Sergiusz Bazanski | 30317b4 | 2019-08-01 16:50:41 +0200 | [diff] [blame] | 1 | package mirko |
| 2 | |
| 3 | // Migration support via github.com/golang-migrations/migrate for go_embed data in Bazel. |
| 4 | // For example usage, see go/mirko/tests/sql. |
| 5 | |
| 6 | import ( |
| 7 | "bytes" |
| 8 | "fmt" |
| 9 | "io" |
| 10 | "io/ioutil" |
| 11 | "os" |
| 12 | "strconv" |
| 13 | "strings" |
| 14 | |
| 15 | "github.com/golang-migrate/migrate/v4/source" |
| 16 | ) |
| 17 | |
| 18 | func NewMigrationsFromBazel(data map[string][]byte) (source.Driver, error) { |
| 19 | migrations := make(map[uint]*migration) |
| 20 | |
| 21 | for k, v := range data { |
| 22 | parts := strings.Split(k, ".") |
| 23 | errInvalid := fmt.Errorf("invalid migration filename: %q", k) |
| 24 | |
| 25 | if len(parts) != 3 { |
| 26 | return nil, errInvalid |
| 27 | } |
| 28 | if parts[2] != "sql" { |
| 29 | return nil, errInvalid |
| 30 | } |
| 31 | if parts[1] != "up" && parts[1] != "down" { |
| 32 | return nil, errInvalid |
| 33 | } |
| 34 | direction := parts[1] |
| 35 | |
| 36 | nameParts := strings.SplitN(parts[0], "_", 2) |
| 37 | if len(nameParts) != 2 { |
| 38 | return nil, errInvalid |
| 39 | } |
| 40 | |
| 41 | name := nameParts[1] |
| 42 | |
| 43 | version32, err := strconv.ParseUint(nameParts[0], 10, 32) |
| 44 | if err != nil { |
| 45 | return nil, errInvalid |
| 46 | } |
| 47 | version := uint(version32) |
| 48 | |
| 49 | m, ok := migrations[version] |
| 50 | if !ok { |
| 51 | migrations[version] = &migration{ |
| 52 | version: version, |
| 53 | name: name, |
| 54 | } |
| 55 | m = migrations[version] |
| 56 | } else { |
| 57 | if m.name != name { |
| 58 | if err != nil { |
| 59 | return nil, fmt.Errorf("migration version %d exists under diffrent names (%q vs %q)", version, name, m.name) |
| 60 | } |
| 61 | } |
| 62 | } |
| 63 | |
| 64 | if direction == "up" { |
| 65 | m.up = v |
| 66 | } else { |
| 67 | m.down = v |
| 68 | } |
| 69 | } |
| 70 | |
| 71 | var first uint |
| 72 | for version, migration := range migrations { |
| 73 | if migration.up == nil { |
| 74 | return nil, fmt.Errorf("migration version %d has no up file", version) |
| 75 | } |
| 76 | if migration.down == nil { |
| 77 | return nil, fmt.Errorf("migration version %d has no down file", version) |
| 78 | } |
| 79 | if first == 0 { |
| 80 | first = version |
| 81 | } |
| 82 | if version < first { |
| 83 | first = version |
| 84 | } |
| 85 | } |
| 86 | |
| 87 | if first == 0 { |
| 88 | return nil, fmt.Errorf("no migrations, or lowest migration version is 0") |
| 89 | } |
| 90 | |
| 91 | return &migrationSource{ |
| 92 | migrations: migrations, |
| 93 | first: first, |
| 94 | }, nil |
| 95 | } |
| 96 | |
| 97 | type migrationSource struct { |
| 98 | migrations map[uint]*migration |
| 99 | first uint |
| 100 | } |
| 101 | |
| 102 | type migration struct { |
| 103 | version uint |
| 104 | name string |
| 105 | up []byte |
| 106 | down []byte |
| 107 | } |
| 108 | |
| 109 | func (s *migrationSource) Open(url string) (source.Driver, error) { |
| 110 | if url != "" { |
| 111 | return nil, fmt.Errorf("bazel migration source is not configure via an URL") |
| 112 | } |
| 113 | return s, nil |
| 114 | } |
| 115 | |
| 116 | func (s *migrationSource) Close() error { |
| 117 | return nil |
| 118 | } |
| 119 | |
| 120 | func (s *migrationSource) First() (uint, error) { |
| 121 | return s.first, nil |
| 122 | } |
| 123 | |
| 124 | func (s *migrationSource) Prev(version uint) (uint, error) { |
| 125 | var prev uint |
| 126 | for ver, _ := range s.migrations { |
| 127 | if ver > prev && ver < version { |
| 128 | prev = ver |
| 129 | } |
| 130 | } |
| 131 | if prev == 0 { |
| 132 | return 0, os.ErrNotExist |
| 133 | } |
| 134 | return prev, nil |
| 135 | } |
| 136 | |
| 137 | func (s *migrationSource) Next(version uint) (uint, error) { |
| 138 | var next uint |
| 139 | for ver, _ := range s.migrations { |
| 140 | if ver <= version { |
| 141 | continue |
| 142 | } |
| 143 | if next == 0 { |
| 144 | next = ver |
| 145 | } |
| 146 | if ver < next { |
| 147 | next = ver |
| 148 | } |
| 149 | } |
| 150 | if next <= version { |
| 151 | return 0, os.ErrNotExist |
| 152 | } |
| 153 | return next, nil |
| 154 | } |
| 155 | |
| 156 | func (s *migrationSource) ReadUp(version uint) (io.ReadCloser, string, error) { |
| 157 | m, ok := s.migrations[version] |
| 158 | if !ok { |
| 159 | return nil, "", os.ErrNotExist |
| 160 | } |
| 161 | |
| 162 | return ioutil.NopCloser(bytes.NewReader(m.up)), m.name, nil |
| 163 | } |
| 164 | |
| 165 | func (s *migrationSource) ReadDown(version uint) (io.ReadCloser, string, error) { |
| 166 | m, ok := s.migrations[version] |
| 167 | if !ok { |
| 168 | return nil, "", os.ErrNotExist |
| 169 | } |
| 170 | |
| 171 | return ioutil.NopCloser(bytes.NewReader(m.down)), m.name, nil |
| 172 | } |