Notify Slack people when new posts are published

lib/changelog/notifier.ex

@@ -39,6 +39,11 @@ defmodule Changelog.Notifier do
   def notify(item = %NewsItem{}) do
     item = NewsItem.preload_all(item)
 
+    if NewsItem.is_post(item) do
+      post = item |> NewsItem.load_object() |> Map.get(:object)
+      deliver_slack_new_post_message(post)
+    end
+
     if item.submitter == item.author do
       deliver_submitter_email(item.submitter, item)
     else
@@ -194,6 +199,11 @@ defmodule Changelog.Notifier do
     Slack.Client.message("#main", message)
   end
 
+  defp deliver_slack_new_post_message(post) do
+    message = Slack.Messages.new_post(post)
+    Slack.Client.message("#main", message)
+  end
+
   defp deliver_submitter_email(nil, _item), do: false
 
   defp deliver_submitter_email(person, item) do

lib/changelog/slack/messages.ex

@@ -1,5 +1,5 @@
 defmodule Changelog.Slack.Messages do
-  alias ChangelogWeb.{NewsItemView, EpisodeView}
+  alias ChangelogWeb.{NewsItemView, EpisodeView, PostView}
 
   def new_comment(comment) do
     ~s"""
@@ -13,6 +13,12 @@ defmodule Changelog.Slack.Messages do
     """
   end
 
+  def new_post(post) do
+    ~s"""
+    #{post.title} #{celebrate_emoji()} #{PostView.url(post)}
+    """
+  end
+
   def welcome do
     ~s"""
     Welcome to Changelog's Community Slack! :clap:

lib/changelog_web/views/post_view.ex

@@ -26,5 +26,5 @@ defmodule ChangelogWeb.PostView do
     |> length()
   end
 
-  def url(post, action), do: Routes.post_url(Endpoint, action, post.slug)
+  def url(post, action \\ :show), do: Routes.post_url(Endpoint, action, post.slug)
 end

test/changelog/notifier_test.exs

@@ -460,4 +460,23 @@ defmodule Changelog.NotifierTest do
       assert_no_emails_delivered()
     end
   end
+
+  describe "notify/1 with a post item" do
+    setup_with_mocks([
+      {Slack.Client, [], [message: fn _, _ -> true end]}
+    ]) do
+      :ok
+    end
+
+    test "when post is published" do
+      post = insert(:published_post)
+      item = post |> post_news_item() |> insert()
+      Notifier.notify(item)
+
+      assert %{success: 0, failure: 0} = Oban.drain_queue(queue: :email)
+
+      assert_no_emails_delivered()
+      assert called(Slack.Client.message("#main", :_))
+    end
+  end
 end