cmd/build-lambda-zip: Produce valid .zips for provided runtime functions (#307)

* cmd/build-lambda-zip: Produce valid .zips for provided runtime functions

* Update main.go

* Update main_test.go

Author: bmoffatt

cmd/build-lambda-zip/main.go

@@ -1,10 +1,13 @@
+// Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved
+
 package main
 
 import (
 	"archive/zip"
 	"errors"
 	"fmt"
 	"io/ioutil"
+	"log"
 	"os"
 	"path/filepath"
 
@@ -37,6 +40,7 @@ func main() {
 			if err := compressExeAndArgs(outputZip, inputExe, c.Args().Tail()); err != nil {
 				return fmt.Errorf("failed to compress file: %v", err)
 			}
+			log.Print("wrote " + outputZip)
 			return nil
 		},
 	}
@@ -48,6 +52,18 @@ func main() {
 }
 
 func writeExe(writer *zip.Writer, pathInZip string, data []byte) error {
+	if pathInZip != "bootstrap" {
+		header := &zip.FileHeader{Name: "bootstrap", Method: zip.Deflate}
+		header.SetMode(0755 | os.ModeSymlink)
+		link, err := writer.CreateHeader(header)
+		if err != nil {
+			return err
+		}
+		if _, err := link.Write([]byte(pathInZip)); err != nil {
+			return err
+		}
+	}
+
 	exe, err := writer.CreateHeader(&zip.FileHeader{
 		CreatorVersion: 3 << 8,     // indicates Unix
 		ExternalAttrs:  0777 << 16, // -rwxrwxrwx file permissions

cmd/build-lambda-zip/main_test.go

@@ -0,0 +1,159 @@
+// Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved
+
+package main
+
+import (
+	"archive/zip"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestSizes(t *testing.T) {
+	if testing.Short() {
+		t.Skip()
+		return
+	}
+	t.Log("test how different arguments affect binary and archive sizes")
+	cases := []struct {
+		file string
+		args []string
+	}{
+		{"testdata/apigw.go", nil},
+		{"testdata/noop.go", nil},
+		{"testdata/noop.go", []string{"-tags", "lambda.norpc"}},
+		{"testdata/noop.go", []string{"-ldflags=-s -w"}},
+		{"testdata/noop.go", []string{"-tags", "lambda.norpc", "-ldflags=-s -w"}},
+	}
+	testDir, err := os.Getwd()
+	require.NoError(t, err)
+	tempDir, err := ioutil.TempDir("/tmp", "build-lambda-zip")
+	require.NoError(t, err)
+	for _, test := range cases {
+		require.NoError(t, os.Chdir(testDir))
+		testName := fmt.Sprintf("%s, %v", test.file, test.args)
+		t.Run(testName, func(t *testing.T) {
+			binPath := path.Join(tempDir, test.file+".bin")
+			zipPath := path.Join(tempDir, test.file+".zip")
+
+			buildArgs := []string{"build", "-o", binPath}
+			buildArgs = append(buildArgs, test.args...)
+			buildArgs = append(buildArgs, test.file)
+
+			gocmd := exec.Command("go", buildArgs...)
+			gocmd.Env = append(os.Environ(), "GOOS=linux")
+			gocmd.Stderr = os.Stderr
+			require.NoError(t, gocmd.Run())
+			require.NoError(t, os.Chdir(filepath.Dir(binPath)))
+			require.NoError(t, compressExeAndArgs(zipPath, binPath, []string{}))
+
+			binInfo, err := os.Stat(binPath)
+			require.NoError(t, err)
+			zipInfo, err := os.Stat(zipPath)
+			require.NoError(t, err)
+
+			t.Logf("zip size = %d Kb, bin size = %d Kb", zipInfo.Size()/1024, binInfo.Size()/1024)
+		})
+	}
+
+}
+
+func TestCompressExeAndArgs(t *testing.T) {
+	tempDir, err := ioutil.TempDir("/tmp", "build-lambda-zip")
+	require.NoError(t, err)
+	defer os.RemoveAll(tempDir)
+
+	fileNames := []string{"the-exe", "the-config", "other-config"}
+	filePaths := make([]string, len(fileNames))
+	for i, fileName := range fileNames {
+		filePaths[i] = filepath.Join(tempDir, fileName)
+		f, err := os.Create(filePaths[i])
+		require.NoError(t, err)
+		_, _ = fmt.Fprintf(f, "Hello file %d!", i)
+		err = f.Close()
+		require.NoError(t, err)
+	}
+	outZipPath := filepath.Join(tempDir, "lambda.zip")
+
+	err = compressExeAndArgs(outZipPath, filePaths[0], filePaths[1:])
+	require.NoError(t, err)
+
+	t.Run("handler exe configured in zip root", func(t *testing.T) {
+		require.NotEqual(t, filePaths[0], filepath.Base(filePaths[0]), "test precondition")
+		zipReader, err := zip.OpenReader(outZipPath)
+		require.NoError(t, err)
+		defer zipReader.Close()
+		for _, zf := range zipReader.File {
+			if zf.Name == filepath.Base(filePaths[0]) {
+				assert.True(t, zf.FileInfo().Mode().IsRegular())
+				permissions := int(zf.FileInfo().Mode() & 0777)
+				assert.Equal(t, 0111, permissions&0111, "file permissions: %#o, aren't executable", permissions)
+				assert.Equal(t, 0444, permissions&0444, "file permissions: %#o, aren't readable", permissions)
+				return
+			}
+		}
+		t.Fatalf("failed to find handler exe in zip")
+	})
+
+	t.Run("boostrap is a symlink to handler exe", func(t *testing.T) {
+		zipReader, err := zip.OpenReader(outZipPath)
+		require.NoError(t, err)
+		defer zipReader.Close()
+		var bootstrap *zip.File
+		for _, f := range zipReader.File {
+			if f.Name == "bootstrap" {
+				bootstrap = f
+			}
+		}
+		require.NotNil(t, bootstrap)
+		assert.Equal(t, 0755|os.ModeSymlink, bootstrap.FileInfo().Mode())
+		link, err := bootstrap.Open()
+		require.NoError(t, err)
+		defer link.Close()
+		linkTarget, err := ioutil.ReadAll(link)
+		require.NoError(t, err)
+		assert.Equal(t, filepath.Base(filePaths[0]), string(linkTarget))
+	})
+
+	t.Run("resource file paths", func(t *testing.T) {
+		zipReader, err := zip.OpenReader(outZipPath)
+		require.NoError(t, err)
+		defer zipReader.Close()
+	eachFile:
+		for _, path := range filePaths[1:] {
+			for _, zipFileEntry := range zipReader.File {
+				if zipFileEntry.Name == path {
+					continue eachFile
+				}
+			}
+			t.Logf("failed to find resource file %s in zip", path)
+			t.Fail()
+		}
+	})
+
+	t.Run("file contents match", func(t *testing.T) {
+		zipReader, err := zip.OpenReader(outZipPath)
+		require.NoError(t, err)
+		defer zipReader.Close()
+		expectedIndex := 0
+		for _, zf := range zipReader.File {
+			if zf.FileInfo().Mode().IsRegular() {
+				f, err := zf.Open()
+				require.NoError(t, err)
+				defer f.Close()
+				content, err := ioutil.ReadAll(f)
+				require.NoError(t, err)
+				assert.Equal(t, fmt.Sprintf("Hello file %d!", expectedIndex), string(content), "in file: %s", zf.Name)
+				expectedIndex++
+			}
+		}
+	})
+
+}

cmd/build-lambda-zip/testdata/apigw.go

@@ -0,0 +1,18 @@
+// Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved
+
+package main
+
+import (
+	"context"
+	"fmt"
+	"github.com/aws/aws-lambda-go/events"
+	"github.com/aws/aws-lambda-go/lambda"
+)
+
+func main () {
+	lambda.Start(func (ctx context.Context, event events.APIGatewayV2HTTPRequest) (*events.APIGatewayProxyResponse, error) {
+		return &events.APIGatewayProxyResponse{
+			Body: fmt.Sprintf("Hello %v", event),
+		}, nil
+	})
+}

cmd/build-lambda-zip/testdata/noop.go

@@ -0,0 +1,21 @@
+// Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved
+
+package main
+
+import (
+	"context"
+	"github.com/aws/aws-lambda-go/lambda"
+)
+
+type BinaryHandler func(context.Context, []byte) ([]byte, error)
+func (bh BinaryHandler) Invoke(ctx context.Context, req []byte) ([]byte, error) {
+	return bh(ctx, req)
+}
+
+func noop (ctx context.Context, req []byte) ([]byte, error) {
+	return req, nil
+}
+
+func main() {
+	lambda.StartHandler(BinaryHandler(noop))
+}