feat: implement Oban connection pooling

Add dedicated Oban repository with connection pooling to improve database performance and prevent connection starvation. Includes dynamic repo selection for transaction handling.

Author: zcesur

config/config.exs

@@ -41,7 +41,8 @@ config :algora, AlgoraWeb.Endpoint,
 
 config :algora, Oban,
   notifier: Oban.Notifiers.PG,
-  repo: Algora.Repo,
+  repo: Algora.ObanRepo,
+  get_dynamic_repo: {Algora.Repo, :oban_repo, []},
   queues: [
     # --- #
     event_consumers: 1,

config/dev.exs

@@ -33,6 +33,15 @@ config :algora, Algora.Repo,
   migration_primary_key: [type: :string],
   migration_timestamps: [type: :utc_datetime_usec]
 
+# Configure dedicated Oban database repository
+config :algora, Algora.ObanRepo,
+  url: System.get_env("DATABASE_URL"),
+  stacktrace: true,
+  show_sensitive_data_on_connection_error: true,
+  pool_size: 10,
+  migration_primary_key: [type: :string],
+  migration_timestamps: [type: :utc_datetime_usec]
+
 config :ex_aws,
   json_codec: Jason,
   access_key_id: System.get_env("AWS_ACCESS_KEY_ID"),

config/runtime.exs

@@ -61,6 +61,16 @@ if config_env() == :prod do
     migration_timestamps: [type: :utc_datetime_usec],
     queue_target: 5000
 
+  # Configure dedicated Oban database repository
+  config :algora, Algora.ObanRepo,
+    # ssl: true,
+    url: database_url,
+    pool_size: String.to_integer(System.get_env("OBAN_POOL_SIZE") || "10"),
+    socket_options: maybe_ipv6,
+    migration_primary_key: [type: :string],
+    migration_timestamps: [type: :utc_datetime_usec],
+    queue_target: 5000
+
   config :ex_aws,
     json_codec: Jason,
     access_key_id: System.fetch_env!("AWS_ACCESS_KEY_ID"),

config/test.exs

@@ -12,6 +12,14 @@ config :algora, Algora.Repo,
   migration_primary_key: [type: :string],
   migration_timestamps: [type: :utc_datetime_usec]
 
+# Configure dedicated Oban database repository for testing
+config :algora, Algora.ObanRepo,
+  url: System.get_env("TEST_DATABASE_URL"),
+  pool: Ecto.Adapters.SQL.Sandbox,
+  pool_size: System.schedulers_online() * 2,
+  migration_primary_key: [type: :string],
+  migration_timestamps: [type: :utc_datetime_usec]
+
 # We don't run a server during test. If one is required,
 # you can enable the server option below.
 config :algora, AlgoraWeb.Endpoint,

lib/algora/application.ex

@@ -14,6 +14,7 @@ defmodule Algora.Application do
       {NodeJS.Supervisor, [path: LiveSvelte.SSR.NodeJS.server_path(), pool_size: 4]},
       AlgoraWeb.Telemetry,
       Algora.Repo,
+      Algora.ObanRepo,
       {Oban, Application.fetch_env!(:algora, Oban)},
       {DNSCluster, query: Application.get_env(:algora, :dns_cluster_query) || :ignore},
       {Phoenix.PubSub, name: Algora.PubSub},

lib/algora/oban_repo.ex

@@ -0,0 +1,5 @@
+defmodule Algora.ObanRepo do
+  use Ecto.Repo,
+    adapter: Ecto.Adapters.Postgres,
+    otp_app: :algora
+end

lib/algora/repo.ex

@@ -3,6 +3,14 @@ defmodule Algora.Repo do
     otp_app: :algora,
     adapter: Ecto.Adapters.Postgres
 
+  def oban_repo do
+    if in_transaction?() do
+      __MODULE__
+    else
+      Algora.ObanRepo
+    end
+  end
+
   alias Algora.Activities.Activity
   alias Algora.Activities.Notifier