Use AWS Redshift Data API

README.md

@@ -13,17 +13,51 @@ Add `redshift_ecto` to your list of dependencies in `mix.exs`:
 ```elixir
 def deps do
   [
-    {:redshift_ecto, "~> 0.1.0"}
+    {:redshift_ecto, "~> 0.2.0"}
   ]
 end
 ```
 
-### Example configuration
+## Connecting
+
+`RedshiftEcto` communicates with Redshift through the
+[Redshift Data API](https://docs.aws.amazon.com/redshift/latest/mgmt/data-api.html)
+via the [`AWS.RedshiftData`](https://hexdocs.pm/aws/AWS.RedshiftData.html)
+module. The repository configuration accepts the connection options required
+by the AWS client.
+
+### Production cluster
+
+Provide your AWS credentials through the environment or explicitly in the
+configuration. Specify the cluster identifier, database name and either a
+database user or a Secrets Manager ARN:
+
+```elixir
+config :my_app, MyApp.Repo,
+  adapter: RedshiftEcto,
+  region: "us-east-1",
+  cluster_identifier: "my-redshift-cluster",
+  database: "dev",
+  db_user: "awsuser"
+  # or: secret_arn: "arn:aws:secretsmanager:..."
+```
+
+### Localstack
+
+When developing locally you can point the adapter at a Localstack instance
+that provides the Redshift Data API. Use the Localstack endpoint and dummy
+credentials:
 
 ```elixir
 config :my_app, MyApp.Repo,
   adapter: RedshiftEcto,
-  url: "ecto://user:pass@data-warehouse.abc123.us-east-1.redshift.amazonaws.com:5439/db"
+  region: "us-east-1",
+  cluster_identifier: "local",
+  database: "dev",
+  db_user: "test",
+  access_key_id: "test",
+  secret_access_key: "test",
+  endpoint: "http://localhost:4566"
 ```
 
 ## Testing

config/config.exs

@@ -1,3 +1,3 @@
-use Mix.Config
+import Config
 
-config :postgrex, :json_library, Jason
+config :aws, :json_library, Jason

lib/redshift_ecto.ex

@@ -2,8 +2,9 @@ defmodule RedshiftEcto do
   @moduledoc """
   Ecto adapter for [AWS Redshift](https://aws.amazon.com/redshift/).
 
-  It uses `Postgrex` for communicating to the database and a connection pool,
-  such as `DBConnection.Poolboy`.
+  It communicates with Redshift through the AWS Redshift Data API via the
+  [`AWS.RedshiftData`](https://hexdocs.pm/aws/AWS.RedshiftData.html) module.
+  Connections are managed using `DBConnection`.
 
   This adapter is based on Ecto's builtin `Ecto.Adapters.Postgres` adapter. It
   delegates some functions to it but changes the implementation of most that
@@ -95,7 +96,7 @@ defmodule RedshiftEcto do
   """
 
   # Inherit all behaviour from Ecto.Adapters.SQL
-  use Ecto.Adapters.SQL, driver: :postgrex, migration_lock: nil
+  use Ecto.Adapters.SQL, driver: :aws, migration_lock: nil
 
   alias Ecto.Adapters.Postgres
 
@@ -203,43 +204,9 @@ defmodule RedshiftEcto do
   ## Helpers
 
   defp run_query(sql, opts) do
-    {:ok, _} = Application.ensure_all_started(:postgrex)
-
-    opts =
-      opts
-      |> Keyword.drop([:name, :log])
-      |> Keyword.put(:pool, DBConnection.Connection)
-      |> Keyword.put(:backoff_type, :stop)
-
-    {:ok, pid} = Task.Supervisor.start_link()
-
-    task =
-      Task.Supervisor.async_nolink(pid, fn ->
-        {:ok, conn} = Postgrex.start_link(opts)
-
-        value = RedshiftEcto.Connection.execute(conn, sql, [], opts)
-        GenServer.stop(conn)
-        value
-      end)
-
-    timeout = Keyword.get(opts, :timeout, 15_000)
-
-    case Task.yield(task, timeout) || Task.shutdown(task) do
-      {:ok, {:ok, result}} ->
-        {:ok, result}
-
-      {:ok, {:error, error}} ->
-        {:error, error}
-
-      {:exit, {%{__struct__: struct} = error, _}}
-      when struct in [Postgrex.Error, DBConnection.Error] ->
-        {:error, error}
-
-      {:exit, reason} ->
-        {:error, RuntimeError.exception(Exception.format_exit(reason))}
-
-      nil ->
-        {:error, RuntimeError.exception("command timed out")}
-    end
+    {:ok, conn} = RedshiftEcto.DataAPI.start_link(opts)
+    result = RedshiftEcto.DataAPI.execute(conn, sql, [])
+    GenServer.stop(conn)
+    result
   end
 end