daddy/internal/database/version_resolver.go

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package database
import (
"context"
"github.com/jackc/pgx/v4"
"github.com/jackc/pgx/v4/pgxpool"
"github.com/pkg/errors"
)
type VersionResolver struct {
pool *pgxpool.Pool
}
func (r *VersionResolver) Current(ctx context.Context) (string, error) {
var version string
err := WithTx(ctx, r.pool, func(ctx context.Context, tx pgx.Tx) error {
err := tx.QueryRow(ctx, `SELECT version FROM database_schema WHERE is_current = true;`).
Scan(&version)
if errors.Is(err, pgx.ErrNoRows) {
return nil
}
return err
})
if err != nil {
return "", errors.Wrap(err, "could execute version resolver init transaction")
}
return version, nil
}
func (r *VersionResolver) Set(ctx context.Context, version string) error {
err := WithTx(ctx, r.pool, func(ctx context.Context, tx pgx.Tx) error {
if version != "" {
_, err := tx.Exec(ctx, `
INSERT INTO database_schema (version, is_current, migrated_at)
VALUES
(
$1,
true,
now()
)
ON CONFLICT ON CONSTRAINT unique_version
DO UPDATE SET migrated_at = now(), is_current = true;
`, version)
if err != nil {
return err
}
}
_, err := tx.Exec(ctx, `
UPDATE database_schema SET is_current = false, migrated_at = null WHERE version <> $1;
`, version)
return err
})
if err != nil {
return errors.Wrap(err, "could not update schema version")
}
return nil
}
func (r *VersionResolver) Init(ctx context.Context) error {
err := WithTx(ctx, r.pool, func(ctx context.Context, tx pgx.Tx) error {
_, err := tx.Exec(ctx, `
CREATE TABLE IF NOT EXISTS database_schema(
version TEXT NOT NULL,
migrated_at TIME,
is_current BOOLEAN,
CONSTRAINT unique_version UNIQUE(version)
);`)
return err
})
if err != nil {
return errors.Wrap(err, "could execute version resolver init transaction")
}
return nil
}
func NewVersionResolver(pool *pgxpool.Pool) *VersionResolver {
return &VersionResolver{
pool: pool,
}
}