First commit

.github/workflows/ci.yml

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+name: CI
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    branches: [master]
+
+concurrency:
+  group: "${{ github.workflow }}-${{ github.head_ref }}"
+  cancel-in-progress: true
+
+jobs:
+  ci:
+    runs-on: ubuntu
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Set up Go
+        uses: actions/setup-go@v3
+        with:
+          go-version: 1.18
+
+      - name: Verify dependencies
+        run: go mod verify
+
+      - name: Install dependencies
+        run: go mod download
+
+      - name: Build
+        run: go build -v ./...
+
+      - name: Run go vet
+        run: go vet ./...
+
+      - name: Install staticcheck
+        run: go install honnef.co/go/tools/cmd/staticcheck@latest
+
+      - name: Run staticcheck
+        run: staticcheck ./...
+
+      - name: Install golint
+        run: go install golang.org/x/lint/golint@latest
+
+      - name: Run golint
+        run: golint ./...
+
+      - name: Run tests
+        run: go test -race -vet=off ./...

block_signature.go

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+package tfsig
+
+import (
+	"github.com/hashicorp/hcl/v2/hclwrite"
+	"github.com/zclconf/go-cty/cty"
+
+	"github.com/yoanm/tfsig/tokens"
+)
+
+/** Public **/
+
+func NewSignature(name string, labels []string, elements BodyElements) *BlockSignature {
+	return &BlockSignature{
+		typeName: name,
+		labels:   labels,
+		elements: elements,
+	}
+}
+func NewEmptySignature(name string, labels ...string) *BlockSignature {
+	return NewSignature(name, labels, BodyElements{})
+}
+
+func NewEmptyResource(name, id string, labels ...string) *BlockSignature {
+	return NewEmptySignature("resource", append([]string{name, id}, labels...)...)
+}
+
+type BlockSignature struct {
+	typeName string
+	labels   []string
+	elements BodyElements
+}
+
+func (signature *BlockSignature) GetType() string {
+	return signature.typeName
+}
+func (signature *BlockSignature) GetLabels() []string {
+	return signature.labels
+}
+func (signature *BlockSignature) GetElements() BodyElements {
+	return signature.elements
+}
+func (signature *BlockSignature) SetElements(elements BodyElements) {
+	signature.elements = elements
+}
+func (signature *BlockSignature) AppendElement(element BodyElement) {
+	signature.elements = append(signature.elements, element)
+}
+
+func (signature *BlockSignature) AppendAttribute(name string, value cty.Value) {
+	signature.AppendElement(NewBodyAttribute(name, value))
+}
+func (signature *BlockSignature) AppendChild(child *BlockSignature) {
+	signature.AppendElement(NewBodyBlock(child))
+}
+func (signature *BlockSignature) AppendEmptyLine() {
+	signature.AppendElement(NewBodyEmptyLine())
+}
+
+func (signature *BlockSignature) Build() *hclwrite.Block {
+	block := hclwrite.NewBlock(signature.GetType(), signature.GetLabels())
+
+	signature.WriteElementsToBody(block.Body())
+
+	return block
+}
+
+func (signature *BlockSignature) BuildTokens() (tks hclwrite.Tokens) {
+	if block := signature.Build(); block != nil {
+		blockTks := block.BuildTokens(nil)
+		// Remove trailing new line automatically added (=remove last token)
+		tks = append(hclwrite.Tokens{}, blockTks[0:len(blockTks)-1]...)
+	}
+
+	return tks
+}
+
+func (signature *BlockSignature) WriteElementsToBody(body *hclwrite.Body) {
+	for _, value := range signature.GetElements() {
+		if value.IsBodyBlock() {
+			body.AppendBlock(value.Build())
+		} else if value.IsBodyAttribute() {
+			if tokens.ContainsCapsule(value.attr) {
+				body.SetAttributeRaw(value.GetName(), tokens.Generate(value.attr))
+			} else {
+				body.SetAttributeValue(value.GetName(), *value.attr)
+			}
+		} else if value.IsBodyEmptyLine() {
+			body.AppendNewline()
+		}
+	}
+}
+
+// DependsOn adds an empty line and the 'depends_on terraform directive with provided id list
+func (s *BlockSignature) DependsOn(idList []string) {
+	if idList == nil {
+		return
+	}
+
+	s.AppendEmptyLine()
+	s.AppendAttribute("depends_on", *tokens.NewIdentListValue(idList))
+}
+
+type LifecycleCondition struct {
+	condition    string
+	errorMessage string
+}
+type LifecycleConfig struct {
+	CreateBeforeDestroy *bool
+	PreventDestroy      *bool
+	IgnoreChanges       []string
+	ReplaceTriggeredBy  []string
+	Precondition        *LifecycleCondition
+	Postcondition       *LifecycleCondition
+}
+
+// Lifecycle adds an empty line and the 'lifecycle terraform directive, or return the existing signature
+func (s *BlockSignature) Lifecycle(config LifecycleConfig) {
+	sig := NewEmptySignature("lifecycle")
+
+	appendLifecycleBoolAttribute(sig, "create_before_destroy", config.CreateBeforeDestroy)
+	appendLifecycleBoolAttribute(sig, "prevent_destroy", config.PreventDestroy)
+
+	if config.IgnoreChanges != nil {
+		sig.AppendAttribute("ignore_changes", *tokens.NewIdentListValue(config.IgnoreChanges))
+	}
+
+	appendLifecycleConditionBlock(sig, "precondition", config.Precondition)
+	appendLifecycleConditionBlock(sig, "postcondition", config.Postcondition)
+
+	s.AppendEmptyLine()
+	s.AppendChild(sig)
+}
+
+/** Private **/
+
+func appendLifecycleConditionBlock(lifecycleSig *BlockSignature, name string, c *LifecycleCondition) {
+	if c == nil {
+		return
+	}
+	cond := NewEmptySignature(name)
+
+	cond.AppendAttribute("condition", *tokens.NewIdentValue(c.condition))
+	cond.AppendAttribute("error_message", *tokens.NewIdentValue(c.errorMessage))
+
+	lifecycleSig.AppendChild(cond)
+}
+
+func appendLifecycleBoolAttribute(lifecycleSig *BlockSignature, name string, value *bool) {
+	if value == nil {
+		return
+	}
+	val := "false"
+	if *value {
+		val = "true"
+	}
+	lifecycleSig.AppendAttribute(name, *tokens.NewIdentValue(val))
+}

block_signature_example_test.go

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+package tfsig
+
+import (
+	"fmt"
+
+	"github.com/hashicorp/hcl/v2/hclwrite"
+	"github.com/zclconf/go-cty/cty"
+)
+
+func Example() {
+	// Create a resource block
+	sig := NewEmptyResource("res_name", "res_id")
+	sig.AppendAttribute("attribute1", cty.StringVal("value1"))
+	sig.AppendEmptyLine()
+	sig.AppendAttribute("attribute2", cty.BoolVal(true))
+	sig.AppendAttribute("attribute3", cty.NumberFloatVal(-12.34))
+	sig.AppendEmptyLine()
+
+	hclFile := hclwrite.NewEmptyFile()
+	hclFile.Body().AppendBlock(sig.Build())
+
+	fmt.Println(string(hclFile.Bytes()))
+	// Output:
+	// resource "res_name" "res_id" {
+	//   attribute1 = "value1"
+	//
+	//   attribute2 = true
+	//   attribute3 = -12.34
+	//
+	// }
+}
+
+func Example_second() {
+	// Enhance an existing signature
+	sig := NewEmptyResource("res_name", "res_id")
+	sig.AppendAttribute("attribute1", cty.StringVal("value1"))
+	sig.AppendEmptyLine()
+	sig.AppendAttribute("attribute2", cty.BoolVal(true))
+	sig.AppendAttribute("attribute3", cty.NumberFloatVal(-12.34))
+	sig.AppendEmptyLine()
+
+	// ... Later in the code
+	// Enhance signature by removing empty lines and add an attribute below attribute2
+	newElems := BodyElements{}
+	for _, v := range sig.GetElements() {
+		// Remove all empty lines
+		if !v.IsBodyEmptyLine() {
+			newElems = append(newElems, v)
+		}
+		// Append a new attribute right after attribute2
+		if v.GetName() == "attribute2" {
+			newElems = append(newElems, NewBodyAttribute("attribute22", cty.BoolVal(false)))
+		}
+	}
+	sig.SetElements(newElems)
+
+	// ... Finally
+	hclFile := hclwrite.NewEmptyFile()
+	hclFile.Body().AppendBlock(sig.Build())
+
+	fmt.Println(string(hclFile.Bytes()))
+	// Output:
+	// resource "res_name" "res_id" {
+	//   attribute1  = "value1"
+	//   attribute2  = true
+	//   attribute22 = false
+	//   attribute3  = -12.34
+	// }
+}
+
+func Example_third() {
+	sig := NewEmptyResource("res_name", "res_id")
+	sig.AppendAttribute("attribute1", cty.StringVal("value1"))
+	sig.AppendAttribute("attribute2", cty.BoolVal(true))
+	sig.AppendAttribute("attribute3", cty.NumberFloatVal(-12.34))
+	sig.AppendEmptyLine()
+	sig.AppendAttribute("attribute4", cty.NumberIntVal(42))
+	sig.AppendAttribute("attribute5", cty.StringVal("value5"))
+
+	// ... Later in the code
+	// Re-order elements and remove empty lines
+	newElems := make(BodyElements, len(sig.GetElements()))
+	extraElemCont := 0
+	for _, v := range sig.GetElements() {
+		if v.GetName() == "attribute1" {
+			newElems[2] = v
+		} else if v.GetName() == "attribute4" {
+			newElems[1] = v
+		} else if v.GetName() == "attribute3" {
+			newElems[0] = v
+		} else if !v.IsBodyEmptyLine() {
+			newElems[3+extraElemCont] = v
+			extraElemCont++
+		}
+	}
+	sig.SetElements(newElems)
+
+	hclFile := hclwrite.NewEmptyFile()
+	hclFile.Body().AppendBlock(sig.Build())
+
+	fmt.Println(string(hclFile.Bytes()))
+	// Output:
+	// resource "res_name" "res_id" {
+	//   attribute3 = -12.34
+	//   attribute4 = 42
+	//   attribute1 = "value1"
+	//   attribute2 = true
+	//   attribute5 = "value5"
+	// }
+}