chore: allow running Redis standalone

.env.template

@@ -19,6 +19,7 @@ MBTA_API_BASE_URL=https://api-dev.mbtace.com
 # If you're using Redis for local development, the port is 30001
 # REDIS_HOST=
 # REDIS_PORT=
+REDIS_STANDALONE=true
 
 # These credentials control access to resetting cache entries for the CMS.
 # You can set them to be whatever you want.

README.md

@@ -105,6 +105,12 @@ Welcome to [Dotcom](https://www.notion.so/mbta-downtown-crossing/Dotcom-6aa7b0f0
     Minor note - you may see a prompt to upgrade `npm`. This isn't needed, and `"lockfileVersion": 1` in our `assets/package-lock.json` file means it was generated with an `npm` version prior to 7.
 
 
+1. Update the MBTA Metro assets. From the root of this repo:
+    ```
+    mix mbta_metro.update_assets
+    ```
+
+
 1. Set up required environment variables:
     ```
     cp .env.template .env
@@ -121,57 +127,13 @@ For details on environment configuration, including optional variables, see
 
 ## Running the Server
 
-The easiest way to develop MBTA dotcom is to use Docker Compose.
-
-```
-docker compose -f deploy/dev.yml up -d --build
-```
-
-This will set up Redis in cluster mode and run two versions of Dotcom with nginx load balancing requests between them.
-Visit http://localhost:4001 to hit the load balancer.
-http://localhost:4002 and http://localhost:4003 will take you directly to either of the two nodes.
-
-You can even connect to individual Elixir nodes in order to run commands.
-Let's say you want to connect to dotcom2 (the one running at http://localhost:4003).
-
-```
-docker exec -it deploy-dotcom-2-1 iex --sname foobarbaz --cookie foobarbaz
-
-iex(foobarbaz@0b061394460f)1> node = :dotcom2@0b061394460f
-:dotcom2@0b061394460f
-iex(foobarbaz@0b061394460f)2> Node.connect(node)
-true
-iex(foobarbaz@0b061394460f)3> :rpc.call(node, Dotcom.Cache.Multilevel, :get, ["cms.repo|important-notices"])
-...
-```
-
-Note that the address (the @... part) will be different every time.
-
----
-
-If you choose not to use Docker Compose, you'll still have to run Redis cluster.
-The easiest way to get it running is to download and compile it.
+To run the server, you'll need to have a Redis instance running. You can either install it manually, or run it via Docker:
 
-```
-cd $HOME
-wget https://github.com/redis/redis/archive/7.2.4.tar.gz
-tar xvf 7.2.4.tar.gz
-cd redis-7.2.4
-make
-./utils/create-cluster/create-cluster start
-./utils/create-cluster/create-cluster create -f
-```
-
-When you're done with it:
-
-```
-./utils/create-cluster/create-cluster stop
-cd $HOME
-rm 7.2.4.tar.gz
-rm -rf redis-7.2.4
+``` shell
+docker run --rm -p 6379:6379 redis:7.2.4
 ```
 
-Start the server with `iex -S mix phx.server`
+Then, start the server with `iex -S mix phx.server`
 
 Then, visit the site at http://localhost:4001.
 

config/runtime.exs

@@ -48,6 +48,13 @@ end
 redis_host_env = System.get_env("REDIS_HOST", "127.0.0.1")
 redis_port_env = System.get_env("REDIS_PORT", "6379")
 
+redis_mode =
+  if System.get_env("REDIS_STANDALONE") == nil do
+    :redis_cluster
+  else
+    :standalone
+  end
+
 redis_host =
   if redis_host_env == "",
     do: "127.0.0.1",
@@ -58,22 +65,25 @@ redis_port =
     do: 6379,
     else: String.to_integer(redis_port_env)
 
+redis_conn_opts = [
+  host: redis_host,
+  port: redis_port
+]
+
 redis_config = [
-  mode: :redis_cluster,
+  mode: redis_mode,
+  conn_opts: redis_conn_opts,
   redis_cluster: [
     configuration_endpoints: [
-      conn_opts: [
-        host: redis_host,
-        port: redis_port
-      ]
+      conn_opts: redis_conn_opts
     ]
   ],
   stats: true,
   telemetry: true
 ]
 
 # This is used by PubSub, we only use the first node in the cluster
-config :dotcom, :redis_config, redis_config[:redis_cluster][:configuration_endpoints][:conn_opts]
+config :dotcom, :redis_config, redis_conn_opts
 
 # Set caches that use the Redis cluster
 config :dotcom, Dotcom.Cache.Multilevel,

docs/RedisClustering.md

@@ -0,0 +1,65 @@
+# Testing Redis Clustering
+
+The default development environment only runs under a single Redis instance.
+Some features (cross-cluster delete) do need a full cluster to test, so this
+document describes how to run such as cluster locally for testing.
+
+These instructions assume you've already gotten a normal development environment running.
+
+## Docker Compose
+
+The easiest way to run the Redis Cluster is to use Docker Compose.
+
+```
+docker compose -f deploy/dev.yml up -d --build
+```
+
+This will set up Redis in cluster mode and run two versions of Dotcom with nginx load balancing requests between them.
+Visit http://localhost:4001 to hit the load balancer.
+http://localhost:4002 and http://localhost:4003 will take you directly to either of the two nodes.
+
+You can even connect to individual Elixir nodes in order to run commands.
+Let's say you want to connect to dotcom2 (the one running at http://localhost:4003).
+
+```
+docker exec -it deploy-dotcom-2-1 iex --sname foobarbaz --cookie foobarbaz
+
+iex(foobarbaz@0b061394460f)1> node = :dotcom2@0b061394460f
+:dotcom2@0b061394460f
+iex(foobarbaz@0b061394460f)2> Node.connect(node)
+true
+iex(foobarbaz@0b061394460f)3> :rpc.call(node, Dotcom.Cache.Multilevel, :get, ["cms.repo|important-notices"])
+...
+```
+
+Note that the address (the @... part) will be different every time.
+
+
+## Running Redis Locally
+
+If you choose not to use Docker Compose, you'll still have to run Redis cluster.
+The easiest way to get it running is to download and compile it.
+
+```
+cd $HOME
+wget https://github.com/redis/redis/archive/7.2.4.tar.gz
+tar xvf 7.2.4.tar.gz
+cd redis-7.2.4
+make
+./utils/create-cluster/create-cluster start
+./utils/create-cluster/create-cluster create -f
+```
+
+Start the server with `iex -S mix phx.server`
+
+Then, visit the site at http://localhost:4001.
+
+When you're done with the cluster:
+
+```
+./utils/create-cluster/create-cluster stop
+cd $HOME
+rm 7.2.4.tar.gz
+rm -rf redis-7.2.4
+```
+