rdbtools

Overview ¶

Package rdbtools is a Redis RDB snapshot file parser.

Parsing a file ¶

Example of how to parse a RDB file.

ctx := rdbtools.ParserContext{
	ListMetadataCh: make(chan rdbtools.ListMetadata),
	ListDataCh: make(chan interface{}),
}
p := rdbtools.NewParser(ctx)

go func() {
	stop := false
	for !stop {
		select {
		case md, ok := <-ctx.ListMetadataCh:
			if !ok {
				ctx.ListMetadataCh = nil
				break
			}

			// do something with the metadata
		case d, ok := <-ctx.ListDataCh:
			if !ok {
				ctx.ListDataCh = nil
				break
			}

			str := rdbtools.DataToString(d)
			// do something with the string
		}

		if ctx.Invalid() {
			break
		}
	}
}()

f, _ := os.Open("/var/lib/redis/dump.rdb")
if err := p.Parse(f); err != nil {
	log.Fatalln(err)
}

The context holds the channels you will use to receive data from the parser. You only need to provide a channel if you care about it. In the example above, we only care about the lists in the RDB file, so we don't provide all the other channels.

The parser only has one method Parse(ParserContext) which takes a context. After a call to Parse, the parser can't be reused. We plan to change that though.

Why interfaces everywhere ¶

interface{} is used everywhere in rdbtools. The reason is simple: in RDB files, keys and values can be encoded as strings or integers or even binary data. You might call a key "1" but Redis will happily encode that as an integer.

The majority of the time you will have strings in your keys, and a lot of the times your values will be strings as well. For this reason, we provided the function DataToString(interface{}) which takes care of casting or converting to a string.