feat: add cached og images for repos (#19)

Author: zcesur

config/config.exs

@@ -28,7 +28,11 @@ config :algora, AlgoraWeb.Endpoint,
 
 config :algora, Oban,
   repo: Algora.Repo,
-  queues: [event_consumers: 1, comment_consumers: 1]
+  queues: [
+    event_consumers: 1,
+    comment_consumers: 1,
+    github_og_image: 5
+  ]
 
 # Configures the mailer
 #

lib/algora/workspace/jobs/update_repository_og_image.ex

@@ -0,0 +1,50 @@
+defmodule Algora.Workspace.Jobs.UpdateRepositoryOgImage do
+  @moduledoc false
+  use Oban.Worker, queue: :github_og_image
+
+  alias Algora.Repo
+  alias Algora.Workspace.Repository
+
+  require Logger
+
+  @impl Oban.Worker
+  def perform(%Oban.Job{args: %{"repository_id" => repository_id}}) do
+    repository =
+      Repository
+      |> Repo.get(repository_id)
+      |> Repo.preload(:user)
+
+    case repository do
+      nil -> {:error, :not_found}
+      repository -> update_og_image(repository)
+    end
+  end
+
+  defp update_og_image(repository) do
+    repo_owner = repository.user.provider_login
+    repo_name = repository.name
+    object = "repositories/#{repo_owner}/#{repo_name}/og.png"
+
+    req = Finch.build(:get, repository.og_image_url)
+
+    with {:ok, %Finch.Response{body: body}} <- Finch.request(req, Algora.Finch),
+         {:ok, _} <- Algora.S3.upload(body, object, content_type: "image/png"),
+         url = Algora.S3.bucket_url() <> "/" <> object,
+         {:ok, updated_repository} <- update_repository_url(repository, url) do
+      {:ok, updated_repository}
+    else
+      error ->
+        Logger.error("Failed to fetch/upload image for #{repo_owner}/#{repo_name}: #{inspect(error)}")
+        error
+    end
+  end
+
+  defp update_repository_url(repository, url) do
+    repository
+    |> Ecto.Changeset.change(%{
+      og_image_url: url,
+      og_image_updated_at: DateTime.utc_now()
+    })
+    |> Repo.update()
+  end
+end

lib/algora/workspace/schemas/repository.ex

@@ -6,31 +6,45 @@ defmodule Algora.Workspace.Repository do
 
   @derive {Inspect, except: [:provider_meta]}
   typed_schema "repositories" do
-    field :provider, :string
-    field :provider_id, :string
-    field :provider_meta, :map
+    field :provider, :string, null: false
+    field :provider_id, :string, null: false
+    field :provider_meta, :map, null: false
 
-    field :name, :string
-    field :url, :string
+    field :name, :string, null: false
+    field :url, :string, null: false
+    field :description, :string
+    field :og_image_url, :string, null: false
+    field :og_image_updated_at, :utc_datetime_usec
 
     has_many :tickets, Algora.Workspace.Ticket
-    belongs_to :user, Algora.Accounts.User
+    belongs_to :user, Algora.Accounts.User, null: false
 
     timestamps()
   end
 
+  defp og_image_base_url, do: "https://opengraph.githubassets.com"
+
+  def has_default_og_image?(%Repository{} = repository),
+    do: String.starts_with?(repository.og_image_url, og_image_base_url())
+
+  def default_og_image_url(repo_owner, repo_name), do: "#{og_image_base_url()}/0/#{repo_owner}/#{repo_name}"
+
   def github_changeset(meta, user) do
     params = %{
       provider_id: to_string(meta["id"]),
       name: meta["name"],
+      description: meta["description"],
+      og_image_url: default_og_image_url(meta["owner"]["login"], meta["name"]),
+      og_image_updated_at: DateTime.utc_now(),
       url: meta["html_url"],
       user_id: user.id
     }
 
     %Repository{provider: "github", provider_meta: meta}
-    |> cast(params, [:provider_id, :name, :url, :user_id])
+    |> cast(params, [:provider_id, :name, :url, :description, :og_image_url, :og_image_updated_at, :user_id])
     |> generate_id()
     |> validate_required([:provider_id, :name, :url, :user_id])
+    |> foreign_key_constraint(:user_id)
     |> unique_constraint([:provider, :provider_id])
   end
 end

lib/algora/workspace/workspace.ex

@@ -6,6 +6,7 @@ defmodule Algora.Workspace do
   alias Algora.Github
   alias Algora.Repo
   alias Algora.Workspace.Installation
+  alias Algora.Workspace.Jobs
   alias Algora.Workspace.Repository
   alias Algora.Workspace.Ticket
 
@@ -49,10 +50,34 @@ defmodule Algora.Workspace do
         where: u.provider_login == ^owner
       )
 
-    case Repo.one(repository_query) do
-      %Repository{} = repository -> {:ok, repository}
-      nil -> create_repository_from_github(token, owner, repo)
+    res =
+      case Repo.one(repository_query) do
+        %Repository{} = repository -> {:ok, repository}
+        nil -> create_repository_from_github(token, owner, repo)
+      end
+
+    case res do
+      {:ok, repository} -> maybe_schedule_og_image_update(repository)
+      error -> error
+    end
+
+    res
+  end
+
+  defp maybe_schedule_og_image_update(%Repository{} = repository) do
+    one_day_ago = DateTime.add(DateTime.utc_now(), -1, :day)
+
+    needs_update? =
+      Repository.has_default_og_image?(repository) ||
+        (repository.og_image_updated_at && DateTime.before?(repository.og_image_updated_at, one_day_ago))
+
+    if needs_update? do
+      %{repository_id: repository.id}
+      |> Jobs.UpdateRepositoryOgImage.new()
+      |> Oban.insert()
     end
+
+    :ok
   end
 
   def create_repository_from_github(token, owner, repo) do

priv/repo/migrations/20250105152749_add_repo_fields.exs

@@ -0,0 +1,23 @@
+defmodule Algora.Repo.Migrations.AddRepoFields do
+  use Ecto.Migration
+
+  def change do
+    alter table(:repositories) do
+      add :description, :text
+      add :og_image_url, :string
+      add :og_image_updated_at, :utc_datetime_usec
+    end
+
+    # Backfill existing repositories with default values
+    execute """
+    UPDATE repositories
+    SET og_image_url = REPLACE(url, 'https://github.com', 'https://opengraph.githubassets.com/0')
+    WHERE og_image_url IS NULL
+    """
+
+    # Make columns non-nullable after backfill
+    alter table(:repositories) do
+      modify :og_image_url, :string, null: false
+    end
+  end
+end