benvin
91 lines
2.3 KiB
Go
91 lines
2.3 KiB
Go
// Package database provides the Postgres connection pool and schema migrations
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// for tomswallapi.
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package database
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import (
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"context"
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"embed"
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"fmt"
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"sort"
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"strings"
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"github.com/jackc/pgx/v5"
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"github.com/jackc/pgx/v5/pgxpool"
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)
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//go:embed migrations/*.sql
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var migrationsFS embed.FS
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// DB wraps a pgx connection pool.
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type DB struct {
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Pool *pgxpool.Pool
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}
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// New opens a connection pool and verifies connectivity.
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func New(ctx context.Context, dsn string) (*DB, error) {
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pool, err := pgxpool.New(ctx, dsn)
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if err != nil {
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return nil, fmt.Errorf("creating pool: %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("pinging database: %w", err)
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}
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return &DB{Pool: pool}, nil
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}
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// Close releases the pool.
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func (db *DB) Close() { db.Pool.Close() }
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// Migrate applies any pending embedded SQL migrations in lexical order. Each
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// migration file is recorded in schema_migrations and applied at most once.
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func (db *DB) Migrate(ctx context.Context) error {
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if _, err := db.Pool.Exec(ctx, `
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CREATE TABLE IF NOT EXISTS schema_migrations (
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version TEXT PRIMARY KEY,
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applied_at TIMESTAMPTZ NOT NULL DEFAULT now()
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)`); err != nil {
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return fmt.Errorf("creating schema_migrations: %w", err)
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}
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entries, err := migrationsFS.ReadDir("migrations")
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if err != nil {
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return fmt.Errorf("reading migrations: %w", err)
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}
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var files []string
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for _, e := range entries {
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if !e.IsDir() && strings.HasSuffix(e.Name(), ".sql") {
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files = append(files, e.Name())
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}
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}
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sort.Strings(files)
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for _, name := range files {
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var exists bool
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if err := db.Pool.QueryRow(ctx,
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`SELECT EXISTS(SELECT 1 FROM schema_migrations WHERE version = $1)`, name,
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).Scan(&exists); err != nil {
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return fmt.Errorf("checking migration %s: %w", name, err)
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}
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if exists {
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continue
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}
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body, err := migrationsFS.ReadFile("migrations/" + name)
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if err != nil {
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return fmt.Errorf("reading migration %s: %w", name, err)
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}
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if err := pgx.BeginFunc(ctx, db.Pool, func(tx pgx.Tx) error {
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if _, err := tx.Exec(ctx, string(body)); err != nil {
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return fmt.Errorf("applying %s: %w", name, err)
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}
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_, err := tx.Exec(ctx, `INSERT INTO schema_migrations (version) VALUES ($1)`, name)
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return err
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}); err != nil {
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return err
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}
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}
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return nil
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}
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