DiunDashboard/.planning/phases/02-backend-refactor/02-01-SUMMARY.md

phase, plan, subsystem, tags, requires, provides, affects, tech-stack, key-files, key-decisions, patterns-established, requirements-completed, duration, completed

phase	plan	subsystem	tags	requires	provides	affects	tech-stack	key-files	key-decisions	patterns-established	requirements-completed	duration	completed
02-backend-refactor	01	database	golang-migrate sqlite store-interface dependency-injection migrations embed-fs	phase provides 01-data-integrity PRAGMA foreign_keys enforcement and UPSERT semantics in existing diunwebhook.go	Store interface with 9 methods covering all persistence operations SQLiteStore implementing Store with exact SQL from current handlers RunMigrations function using golang-migrate + embed.FS (iofs source) Baseline migration 0001 with full current schema (CREATE TABLE IF NOT EXISTS)	02-02 (Server struct refactor will use Store interface and RunMigrations) 03-postgresql (PostgreSQLStore will implement same Store interface)	added patterns github.com/golang-migrate/migrate/v4 v4.19.1 github.com/golang-migrate/migrate/v4/database/sqlite (modernc.org/sqlite driver, no CGO) github.com/golang-migrate/migrate/v4/source/iofs (embed.FS migration source) Store interface pattern - persistence abstraction hiding *sql.DB from handlers SQLiteStore with per-struct sync.Mutex (replaces package-level global) golang-migrate with embedded SQL files via //go:embed migrations/sqlite ErrNoChange guard in RunMigrations (startup idempotency) CREATE TABLE IF NOT EXISTS in baseline migration (backward compatible with existing databases)	created modified pkg/diunwebhook/store.go pkg/diunwebhook/sqlite_store.go pkg/diunwebhook/migrate.go pkg/diunwebhook/migrations/sqlite/0001_initial_schema.up.sql pkg/diunwebhook/migrations/sqlite/0001_initial_schema.down.sql go.mod go.sum	Used database/sqlite sub-package (not database/sqlite3) to avoid CGO - confirmed modernc.org/sqlite usage in sqlite.go source Single 0001 baseline migration with full schema including acknowledged_at - safe for existing databases via CREATE TABLE IF NOT EXISTS NewSQLiteStore sets MaxOpenConns(1) and PRAGMA foreign_keys = ON - moved from InitDB which will be removed in Plan 02 AssignTag preserves INSERT OR REPLACE (not ON CONFLICT DO UPDATE) per research Pitfall 6 - correct semantics for tag_assignments PRIMARY KEY defer rows.Close() directly (not verbose closure pattern) as plan specifies	Store interface: all persistence behind 9 named methods, no *sql.DB in interface signature SQLiteStore field mutex: sync.Mutex as struct field, not package global - enables parallel test isolation Migration files: versioned SQL files embedded via //go:embed, applied via golang-migrate at startup ErrNoChange is not an error: errors.Is(err, migrate.ErrNoChange) guard ensures idempotent startup	REFAC-01 REFAC-03	6min	2026-03-23

Phase 02 Plan 01: Store Interface and Migration Infrastructure Summary

Store interface (9 methods) + SQLiteStore implementation + golang-migrate v4.19.1 migration infrastructure with embedded SQL files

Performance

• Duration: ~6 min
• Started: 2026-03-23T20:50:31Z
• Completed: 2026-03-23T20:56:56Z
• Tasks: 2
• Files modified: 7

Accomplishments

• Store interface with 9 methods extracted from current handler SQL (UpsertEvent, GetUpdates, AcknowledgeUpdate, ListTags, CreateTag, DeleteTag, AssignTag, UnassignTag, TagExists)
• SQLiteStore implementing all 9 Store methods with exact SQL semantics preserved from diunwebhook.go
• golang-migrate v4.19.1 migration infrastructure with RunMigrations using embed.FS and iofs source
• Baseline migration 0001 with full current schema using CREATE TABLE IF NOT EXISTS (safe for existing databases)
• All existing tests pass; no existing code modified (additive-only changes as specified)

Task Commits

Each task was committed atomically:

1. Task 1: Create Store interface and SQLiteStore implementation - 57bf3bd (feat)
2. Task 2: Create migration infrastructure and SQL files - 6506d93 (feat)

Plan metadata: (docs commit follows)

Files Created/Modified

• pkg/diunwebhook/store.go - Store interface with 9 persistence methods
• pkg/diunwebhook/sqlite_store.go - SQLiteStore struct implementing Store; NewSQLiteStore sets MaxOpenConns(1) and PRAGMA foreign_keys = ON
• pkg/diunwebhook/migrate.go - RunMigrations using golang-migrate + embed.FS + iofs; handles ErrNoChange
• pkg/diunwebhook/migrations/sqlite/0001_initial_schema.up.sql - Full baseline schema (updates, tags, tag_assignments) with CREATE TABLE IF NOT EXISTS
• pkg/diunwebhook/migrations/sqlite/0001_initial_schema.down.sql - DROP TABLE IF EXISTS for all three tables
• go.mod - Added github.com/golang-migrate/migrate/v4 v4.19.1 and sub-packages
• go.sum - Updated checksums

Decisions Made

• Used database/sqlite (not database/sqlite3) for golang-migrate driver — confirmed at source level that it imports modernc.org/sqlite, satisfying no-CGO constraint
• Single 0001 baseline migration includes acknowledged_at from the start; safe for existing databases because CREATE TABLE IF NOT EXISTS makes it idempotent on pre-existing schemas
• NewSQLiteStore sets MaxOpenConns(1) and PRAGMA foreign_keys = ON — these will no longer live in InitDB once Plan 02 removes globals
• AssignTag uses INSERT OR REPLACE (not ON CONFLICT DO UPDATE) — preserves semantics per research Pitfall 6

Deviations from Plan

None - plan executed exactly as written.

Issues Encountered

• go vet reports a pre-existing issue in diunwebhook_test.go:227 (call to (*testing.T).Fatalf from a non-test goroutine) — confirmed pre-existing before any changes; out of scope for this plan. Logged to deferred-items.
• mattn/go-sqlite3 appears in go mod graph as an indirect dependency of the golang-migrate module itself, but our code only imports database/sqlite (confirmed no CGO import in our code chain via go mod graph | grep sqlite3 | grep -v golang-migrate).

User Setup Required

None - no external service configuration required.

Next Phase Readiness

• Store interface and SQLiteStore ready for Plan 02 to wire into Server struct
• RunMigrations ready to call from main.go instead of InitDB
• All existing tests pass — Plan 02 can refactor handlers with confidence
• Blocker: Plan 02 must redesign export_test.go (currently references package-level globals that will be removed)

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Phase: 02-backend-refactor Completed: 2026-03-23