About
Redgrid performs automatic Erlang node discovery through a shared Redis pub/sub channel.
Build
$ make
Run
Start Redgrid with no arguments
$ erl -pa ebin deps/*/ebin
1> redgrid:start_link().
{ok,<0.33.0>}
2> whereis(redgrid).
<0.33.0>
Start Redgrid with custom Redis url
$ erl -pa ebin deps/*/ebin
1> redgrid:start_link([{redis_url, "redis://localhost:6379/"}]).
{ok,<0.33.0>}
Start Redgrid as a non-registered (anonymous) process
$ erl -pa ebin deps/*/ebin
1> redgrid:start_link([anonymous]).
{ok,<0.33.0>}
Start with arbitrary meta data
$ erl -pa ebin deps/*/ebin
1> redgrid:start_link([{<<"foo">>, <<"bar">>}]).
{ok,<0.33.0>}
Example
TAB 1
Start foo node
$ erl -pa ebin deps/*/ebin -name foo@`hostname`
(foo@Jacob-Vorreuters-MacBook-Pro.local)1> redgrid:start_link().
{ok,<0.39.0>}
TAB 2
Start bar node
$ erl -pa ebin deps/*/ebin -name bar@`hostname`
(bar@Jacob-Vorreuters-MacBook-Pro.local)1> redgrid:start_link().
{ok,<0.39.0>}
View registered nodes
(bar@Jacob-Vorreuters-MacBook-Pro.local)2> redgrid:nodes().
[{'bar@Jacob-Vorreuters-MacBook-Pro.local',[<<"ip">>, <<"localhost">>]},
{'foo@Jacob-Vorreuters-MacBook-Pro.local',[{<<"ip">>, <<"localhost">>}]}]
(bar@Jacob-Vorreuters-MacBook-Pro.local)3> [node()|nodes()].
['bar@Jacob-Vorreuters-MacBook-Pro.local', 'foo@Jacob-Vorreuters-MacBook-Pro.local']
Update meta data for bar node
(bar@Jacob-Vorreuters-MacBook-Pro.local)4> redgrid:update_meta([{weight, 50}]).
ok
TAB 1
View registered nodes (including updated meta data for bar)
(foo@Jacob-Vorreuters-MacBook-Pro.local)2> redgrid:nodes().
[{'foo@Jacob-Vorreuters-MacBook-Pro.local',[<<"ip">>, <<"localhost">>]},
{'bar@Jacob-Vorreuters-MacBook-Pro.local',[{<<"ip">>,<<"localhost">>},
{<<"weight">>, <<"50">>}]}]
Diagram
This diagram demonstrates what's happening underneath the covers when the foo node joins a cluster comprised of a single node (bar).
ENV VARS
LOCAL_IP: The IP written to Redis to which other nodes will attempt to connect
DOMAIN: Used to build Redis key and channel names
VERSION: Used to build Redis key and channel names