Merge pull request #133 from WeTransfer/gh-131-new-rate-limiter

Move to Redis backend for our rate limiter

.travis.yml

@@ -5,6 +5,7 @@ matrix:
       elixir: 1.4.0
 services:
   - postgresql
+  - redis-server
 addons:
   postgresql: "9.5"
 cache:

config/config.exs

@@ -33,6 +33,8 @@ config :phoenix, :generators,
 config :xperiments, :cors,
   origin: "*"
 
+config :xperiments, redis_url: "redis://localhost"
+
 config :xperiments, :js_config,
   reporting_url: "https://analytics.google.com/analytics/web/?authuser=1#my-reports/5IyMQAn0Tcqdu2Va8V9BIg/a69714416w130256140p134086343/%3F_u.date00%3D20170227%26_u.date01%3D20170227%26_u.sampleOption%3Dmoreprecision%26_u.sampleSize%3D500000/"
 
@@ -58,6 +60,7 @@ config :guardian, Guardian,
 
 config :bodyguard, current_user: {Guardian.Plug, :current_resource}
 
+
 # Import environment specific config. This must remain at the bottom
 # of this file so it overrides the configuration defined above.
 import_config "#{Mix.env}.exs"

config/prod.exs

@@ -4,6 +4,7 @@ config :xperiments, Xperiments.Web.Endpoint,
   http: [port: 8080],
   url: [host: {:system, "HOST", "xperiments.wetransfer.net"}, port: 80],
   cache_static_manifest: "priv/static/cache_manifest.json",
+  secret_key_base: "${SECRET_KEY_BASE}",
   server: true,
   root: ".",
   version: Mix.Project.config[:version]
@@ -22,8 +23,7 @@ config :ueberauth, Ueberauth.Strategy.Google.OAuth,
   client_secret: "${GOOGLE_CLIENT_SECRET}",
   redirect_uri: "${GOOGLE_OAUTH_CALLBACK}"
 
-config :xperiments, Xperiments.Web.Endpoint,
-  secret_key_base: "${SECRET_KEY_BASE}"
+config :xperiments, redis_url: "${REDIS_URL}"
 
 config :guardian, Guardian,
   secret_key: "${SECRET_KEY_BASE}"

lib/xperiments.ex

@@ -9,8 +9,8 @@ defmodule Xperiments do
     # Define workers and child supervisors to be supervised
     children = [
       supervisor(Xperiments.Repo, []),
-      worker(Hammer.Backend.ETS, [[expiry_ms: 1000 * 60 * 60,
-                                   cleanup_interval_ms: 1000 * 60 * 10]]),
+      worker(Hammer.Backend.Redis, [[expiry_ms: 1000 * 60 * 60,
+                                     redix_config: Application.get_env(:xperiments, :redis_url)]]),
       supervisor(Xperiments.Web.Endpoint, []),
       supervisor(Xperiments.Assigner.Supervisor, [])
     ]

lib/xperiments/web/plugs/rate_limit_plug.ex

@@ -1,5 +1,5 @@
 defmodule Xperiments.Plug.RateLimit do
-  use Hammer, backend: Hammer.Backend.ETS, only: [:check_rate]
+  use Hammer, backend: Hammer.Backend.Redis, only: [:check_rate]
   import Phoenix.Controller, only: [json: 2]
   import Plug.Conn
   require Logger

mix.exs

@@ -47,6 +47,7 @@ defmodule Xperiments.Mixfile do
      {:appsignal, "~> 0.0"},
      {:remote_ip, "~> 0.1.0"},
      {:hammer, "~> 0.1.0"},
+     {:hammer_backend_redis, "~> 0.1.0"},
      {:ex_machina, "~> 1.0", only: :test},
      {:mock, "~> 0.2.0", only: :test}]
   end

test/controllers/assigner_controller_test.exs

@@ -2,7 +2,7 @@ defmodule Xperiments.AssignerControllerTest do
   use Xperiments.Web.ConnCase, async: false
   import Mock
   alias Xperiments.Assigner.ExperimentSupervisor
-  use Hammer, backend: Hammer.Backend.ETS, only: [:delete_buckets]
+  use Hammer, backend: Hammer.Backend.Redis, only: [:delete_buckets]
 
   setup do
     for e_pid <- ExperimentSupervisor.experiment_pids() do