fs_adapter

Filesystem adapter for waterlink/active_record.

require it in your code and set FSDB_PATH in your ENV (either from the outside, like from the shell, or from the inside: ENV["FSDB_PATH"] = "/some/folder").

Storage format

Directory structure

Example structure:

./
`--fsdb.lock              /* locked on open */
`--fsdb/
   `--metadata.lock
   `--metadata            /* db settings */
   `--0_users.lock
   `--0_users/            /* table in the form of id_name */
      `--metadata.lock
      `--metadata         /* table settings (fields) */
      `--0.lock
      `--0                /* single table row */

Lockfiles are implemented using flock(2) and are shared for reads and exclusive for writes.

Databases (schemas)

Metadata contains information that cannot be inferred from the directory structure (currently nothing).

Tables

Contains the table's fields description.

Row fields description

Comma-separated list of colon-separated name/type tuples. Example: name:string,age:int64

Rows

A row is represented by a single file named after the row's id. It contains the columns' encoded data.

Column data encoding

Field = { Int64 | String }
Int64 = binary data
String = length Int64 + binary data