eliasdb/README.md

EliasDB

EliasDB is a graph-based database which aims to provide a lightweight solution for projects which want to store their data as a graph.

Features

• Build on top of a fast key-value store which supports transactions and memory-only storage.
• Data is stored in nodes (key-value objects) which are connected via edges.
• Stored graphs can be separated via partitions.
• Stored graphs support cascading deletions - delete one node and all its "children".
• All stored data is indexed and can be quickly searched via a full text phrase search.
• For more complex queries EliasDB has an own query language called EQL with an sql-like syntax.
• EliasDB has a GraphQL interface which can be used to store and retrieve data.
• Written in Go from scratch. Only uses gorilla/websocket to support websockets for GraphQL subscriptions.
• The database can be embedded or used as a standalone application.
• When used as a standalone application it comes with an internal HTTPS webserver which provides a REST API and a basic file server.
• When used as an embedded database it supports transactions with rollbacks, iteration of data and rule based consistency management.

Getting Started (standalone application)

You can download a precompiled package for Windows (win64) or Linux (amd64) here.

Extract it and execute the executable. The executable should automatically create 3 subfolders and a configuration file. It should start an HTTPS server on port 9090. To see a terminal point your webbrowser to:

https://localhost:9090/db/term.html

After accepting the self-signed certificate from the server you should see a web terminal. EliasDB can be stopped with a simple CTRL+C or by overwriting the content in eliasdb.lck with a single character.

Tutorial:

To get an idea of what EliasDB is about have a look at the tutorial.

REST API:

The terminal uses a REST API to communicate with the backend. The REST API can be browsed using a dynamically generated swagger.json definition (https://localhost:9090/db/swagger.json). You can browse the API of EliasDB's latest version here.

Command line options

The main EliasDB executable has two main tools:

Usage of ./eliasdb <tool>

EliasDB graph based database

Available commands:

    console   EliasDB server console
    server    Start EliasDB server

The most important one is server which starts the database server. The server has several options:

Usage of ./eliasdb server [options]

  -export string
    	Export the current database to a zip file
  -help
    	Show this help message
  -import string
    	Import a database from a zip file
  -no-serv
    	Do not start the server after initialization

Once the server is started the console tool can be used to interact with the server. The options of the console tool are:

Usage of ./eliasdb console [options]

  -exec string
    	Execute a single line and exit
  -file string
    	Read commands from a file and exit
  -help
    	Show this help message
  -host string
    	Host of the EliasDB server (default "localhost")
  -port string
    	Port of the EliasDB server (default "9090")

On the console type 'q' to exit and 'help' to get an overview of available commands:

Command Description
export  Exports the last output.
find    Do a full-text search of the database.
help    Display descriptions for all available commands.
info    Returns general database information.
part    Displays or sets the current partition.
ver     Displays server version information.

It is also possible to directly run EQL queries on the console. Use the arrow keys to cycle through the command history.

Configuration

EliasDB uses a single configuration file called eliasdb.config.json. After starting EliasDB for the first time it should create a default configuration file. Available configurations are:

Configuration Option	Description
ClusterConfigFile	Cluster configuration file.
ClusterLogHistory	File which is used to store the console history.
ClusterStateInfoFile	File which is used to store the cluster state.
CookieMaxAgeSeconds	Lifetime for cookies used by EliasDB.
EnableAccessControl	Flag if access control for EliasDB should be enabled. This provides user authentication and authorization features.
EnableCluster	Flag if EliasDB clustering support should be enabled. EXPERIMENTAL!
EnableClusterTerminal	Flag if the cluster terminal file /web/db/cluster.html should be created.
EnableReadOnly	Flag if the datastore should be open read-only.
EnableWebFolder	Flag if the files in the webfolder /web should be served up by the webserver. If false only the REST API is accessible.
EnableWebTerminal	Flag if the web terminal file /web/db/term.html should be created.
HTTPSCertificate	Name of the webserver certificate which should be used. A new one is created if it does not exist.
HTTPSHost	Hostname the webserver should listen to. This host is also used in the dynamically generated swagger definition.
HTTPSKey	Name of the webserver private key which should be used. A new one is created if it does not exist.
HTTPSPort	Port on which the webserver should listen on.
LocationAccessDB	File which is used to store access control information. This file can be edited while the server is running and changes will be picked up immediately.
LocationDatastore	Directory for datastore files.
LocationHTTPS	Directory for the webserver's SSL related files.
LocationUserDB	File which is used to store (hashed) user passwords.
LocationWebFolder	Directory of the webserver's webfolder.
LockFile	Lockfile for the webserver which will be watched duing runtime. Replacing the content of this file with a single character will shutdown the webserver gracefully.
MemoryOnlyStorage	Flag if the datastore should only be kept in memory.
ResultCacheMaxAgeSeconds	EQL queries create result sets which are cached. The value describes the amount of time in seconds a result is kept in the cache.
ResultCacheMaxSize	EQL queries create result sets which are cached. The value describes the number of results which can be kept in the cache.

Note: It is not (and will never be) possible to access the REST API via HTTP.

Building EliasDB

To build EliasDB from source you need to have Go installed. There a are two options:

Checkout from github (use this method if you want code + documentation and tutorials):

Create a directory, change into it and run:

git clone https://devt.de/krotik/eliasdb/ .

Assuming your GOPATH is set to the new directory you should be able to build the binary with:

go install devt.de/eliasdb/cli

Using go get (use this method if you want to embed EliasDB in your project):

Create a directory, change into it and run:

go get devt.de/common/... devt.de/eliasdb/...

Assuming your GOPATH is set to the new directory you should be able to build the binary with:

go build devt.de/eliasdb/cli

Further Reading

• A design document which describes the different components of the graph database. Link
• A reference for the EliasDB query language EQL. Link
• A quick overview of what you can do when you embed EliasDB in your own Go project. Link

License

EliasDB source code is available under the Mozilla Public License.