Masahiko AMANO
2c83073903
db/db.go: TxFromContext/ContextWithTx for transaction propagation, Querier interface (QueryRow/Query/Exec), ScanRow generic helper, ClampLimit/ClampOffset pagination guards. db/postgres/postgres.go: NewPool with ping validation, Transactor backed by pgxpool (BeginTx → fn → commit/rollback), connOrTx helper that returns the active transaction from context or falls back to pool. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
68 lines
1.8 KiB
Go
68 lines
1.8 KiB
Go
// Package postgres provides the PostgreSQL implementations of the port interfaces.
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package postgres
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import (
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"context"
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"fmt"
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"github.com/jackc/pgx/v5"
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"github.com/jackc/pgx/v5/pgxpool"
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"tanabata/backend/internal/db"
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)
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// NewPool creates and validates a *pgxpool.Pool from the given connection URL.
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// The pool is ready to use; the caller is responsible for closing it.
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func NewPool(ctx context.Context, url string) (*pgxpool.Pool, error) {
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pool, err := pgxpool.New(ctx, url)
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if err != nil {
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return nil, fmt.Errorf("pgxpool.New: %w", err)
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}
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if err := pool.Ping(ctx); err != nil {
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pool.Close()
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return nil, fmt.Errorf("postgres ping: %w", err)
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}
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return pool, nil
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}
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// Transactor implements port.Transactor using a pgxpool.Pool.
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type Transactor struct {
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pool *pgxpool.Pool
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}
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// NewTransactor creates a Transactor backed by pool.
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func NewTransactor(pool *pgxpool.Pool) *Transactor {
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return &Transactor{pool: pool}
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}
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// WithTx begins a transaction, stores it in ctx, and calls fn. If fn returns
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// an error the transaction is rolled back; otherwise it is committed.
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func (t *Transactor) WithTx(ctx context.Context, fn func(ctx context.Context) error) error {
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tx, err := t.pool.BeginTx(ctx, pgx.TxOptions{})
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if err != nil {
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return fmt.Errorf("begin tx: %w", err)
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}
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txCtx := db.ContextWithTx(ctx, tx)
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if err := fn(txCtx); err != nil {
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_ = tx.Rollback(ctx)
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return err
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}
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if err := tx.Commit(ctx); err != nil {
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return fmt.Errorf("commit tx: %w", err)
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}
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return nil
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}
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// connOrTx returns the pgx.Tx stored in ctx by WithTx, or the pool itself when
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// no transaction is active. The returned value satisfies db.Querier and can be
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// used directly for queries and commands.
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func connOrTx(ctx context.Context, pool *pgxpool.Pool) db.Querier {
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if tx, ok := db.TxFromContext(ctx); ok {
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return tx
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}
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return pool
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}
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