Add the ability to write a procfile

.gitignore

@@ -27,3 +27,4 @@ lambda-builder
 lambda.zip
 
 response.json
+Procfile

builders/dotnet.go

@@ -23,10 +23,6 @@ func NewDotnetBuilder(config Config) (DotnetBuilder, error) {
 	}, nil
 }
 
-func (b DotnetBuilder) BuildImage() string {
-	return b.Config.BuilderBuildImage
-}
-
 func (b DotnetBuilder) Detect() bool {
 	if io.FileExistsInDirectory(b.Config.WorkingDirectory, "Function.cs") {
 		return true
@@ -36,13 +32,22 @@ func (b DotnetBuilder) Detect() bool {
 }
 
 func (b DotnetBuilder) Execute() error {
+	b.Config.HandlerMap = b.GetHandlerMap()
 	return executeBuilder(b.script(), b.GetTaskBuildDir(), b.Config)
 }
 
+func (b DotnetBuilder) GetBuildImage() string {
+	return b.Config.BuilderBuildImage
+}
+
 func (b DotnetBuilder) GetConfig() Config {
 	return b.Config
 }
 
+func (b DotnetBuilder) GetHandlerMap() map[string]string {
+	return map[string]string{}
+}
+
 func (b DotnetBuilder) GetTaskBuildDir() string {
 	return "/var/task"
 }

builders/go.go

@@ -23,10 +23,6 @@ func NewGoBuilder(config Config) (GoBuilder, error) {
 	}, nil
 }
 
-func (b GoBuilder) BuildImage() string {
-	return b.Config.BuilderBuildImage
-}
-
 func (b GoBuilder) Detect() bool {
 	if io.FileExistsInDirectory(b.Config.WorkingDirectory, "go.sum") {
 		return true
@@ -36,13 +32,24 @@ func (b GoBuilder) Detect() bool {
 }
 
 func (b GoBuilder) Execute() error {
+	b.Config.HandlerMap = b.GetHandlerMap()
 	return executeBuilder(b.script(), b.GetTaskBuildDir(), b.Config)
 }
 
+func (b GoBuilder) GetBuildImage() string {
+	return b.Config.BuilderBuildImage
+}
+
 func (b GoBuilder) GetConfig() Config {
 	return b.Config
 }
 
+func (b GoBuilder) GetHandlerMap() map[string]string {
+	return map[string]string{
+		"bootstrap": "bootstrap",
+	}
+}
+
 func (b GoBuilder) GetTaskBuildDir() string {
 	return "/go/src/handler"
 }

builders/handler.go

@@ -0,0 +1,27 @@
+package builders
+
+import (
+	"fmt"
+	"lambda-builder/io"
+	"os"
+	"path/filepath"
+)
+
+func getFunctionHandler(directory string, config Config) string {
+	if config.Handler != "" {
+		return config.Handler
+	}
+
+	for file, handler := range config.HandlerMap {
+		if io.FileExistsInDirectory(directory, file) {
+			return handler
+		}
+	}
+
+	return ""
+}
+
+func writeProcfile(handler string, directory string) error {
+	b := []byte(fmt.Sprintf("web: %s\n", handler))
+	return os.WriteFile(filepath.Join(directory, "Procfile"), b, 0644)
+}

builders/main.go

@@ -14,22 +14,26 @@ import (
 )
 
 type Builder interface {
-	GetConfig() Config
-	GetTaskBuildDir() string
 	Detect() bool
 	Execute() error
-	BuildImage() string
+	GetBuildImage() string
+	GetConfig() Config
+	GetHandlerMap() map[string]string
+	GetTaskBuildDir() string
 	Name() string
 }
 
 type Config struct {
 	BuildImage        bool
 	BuilderBuildImage string
 	BuilderRunImage   string
+	Handler           string
+	HandlerMap        map[string]string
 	Identifier        string
 	ImageLabels       []string
 	ImageTag          string
 	RunQuiet          bool
+	WriteProcfile     bool
 	WorkingDirectory  string
 }
 
@@ -62,10 +66,29 @@ func executeBuilder(script string, taskBuildDir string, config Config) error {
 		return err
 	}
 
+	handler := getFunctionHandler(tmp, config)
+	if config.WriteProcfile && !io.FileExistsInDirectory(tmp, "Procfile") {
+		if handler == "" {
+			fmt.Printf(" !     Unable to detect handler in build directory\n")
+		} else {
+			fmt.Printf("=====> Writing Procfile from handler: %s\n", handler)
+
+			fmt.Printf("       Writing to working directory\n")
+			if err := writeProcfile(handler, config.WorkingDirectory); err != nil {
+				return fmt.Errorf("error writing Procfile to working directory: %s", err.Error())
+			}
+
+			fmt.Printf("       Writing to build directory\n")
+			if err := writeProcfile(handler, tmp); err != nil {
+				return fmt.Errorf("error writing Procfile to temporary build directory: %s", err.Error())
+			}
+		}
+	}
+
 	if config.BuildImage {
 		fmt.Printf("=====> Building image\n")
 		fmt.Printf("       Generating temporary Dockerfile\n")
-		if err := generateDockerfile(tmp, config); err != nil {
+		if err := generateDockerfile(handler, tmp, config); err != nil {
 			return err
 		}
 
@@ -111,22 +134,26 @@ func executeBuildContainer(tmp string, script string, taskBuildDir string, confi
 	return nil
 }
 
-func generateDockerfile(tmp string, config Config) error {
-	dockerfileName := filepath.Join(tmp, fmt.Sprintf("%s.Dockerfile", config.Identifier))
+func generateDockerfile(cmd string, directory string, config Config) error {
+	dockerfileName := filepath.Join(directory, fmt.Sprintf("%s.Dockerfile", config.Identifier))
 	f, err := os.Create(dockerfileName)
 	if err != nil {
 		return fmt.Errorf("error creating Dockerfile: %s", err)
 	}
 
 	tpl, err := template.New("t1").Parse(`
 FROM {{ .run_image }}
+{{ if ne .command "" }}
+CMD ["{{ .cmd }}"]
+{{ end }}
 COPY . /var/task
 `)
 	if err != nil {
 		return fmt.Errorf("error generating template: %s", err)
 	}
 
 	data := map[string]string{
+		"cmd":       cmd,
 		"run_image": config.BuilderRunImage,
 	}
 
@@ -137,11 +164,11 @@ COPY . /var/task
 	return nil
 }
 
-func buildDockerImage(tmp string, config Config) error {
+func buildDockerImage(directory string, config Config) error {
 	args := []string{
 		"image",
 		"build",
-		"--file", filepath.Join(tmp, fmt.Sprintf("%s.Dockerfile", config.Identifier)),
+		"--file", filepath.Join(directory, fmt.Sprintf("%s.Dockerfile", config.Identifier)),
 		"--progress", "plain",
 		"--tag", config.GetImageTag(),
 	}
@@ -150,7 +177,7 @@ func buildDockerImage(tmp string, config Config) error {
 		args = append(args, "--label", label)
 	}
 
-	args = append(args, tmp)
+	args = append(args, directory)
 
 	cmd := execute.ExecTask{
 		Args:        args,

builders/nodejs.go

@@ -23,10 +23,6 @@ func NewNodejsBuilder(config Config) (NodejsBuilder, error) {
 	}, nil
 }
 
-func (b NodejsBuilder) BuildImage() string {
-	return b.Config.BuilderBuildImage
-}
-
 func (b NodejsBuilder) Detect() bool {
 	if io.FileExistsInDirectory(b.Config.WorkingDirectory, "package-lock.json") {
 		return true
@@ -36,13 +32,25 @@ func (b NodejsBuilder) Detect() bool {
 }
 
 func (b NodejsBuilder) Execute() error {
+	b.Config.HandlerMap = b.GetHandlerMap()
 	return executeBuilder(b.script(), b.GetTaskBuildDir(), b.Config)
 }
 
+func (b NodejsBuilder) GetBuildImage() string {
+	return b.Config.BuilderBuildImage
+}
+
 func (b NodejsBuilder) GetConfig() Config {
 	return b.Config
 }
 
+func (b NodejsBuilder) GetHandlerMap() map[string]string {
+	return map[string]string{
+		"function.js":        "function.handler",
+		"lambda_function.js": "lambda_function.handler",
+	}
+}
+
 func (b NodejsBuilder) GetTaskBuildDir() string {
 	return "/var/task"
 }

builders/python.go

@@ -43,10 +43,6 @@ func NewPythonBuilder(config Config) (PythonBuilder, error) {
 	}, nil
 }
 
-func (b PythonBuilder) BuildImage() string {
-	return b.Config.BuilderBuildImage
-}
-
 func (b PythonBuilder) Detect() bool {
 	if io.FileExistsInDirectory(b.Config.WorkingDirectory, "requirements.txt") {
 		return true
@@ -64,13 +60,27 @@ func (b PythonBuilder) Detect() bool {
 }
 
 func (b PythonBuilder) Execute() error {
+	b.Config.HandlerMap = b.GetHandlerMap()
 	return executeBuilder(b.script(), b.GetTaskBuildDir(), b.Config)
 }
 
+func (b PythonBuilder) GetBuildImage() string {
+	return b.Config.BuilderBuildImage
+}
+
 func (b PythonBuilder) GetConfig() Config {
 	return b.Config
 }
 
+func (b PythonBuilder) GetHandlerMap() map[string]string {
+	return map[string]string{
+		"app.py":             "app.handler",
+		"function.py":        "function.handler",
+		"lambda_function.py": "lambda_function.handler",
+		"main.py":            "main.handler",
+	}
+}
+
 func (b PythonBuilder) GetTaskBuildDir() string {
 	return "/var/task"
 }

builders/ruby.go

@@ -23,10 +23,6 @@ func NewRubyBuilder(config Config) (RubyBuilder, error) {
 	}, nil
 }
 
-func (b RubyBuilder) BuildImage() string {
-	return b.Config.BuilderBuildImage
-}
-
 func (b RubyBuilder) Detect() bool {
 	if io.FileExistsInDirectory(b.Config.WorkingDirectory, "Gemfile.lock") {
 		return true
@@ -35,15 +31,27 @@ func (b RubyBuilder) Detect() bool {
 	return false
 }
 
+func (b RubyBuilder) GetBuildImage() string {
+	return b.Config.BuilderBuildImage
+}
+
 func (b RubyBuilder) GetConfig() Config {
 	return b.Config
 }
 
+func (b RubyBuilder) GetHandlerMap() map[string]string {
+	return map[string]string{
+		"function.rb":        "function.handler",
+		"lambda_function.rb": "lambda_function.handler",
+	}
+}
+
 func (b RubyBuilder) GetTaskBuildDir() string {
 	return "/var/task"
 }
 
 func (b RubyBuilder) Execute() error {
+	b.Config.HandlerMap = b.GetHandlerMap()
 	return executeBuilder(b.script(), b.GetTaskBuildDir(), b.Config)
 }
 

commands/build.go

@@ -20,10 +20,12 @@ type BuildCommand struct {
 	command.Meta
 
 	buildImage       bool
+	handler          string
 	imageTag         string
 	labels           []string
 	quiet            bool
 	workingDirectory string
+	writeProcfile    bool
 }
 
 func (c *BuildCommand) Name() string {
@@ -65,8 +67,10 @@ func (c *BuildCommand) FlagSet() *flag.FlagSet {
 	}
 
 	f := c.Meta.FlagSet(c.Name(), command.FlagSetClient)
-	f.BoolVar(&c.quiet, "quiet", false, "run builder in quiet mode")
 	f.BoolVar(&c.buildImage, "build-image", false, "build a docker image")
+	f.BoolVar(&c.quiet, "quiet", false, "run builder in quiet mode")
+	f.BoolVar(&c.writeProcfile, "write-procfile", false, "writes a Procfile if a handler is specified or detected")
+	f.StringVar(&c.handler, "handler", "", "handler override to specify as the default command to run in a built image")
 	f.StringVarP(&c.imageTag, "tag", "t", "", "name and optionally a tag in the 'name:tag' format")
 	f.StringVar(&c.workingDirectory, "working-directory", workingDirectory, "working directory")
 	f.StringArrayVar(&c.labels, "label", []string{}, " set metadata for an image")
@@ -77,8 +81,9 @@ func (c *BuildCommand) AutocompleteFlags() complete.Flags {
 	return command.MergeAutocompleteFlags(
 		c.Meta.AutocompleteFlags(command.FlagSetClient),
 		complete.Flags{
-			"--build-image": complete.PredictNothing,
-			"--quiet":       complete.PredictNothing,
+			"--build-image":    complete.PredictNothing,
+			"--quiet":          complete.PredictNothing,
+			"--write-procfile": complete.PredictNothing,
 		},
 	)
 }
@@ -122,6 +127,7 @@ func (c *BuildCommand) Run(args []string) int {
 		ImageLabels:      c.labels,
 		ImageTag:         c.imageTag,
 		RunQuiet:         c.quiet,
+		WriteProcfile:    c.writeProcfile,
 		WorkingDirectory: c.workingDirectory,
 	}
 
@@ -134,7 +140,7 @@ func (c *BuildCommand) Run(args []string) int {
 
 	c.Ui.Info(fmt.Sprintf("Detected %s builder", builder.Name()))
 
-	logger.LogHeader1(fmt.Sprintf("Building app with image %s", builder.BuildImage()))
+	logger.LogHeader1(fmt.Sprintf("Building app with image %s", builder.GetBuildImage()))
 	if err := builder.Execute(); err != nil {
 		c.Ui.Error(err.Error())
 		return 1