From 71fb89e02889ec64db3659ddf13740ac2fe22407 Mon Sep 17 00:00:00 2001 From: Ben Busby Date: Wed, 10 Nov 2021 11:50:19 -0700 Subject: [PATCH] Move instance selection logic out of router The process of selecting a random (working) instance for a specified service has been moved out of the router and into lib/farside.ex. Moving forward, the router itself should have very simple and easy to follow logic for all paths. --- lib/farside.ex | 31 +++++++++++++++++++++++++++++++ lib/farside/router.ex | 29 +---------------------------- 2 files changed, 32 insertions(+), 28 deletions(-) diff --git a/lib/farside.ex b/lib/farside.ex index f87706a..0595e33 100644 --- a/lib/farside.ex +++ b/lib/farside.ex @@ -1,5 +1,6 @@ defmodule Farside do @service_prefix Application.fetch_env!(:farside, :service_prefix) + @fallback_str Application.fetch_env!(:farside, :fallback_str) def get_services_map do {:ok, service_list} = Redix.command(:redix, ["KEYS", "#{@service_prefix}*"]) @@ -24,6 +25,36 @@ defmodule Farside do end) end + def pick_instance(service) do + {:ok, instances} = + Redix.command( + :redix, + [ + "LRANGE", + "#{@service_prefix}#{service}", + "0", + "-1" + ] + ) + + # Either pick a random available instance, + # or fall back to the default one + instance = + if Enum.count(instances) > 0 do + Enum.random(instances) + else + {:ok, result} = + Redix.command( + :redix, + ["GET", "#{service}#{@fallback_str}"] + ) + + result + end + + instance + end + def get_last_updated do {:ok, last_updated} = Redix.command( diff --git a/lib/farside/router.ex b/lib/farside/router.ex index 82b3757..7f31e04 100644 --- a/lib/farside/router.ex +++ b/lib/farside/router.ex @@ -1,7 +1,5 @@ defmodule Farside.Router do @index Application.fetch_env!(:farside, :index) - @fallback_str Application.fetch_env!(:farside, :fallback_str) - @service_prefix Application.fetch_env!(:farside, :service_prefix) use Plug.Router @@ -27,32 +25,7 @@ defmodule Farside.Router do get "/:service/*glob" do path = Enum.join(glob, "/") - - {:ok, instances} = - Redix.command( - :redix, - [ - "LRANGE", - "#{@service_prefix}#{service}", - "0", - "-1" - ] - ) - - # Either pick a random available instance, - # or fall back to the default one - instance = - if Enum.count(instances) > 0 do - Enum.random(instances) - else - {:ok, result} = - Redix.command( - :redix, - ["GET", "#{service}#{@fallback_str}"] - ) - - result - end + instance = Farside.pick_instance(service) # Redirect to the available instance conn