tflint: Add WalkResourceBlocks API

go.sum

@@ -73,7 +73,6 @@ github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXf
 github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/vmihailenco/msgpack v3.3.3+incompatible/go.mod h1:fy3FlTQTDXWkZ7Bh6AcGMlsjHatGryHQYUTf1ShIgkk=
-github.com/zclconf/go-cty v1.2.0 h1:sPHsy7ADcIZQP3vILvTjrh74ZA175TFP5vqiNK1UmlI=
 github.com/zclconf/go-cty v1.2.0/go.mod h1:hOPWgoHbaTUnI5k4D2ld+GRpFJSCe6bCM7m1q/N4PQ8=
 github.com/zclconf/go-cty v1.4.1 h1:Xzr4m4utRDhHDifag1onwwUSq32HLoLBsp+w6tD0880=
 github.com/zclconf/go-cty v1.4.1/go.mod h1:nHzOclRkoj++EU9ZjSrZvRG0BXIWt8c7loYc0qXAFGQ=
@@ -115,7 +114,6 @@ golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8T
 google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=
 google.golang.org/appengine v1.4.0/go.mod h1:xpcJRLb0r/rnEns0DIKYYv+WjYCduHsrkT7/EB5XEv4=
 google.golang.org/genproto v0.0.0-20170818010345-ee236bd376b0/go.mod h1:JiN7NxoALGmiZfu7CAH4rXhgtRTLTxftemlI0sWmxmc=
-google.golang.org/genproto v0.0.0-20180817151627-c66870c02cf8 h1:Nw54tB0rB7hY/N0NQvRW8DG4Yk3Q6T9cu9RcFQDu1tc=
 google.golang.org/genproto v0.0.0-20180817151627-c66870c02cf8/go.mod h1:JiN7NxoALGmiZfu7CAH4rXhgtRTLTxftemlI0sWmxmc=
 google.golang.org/genproto v0.0.0-20190819201941-24fa4b261c55 h1:gSJIx1SDwno+2ElGhA4+qG2zF97qiUzTM+rQ0klBOcE=
 google.golang.org/genproto v0.0.0-20190819201941-24fa4b261c55/go.mod h1:DMBHOl98Agz4BDEuKkezgsaosCRResVns1a3J2ZsMNc=

tflint/client.go

@@ -80,6 +80,66 @@ func (c *Client) WalkResourceAttributes(resource, attributeName string, walker f
 	return nil
 }
 
+// BlocksRequest is the interface used to communicate via RPC.
+type BlocksRequest struct {
+	Resource  string
+	BlockName string
+}
+
+// BlocksResponse is the interface used to communicate via RPC.
+type BlocksResponse struct {
+	Blocks []*Block
+	Err    error
+}
+
+// Block is an intermediate representation of hcl.Block.
+// It has an body as a string of bytes so that hcl.Body is not transferred via RPC.
+type Block struct {
+	Type      string
+	Labels    []string
+	Body      []byte
+	BodyRange hcl.Range
+
+	DefRange    hcl.Range
+	TypeRange   hcl.Range
+	LabelRanges []hcl.Range
+}
+
+// WalkResourceBlocks queries the host process, receives a list of blocks that match the conditions,
+// and passes each to the walker function.
+func (c *Client) WalkResourceBlocks(resource, blockName string, walker func(*hcl.Block) error) error {
+	log.Printf("[DEBUG] Walk `%s.*.%s` block", resource, blockName)
+
+	var response BlocksResponse
+	if err := c.rpcClient.Call("Plugin.Blocks", BlocksRequest{Resource: resource, BlockName: blockName}, &response); err != nil {
+		return err
+	}
+	if response.Err != nil {
+		return response.Err
+	}
+
+	for _, block := range response.Blocks {
+		file, diags := parseConfig(block.Body, block.BodyRange.Filename, block.BodyRange.Start)
+		if diags.HasErrors() {
+			return diags
+		}
+		b := &hcl.Block{
+			Type:        block.Type,
+			Labels:      block.Labels,
+			Body:        file.Body,
+			DefRange:    block.DefRange,
+			TypeRange:   block.TypeRange,
+			LabelRanges: block.LabelRanges,
+		}
+
+		if err := walker(b); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
 // EvalExprRequest is the interface used to communicate via RPC.
 type EvalExprRequest struct {
 	Expr      []byte
@@ -202,3 +262,21 @@ func parseExpression(src []byte, filename string, start hcl.Pos) (hcl.Expression
 
 	panic(fmt.Sprintf("Unexpected file: %s", filename))
 }
+
+func parseConfig(src []byte, filename string, start hcl.Pos) (*hcl.File, hcl.Diagnostics) {
+	if strings.HasSuffix(filename, ".tf") {
+		return hclsyntax.ParseConfig(src, filename, start)
+	}
+
+	if strings.HasSuffix(filename, ".tf.json") {
+		return nil, hcl.Diagnostics{
+			&hcl.Diagnostic{
+				Severity: hcl.DiagError,
+				Summary:  "JSON configuration syntax is not supported",
+				Subject:  &hcl.Range{Filename: filename, Start: start, End: start},
+			},
+		}
+	}
+
+	panic(fmt.Sprintf("Unexpected file: %s", filename))
+}

tflint/client_test.go

@@ -1,7 +1,6 @@
 package tflint
 
 import (
-	"encoding/gob"
 	"errors"
 	"io/ioutil"
 	"net"
@@ -39,6 +38,24 @@ func (*mockServer) Attributes(req *AttributesRequest, resp *AttributesResponse)
 	return nil
 }
 
+func (*mockServer) Blocks(req *BlocksRequest, resp *BlocksResponse) error {
+	*resp = BlocksResponse{Blocks: []*Block{
+		{
+			Type:      "resource",
+			Labels:    []string{"aws_instance", "foo"},
+			Body:      []byte(`instance_type = "t2.micro"`),
+			BodyRange: hcl.Range{Filename: "example.tf", Start: hcl.Pos{Line: 2, Column: 3}, End: hcl.Pos{Line: 2, Column: 28}},
+			DefRange:  hcl.Range{Filename: "example.tf", Start: hcl.Pos{Line: 1, Column: 1}, End: hcl.Pos{Line: 1, Column: 29}},
+			TypeRange: hcl.Range{Filename: "example.tf", Start: hcl.Pos{Line: 1, Column: 1}, End: hcl.Pos{Line: 1, Column: 8}},
+			LabelRanges: []hcl.Range{
+				{Filename: "example.tf", Start: hcl.Pos{Line: 1, Column: 10}, End: hcl.Pos{Line: 3, Column: 23}},
+				{Filename: "example.tf", Start: hcl.Pos{Line: 1, Column: 25}, End: hcl.Pos{Line: 3, Column: 29}},
+			},
+		},
+	}, Err: nil}
+	return nil
+}
+
 func (*mockServer) EvalExpr(req *EvalExprRequest, resp *EvalExprResponse) error {
 	*resp = EvalExprResponse{Val: cty.StringVal("1"), Err: nil}
 	return nil
@@ -49,8 +66,6 @@ func (s *mockServer) EmitIssue(req *EmitIssueRequest, resp *interface{}) error {
 }
 
 func startMockServer(t *testing.T) (*Client, *mockServer) {
-	gob.Register(&hclsyntax.LiteralValueExpr{})
-
 	addy, err := net.ResolveTCPAddr("tcp", "0.0.0.0:42586")
 	if err != nil {
 		t.Fatal(err)
@@ -106,6 +121,64 @@ func Test_WalkResourceAttributes(t *testing.T) {
 	}
 }
 
+func Test_WalkResourceBlocks(t *testing.T) {
+	client, server := startMockServer(t)
+	defer server.Listener.Close()
+
+	walked := []*hcl.Block{}
+	walker := func(block *hcl.Block) error {
+		walked = append(walked, block)
+		return nil
+	}
+
+	if err := client.WalkResourceBlocks("foo", "bar", walker); err != nil {
+		t.Fatal(err)
+	}
+
+	expected := []*hcl.Block{
+		{
+			Type:   "resource",
+			Labels: []string{"aws_instance", "foo"},
+			Body: &hclsyntax.Body{
+				Attributes: hclsyntax.Attributes{
+					"instance_type": {
+						Name: "instance_type",
+						Expr: &hclsyntax.TemplateExpr{
+							Parts: []hclsyntax.Expression{
+								&hclsyntax.LiteralValueExpr{
+									SrcRange: hcl.Range{Filename: "example.tf", Start: hcl.Pos{Line: 2, Column: 20}, End: hcl.Pos{Line: 2, Column: 28}},
+								},
+							},
+							SrcRange: hcl.Range{Filename: "example.tf", Start: hcl.Pos{Line: 2, Column: 19}, End: hcl.Pos{Line: 2, Column: 29}},
+						},
+						SrcRange:    hcl.Range{Filename: "example.tf", Start: hcl.Pos{Line: 2, Column: 3}, End: hcl.Pos{Line: 2, Column: 29}},
+						NameRange:   hcl.Range{Filename: "example.tf", Start: hcl.Pos{Line: 2, Column: 3}, End: hcl.Pos{Line: 2, Column: 16}},
+						EqualsRange: hcl.Range{Filename: "example.tf", Start: hcl.Pos{Line: 2, Column: 17}, End: hcl.Pos{Line: 2, Column: 18}},
+					},
+				},
+				Blocks:   hclsyntax.Blocks{},
+				SrcRange: hcl.Range{Filename: "example.tf", Start: hcl.Pos{Line: 2, Column: 3}, End: hcl.Pos{Line: 2, Column: 29}},
+				EndRange: hcl.Range{Filename: "example.tf", Start: hcl.Pos{Line: 2, Column: 29}, End: hcl.Pos{Line: 2, Column: 29}},
+			},
+			DefRange:  hcl.Range{Filename: "example.tf", Start: hcl.Pos{Line: 1, Column: 1}, End: hcl.Pos{Line: 1, Column: 29}},
+			TypeRange: hcl.Range{Filename: "example.tf", Start: hcl.Pos{Line: 1, Column: 1}, End: hcl.Pos{Line: 1, Column: 8}},
+			LabelRanges: []hcl.Range{
+				{Filename: "example.tf", Start: hcl.Pos{Line: 1, Column: 10}, End: hcl.Pos{Line: 3, Column: 23}},
+				{Filename: "example.tf", Start: hcl.Pos{Line: 1, Column: 25}, End: hcl.Pos{Line: 3, Column: 29}},
+			},
+		},
+	}
+
+	opts := []cmp.Option{
+		cmpopts.IgnoreUnexported(hclsyntax.Body{}),
+		cmpopts.IgnoreFields(hclsyntax.LiteralValueExpr{}, "Val"),
+		cmpopts.IgnoreFields(hcl.Pos{}, "Byte"),
+	}
+	if !cmp.Equal(expected, walked, opts...) {
+		t.Fatalf("Diff: %s", cmp.Diff(expected, walked, opts...))
+	}
+}
+
 func Test_EvaluateExpr(t *testing.T) {
 	client, server := startMockServer(t)
 	defer server.Listener.Close()

tflint/interface.go

@@ -7,6 +7,7 @@ import (
 // Runner acts as a client for each plugin to query the host process about the Terraform configurations.
 type Runner interface {
 	WalkResourceAttributes(string, string, func(*hcl.Attribute) error) error
+	WalkResourceBlocks(string, string, func(*hcl.Block) error) error
 	EvaluateExpr(expr hcl.Expression, ret interface{}) error
 	EmitIssue(rule Rule, message string, location hcl.Range, meta Metadata) error
 	EnsureNoError(error, func() error) error