Is it possible to query a custom query with dynamic repo?

Questions / Help
,
1

I made MyApp.Repo module following Replicas and dynamic repositories — Ecto v3.8.4.

It works for functions in MyApp.Repo, but not works for custom queries.

defmodule MyApp.Repo do
  use Ecto.Repo,
    otp_app: :carrier,
    adapter: Ecto.Adapters.Postgres

  def with_dynamic_repo(credentials, callback) do
    default_dynamic_repo = get_dynamic_repo()
    start_opts = [name: nil, pool_size: 1] ++ credentials
    {:ok, repo} = __MODULE__.start_link(start_opts)

    try do
      put_dynamic_repo(repo)
      callback.()
    after
      put_dynamic_repo(default_dynamic_repo)
      Supervisor.stop(repo)
    end
  end
end

credentials = [
  hostname: "localhost",
  username: "customer",
  password: "password",
  port: 48141,
  database: "customer_db"
]

MyApp.Repo.with_dynamic_repo(credentials, fn ->
  # 'orders' table is in 'customer_db' table
  """
  SELECT * FROM orders LIMIT 10;
  """
  
  Ecto.Adapters.SQL.query!(MyApp.Repo, query, [])
end)

# relation "orders" does not exist

It works on below.

defmodule MyApp.Repo do
  use Ecto.Repo,
    otp_app: :carrier,
    adapter: Ecto.Adapters.Postgres

  def with_dynamic_repo(credentials, callback) do
    default_dynamic_repo = get_dynamic_repo()
    start_opts = [name: nil, pool_size: 1] ++ credentials
    {:ok, repo} = __MODULE__.start_link(start_opts)

    try do
      put_dynamic_repo(repo)
      callback.(repo)
    after
      put_dynamic_repo(default_dynamic_repo)
      Supervisor.stop(repo)
    end
  end
end

credentials = [
  hostname: "localhost",
  username: "customer",
  password: "password",
  port: 48141,
  database: "customer_db"
]

MyApp.Repo.with_dynamic_repo(credentials, fn repo ->
  # 'orders' table is in 'customer_db' table
  """
  SELECT * FROM orders LIMIT 10;
  """
  
  Ecto.Adapters.SQL.query!(repo, query, [])
end)

But with that, there is no meaning to using dynamic repo.
I don’t know how to use transaction with pid of repo.

Is it possible to query a custom query with dynamic repo?

2

From the docs for Ecto.Adapters.SQL:

Generally speaking, you must invoke those functions directly from your repository, for example: MyApp.Repo.query("SELECT true") . You can also invoke them direcltly from Ecto.Adapters.SQL, but keep in mind that in such cases features such as “dynamic repositories” won’t be available.

You want the functions that are added to your repo, for instance MyApp.Repo.query!:

2 Likes
3

Thanks a lot!