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https://github.com/eiri/grass
Toy graph database with LevelDB backend
https://github.com/eiri/grass
Last synced: 28 days ago
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Toy graph database with LevelDB backend
- Host: GitHub
- URL: https://github.com/eiri/grass
- Owner: eiri
- License: mit
- Created: 2012-09-30T16:51:08.000Z (about 12 years ago)
- Default Branch: master
- Last Pushed: 2013-11-13T00:35:58.000Z (almost 11 years ago)
- Last Synced: 2023-03-25T21:58:02.871Z (over 1 year ago)
- Language: Erlang
- Homepage:
- Size: 328 KB
- Stars: 7
- Watchers: 2
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: License
Awesome Lists containing this project
README
Grass
======
## Synopsis
Erlang graph database compatable with [Gremlin](https://github.com/tinkerpop/gremlin/wiki). Backend on Basho's [LevelDB](https://github.com/basho/leveldb), REST interface with [Webmachine](https://github.com/basho/webmachine/wiki)
## Motivation
I am interested in studing of graph theory, so writing a toy graph database seems to be an obvious way to go about it.
## Notes and ToDo
Currently (ver 0.2) Grass supports multiple undirected annotated graphs and provides read-only web interface for graphs' representation in [DOT langage](http://www.graphviz.org/content/dot-language)
On the roadmap: support for graphs' nodes annotation, support for directed graphs, complete REST interface and complaiance with Tinkerpop stack.
## Installation
_Note: erl and rebar should be presented in $PATH_
```bash
$ git clone https://github.com/eiri/grass.git
$ cd grass
$ make build
$ make run
```
```erlang
...
* Starting grass: [ok]
22:49:56.615 [debug] Supervisor grass started gs_leveldb_server:start_link([]) at pid <0.103.0>
22:49:56.615 [info] Application grass started on node grass@StarFortress
22:49:56.865 [debug] Lager installed handler lager_backend_throttle into lager_event
(grass@StarFortress)1>
```
## Quick example
There are built-in function `grass:example(Key)` created for demonstration proposes. It creates a graph out of one of the three poems, where each word made to a vertex and edged to the immidiate neighbours. Available values for `Key`: `limeric`, `tiger` or `jabberwocky`.
### How to run
_Note: To draw the graph [GraphViz](http://www.graphviz.org/Documentation.php) need to be installed._
_On MacOSX: `$ brew install brew install graphviz --with-app --with-freetype`_
```erlang
...
22:50:41.157 [info] * Starting grass: [ok]
(grass@StarFortress)1> grass:example(limeric).
done
(grass@StarFortress)2>
```
In next terminal ( _grass' node needs to be up_ )
```bash
$ curl http://localhost:9922?graph=limeric | dot -Tpng -o limeric.png
$ open limeric.png
```
You should get something like:
## General usage
Create and populate a graph
```erlang
(grass@StarFortress)> grass:graphs().
[]
(grass@StarFortress)> grass:create(<<"G">>).
21:48:05.115 [debug] Supervisor gs_graph_sup started gs_graph_server:start_link([{<<"G">>,"/Users/eiri/...
ok
(grass@StarFortress)> grass:verticies(<<"G">>).
[]
(grass@StarFortress)> grass:edges(<<"G">>).
[]
(grass@StarFortress)> grass:add_vertex(<<"G">>, <<"a">>).
ok
(grass@StarFortress)> grass:add_vertex(<<"G">>, <<"b">>).
ok
(grass@StarFortress)> grass:add_vertex(<<"G">>, <<"c">>).
ok
(grass@StarFortress)> grass:add_vertex(<<"G">>, <<"d">>).
ok
(grass@StarFortress)> grass:add_edge(<<"G">>, <<"a">>, <<"b">>).
ok
(grass@StarFortress)> grass:add_edge(<<"G">>, <<"a">>, <<"c">>).
ok
(grass@StarFortress)> grass:add_edge(<<"G">>, <<"b">>, <<"c">>).
ok
(grass@StarFortress)> grass:add_edge(<<"G">>, <<"c">>, <<"d">>).
ok
(grass@StarFortress)> grass:vertex_exists(<<"G">>, <<"a">>).
true
(grass@StarFortress)> grass:vertex_exists(<<"G">>, <<"z">>).
false
(grass@StarFortress)> grass:edge_exists(<<"G">>, <<"a">>, <<"c">>).
true
(grass@StarFortress)> grass:edge_exists(<<"G">>, <<"a">>, <<"b">>).
true
(grass@StarFortress)> grass:edge_exists(<<"G">>, <<"a">>, <<"d">>).
false
(grass@StarFortress)> grass:tags(<<"G">>, <<"a">>).
[]
(grass@StarFortress)> grass:add_tag(<<"G">>, <<"a">>, <<"sound">>, <<"vowel">>).
ok.
(grass@StarFortress)> grass:add_tag(<<"G">>, <<"a">>, <<"order">>, 1).
ok.
(grass@StarFortress)> grass:tags(<<"G">>, <<"a">>).
[{<<"order">>,1},{<<"sound">>,<<"vowel">>}]
(grass@StarFortress)> grass:verticies(<<"G">>).
[<<"a">>,<<"b">>,<<"c">>,<<"d">>]
(grass@StarFortress)> grass:edges(<<"G">>).
[[<<"a">>, <<"b">>],
[<<"a">>, <<"c">>],
[<<"b">>, <<"c">>],
[<<"c">>, <<"d">>]]
(grass@StarFortress)> grass:add_vertex(<<"G">>, <<"e">>).
ok
(grass@StarFortress)> grass:add_vertex(<<"G">>, <<"f">>).
ok
(grass@StarFortress)> grass:add_edge(<<"G">>, <<"b">>, <<"e">>), grass:add_edge(<<"G">>, <<"e">>, <<"f">>), grass:add_edge(<<"G">>, <<"c">>, <<"f">>).
ok
(grass@StarFortress)> grass_utils:find_path(<<"G">>, <<"a">>, <<"f">>).
[<<"a">>,<<"b">>,<<"c">>,<<"f">>]
(grass@StarFortress)> grass_utils:find_short_path(<<"G">>, <<"a">>, <<"f">>).
[<<"a">>,<<"c">>,<<"f">>]
```
Web interface
```bash
$ curl http://localhost:9922?graph=G
graph G {
node [ shape = polygon, sides = 4, fontname = "Helvetica-Outline" ];
"a" [order=1, sound="vowel"];
"b" [];
"c" [];
"d" [];
"e" [];
"f" [];
"a" -- "b";
"a" -- "c";
"b" -- "c";
"b" -- "e";
"c" -- "d";
"c" -- "f";
"e" -- "f";
}
```
Clean up
```erlang
(grass@StarFortress)> grass:drop(<<"G">>).
ok
(grass@StarFortress)> grass:verticies(<<"G">>).
[]
(grass@StarFortress)> grass:graphs().
[<<"G">>]
(grass@StarFortress)> grass:destroy(<<"G">>).
ok
(grass@StarFortress)> grass:graphs().
[]
```
## Complete API
[API wiki](https://github.com/eiri/grass/wiki/API)
## Documentation
Check out [Wiki](https://github.com/eiri/grass/wiki) or build a local documentation:
```bash
$ make docs
$ cd doc
$ open index.html
```
## Tests
API covered with suite of unit tests. CI and code coverage to follow.
```bash
...
$ make test
======================== EUnit ========================
module 'grass'
grass:278: test_add_vertex (Add vertex)...ok
...
[done in 0.189 s]
=======================================================
All 64 tests passed.
```
## License
MIT. See [License](https://github.com/eiri/grass/blob/master/License "MIT License")