From 84e954a627b44362f5ebd72f6b7c4b97ba3f7d3a Mon Sep 17 00:00:00 2001
From: Zack Siri <me@zacksiri.dev>
Date: Sat, 11 Nov 2023 12:37:30 +0700
Subject: [PATCH] Resolve race condition for deployment

Signed-off-by: Zack Siri <me@zacksiri.dev>
---
 lib/uplink/packages/deployment.ex         |  3 +++
 lib/uplink/packages/deployment/manager.ex | 33 ++++++++++++++++++++---
 2 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/lib/uplink/packages/deployment.ex b/lib/uplink/packages/deployment.ex
index 8b2ff9dd..a41b2857 100644
--- a/lib/uplink/packages/deployment.ex
+++ b/lib/uplink/packages/deployment.ex
@@ -49,6 +49,9 @@ defmodule Uplink.Packages.Deployment do
     deployment
     |> cast(params, @valid_attrs)
     |> validate_required(@required_attrs)
+    |> unique_constraint(:hash,
+      name: :deployments_app_id_hash_index
+    )
   end
 
   def update_changeset(deployment, params) do
diff --git a/lib/uplink/packages/deployment/manager.ex b/lib/uplink/packages/deployment/manager.ex
index 78d6a96b..b838090f 100644
--- a/lib/uplink/packages/deployment/manager.ex
+++ b/lib/uplink/packages/deployment/manager.ex
@@ -36,22 +36,47 @@ defmodule Uplink.Packages.Deployment.Manager do
   end
 
   @spec get_or_create(%App{}, map) :: {:ok, %Deployment{}}
-  def get_or_create(%App{id: app_id}, params) do
+  def get_or_create(%App{id: app_id} = app, params) do
     hash = Map.get(params, :hash) || Map.get(params, "hash")
 
     Deployment
     |> Repo.get_by(app_id: app_id, hash: hash)
     |> case do
       nil ->
-        %Deployment{app_id: app_id}
-        |> Deployment.changeset(params)
-        |> Repo.insert()
+        create(app, params)
 
       %Deployment{} = deployment ->
         {:ok, deployment}
     end
   end
 
+  def create(%App{id: app_id}, params) do
+    %Deployment{app_id: app_id}
+    |> Deployment.changeset(params)
+    |> Repo.insert()
+    |> case do
+      {:ok, deployment} ->
+        {:ok, deployment}
+
+      {:error,
+       %Ecto.Changeset{
+         changes: %{hash: hash},
+         errors: [
+           hash:
+             {_,
+              [
+                constraint: :unique,
+                constraint_name: "deployments_app_id_hash_index"
+              ]}
+         ]
+       }} ->
+        {:ok, Repo.get_by!(Deployment, app_id: app_id, hash: hash)}
+
+      error ->
+        error
+    end
+  end
+
   def update(%Deployment{} = deployment, params) do
     deployment
     |> Deployment.update_changeset(params)