admin: add a check for compatible migration version

Add the ability to check migration version of the database before
running an admin command so you know you are operating on a compatible
database schema.

Signed-off-by: crozzy <joseph.crosland@gmail.com>

cmd/clairctl/admin.go

@@ -297,9 +297,12 @@ func adminPre473(c *cli.Context) error {
 
 func updateGoPackages(c *cli.Context) error {
 	const (
-		getPackageNames = "SELECT DISTINCT package_name FROM vuln WHERE updater = 'osv/go'"
-		getPackages     = "SELECT id, version FROM package WHERE name = $1 and norm_version IS NULL"
-		updatePackages  = "UPDATE package SET norm_version=$1::int[], norm_kind=$2 WHERE id = $3 and norm_version IS NULL"
+		// TODO (crozzy): This could describe something more interesting like >6 or 6-10 but
+		// at the moment that seems like overkill.
+		compatibleMigrationVersion = 7
+		getPackageNames            = "SELECT DISTINCT package_name FROM vuln WHERE updater = 'osv/go'"
+		getPackages                = "SELECT id, version FROM package WHERE name = $1 and norm_version IS NULL"
+		updatePackages             = "UPDATE package SET norm_version=$1::int[], norm_kind=$2 WHERE id = $3 and norm_version IS NULL"
 	)
 
 	ctx := c.Context
@@ -344,6 +347,10 @@ func updateGoPackages(c *cli.Context) error {
 		return fmt.Errorf("error creating indexer pool: %w", err)
 	}
 	defer indexerPool.Close()
+	err = checkMigrationVersion(ctx, indexerPool, "libindex_migrations", []int{compatibleMigrationVersion})
+	if err != nil {
+		return fmt.Errorf("error checking migration version: %w", err)
+	}
 
 	for _, p := range packageNames {
 		err := indexerPool.AcquireFunc(ctx, func(conn *pgxpool.Conn) error {
@@ -403,6 +410,36 @@ func updateGoPackages(c *cli.Context) error {
 	return nil
 }
 
+type ErrNonCompatibleMigrationVersion struct {
+	version            int
+	acceptableVersions []int
+}
+
+func NewErrNonCompatibleMigrationVersion(version int, acceptableVersions []int) ErrNonCompatibleMigrationVersion {
+	return ErrNonCompatibleMigrationVersion{version: version, acceptableVersions: acceptableVersions}
+}
+
+func (e ErrNonCompatibleMigrationVersion) Error() string {
+	return fmt.Sprintf("non-compatible migration version %d (acceptable versions: %v)", e.version, e.acceptableVersions)
+}
+
+func checkMigrationVersion(ctx context.Context, pool *pgxpool.Pool, migrationTable string, acceptableVersions []int) error {
+	checkMigrationVersionQuery := fmt.Sprintf("SELECT MAX(version) FROM %s", migrationTable)
+	return pool.AcquireFunc(ctx, func(conn *pgxpool.Conn) error {
+		var version int
+		err := conn.QueryRow(ctx, checkMigrationVersionQuery).Scan(&version)
+		if err != nil {
+			return err
+		}
+		for _, v := range acceptableVersions {
+			if v == version {
+				return nil
+			}
+		}
+		return NewErrNonCompatibleMigrationVersion(version, acceptableVersions)
+	})
+}
+
 func createConnPool(ctx context.Context, dsn string, maxConns int32) (*pgxpool.Pool, error) {
 	pgcfg, err := pgxpool.ParseConfig(dsn)
 	if err != nil {