|
| 1 | +package main |
| 2 | + |
| 3 | +import ( |
| 4 | + "fmt" |
| 5 | + |
| 6 | + "github.com/coreos/bbolt" |
| 7 | +) |
| 8 | + |
| 9 | +const ( |
| 10 | + dbFilePermission = 0600 |
| 11 | + defaultTxMaxSize = 65536 |
| 12 | +) |
| 13 | + |
| 14 | +type compactDBCommand struct { |
| 15 | + TxMaxSize int64 `long:"txmaxsize" description:"Maximum transaction size. (default 65536)"` |
| 16 | + SourceDB string `long:"sourcedb" description:"The lnd channel.db file to create the database backup from."` |
| 17 | + DestDB string `long:"destdb" description:"The lnd new channel.db file to copy the compacted database to."` |
| 18 | +} |
| 19 | + |
| 20 | +func (c *compactDBCommand) Execute(_ []string) error { |
| 21 | + // Check that we have a source and destination channel DB. |
| 22 | + if c.SourceDB == "" { |
| 23 | + return fmt.Errorf("source channel DB is required") |
| 24 | + } |
| 25 | + if c.DestDB == "" { |
| 26 | + return fmt.Errorf("destination channel DB is required") |
| 27 | + } |
| 28 | + if c.TxMaxSize <= 0 { |
| 29 | + c.TxMaxSize = defaultTxMaxSize |
| 30 | + } |
| 31 | + src, err := c.openDB(c.SourceDB, true) |
| 32 | + if err != nil { |
| 33 | + return fmt.Errorf("error opening source DB: %v", err) |
| 34 | + } |
| 35 | + dst, err := c.openDB(c.DestDB, false) |
| 36 | + if err != nil { |
| 37 | + return fmt.Errorf("error opening destination DB: %v", err) |
| 38 | + } |
| 39 | + err = c.compact(dst, src) |
| 40 | + if err != nil { |
| 41 | + return fmt.Errorf("error compacting DB: %v", err) |
| 42 | + } |
| 43 | + return nil |
| 44 | +} |
| 45 | + |
| 46 | +func (c *compactDBCommand) openDB(path string, ro bool) (*bbolt.DB, error) { |
| 47 | + options := &bbolt.Options{ |
| 48 | + NoFreelistSync: false, |
| 49 | + FreelistType: bbolt.FreelistMapType, |
| 50 | + ReadOnly: ro, |
| 51 | + } |
| 52 | + |
| 53 | + bdb, err := bbolt.Open(path, dbFilePermission, options) |
| 54 | + if err != nil { |
| 55 | + return nil, err |
| 56 | + } |
| 57 | + return bdb, nil |
| 58 | +} |
| 59 | + |
| 60 | +func (c *compactDBCommand) compact(dst, src *bbolt.DB) error { |
| 61 | + // commit regularly, or we'll run out of memory for large datasets if |
| 62 | + // using one transaction. |
| 63 | + var size int64 |
| 64 | + tx, err := dst.Begin(true) |
| 65 | + if err != nil { |
| 66 | + return err |
| 67 | + } |
| 68 | + defer tx.Rollback() |
| 69 | + |
| 70 | + if err := c.walk(src, func(keys [][]byte, k, v []byte, seq uint64) error { |
| 71 | + // On each key/value, check if we have exceeded tx size. |
| 72 | + sz := int64(len(k) + len(v)) |
| 73 | + if size+sz > c.TxMaxSize && c.TxMaxSize != 0 { |
| 74 | + // Commit previous transaction. |
| 75 | + if err := tx.Commit(); err != nil { |
| 76 | + return err |
| 77 | + } |
| 78 | + |
| 79 | + // Start new transaction. |
| 80 | + tx, err = dst.Begin(true) |
| 81 | + if err != nil { |
| 82 | + return err |
| 83 | + } |
| 84 | + size = 0 |
| 85 | + } |
| 86 | + size += sz |
| 87 | + |
| 88 | + // Create bucket on the root transaction if this is the first |
| 89 | + // level. |
| 90 | + nk := len(keys) |
| 91 | + if nk == 0 { |
| 92 | + bkt, err := tx.CreateBucket(k) |
| 93 | + if err != nil { |
| 94 | + return err |
| 95 | + } |
| 96 | + if err := bkt.SetSequence(seq); err != nil { |
| 97 | + return err |
| 98 | + } |
| 99 | + return nil |
| 100 | + } |
| 101 | + |
| 102 | + // Create buckets on subsequent levels, if necessary. |
| 103 | + b := tx.Bucket(keys[0]) |
| 104 | + if nk > 1 { |
| 105 | + for _, k := range keys[1:] { |
| 106 | + b = b.Bucket(k) |
| 107 | + } |
| 108 | + } |
| 109 | + |
| 110 | + // Fill the entire page for best compaction. |
| 111 | + b.FillPercent = 1.0 |
| 112 | + |
| 113 | + // If there is no value then this is a bucket call. |
| 114 | + if v == nil { |
| 115 | + bkt, err := b.CreateBucket(k) |
| 116 | + if err != nil { |
| 117 | + return err |
| 118 | + } |
| 119 | + if err := bkt.SetSequence(seq); err != nil { |
| 120 | + return err |
| 121 | + } |
| 122 | + return nil |
| 123 | + } |
| 124 | + |
| 125 | + // Otherwise treat it as a key/value pair. |
| 126 | + return b.Put(k, v) |
| 127 | + }); err != nil { |
| 128 | + return err |
| 129 | + } |
| 130 | + |
| 131 | + return tx.Commit() |
| 132 | +} |
| 133 | + |
| 134 | +// walkFunc is the type of the function called for keys (buckets and "normal" |
| 135 | +// values) discovered by Walk. keys is the list of keys to descend to the bucket |
| 136 | +// owning the discovered key/value pair k/v. |
| 137 | +type walkFunc func(keys [][]byte, k, v []byte, seq uint64) error |
| 138 | + |
| 139 | +// walk walks recursively the bolt database db, calling walkFn for each key it |
| 140 | +// finds. |
| 141 | +func (c *compactDBCommand) walk(db *bbolt.DB, walkFn walkFunc) error { |
| 142 | + return db.View(func(tx *bbolt.Tx) error { |
| 143 | + return tx.ForEach(func(name []byte, b *bbolt.Bucket) error { |
| 144 | + return c.walkBucket( |
| 145 | + b, nil, name, nil, b.Sequence(), walkFn, |
| 146 | + ) |
| 147 | + }) |
| 148 | + }) |
| 149 | +} |
| 150 | + |
| 151 | +func (c *compactDBCommand) walkBucket(b *bbolt.Bucket, keypath [][]byte, |
| 152 | + k, v []byte, seq uint64, fn walkFunc) error { |
| 153 | + // Execute callback. |
| 154 | + if err := fn(keypath, k, v, seq); err != nil { |
| 155 | + return err |
| 156 | + } |
| 157 | + |
| 158 | + // If this is not a bucket then stop. |
| 159 | + if v != nil { |
| 160 | + return nil |
| 161 | + } |
| 162 | + |
| 163 | + // Iterate over each child key/value. |
| 164 | + keypath = append(keypath, k) |
| 165 | + return b.ForEach(func(k, v []byte) error { |
| 166 | + if v == nil { |
| 167 | + bkt := b.Bucket(k) |
| 168 | + return c.walkBucket( |
| 169 | + bkt, keypath, k, nil, bkt.Sequence(), fn, |
| 170 | + ) |
| 171 | + } |
| 172 | + return c.walkBucket(b, keypath, k, v, b.Sequence(), fn) |
| 173 | + }) |
| 174 | +} |
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