Fix issue #20 "unexpected end of JSON input" error (#64)

* correct input reading logic

This addresses #20 and
ensures input is read from the plan file -- and not via STDIN -- if a
plan file argument is provided.

This also seeks to improve some of the error messaging to be a bit more
clear.

* demo issue 20 fix via GH Actions

Ideally, tf-summarize would feature a suite of automated tests verifying
its functionality. In absenece of that, this demos the issue #20 fix via
GH Actions.

* use consistent TF version when invoking TF

- ensure the generation of the `example` directory data is done in a
  consistent, reproducible fashion
- ensure GH Actions uses the same version of TF expected by the `example` directory
- add plan and plan JSON files to source control, for testing purposes

* add automated test verifying STDIN vs file-provided input

This adds a basic automated test verifying the validity of the issue #20
fix.

* remove `demo` job from Build GH Actions workflow

Per code review request, @dineshba would prefer this be kept in a
separate file.

.github/workflows/build.yml

@@ -2,34 +2,33 @@ name: Build
 
 on:
   push:
-    branches: [ main ]
+    branches: [main]
   pull_request:
-    branches: [ main ]
+    branches: [main]
 
 jobs:
-
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v4
+      - uses: actions/checkout@v4
 
-    - name: Run Gosec Security Scanner
-      uses: securego/gosec@master
-      with:
-        args: -exclude=G204 ./...
+      - name: Run Gosec Security Scanner
+        uses: securego/gosec@master
+        with:
+          args: -exclude=G204 ./...
 
-    - name: Set up Go
-      uses: actions/setup-go@v4
-      with:
-        go-version: '1.21'
+      - name: Set up Go
+        uses: actions/setup-go@v4
+        with:
+          go-version: "1.21"
 
-    - name: golangci-lint
-      uses: golangci/golangci-lint-action@v3
-      with:
-        version: latest
+      - name: golangci-lint
+        uses: golangci/golangci-lint-action@v3
+        with:
+          version: latest
 
-    - name: Test
-      run: go test -v ./...
+      - name: Test
+        run: go test -v ./...
 
-    - name: Build
-      run: go build
+      - name: Build
+        run: go build

.github/workflows/demo.yml

@@ -11,49 +11,54 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
-
-    - name: Setup Terraform
-      uses: hashicorp/setup-terraform@v2
-      with:
-        terraform_wrapper: false
-
-    - name: Install terraform-plan-summary
-      run: |
-        REPO="dineshba/tf-summarize"
-        curl -LO https://github.com/$REPO/releases/latest/download/tf-summarize_linux_amd64.zip
-        tmpDir=$(mktemp -d -t tmp.XXXXXXXXXX)
-        mv tf-summarize_linux_amd64.zip $tmpDir
-        cd $tmpDir
-        unzip tf-summarize_linux_amd64.zip
-        chmod +x tf-summarize
-        echo $PWD >> $GITHUB_PATH
-
-    - name: Print tf-summarize version and help
-      run: |
-        tf-summarize -v
-        tf-summarize -h
-
-    - name: Terraform Init
-      run: terraform init
-      working-directory: ./example
-
-    - name: Terraform Plan
-      run: terraform plan -out=tfplan -refresh=false # -refresh=false is only for demo workflow
-      working-directory: ./example
-
-    - name: summary in table format
-      run: terraform show -json tfplan | tf-summarize
-      working-directory: ./example
-
-    - name: summary in tree format
-      run: terraform show -json tfplan | tf-summarize -tree
-      working-directory: ./example
-
-    - name: summary in separate tree format
-      run: terraform show -json tfplan | tf-summarize -separate-tree
-      working-directory: ./example
-
-    - name: summary in draw visual tree format
-      run: terraform show -json tfplan | tf-summarize -tree -draw
-      working-directory: ./example
+      - uses: actions/checkout@v3
+
+      - name: Set Terraform version
+        id: set-terraform-version
+        run: echo "terraform-version=$(cat example/.terraform-version)" >> $GITHUB_OUTPUT
+
+      - name: Setup Terraform
+        uses: hashicorp/setup-terraform@v2
+        with:
+          terraform_wrapper: false
+          terraform_version: ${{ steps.set-terraform-version.outputs.terraform-version }}
+
+      - name: Install terraform-plan-summary
+        run: |
+          REPO="dineshba/tf-summarize"
+          curl -LO https://github.com/$REPO/releases/latest/download/tf-summarize_linux_amd64.zip
+          tmpDir=$(mktemp -d -t tmp.XXXXXXXXXX)
+          mv tf-summarize_linux_amd64.zip $tmpDir
+          cd $tmpDir
+          unzip tf-summarize_linux_amd64.zip
+          chmod +x tf-summarize
+          echo $PWD >> $GITHUB_PATH
+
+      - name: Print tf-summarize version and help
+        run: |
+          tf-summarize -v
+          tf-summarize -h
+
+      - name: Terraform Init
+        run: terraform init
+        working-directory: ./example
+
+      - name: Terraform Plan
+        run: terraform plan -out=tfplan -refresh=false # -refresh=false is only for demo workflow
+        working-directory: ./example
+
+      - name: summary in table format
+        run: terraform show -json tfplan | tf-summarize
+        working-directory: ./example
+
+      - name: summary in tree format
+        run: terraform show -json tfplan | tf-summarize -tree
+        working-directory: ./example
+
+      - name: summary in separate tree format
+        run: terraform show -json tfplan | tf-summarize -separate-tree
+        working-directory: ./example
+
+      - name: summary in draw visual tree format
+        run: terraform show -json tfplan | tf-summarize -tree -draw
+        working-directory: ./example

.gitignore

@@ -5,3 +5,5 @@ tf-summarize
 **/.envrc
 **/.terraform
 *.swp
+
+example/tfplan

Makefile

@@ -1,3 +1,5 @@
+TERRAFORM_VERSION:=$(shell cat example/.terraform-version)
+
 .PHONY: help
 help: ## prints help (only for tasks with comment)
 	@grep -E '^[a-zA-Z._-]+:.*?## .*$$' $(MAKEFILE_LIST) | sort | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-30s\033[0m %s\n", $$1, $$2}'
@@ -17,4 +19,22 @@ test: lint
 i: install ## build and install to /usr/local/bin/
 
 lint:
-	golangci-lint run --timeout 10m -v
+	golangci-lint run --timeout 10m -v
+
+define generate-example
+	docker run \
+		--interactive \
+		--tty \
+		--volume $(shell pwd):/src \
+		--workdir /src/example \
+		--entrypoint /bin/sh \
+		hashicorp/terraform:$(1) \
+			-c \
+				"terraform init && \
+				terraform plan -out tfplan && \
+				terraform show -json tfplan > tfplan.json"
+endef
+
+example:
+	$(call generate-example,$(TERRAFORM_VERSION))
+.PHONY: example

example/.terraform-version

@@ -0,0 +1 @@
+1.1.4

main.go

@@ -38,7 +38,7 @@ func main() {
 	err := validateFlags(*tree, *separateTree, *drawable, *md, args)
 	logIfErrorAndExit("invalid input flags: %s\n", err, flag.Usage)
 
-	newReader, err := reader.CreateReader(os.Stdin, args)
+	newReader, err := reader.CreateReader(args)
 	logIfErrorAndExit("error creating input reader: %s\n", err, flag.Usage)
 
 	input, err := newReader.Read()

main_test.go

@@ -0,0 +1,95 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"os/exec"
+	"strings"
+	"testing"
+)
+
+const (
+	testVersion    string = "test"
+	testExecutable string = "tf-summarize-test"
+)
+
+func TestMain(m *testing.M) {
+	// compile a 'tf-summarize' for use in running tests
+	exe := exec.Command("go", "build", "-ldflags", fmt.Sprintf("-X main.version=%s", testVersion), "-o", testExecutable)
+	err := exe.Run()
+	if err != nil {
+		os.Exit(1)
+	}
+
+	m.Run()
+
+	// delete the compiled tf-summarize
+	err = os.Remove(testExecutable)
+	if err != nil {
+		log.Fatal(err)
+	}
+}
+
+func TestVersionArg(t *testing.T) {
+	args := []string{
+		"-v",
+	}
+
+	for _, arg := range args {
+		t.Run(fmt.Sprintf("when tf-summarize is passed '%s'", arg), func(t *testing.T) {
+			output, err := exec.Command(fmt.Sprintf("./%s", testExecutable), arg).CombinedOutput()
+			if err != nil {
+				t.Errorf("expected '%s' not to cause error; got '%v'", arg, err)
+			}
+
+			if !strings.Contains(string(output), testVersion) {
+				t.Errorf("expected '%s' to output version '%s'; got '%s'", arg, testVersion, output)
+			}
+		})
+	}
+}
+
+func TestTFSummarize(t *testing.T) {
+	tests := []struct {
+		command        string
+		expectedError  error
+		expectedOutput string
+	}{{
+		command:        fmt.Sprintf("./%s -md example/tfplan.json", testExecutable),
+		expectedOutput: "basic.txt",
+	}, {
+		command:        fmt.Sprintf("cat example/tfplan.json | ./%s -md", testExecutable),
+		expectedOutput: "basic.txt",
+	}}
+
+	for _, test := range tests {
+		t.Run(fmt.Sprintf("when tf-summarize is passed '%q'", test.command), func(t *testing.T) {
+			output, err := exec.Command("/bin/sh", "-c", test.command).CombinedOutput()
+			if err != nil && test.expectedError == nil {
+				t.Errorf("expected '%s' not to error; got '%v'", test.command, err)
+			}
+
+			b, err := os.ReadFile(fmt.Sprintf("testdata/%s", test.expectedOutput))
+			if err != nil {
+				t.Errorf("error reading file '%s': '%v'", test.expectedOutput, err)
+			}
+
+			expected := string(b)
+
+			if test.expectedError != nil && err == nil {
+				t.Errorf("expected error '%s'; got '%v'", test.expectedError.Error(), err)
+			}
+
+			if test.expectedError != nil && err != nil && test.expectedError.Error() != err.Error() {
+				t.Errorf("expected error '%s'; got '%v'", test.expectedError.Error(), err.Error())
+			}
+
+			if string(output) != expected {
+				t.Logf("expected output: \n%s", expected)
+				t.Logf("got output: \n%s", output)
+				t.Errorf("received unexpected output from '%s'", test.command)
+			}
+		})
+	}
+}

reader/reader.go

@@ -2,9 +2,10 @@ package reader
 
 import (
 	"bufio"
+	"errors"
 	"fmt"
 	"io"
-	"os"
+	"strings"
 )
 
 type Reader interface {
@@ -22,19 +23,22 @@ func readFile(f io.Reader) ([]byte, error) {
 		input = append(input, line...)
 	}
 	if err != io.EOF {
-		return nil, fmt.Errorf("error reading file: %s", err.Error())
+		return nil, fmt.Errorf("error reading input: %s", err.Error())
+	}
+	if len(input) == 0 {
+		return nil, errors.New("no input data; expected input via a non-empty file or via STDIN")
 	}
 	return input, nil
 }
 
-func CreateReader(stdin *os.File, args []string) (Reader, error) {
-	stat, _ := stdin.Stat()
-	if (stat.Mode() & os.ModeCharDevice) == 0 {
-		return NewStdinReader(), nil
+func CreateReader(args []string) (Reader, error) {
+	if len(args) > 1 {
+		return nil, fmt.Errorf("expected input via a single filename argument or via STDIN; received multiple arguments: %s", strings.Join(args, ", "))
 	}
-	if len(args) < 1 {
-		return nil, fmt.Errorf("should have either stdin input through pipe or first argument should be file")
+
+	if len(args) == 1 {
+		return NewFileReader(args[0]), nil
 	}
-	fileName := args[0]
-	return NewFileReader(fileName), nil
+
+	return NewStdinReader(), nil
 }

testdata/basic.txt

@@ -0,0 +1,9 @@
+| CHANGE |                                RESOURCE                                |
+|--------|------------------------------------------------------------------------|
+| add    | `github_repository.terraform_plan_summary`                             |
+|        | `module.github["demo-repository"].github_branch.development`           |
+|        | `module.github["demo-repository"].github_branch.main`                  |
+|        | `module.github["demo-repository"].github_repository.repository`        |
+|        | `module.github["terraform-plan-summary"].github_branch.development`    |
+|        | `module.github["terraform-plan-summary"].github_branch.main`           |
+|        | `module.github["terraform-plan-summary"].github_repository.repository` |