH", "difficulty": "EXPERT", "estimateMinutes": 240, "phaseId": "slots", "dependsOn": [ "CUPDATE-104" ], "scenario": "A power cut during selector change leaves no recoverable activation decision. Journal intent and candidate identity.", "acceptanceCriteria": [ "Intent is durable before selector change", "Recovery identifies pending activation", "Repeated recovery is deterministic" ], "implementationNotes": [ "Do not execute image bytes; use boot-result stubs." ], "verification": [ "Cut before selector update", "Cut after selector update" ], "deliverables": [ "Activation journal and cut-point matrix" ], "rollout": "Restore prior validated selector when activation state is ambiguous.", "skills": [ "Crash consistency", "State machines" ], "fieldMix": [ { "field": "Storage systems", "percentage": 50 }, { "field": "Embedded and edge", "percentage": 50 } ], "patterns": [] }, { "id": "a5a8a264-c9bf-42ef-bc94-21876d1f90fc", "key": "CUPDATE-106", "title": "Mark an edge-update candidate healthy only after simulated boot confirmation", "type": "TASK", "priority": "HIGH", "difficulty": "INTERMEDIATE", "estimateMinutes": 135, "phaseId": "slots", "dependsOn": [ "CUPDATE-105" ], "scenario": "Merely selecting a slot labels the update successful. Require an explicit boot acknowledgement from the emulator.", "acceptanceCriteria": [ "Selection yields pending health", "Confirmation marks success", "Missing confirmation reaches bounded failure state" ], "implementationNotes": [ "Health means only the declared simulator check." ], "verification": [ "Confirm successful boot", "Omit confirmation past deadline" ], "deliverables": [ "Health transition and timer cases" ], "rollout": "Keep prior slot available until health acknowledgement commits.", "skills": [ "State transitions", "Time" ], "fieldMix": [ { "field": "Embedded and edge", "percentage": 70 }, { "field": "Site reliability", "percentage": 30 } ], "patterns": [] }, { "id": "245c05eb-20e8-4eee-945c-bccdc1b7bbbd", "key": "CUPDATE-107", "title": "Roll back failed edge-update boots without retry loops", "type": "STORY", "priority": "HIGH", "difficulty": "ADVANCED", "estimateMinutes": 180, "phaseId": "slots", "dependsOn": [ "CUPDATE-105", "CUPDATE-106" ], "scenario": "A failing candidate is selected repeatedly on each restart. Persist failed-candidate disposition and restore the known-good slot.", "acceptanceCriteria": [ "Failed candidate does not auto-reactivate", "Prior slot is selected", "No valid fallback produces explicit recovery-required state" ], "implementationNotes": [ "Do not label fallback existence without validating its metadata." ], "verification": [ "Fail candidate boot", "Invalidate both slot manifests" ], "deliverables": [ "Rollback coordinator and failure cases" ], "rollout": "Stop automatic activation when no validated fallback exists.", "skills": [ "Recovery", "Failure handling" ], "fieldMix": [ { "field": "Embedded and edge", "percentage": 60 }, { "field": "Site reliability", "percentage": 40 } ], "patterns": [] }, { "id": "a215a6f6-d181-4fda-83a5-e7b9ef984e5e", "key": "CUPDATE-108", "title": "Reject unintended edge-update downgrades under an explicit version policy", "type": "TASK", "priority": "HIGH", "difficulty": "ADVANCED", "estimateMinutes": 165, "phaseId": "fleet", "dependsOn": [ "CUPDATE-103", "CUPDATE-107" ], "scenario": "Replaying an older signed image silently reverts a device. Add a declared minimum-version policy with a separate recovery mode.", "acceptanceCriteria": [ "Normal mode rejects lower versions", "Equal-version replay is idempotent", "Recovery override is explicit and audited locally" ], "implementationNotes": [ "Version order must be defined, not string-compared casually." ], "verification": [ "Accept newer fixture", "Replay older signed fixture" ], "deliverables": [ "Version policy and override cases" ], "rollout": "Disable updates if version comparison is ambiguous.", "skills": [ "Versioning", "Security" ], "fieldMix": [ { "field": "Security", "percentage": 60 }, { "field": "Embedded and edge", "percentage": 40 } ], "patterns": [] }, { "id": "7fac0b9c-2b33-46fa-9919-fb58e6f101bd", "key": "CUPDATE-109", "title": "Limit concurrent downloads in the simulated kiosk update cohort", "type": "CHORE", "priority": "MEDIUM", "difficulty": "INTERMEDIATE", "estimateMinutes": 120, "phaseId": "fleet", "dependsOn": [ "CUPDATE-104", "CUPDATE-108" ], "scenario": "A local cohort starts every download at once and overwhelms the provider stub. Bound concurrency and retain per-device outcome.", "acceptanceCriteria": [ "Active transfers stay within limit", "Failures release slots", "One device retry cannot starve all others" ], "implementationNotes": [ "Cohort fixtures contain synthetic device IDs only." ], "verification": [ "Update small cohort", "Fail one transfer repeatedly" ], "deliverables": [ "Download scheduler and fairness cases" ], "rollout": "Reduce concurrency to one while queue behavior is repaired.", "skills": [ "Scheduling", "Resource management" ], "fieldMix": [ { "field": "Performance engineering", "percentage": 40 }, { "field": "Embedded and edge", "percentage": 40 }, { "field": "Networking", "percentage": 20 } ], "patterns": [] }, { "id": "fbe52a33-002e-4e60-89eb-8fd0d29ffd45", "key": "CUPDATE-110", "title": "Report edge-update stages without overstating fleet success", "type": "STORY", "priority": "MEDIUM", "difficulty": "INTERMEDIATE", "estimateMinutes": 120, "phaseId": "fleet", "dependsOn": [ "CUPDATE-107", "CUPDATE-109" ], "scenario": "Dashboard counts downloaded images as updated kiosks. Project download, staged, boot-pending, healthy and rolled-back separately.", "acceptanceCriteria": [ "Healthy requires committed boot confirmation", "Rollback remains visible", "Unknown outcomes are not counted successful" ], "implementationNotes": [ "Reports describe simulator outcomes, not real-device certification." ], "verification": [ "Complete one simulated update", "Interrupt another before boot confirmation" ], "deliverables": [ "Update status report and consistency checks" ], "rollout": "Hide aggregate success if per-device authority is unresolved.", "skills": [ "Reporting", "State projection" ], "fieldMix": [ { "field": "Frontend", "percentage": 50 }, { "field": "Embedded and edge", "percentage": 30 }, { "field": "Site reliability", "percentage": 20 } ], "patterns": [] } ] } ] }