Elli is a webserver you can run inside your Erlang application to expose an HTTP API. It is aimed exclusively at building high-throughput, low-latency HTTP APIs. If robustness and performance is more important to you than general purpose features, then Elli might be for you. If you find yourself digging into the implementation of a webserver, then Elli might be for you. If you're building web services, not web sites, then Elli might be for you.
Elli requires OTP 22.0 or newer.
Add elli to your application as a dependency to your
rebar.config:
{deps, [
{elli, "3.3.0"}
]}.Afterwards, to compile it, you can run:
rebar3 compileTo boot Elli inside an Erlang shell, run:
rebar3 shell%% starting elli
1> {ok, Pid} = elli:start_link([{callback, elli_example_callback}, {port, 3000}]).The best source to learn how to write a callback module
is elli_example_callback.
There are also a bunch
of examples used in the tests as well as descriptions of all the events.
A minimal callback module looks something like this:
-module(elli_minimal_callback).
-behaviour(elli_handler).
-include_lib("elli/include/elli.hrl").
-export([handle/2, handle_event/3]).
handle(Req, _Args) ->
%% Delegate to our handler function
Method = Req#req.method,
Path = elli_request:path(Req),
handle(Method, Path, Req).
handle('GET' = _Method, [<<"hello">>, <<"world">>] = _Path, _Req) ->
%% Reply with a normal response. `ok' can be used instead of `200'
%% to signal success.
StatusCode = ok,
Headers = [],
Body = <<"Hello World!">>,
{StatusCode, Headers, Body};
handle(_Method, _Path, _Req) ->
{404, [], <<"Not Found">>}.
%% @doc Handle request events: request completed, exception
%% thrown, client timeout, etc. Must return `ok'.
handle_event(_Event, _Data, _Args) ->
ok.To add elli to a supervisor you can use the following example and adapt it to
your needs.
-module(elli_minimal_sup).
-behaviour(supervisor).
-export([start_link/0, init/1]).
start_link() ->
SupName = {local, ?MODULE},
Module = ?MODULE,
Args = [],
supervisor:start_link(SupName, Module, Args).
init([] = _Args) ->
ElliOpts = [
{callback, elli_minimal_callback},
{port, 3000}
],
ElliSpec = {
_Id = elli_minimal_http,
_Start = {elli, start_link, [ElliOpts]},
_Restart = permanent,
_Shutdown = 5000,
_Worker = worker,
_Modules = [elli]},
{ok, {{_Strategy = one_for_one, _Intensity = 5, _Period = 10}, [ElliSpec]} }.For more information about the features and design philosophy of Elli check
out the overview.
Elli is licensed under The MIT License.