Add Redis PubSub support for distributed clustering

Configures Phoenix.PubSub.Redis adapter when clustering is enabled
and REDIS_URL environment variable is set. This allows PubSub
messages to be shared across Elixir nodes in a distributed
deployment, enabling proper real-time updates in multi-node setups.

- Add phoenix_pubsub_redis dependency (~> 3.0)
- Configure Redis adapter in runtime.exs for production
- Set pool size to 10 for better performance
- Include node name in Redis configuration

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

config/runtime.exs

@@ -122,6 +122,21 @@ if config_env() == :prod do
 
   config :aprsme, :cluster_enabled, cluster_enabled
 
+  # Configure Redis PubSub when clustering is enabled
+  if cluster_enabled and System.get_env("REDIS_URL") do
+    config :aprsme, AprsmeWeb.Endpoint,
+      pubsub_server: Aprsme.PubSub,
+      pubsub: [
+        name: Aprsme.PubSub,
+        adapter: Phoenix.PubSub.Redis,
+        redis_pool_size: 10,
+        node_name: node(),
+        redis_options: [
+          url: System.get_env("REDIS_URL")
+        ]
+      ]
+  end
+
   # Optional: Set the default "from" email address
   config :aprsme,
     default_from_email: "w5isp@aprs.me"

mix.exs

@@ -85,6 +85,7 @@ defmodule Aprsme.MixProject do
       {:phoenix_live_dashboard, "~> 0.8"},
       {:phoenix_live_reload, "~> 1.2", only: :dev},
       {:phoenix_live_view, "~> 1.0.17"},
+      {:phoenix_pubsub_redis, "~> 3.0"},
       {:postgrex, ">= 0.0.0"},
       {:swoosh, "~> 1.16"},
       {:resend, "~> 0.4.1"},

mix.lock

@@ -67,11 +67,13 @@
   "phoenix_live_reload": {:hex, :phoenix_live_reload, "1.6.0", "2791fac0e2776b640192308cc90c0dbcf67843ad51387ed4ecae2038263d708d", [:mix], [{:file_system, "~> 0.2.10 or ~> 1.0", [hex: :file_system, repo: "hexpm", optional: false]}, {:phoenix, "~> 1.4", [hex: :phoenix, repo: "hexpm", optional: false]}], "hexpm", "b3a1fa036d7eb2f956774eda7a7638cf5123f8f2175aca6d6420a7f95e598e1c"},
   "phoenix_live_view": {:hex, :phoenix_live_view, "1.0.17", "beeb16d83a7d3760f7ad463df94e83b087577665d2acc0bf2987cd7d9778068f", [:mix], [{:floki, "~> 0.36", [hex: :floki, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:phoenix, "~> 1.6.15 or ~> 1.7.0 or ~> 1.8.0-rc", [hex: :phoenix, repo: "hexpm", optional: false]}, {:phoenix_html, "~> 3.3 or ~> 4.0", [hex: :phoenix_html, repo: "hexpm", optional: false]}, {:phoenix_template, "~> 1.0", [hex: :phoenix_template, repo: "hexpm", optional: false]}, {:phoenix_view, "~> 2.0", [hex: :phoenix_view, repo: "hexpm", optional: true]}, {:plug, "~> 1.15", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.2 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "a4ca05c1eb6922c4d07a508a75bfa12c45e5f4d8f77ae83283465f02c53741e1"},
   "phoenix_pubsub": {:hex, :phoenix_pubsub, "2.1.3", "3168d78ba41835aecad272d5e8cd51aa87a7ac9eb836eabc42f6e57538e3731d", [:mix], [], "hexpm", "bba06bc1dcfd8cb086759f0edc94a8ba2bc8896d5331a1e2c2902bf8e36ee502"},
+  "phoenix_pubsub_redis": {:hex, :phoenix_pubsub_redis, "3.0.1", "d4d856b1e57a21358e448543e1d091e07e83403dde4383b8be04ed9d2c201cbc", [:mix], [{:phoenix_pubsub, "~> 2.0", [hex: :phoenix_pubsub, repo: "hexpm", optional: false]}, {:poolboy, "~> 1.5.1 or ~> 1.6", [hex: :poolboy, repo: "hexpm", optional: false]}, {:redix, "~> 0.10.0 or ~> 1.0", [hex: :redix, repo: "hexpm", optional: false]}], "hexpm", "0b36a17ff6e9a56159f8df8933d62b5c1f0695eae995a02e0c86c035ace6a309"},
   "phoenix_template": {:hex, :phoenix_template, "1.0.4", "e2092c132f3b5e5b2d49c96695342eb36d0ed514c5b252a77048d5969330d639", [:mix], [{:phoenix_html, "~> 2.14.2 or ~> 3.0 or ~> 4.0", [hex: :phoenix_html, repo: "hexpm", optional: true]}], "hexpm", "2c0c81f0e5c6753faf5cca2f229c9709919aba34fab866d3bc05060c9c444206"},
   "plug": {:hex, :plug, "1.18.1", "5067f26f7745b7e31bc3368bc1a2b818b9779faa959b49c934c17730efc911cf", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:plug_crypto, "~> 1.1.1 or ~> 1.2 or ~> 2.0", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.3 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "57a57db70df2b422b564437d2d33cf8d33cd16339c1edb190cd11b1a3a546cc2"},
   "plug_crypto": {:hex, :plug_crypto, "2.1.1", "19bda8184399cb24afa10be734f84a16ea0a2bc65054e23a62bb10f06bc89491", [:mix], [], "hexpm", "6470bce6ffe41c8bd497612ffde1a7e4af67f36a15eea5f921af71cf3e11247c"},
   "poolboy": {:hex, :poolboy, "1.5.2", "392b007a1693a64540cead79830443abf5762f5d30cf50bc95cb2c1aaafa006b", [:rebar3], [], "hexpm", "dad79704ce5440f3d5a3681c8590b9dc25d1a561e8f5a9c995281012860901e3"},
   "postgrex": {:hex, :postgrex, "0.20.0", "363ed03ab4757f6bc47942eff7720640795eb557e1935951c1626f0d303a3aed", [:mix], [{:db_connection, "~> 2.1", [hex: :db_connection, repo: "hexpm", optional: false]}, {:decimal, "~> 1.5 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:table, "~> 0.1.0", [hex: :table, repo: "hexpm", optional: true]}], "hexpm", "d36ef8b36f323d29505314f704e21a1a038e2dc387c6409ee0cd24144e187c0f"},
+  "redix": {:hex, :redix, "1.5.2", "ab854435a663f01ce7b7847f42f5da067eea7a3a10c0a9d560fa52038fd7ab48", [:mix], [{:castore, "~> 0.1.0 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:nimble_options, "~> 0.5.0 or ~> 1.0", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.0 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "78538d184231a5d6912f20567d76a49d1be7d3fca0e1aaaa20f4df8e1142dcb8"},
   "req": {:hex, :req, "0.5.15", "662020efb6ea60b9f0e0fac9be88cd7558b53fe51155a2d9899de594f9906ba9", [:mix], [{:brotli, "~> 0.3.1", [hex: :brotli, repo: "hexpm", optional: true]}, {:ezstd, "~> 1.0", [hex: :ezstd, repo: "hexpm", optional: true]}, {:finch, "~> 0.17", [hex: :finch, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:mime, "~> 2.0.6 or ~> 2.1", [hex: :mime, repo: "hexpm", optional: false]}, {:nimble_csv, "~> 1.0", [hex: :nimble_csv, repo: "hexpm", optional: true]}, {:plug, "~> 1.0", [hex: :plug, repo: "hexpm", optional: true]}], "hexpm", "a6513a35fad65467893ced9785457e91693352c70b58bbc045b47e5eb2ef0c53"},
   "resend": {:hex, :resend, "0.4.4", "f80c6efb6f5d1043f57a1ae1e02cd366a562cac6338097aca38675c7ebe94156", [:mix], [{:hackney, "~> 1.9", [hex: :hackney, repo: "hexpm", optional: false]}, {:swoosh, "~> 1.3", [hex: :swoosh, repo: "hexpm", optional: false]}, {:tesla, "~> 1.5", [hex: :tesla, repo: "hexpm", optional: false]}], "hexpm", "7dab4e8ae395e8ea984e4402988cc9e02b13739707deef127d8f14d181cb88ed"},
   "rewrite": {:hex, :rewrite, "1.1.2", "f5a5d10f5fed1491a6ff48e078d4585882695962ccc9e6c779bae025d1f92eda", [:mix], [{:glob_ex, "~> 0.1", [hex: :glob_ex, repo: "hexpm", optional: false]}, {:sourceror, "~> 1.0", [hex: :sourceror, repo: "hexpm", optional: false]}, {:text_diff, "~> 0.1", [hex: :text_diff, repo: "hexpm", optional: false]}], "hexpm", "7f8b94b1e3528d0a47b3e8b7bfeca559d2948a65fa7418a9ad7d7712703d39d4"},