move the nil check

plugin/service/host/plugin.go

@@ -32,13 +32,6 @@ type HostPlugin struct {
 	testCatalogStateOpts []awsCatalogPersistedStateOption
 }
 
-type hostSetQuery struct {
-	Id          string
-	Input       *ec2.DescribeInstancesInput
-	Output      *ec2.DescribeInstancesOutput
-	OutputHosts []*pb.ListHostsResponseHost
-}
-
 // Ensure that we are implementing HostPluginServiceServer
 var _ pb.HostPluginServiceServer = (*HostPlugin)(nil)
 
@@ -502,6 +495,13 @@ func (p *HostPlugin) ListHosts(ctx context.Context, req *pb.ListHostsRequest) (*
 	}
 
 	// Build all the queries in advance.
+	type hostSetQuery struct {
+		Id          string
+		Input       *ec2.DescribeInstancesInput
+		Output      *ec2.DescribeInstancesOutput
+		OutputHosts []*pb.ListHostsResponseHost
+	}
+
 	queries := make([]hostSetQuery, len(sets))
 	for i, set := range sets {
 		// Validate Id since we use it in output
@@ -634,6 +634,10 @@ func buildFilters(attrs *SetAttributes) ([]types.Filter, error) {
 }
 
 func buildDescribeInstancesInput(attrs *SetAttributes, dryRun bool) (*ec2.DescribeInstancesInput, error) {
+	if attrs == nil {
+		attrs = &SetAttributes{}
+	}
+
 	filters, err := buildFilters(attrs)
 	if err != nil {
 		return nil, fmt.Errorf("error building filters: %w", err)

plugin/service/host/plugin_test.go

@@ -2383,6 +2383,21 @@ func TestBuildDescribeInstancesInput(t *testing.T) {
 			require.Equal(tc.expected, actual)
 		})
 	}
+
+	t.Run("nil attrs, dry run", func(t *testing.T) {
+		require := require.New(t)
+		actual, err := buildDescribeInstancesInput(nil, true)
+		require.NoError(err)
+		require.Equal(&ec2.DescribeInstancesInput{
+			DryRun: aws.Bool(true),
+			Filters: []types.Filter{
+				{
+					Name:   aws.String("instance-state-name"),
+					Values: []string{string(types.InstanceStateNameRunning)},
+				},
+			},
+		}, actual)
+	})
 }
 
 func TestAwsInstanceToHost(t *testing.T) {