Remove Check method from tflint.RuleSet interface (#258)

plugin/host2plugin/host2plugin_test.go

@@ -87,23 +87,45 @@ func (r *mockRuleSet) NewRunner(runner tflint.Runner) (tflint.Runner, error) {
 	return runner, nil
 }
 
-func (r *mockRuleSet) Check(runner tflint.Runner) error {
-	if r.impl.check != nil {
-		return r.impl.check(runner)
-	}
-	return nil
-}
-
 func newMockRuleSet(name, version string, impl mockRuleSetImpl) *mockRuleSet {
 	return &mockRuleSet{
 		BuiltinRuleSet: tflint.BuiltinRuleSet{
 			Name:    name,
 			Version: version,
+			EnabledRules: []tflint.Rule{
+				&mockRule{check: impl.check},
+			},
 		},
 		impl: impl,
 	}
 }
 
+var _ tflint.Rule = &mockRule{}
+
+type mockRule struct {
+	tflint.DefaultRule
+	check func(tflint.Runner) error
+}
+
+func (r *mockRule) Check(runner tflint.Runner) error {
+	if r.check != nil {
+		return r.check(runner)
+	}
+	return nil
+}
+
+func (r *mockRule) Name() string {
+	return "mock_rule"
+}
+
+func (r *mockRule) Severity() tflint.Severity {
+	return tflint.ERROR
+}
+
+func (r *mockRule) Enabled() bool {
+	return true
+}
+
 func TestRuleSetName(t *testing.T) {
 	// default error check helper
 	neverHappend := func(err error) bool { return err != nil }
@@ -669,7 +691,7 @@ resource "aws_instance" "foo" {
 				return err
 			},
 			ErrCheck: func(err error) bool {
-				return err == nil || err.Error() != "unexpected error"
+				return err == nil || err.Error() != `failed to check "mock_rule" rule: unexpected error`
 			},
 		},
 		{
@@ -681,7 +703,7 @@ resource "aws_instance" "foo" {
 				return errors.New("unexpected error")
 			},
 			ErrCheck: func(err error) bool {
-				return err == nil || err.Error() != "unexpected error"
+				return err == nil || err.Error() != `failed to check "mock_rule" rule: unexpected error`
 			},
 		},
 		{
@@ -696,7 +718,7 @@ resource "aws_instance" "foo" {
 				return errors.New(runner.(*mockCustomRunner).Hello())
 			},
 			ErrCheck: func(err error) bool {
-				return err == nil || err.Error() != "Hello from custom runner!"
+				return err == nil || err.Error() != `failed to check "mock_rule" rule: Hello from custom runner!`
 			},
 		},
 	}

plugin/host2plugin/server.go

@@ -2,6 +2,7 @@ package host2plugin
 
 import (
 	"context"
+	"fmt"
 
 	"github.com/hashicorp/go-plugin"
 	"github.com/terraform-linters/tflint-plugin-sdk/logger"
@@ -107,8 +108,8 @@ func (s *GRPCServer) ApplyConfig(ctx context.Context, req *proto.ApplyConfig_Req
 	return &proto.ApplyConfig_Response{}, nil
 }
 
-// Check calls its own plugin implementation with an gRPC client that can send
-// requests to the host process.
+// Check calls plugin rules with a gRPC client that can send requests
+// to the host process.
 func (s *GRPCServer) Check(ctx context.Context, req *proto.Check_Request) (*proto.Check_Response, error) {
 	conn, err := s.broker.Dial(req.Runner)
 	if err != nil {
@@ -120,9 +121,11 @@ func (s *GRPCServer) Check(ctx context.Context, req *proto.Check_Request) (*prot
 	if err != nil {
 		return nil, toproto.Error(codes.FailedPrecondition, err)
 	}
-	err = s.impl.Check(runner)
-	if err != nil {
-		return nil, toproto.Error(codes.Aborted, err)
+
+	for _, rule := range s.impl.BuiltinImpl().EnabledRules {
+		if err := rule.Check(runner); err != nil {
+			return nil, toproto.Error(codes.Aborted, fmt.Errorf(`failed to check "%s" rule: %s`, rule.Name(), err))
+		}
 	}
 	return &proto.Check_Response{}, nil
 }

tflint/interface.go

@@ -68,9 +68,9 @@ type RuleSet interface {
 	// Custom rulesets can override this method to inject a custom runner.
 	NewRunner(Runner) (Runner, error)
 
-	// Check is a entrypoint for all inspections.
+	// BuiltinImpl returns the receiver itself as BuiltinRuleSet.
 	// This is not supposed to be overridden from custom rulesets.
-	Check(Runner) error
+	BuiltinImpl() *BuiltinRuleSet
 
 	// All Ruleset must embed the builtin ruleset.
 	mustEmbedBuiltinRuleSet()

tflint/ruleset.go

@@ -1,8 +1,6 @@
 package tflint
 
 import (
-	"fmt"
-
 	"github.com/terraform-linters/tflint-plugin-sdk/hclext"
 	"github.com/terraform-linters/tflint-plugin-sdk/logger"
 )
@@ -104,14 +102,10 @@ func (r *BuiltinRuleSet) NewRunner(runner Runner) (Runner, error) {
 	return runner, nil
 }
 
-// Check runs inspection for each rule by applying Runner.
-func (r *BuiltinRuleSet) Check(runner Runner) error {
-	for _, rule := range r.EnabledRules {
-		if err := rule.Check(runner); err != nil {
-			return fmt.Errorf("Failed to check `%s` rule: %s", rule.Name(), err)
-		}
-	}
-	return nil
+// BuiltinImpl returns the receiver itself as BuiltinRuleSet.
+// This is not supposed to be overridden from custom rulesets.
+func (r *BuiltinRuleSet) BuiltinImpl() *BuiltinRuleSet {
+	return r
 }
 
 func (r *BuiltinRuleSet) mustEmbedBuiltinRuleSet() {}