Build a docker image based on the built workspace

README.md

@@ -44,6 +44,21 @@ Alternatively, a given path can be specified via the `--working-directory` flag:
 lambda-builder build --working-directory path/to/app
 ```
 
+In addition to the `lambda.yml`, a docker image can be produced from the generated artifact by specifying the `--build-image` flag. This also allows for multiple `--label`  flags as well as specifying a single image tag via either `-t` or `--tag`:
+
+```shell
+# will write a lambda.zip in the specified path
+# and generate a docker image named `lambda-builder:$APP:latest`
+# where $APP is the last portion of the working directory
+lambda-builder build --build-image
+
+# adds the labels com.example/key=value and com.example/another-key=value
+lambda-builder build --build-image --label com.example/key=value --label com.example/another-key=value
+
+# tags the image as app/awesome:1234
+lambda-builder build --build-image --tag app/awesome:1234
+```
+
 ### How does it work
 
 Internally, `lambda-builder` detects a given language and builds the app according to the script specified by the detected builder within a disposablecontainer environment emulating AWS Lambda. If a builder is not detected, the build will fail. The following languages are supported:
@@ -80,16 +95,22 @@ Internally, `lambda-builder` detects a given language and builds the app accordi
 
 When the app is built, a `lambda.zip` will be produced in the specified working directory. The resulting `lambda.zip` can be uploaded to S3 and used within a Lambda function.
 
-Both the builder and the build image environment can be overriden in an optional `lambda.yml` file in the specified working directory. An example of this file is as follows:
+Both the builder and the build image environment can be overriden in an optional `lambda.yml` file in the specified working directory.
+
+### `lambda.yml`
+
+The following a short description of the `lambda.yml` format.
 
 ```yaml
 ---
 build_image: mlupin/docker-lambda:dotnetcore3.1-build
 builder: dotnet
+run_image: mlupin/docker-lambda:dotnetcore3.1
 ```
 
 - `build_image`: A docker image that is accessible by the docker daemon. The `build_image` _should_ be based on an existing Lambda image - builders may fail if they cannot run within the specified `build_image`. The build will fail if the image is inaccessible by the docker daemon.
 - `builder`: The name of a builder. This may be used if multiple builders match and a specific builder is desired. If an invalid builder is specified, the build will fail.
+- `run_image`: A docker image that is accessible by the docker daemon. The `run_image` _should_ be based on an existing Lambda image - built images may fail to start if they are not compatible with the produced artifact. The generation of the `run` iage will fail if the image is inaccessible by the docker daemon.
 
 ### Deploying
 

builders/dotnet.go

@@ -8,7 +8,12 @@ type DotnetBuilder struct {
 
 func NewDotnetBuilder(config Config) (DotnetBuilder, error) {
 	var err error
-	config.BuildImage, err = getBuilder(config, "mlupin/docker-lambda:dotnet6-build")
+	config.BuilderBuildImage, err = getBuildImage(config, "mlupin/docker-lambda:dotnet6-build")
+	if err != nil {
+		return DotnetBuilder{}, err
+	}
+
+	config.BuilderRunImage, err = getRunImage(config, "mlupin/docker-lambda:dotnet6")
 	if err != nil {
 		return DotnetBuilder{}, err
 	}
@@ -19,11 +24,7 @@ func NewDotnetBuilder(config Config) (DotnetBuilder, error) {
 }
 
 func (b DotnetBuilder) BuildImage() string {
-	return b.Config.BuildImage
-}
-
-func (b DotnetBuilder) GetConfig() Config {
-	return b.Config
+	return b.Config.BuilderBuildImage
 }
 
 func (b DotnetBuilder) Detect() bool {
@@ -35,7 +36,15 @@ func (b DotnetBuilder) Detect() bool {
 }
 
 func (b DotnetBuilder) Execute() error {
-	return executeBuilder(b.script(), b.Config)
+	return executeBuilder(b.script(), b.GetTaskBuildDir(), b.Config)
+}
+
+func (b DotnetBuilder) GetConfig() Config {
+	return b.Config
+}
+
+func (b DotnetBuilder) GetTaskBuildDir() string {
+	return "/var/task"
 }
 
 func (b DotnetBuilder) Name() string {

builders/go.go

@@ -8,7 +8,12 @@ type GoBuilder struct {
 
 func NewGoBuilder(config Config) (GoBuilder, error) {
 	var err error
-	config.BuildImage, err = getBuilder(config, "lambci/lambda:build-go1.x")
+	config.BuilderBuildImage, err = getBuildImage(config, "lambci/lambda:build-go1.x")
+	if err != nil {
+		return GoBuilder{}, err
+	}
+
+	config.BuilderRunImage, err = getRunImage(config, "mlupin/docker-lambda:provided.al2")
 	if err != nil {
 		return GoBuilder{}, err
 	}
@@ -19,11 +24,7 @@ func NewGoBuilder(config Config) (GoBuilder, error) {
 }
 
 func (b GoBuilder) BuildImage() string {
-	return b.Config.BuildImage
-}
-
-func (b GoBuilder) GetConfig() Config {
-	return b.Config
+	return b.Config.BuilderBuildImage
 }
 
 func (b GoBuilder) Detect() bool {
@@ -35,7 +36,15 @@ func (b GoBuilder) Detect() bool {
 }
 
 func (b GoBuilder) Execute() error {
-	return executeBuilder(b.script(), b.Config)
+	return executeBuilder(b.script(), b.GetTaskBuildDir(), b.Config)
+}
+
+func (b GoBuilder) GetConfig() Config {
+	return b.Config
+}
+
+func (b GoBuilder) GetTaskBuildDir() string {
+	return "/go/src/handler"
 }
 
 func (b GoBuilder) Name() string {

builders/main.go

@@ -2,6 +2,7 @@ package builders
 
 import (
 	"fmt"
+	"html/template"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -14,25 +15,70 @@ import (
 
 type Builder interface {
 	GetConfig() Config
+	GetTaskBuildDir() string
 	Detect() bool
 	Execute() error
 	BuildImage() string
 	Name() string
 }
 
 type Config struct {
-	BuildImage       string
-	Identifier       string
-	RunQuiet         bool
-	WorkingDirectory string
+	BuildImage        bool
+	BuilderBuildImage string
+	BuilderRunImage   string
+	Identifier        string
+	ImageLabels       []string
+	ImageTag          string
+	RunQuiet          bool
+	WorkingDirectory  string
+}
+
+func (c Config) GetImageTag() string {
+	if c.ImageTag != "" {
+		return c.ImageTag
+	}
+
+	appName := filepath.Base(c.WorkingDirectory)
+	return fmt.Sprintf("lambda-builder/%s:latest", appName)
 }
 
 type LambdaYML struct {
 	Builder    string `yaml:"builder"`
 	BuildImage string `yaml:"build_image"`
+	RunImage   string `yaml:"run_image"`
+}
+
+func executeBuilder(script string, taskBuildDir string, config Config) error {
+	tmp, err := os.MkdirTemp("", "lambda-builder")
+	defer func() {
+		os.RemoveAll(tmp)
+	}()
+
+	if err != nil {
+		return fmt.Errorf("error preparing temporary build directory: %s", err.Error())
+	}
+
+	if err := executeBuildContainer(tmp, script, taskBuildDir, config); err != nil {
+		return err
+	}
+
+	if config.BuildImage {
+		fmt.Printf("=====> Building image\n")
+		fmt.Printf("       Generating temporary Dockerfile\n")
+		if err := generateDockerfile(tmp, config); err != nil {
+			return err
+		}
+
+		fmt.Printf("       Executing build of %s\n", config.GetImageTag())
+		if err := buildDockerImage(tmp, config); err != nil {
+			return err
+		}
+	}
+
+	return nil
 }
 
-func executeBuilder(script string, config Config) error {
+func executeBuildContainer(tmp string, script string, taskBuildDir string, config Config) error {
 	args := []string{
 		"container",
 		"run",
@@ -41,7 +87,8 @@ func executeBuilder(script string, config Config) error {
 		"--label", "com.dokku.lambda-builder/executor=true",
 		"--name", fmt.Sprintf("lambda-builder-executor-%s", config.Identifier),
 		"--volume", fmt.Sprintf("%s:/tmp/task", config.WorkingDirectory),
-		config.BuildImage,
+		"--volume", fmt.Sprintf("%s:%s", tmp, taskBuildDir),
+		config.BuilderBuildImage,
 		"/bin/bash", "-c", script,
 	}
 
@@ -54,11 +101,71 @@ func executeBuilder(script string, config Config) error {
 
 	res, err := cmd.Execute()
 	if err != nil {
-		return fmt.Errorf("failed to execute builder: %s", err.Error())
+		return fmt.Errorf("error executing builder: %s", err.Error())
 	}
 
 	if res.ExitCode != 0 {
-		return fmt.Errorf("failed to execute builder, exit code %d", res.ExitCode)
+		return fmt.Errorf("error executing builder, exit code %d", res.ExitCode)
+	}
+
+	return nil
+}
+
+func generateDockerfile(tmp string, config Config) error {
+	dockerfileName := filepath.Join(tmp, 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 }}
+COPY . /var/task
+`)
+	if err != nil {
+		return fmt.Errorf("error generating template: %s", err)
+	}
+
+	data := map[string]string{
+		"run_image": config.BuilderRunImage,
+	}
+
+	if err := tpl.Execute(f, data); err != nil {
+		return fmt.Errorf("error writing Dockerfile: %s", err)
+	}
+
+	return nil
+}
+
+func buildDockerImage(tmp string, config Config) error {
+	args := []string{
+		"image",
+		"build",
+		"--file", filepath.Join(tmp, fmt.Sprintf("%s.Dockerfile", config.Identifier)),
+		"--progress", "plain",
+		"--tag", config.GetImageTag(),
+	}
+
+	for _, label := range config.ImageLabels {
+		args = append(args, "--label", label)
+	}
+
+	args = append(args, tmp)
+
+	cmd := execute.ExecTask{
+		Args:        args,
+		Command:     "docker",
+		Cwd:         config.WorkingDirectory,
+		StreamStdio: !config.RunQuiet,
+	}
+
+	res, err := cmd.Execute()
+	if err != nil {
+		return fmt.Errorf("error building image: %s", err.Error())
+	}
+
+	if res.ExitCode != 0 {
+		return fmt.Errorf("error building image, exit code %d", res.ExitCode)
 	}
 
 	return nil
@@ -88,9 +195,9 @@ func ParseLambdaYML(config Config) (LambdaYML, error) {
 	return lambdaYML, nil
 }
 
-func getBuilder(config Config, defaultImage string) (string, error) {
-	if config.BuildImage != "" {
-		return config.BuildImage, nil
+func getBuildImage(config Config, defaultImage string) (string, error) {
+	if config.BuilderBuildImage != "" {
+		return config.BuilderBuildImage, nil
 	}
 
 	lambdaYML, err := ParseLambdaYML(config)
@@ -104,3 +211,20 @@ func getBuilder(config Config, defaultImage string) (string, error) {
 
 	return lambdaYML.BuildImage, nil
 }
+
+func getRunImage(config Config, defaultImage string) (string, error) {
+	if config.BuilderRunImage != "" {
+		return config.BuilderRunImage, nil
+	}
+
+	lambdaYML, err := ParseLambdaYML(config)
+	if err != nil {
+		return "", err
+	}
+
+	if lambdaYML.RunImage == "" {
+		return defaultImage, nil
+	}
+
+	return lambdaYML.RunImage, nil
+}

builders/nodejs.go

@@ -8,7 +8,12 @@ type NodejsBuilder struct {
 
 func NewNodejsBuilder(config Config) (NodejsBuilder, error) {
 	var err error
-	config.BuildImage, err = getBuilder(config, "mlupin/docker-lambda:nodejs14.x-build")
+	config.BuilderBuildImage, err = getBuildImage(config, "mlupin/docker-lambda:nodejs14.x-build")
+	if err != nil {
+		return NodejsBuilder{}, err
+	}
+
+	config.BuilderRunImage, err = getRunImage(config, "mlupin/docker-lambda:nodejs14.x")
 	if err != nil {
 		return NodejsBuilder{}, err
 	}
@@ -19,11 +24,7 @@ func NewNodejsBuilder(config Config) (NodejsBuilder, error) {
 }
 
 func (b NodejsBuilder) BuildImage() string {
-	return b.Config.BuildImage
-}
-
-func (b NodejsBuilder) GetConfig() Config {
-	return b.Config
+	return b.Config.BuilderBuildImage
 }
 
 func (b NodejsBuilder) Detect() bool {
@@ -35,7 +36,15 @@ func (b NodejsBuilder) Detect() bool {
 }
 
 func (b NodejsBuilder) Execute() error {
-	return executeBuilder(b.script(), b.Config)
+	return executeBuilder(b.script(), b.GetTaskBuildDir(), b.Config)
+}
+
+func (b NodejsBuilder) GetConfig() Config {
+	return b.Config
+}
+
+func (b NodejsBuilder) GetTaskBuildDir() string {
+	return "/var/task"
 }
 
 func (b NodejsBuilder) Name() string {