Mount a Bolt database as a FUSE filesystem

Bolt is a key-value store that also supports nested buckets. This makes it look a little bit like a file system tree.

bolt-mount exposes a Bolt database as a FUSE file system.

$ go get bazil.org/bolt-mount
# assuming $GOPATH/bin is in $PATH
$ mkdir mnt
$ bolt-mount mydatabase.bolt mnt &
$ cd mnt
$ mkdir bucket
$ mkdir bucket/sub
$ echo Hello, world >bucket/sub/greeting
$ ls -l bucket
total 0
drwxr-xr-x 1 root root 0 Apr 25 18:00 sub/
$ ls -l bucket/sub
total 0
-rw-r--r-- 1 root root 0 Apr 25 18:00 greeting
$ cat bucket/sub/greeting
Hello, world
$ cd ..
# for Linux
$ fusermount -u mnt
# for OS X
$ umount mnt
[1]+  Done                    bolt-mount mydatabase.bolt mnt

Encoding keys to file names

As Bolt keys can contain arbitrary bytes, but file names cannot, the keys are encoded.

First, we define safe as:

• ASCII letters and numbers
• the characters ".", "," "-", "_" (period/dot, comma, dash, underscore)

A name consisting completely of safe characters, and not starting with a dot, is unaltered. Everything else is hex-encoded. Hex encoding looks like @xx[xx..] where xx are lower case hex digits.

Additionally, any safe prefixes (not starting with a dot) and suffixes longer than than a noise threshold remain unaltered. They are separated from the hex encoded middle part by a semicolon, as in [PREFIX:]MIDDLE[:SUFFIX].

For example:

A Bolt key packing two little-endian uint16 values 42 and 10000 and the string "test" is encoded as filename @002a2710:test.