cdbd

cdbd ("constant database daemon") is a small constant database server: given a key-value file in a format it understands (like CDB), it will serve that file via a protocol it speaks (like memcached).

In the past I have used a company-internal tool like cdbd (called "SSTable Service") to provide precomputed data to production services. The idea is that it's super easy to start a cdbd instance and get the data where you need. In a service-oriented architecture, cdbd makes your static data accessible.

Example

echo '+3,5:one->Hello\n' | cdbmake f.cdb f.cdb.tmp
cdbd --cdb f.cdb --memcached 11211 &
memccat --servers=localhost:11211 one

Installation

Install with Cargo, the Rust package manager, like so:

cargo install cdbd

Usage

Usage: target/debug/cdbd [options]

Options:
        --memcached [HOST:]PORT
                        What port (and optional address) to bind a memcached
                        service on (default address "0.0.0.0")
        --cdb CDB       A CDB file to serve
        --mtbl MTBL     An MTBL file to serve
    -v, --verbose       Print more logging information (may be used more than
                        once for more detail)
    -h, --help          Print this help text

Supported constant databases

• CDB (with flag --cdb FILE)
• MTBL (with flag --mtbl FILE)

Supported protocols

• memcached (with flag --memcached [HOST:]PORT; supports memcached read operations only)

Work to be done

• Loadtests and benchmarks
• Use Tokio
• Support other databases
  • LMDB
  • SQLite?
  • Berkeley DB?
• Support other protocols
  • Redis (get and mget)
  • HTTP?
• Pull protocols out into their own crates? It would allow others to write memcached etc. servers a little more easily, maybe.

License

Copyright 2017 Leon Barrett

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT) at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.