Created
September 4, 2025 19:48
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test multi repo transactions in sandbox
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| defmodule TestRepo do | |
| describe "Multi.run transaction isolation" do | |
| defmodule TestItem do | |
| @moduledoc false | |
| use MyApp.Schema | |
| schema "test_transaction_items" do | |
| field :name, :string | |
| field :value, :string | |
| timestamps() | |
| end | |
| def changeset(item, attrs) do | |
| item | |
| |> Ecto.Changeset.cast(attrs, [:name, :value]) | |
| |> Ecto.Changeset.validate_required([:name]) | |
| end | |
| end | |
| setup do | |
| Sandbox.checkout(Repo) | |
| Repo.query!(""" | |
| CREATE TEMPORARY TABLE test_transaction_items ( | |
| id uuid PRIMARY KEY DEFAULT gen_random_uuid(), | |
| name text NOT NULL, | |
| value text, | |
| inserted_at timestamp NOT NULL DEFAULT NOW(), | |
| updated_at timestamp NOT NULL DEFAULT NOW() | |
| ) | |
| """) | |
| :ok | |
| end | |
| test "SQL logging: MyApp.Repo vs repo argument comparison" do | |
| item_name = "test_item_#{System.unique_integer()}" | |
| # Capture all SQL queries | |
| queries = [] | |
| Logger.configure(level: :debug) | |
| :telemetry.attach("sql-compare", [:my_app, :repo, :query], fn name, measurements, metadata, queries -> | |
| query_info = %{ | |
| query: metadata[:query], | |
| params: metadata[:params], | |
| time: measurements[:total_time], | |
| event: name | |
| } | |
| Agent.update(queries, fn list -> [query_info | list] end) | |
| end, queries) | |
| # Start an Agent to collect queries | |
| {:ok, query_agent} = Agent.start_link(fn -> [] end) | |
| :telemetry.detach("sql-compare") | |
| :telemetry.attach("sql-compare", [:my_app, :repo, :query], fn name, measurements, metadata, agent -> | |
| query_info = %{ | |
| query: String.trim(metadata[:query]), | |
| params: metadata[:params], | |
| time: measurements[:total_time], | |
| source: if(String.contains?(metadata[:query], "BEGIN"), do: "BEGIN", | |
| else: if(String.contains?(metadata[:query], "COMMIT"), do: "COMMIT", | |
| else: if(String.contains?(metadata[:query], "INSERT"), do: "INSERT", | |
| else: if(String.contains?(metadata[:query], "SELECT"), do: "SELECT", else: "OTHER")))) | |
| } | |
| Agent.update(agent, fn list -> [query_info | list] end) | |
| end, query_agent) | |
| IO.puts("\n" <> String.duplicate("=", 80)) | |
| IO.puts("🔍 TESTING: MyApp.Repo vs repo argument - SQL Transaction Analysis") | |
| IO.puts(String.duplicate("=", 80)) | |
| # Test 1: MyApp.Repo pattern | |
| IO.puts("\n🔥 Pattern 1: Using MyApp.Repo directly") | |
| Agent.update(query_agent, fn _ -> [] end) # Clear queries | |
| multi_result_my_app = | |
| Ecto.Multi.new() | |
| |> Ecto.Multi.run(:create_item, fn _repo, _changes -> | |
| IO.puts(" 📍 Creating item with MyApp.Repo...") | |
| %TestItem{} | |
| |> TestItem.changeset(%{name: item_name <> "_my_app", value: "my_app_repo"}) | |
| |> MyApp.Repo.insert() | |
| end) | |
| |> Ecto.Multi.run(:verify, fn repo, %{create_item: item} -> | |
| IO.puts(" 📍 Verifying with transaction repo...") | |
| case repo.get(TestItem, item.id) do | |
| nil -> {:error, "not found"} | |
| found -> {:ok, found} | |
| end | |
| end) | |
| |> Repo.transaction() | |
| my_app_queries = Agent.get(query_agent, & &1) |> Enum.reverse() | |
| IO.puts(" 📊 MyApp.Repo pattern queries:") | |
| Enum.with_index(my_app_queries, 1) |> Enum.each(fn {query, idx} -> | |
| IO.puts(" #{idx}. [#{query.source}] #{String.slice(query.query, 0, 100)}#{if String.length(query.query) > 100, do: "...", else: ""}") | |
| end) | |
| # Test 2: Transaction repo pattern | |
| IO.puts("\n✅ Pattern 2: Using repo argument") | |
| Agent.update(query_agent, fn _ -> [] end) # Clear queries | |
| multi_result_transaction = | |
| Ecto.Multi.new() | |
| |> Ecto.Multi.run(:create_item, fn repo, _changes -> | |
| IO.puts(" 📍 Creating item with transaction repo...") | |
| %TestItem{} | |
| |> TestItem.changeset(%{name: item_name <> "_transaction", value: "transaction_repo"}) | |
| |> repo.insert() | |
| end) | |
| |> Ecto.Multi.run(:verify, fn repo, %{create_item: item} -> | |
| IO.puts(" 📍 Verifying with transaction repo...") | |
| case repo.get(TestItem, item.id) do | |
| nil -> {:error, "not found"} | |
| found -> {:ok, found} | |
| end | |
| end) | |
| |> Repo.transaction() | |
| transaction_queries = Agent.get(query_agent, & &1) |> Enum.reverse() | |
| IO.puts(" 📊 Transaction repo pattern queries:") | |
| Enum.with_index(transaction_queries, 1) |> Enum.each(fn {query, idx} -> | |
| IO.puts(" #{idx}. [#{query.source}] #{String.slice(query.query, 0, 100)}#{if String.length(query.query) > 100, do: "...", else: ""}") | |
| end) | |
| # Analysis | |
| IO.puts("\n📈 ANALYSIS:") | |
| IO.puts(" MyApp.Repo queries: #{length(my_app_queries)}") | |
| IO.puts(" Transaction repo queries: #{length(transaction_queries)}") | |
| my_app_begins = Enum.count(my_app_queries, &(&1.source == "BEGIN")) | |
| transaction_begins = Enum.count(transaction_queries, &(&1.source == "BEGIN")) | |
| IO.puts(" MyApp.Repo BEGIN statements: #{my_app_begins}") | |
| IO.puts(" Transaction repo BEGIN statements: #{transaction_begins}") | |
| if my_app_begins == transaction_begins do | |
| IO.puts(" 🤔 RESULT: Both patterns use the same number of transactions!") | |
| IO.puts(" This suggests Ecto.Sandbox makes them behave identically in tests.") | |
| else | |
| IO.puts(" 🎯 RESULT: Different transaction behavior detected!") | |
| end | |
| :telemetry.detach("sql-compare") | |
| Agent.stop(query_agent) | |
| # Both should succeed in test environment | |
| assert {:ok, %{verify: _}} = multi_result_my_app | |
| assert {:ok, %{verify: _}} = multi_result_transaction | |
| IO.puts(String.duplicate("=", 80)) | |
| end | |
| end | |
| end |
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