Add list_buckets function and tests to Object API

lib/gnat/jetstream/api/object.ex

@@ -145,6 +145,38 @@ defmodule Gnat.Jetstream.API.Object do
     end
   end
 
+  @doc """
+  Returns true if the provided stream is an Object bucket, false otherwise
+  ## Parameters
+  * `stream_name` - the stream name to test
+  """
+  @spec is_object_bucket_stream?(stream_name :: binary()) :: boolean()
+  def is_object_bucket_stream?(stream_name) do
+    String.starts_with?(stream_name, "OBJ_")
+  end
+
+  @doc """
+  Returns a list of all Object buckets
+  """
+  @spec list_buckets(conn :: Gnat.t()) :: {:error, term()} | {:ok, list(String.t())}
+  def list_buckets(conn) do
+    with {:ok, %{streams: streams}} <- Stream.list(conn) do
+      stream_names =
+        streams
+        |> Enum.flat_map(fn bucket ->
+          if is_object_bucket_stream?(bucket) do
+             [bucket |> String.trim_leading(@stream_prefix)]
+          else
+             []
+          end
+        end)
+      {:ok, stream_names}
+    else
+      {:error, reason} ->
+        {:error, reason}
+    end
+  end
+
   defp stream_name(bucket_name) do
     "#{@stream_prefix}#{bucket_name}"
   end

test/jetstream/api/object_test.exs

@@ -150,6 +150,8 @@ defmodule Gnat.Jetstream.API.ObjectTest do
       assert size_after_changelog < size_after_readme
       assert {:ok, [meta]} = Object.list(:gnat, bucket)
       assert meta.name == "WAT"
+
+      assert :ok = Object.delete_bucket(:gnat, bucket)
     end
 
     test "return an error if the object store doesn't exist" do
@@ -185,6 +187,28 @@ defmodule Gnat.Jetstream.API.ObjectTest do
     :ok = Object.delete_bucket(:gnat, bucket)
   end
 
+  describe "list_buckets/2" do
+    test "list buckets when none exists" do
+      assert {:ok, []} = Object.list_buckets(:gnat)
+    end
+
+    test "list buckets properly" do
+      assert {:ok, %{config: _config}} = Object.create_bucket(:gnat, "TEST_BUCKET_1")
+      assert {:ok, %{config: _config}} = Object.create_bucket(:gnat, "TEST_BUCKET_2")
+      assert {:ok, ["TEST_BUCKET_1", "TEST_BUCKET_2"]} = Object.list_buckets(:gnat)
+      :ok = Object.delete_bucket(:gnat, "TEST_BUCKET_1")
+      :ok = Object.delete_bucket(:gnat, "TEST_BUCKET_2")
+    end
+
+    test "ignore streams that are not buckets" do
+      assert {:ok, %{config: _config}} = Object.create_bucket(:gnat, "TEST_BUCKET_1")
+      stream = %Stream{name: "TEST_STREAM_1", subjects: ["TEST_STREAM_1.subject1", "TEST_STREAM_1.subject2"]}
+      assert {:ok, _response} = Stream.create(:gnat, stream)
+      assert {:ok, ["TEST_BUCKET_1"]} = Object.list_buckets(:gnat)
+      :ok = Object.delete_bucket(:gnat, "TEST_BUCKET_1")
+    end
+  end
+
   # create a random 1MB binary file
   # re-use it on subsequent test runs if it already exists
   defp generate_big_file(tmp_dir) do