Exar DB

An event store with streaming support, it uses flat-file based collections.

## Modules

The database is split into the following modules:

• exar-core: the core engine of Exar DB
• exar-net: a TCP protocol for Exar DB
• exar-server: a TCP server built on top of exar-net
• exar-client: a TCP client built on top of exar-net
• exar-db: the main executable of Exar DB

Installation

Install Cargo, then run:

cargo install exar-db

Starting the database

Simply run exar-db.

Configuring the database

The database can be configured using a TOML configuration file, example below:

log4rs_path = "/path/to/log4rs.toml"
[database]
logs_path = "~/exar-db/data"
scanners = { nr_of_scanners = 2, sleep_time_in_ms = 10 }
[database.collections.my-collection]
routing_strategy = "Random"
scanners = { nr_of_scanners = 4, sleep_time_in_ms = 5 }
[server]
host = "127.0.0.1"
port = 38580
username = "my-username"
password = "my-secret"

Then run Exar DB by specifying the config file location: exar-db --config=/path/to/config.toml.

For more information about the database and server configuration sections, check the documentation about DatabaseConfig and ServerConfig.

Logging

Logging can be configured using a log4rs config file in TOML format, example below:

[appenders.console]
kind = "console"

[appenders.console.encoder]
pattern = "[{d(%+)(local)}] [{h({l})}] [{t}] {m}{n}"

[appenders.file]
kind = "file"
path = "exar-db.log"

[appenders.file.encoder]
pattern = "[{d(%+)(local)}] [{h({l})}] [{t}] {m}{n}"

[root]
level = "info"
appenders = ["console", "file"]

Interacting with the database from Rust

To interact with the database from a rust application use exar-client.

Basic connect/publish/subscribe examples are available at the exar-client section of the documentation.

Interacting with the database via TCP

To interact with the database a very simple TCP protocol can be used even via telnet.

telnet 127.0.0.1 38580

Once the TCP connection has been established, you can use the commands defined in the exar-net section of the documentation.

Exar UI

A simple user interface, built with Electron, useful to interact with the database is available here, but it currently needs to be run from source.