feat: set builder images in templates and .faas.yaml (#136)

This commit adds a .builder.yaml file to each template directory. In the file
there is at the moment a single key/value pair, "default: <image>", where the
actual builder image name is <image>. Using a mapping allows the future
possibility that a user may specify a builder image by name via a flag on the
command line. For example,

```console
faas build --builder native
```

When a project is initialized, the .builder.yaml file is read, and the default
builder is saved in the project's .faas.yaml file. The .faas.yaml file is then
consulted when building an image with `faas build`. If the builder image is
specified, then the builder will use it. Otherwise, it will fallback to the
defaults. This allows developers to create custom builders, and specify them
in the configuration file.

After extracting the builder image from .builder.yaml in the project directory,
this file is deleted.

This commit also adds Verbose to the init command.

buildpacks/builder.go

@@ -22,18 +22,25 @@ func NewBuilder() *Builder {
 	return &Builder{}
 }
 
-var Runtimes = map[string]string{
+var RuntimeToBuildpack = map[string]string{
 	"quarkus": "quay.io/boson/faas-quarkus-builder",
 	"node":    "quay.io/boson/faas-nodejs-builder",
 	"go":      "quay.io/boson/faas-go-builder",
 }
 
 // Build the Function at path.
 func (builder *Builder) Build(f faas.Function) (err error) {
-	// dervive the builder from the specificed runtime
-	packBuilder, ok := Runtimes[f.Runtime]
-	if !ok {
-		return errors.New(fmt.Sprint("unsupported runtime: ", f.Runtime))
+
+	// Use the builder found in the Function configuration file
+	// If one isn't found, use the defaults
+	var packBuilder string
+	if f.Builder != "" {
+		packBuilder = f.Builder
+	} else {
+		packBuilder = RuntimeToBuildpack[f.Runtime]
+		if packBuilder == "" {
+			return errors.New(fmt.Sprint("unsupported runtime: ", f.Runtime))
+		}
 	}
 
 	// Build options for the pack client.

client.go

@@ -4,13 +4,17 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"os"
+	"path/filepath"
+
+	"gopkg.in/yaml.v2"
 )
 
 const (
-	DefaultRegistry     = "docker.io"
-	DefaultRuntime      = "go"
-	DefaultTrigger      = "http"
+	DefaultRegistry = "docker.io"
+	DefaultRuntime  = "go"
+	DefaultTrigger  = "http"
 )
 
 // Client for managing Function instances.
@@ -117,15 +121,15 @@ type DNSProvider interface {
 func New(options ...Option) *Client {
 	// Instantiate client with static defaults.
 	c := &Client{
-		builder:           &noopBuilder{output: os.Stdout},
-		pusher:            &noopPusher{output: os.Stdout},
-		deployer:          &noopDeployer{output: os.Stdout},
-		updater:           &noopUpdater{output: os.Stdout},
-		runner:            &noopRunner{output: os.Stdout},
-		remover:           &noopRemover{output: os.Stdout},
-		lister:            &noopLister{output: os.Stdout},
-		dnsProvider:       &noopDNSProvider{output: os.Stdout},
-		progressListener:  &noopProgressListener{},
+		builder:          &noopBuilder{output: os.Stdout},
+		pusher:           &noopPusher{output: os.Stdout},
+		deployer:         &noopDeployer{output: os.Stdout},
+		updater:          &noopUpdater{output: os.Stdout},
+		runner:           &noopRunner{output: os.Stdout},
+		remover:          &noopRemover{output: os.Stdout},
+		lister:           &noopLister{output: os.Stdout},
+		dnsProvider:      &noopDNSProvider{output: os.Stdout},
+		progressListener: &noopProgressListener{},
 	}
 
 	// Apply passed options, which take ultimate precidence.
@@ -345,6 +349,27 @@ func (c *Client) Initialize(cfg Function) (err error) {
 		return
 	}
 
+	// Check if template specifies a builder image. If so, add to configuration
+	builderFilePath := filepath.Join(f.Root, ".builders.yaml")
+	if builderConfig, err := ioutil.ReadFile(builderFilePath); err == nil {
+		// A .builder file was found. Read the default builder and set in the config file
+		// TODO: A command line flag could be used to specify non-default builders
+		builders := make(map[string]string)
+		if err := yaml.Unmarshal(builderConfig, builders); err == nil {
+			f.Builder = builders["default"]
+			if c.verbose {
+				fmt.Printf("Builder: %s\n", f.Builder)
+			}
+		}
+		// Remove the builders.yaml file so the user is not confused by a
+		// configuration file that is only used for project creation/initialization
+		if err := os.Remove(builderFilePath); err != nil {
+			if c.verbose {
+				fmt.Printf("Cannot remove %v. %v\n", builderFilePath, err)
+			}
+		}
+	}
+
 	// Write out the config.
 	if err = writeConfig(f); err != nil {
 		return

cmd/completion_util.go

@@ -28,7 +28,7 @@ func CompleteFunctionList(cmd *cobra.Command, args []string, toComplete string)
 }
 func CompleteRuntimeList(cmd *cobra.Command, args []string, toComplete string) (strings []string, directive cobra.ShellCompDirective) {
 	strings = []string{}
-	for lang := range buildpacks.Runtimes {
+	for lang := range buildpacks.RuntimeToBuildpack {
 		strings = append(strings, lang)
 	}
 	directive = cobra.ShellCompDirectiveDefault

cmd/init.go

@@ -55,7 +55,9 @@ func runInit(cmd *cobra.Command, args []string) error {
 		Trigger: config.Trigger,
 	}
 
-	client := faas.New(faas.WithTemplates(config.Templates))
+	client := faas.New(
+		faas.WithTemplates(config.Templates),
+		faas.WithVerbose(config.Verbose))
 
 	return client.Initialize(function)
 }
@@ -82,6 +84,9 @@ type initConfig struct {
 	// Function which will be invoked with CloudEvents.
 	Trigger string
 
+	// Verbose output
+	Verbose bool
+
 	// Confirm: confirm values arrived upon from environment plus flags plus defaults,
 	// with interactive prompting (only applicable when attached to a TTY).
 	Confirm bool
@@ -103,6 +108,7 @@ func newInitConfig(args []string) initConfig {
 		Templates: viper.GetString("templates"),
 		Trigger:   viper.GetString("trigger"),
 		Confirm:   viper.GetBool("confirm"),
+		Verbose:   viper.GetBool("verbose"),
 	}
 }
 

config.go

@@ -19,6 +19,7 @@ type config struct {
 	Runtime   string `yaml:"runtime"`
 	Image     string `yaml:"image"`
 	Trigger   string `yaml:"trigger"`
+	Builder   string `yaml:"builder"`
 	// Add new values to the toConfig/fromConfig functions.
 }
 
@@ -53,6 +54,7 @@ func fromConfig(c config) (f Function) {
 		Runtime:   c.Runtime,
 		Image:     c.Image,
 		Trigger:   c.Trigger,
+		Builder:   c.Builder,
 	}
 }
 
@@ -64,6 +66,7 @@ func toConfig(f Function) config {
 		Runtime:   f.Runtime,
 		Image:     f.Image,
 		Trigger:   f.Trigger,
+		Builder:   f.Builder,
 	}
 }
 

function.go

@@ -40,6 +40,9 @@ type Function struct {
 	// If Image is provided, it overrides the default of concatenating
 	// "Repo+Name:latest" to derive the Image.
 	Image string
+
+	// Builder represents the CNCF Buildpack builder image for a function
+	Builder string
 }
 
 // NewFunction loads a Function from a path on disk. use .Initialized() to determine if

templates/go/events/.builders.yaml

@@ -0,0 +1 @@
+default: quay.io/boson/faas-go-builder

templates/go/http/.builders.yaml

@@ -0,0 +1 @@
+default: quay.io/boson/faas-go-builder

templates/node/events/.builders.yaml

@@ -0,0 +1 @@
+default: quay.io/boson/faas-nodejs-builder

templates/node/http/.builders.yaml

@@ -0,0 +1 @@
+default: quay.io/boson/faas-nodejs-builder

templates/quarkus/events/.builders.yaml

@@ -0,0 +1 @@
+default: quay.io/boson/faas-quarkus-builder

templates/quarkus/http/.builders.yaml

@@ -0,0 +1 @@
+default: quay.io/boson/faas-quarkus-builder