fnctl: init (#270)

* fnctl: init

* fnctl: conciliate init with master

Fixes #266

fnctl/init.go

@@ -0,0 +1,151 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"strings"
+
+	"github.com/urfave/cli"
+)
+
+var (
+	fileExtToRuntime = map[string]string{
+		".c":     "gcc",
+		".class": "java",
+		".clj":   "leiningen",
+		".cpp":   "gcc",
+		".erl":   "erlang",
+		".ex":    "elixir",
+		".go":    "go",
+		".h":     "gcc",
+		".java":  "java",
+		".js":    "node",
+		".php":   "php",
+		".pl":    "perl",
+		".py":    "python",
+		".scala": "scala",
+	}
+
+	fnRuntimes []string
+)
+
+func init() {
+	for rt := range acceptableFnRuntimes {
+		fnRuntimes = append(fnRuntimes, rt)
+	}
+}
+
+type initFnCmd struct {
+	force   bool
+	runtime string
+}
+
+func initFn() cli.Command {
+	a := initFnCmd{}
+
+	return cli.Command{
+		Name:        "init",
+		Usage:       "create a local function.yaml file",
+		Description: "Entrypoint is the binary file which the container engine will invoke when the request comes in - equivalent to Dockerfile ENTRYPOINT.",
+		ArgsUsage:   "<entrypoint>",
+		Action:      a.init,
+		Flags: []cli.Flag{
+			cli.BoolFlag{
+				Name:        "f",
+				Usage:       "overwrite existing function.yaml",
+				Destination: &a.force,
+			},
+			cli.StringFlag{
+				Name:        "runtime",
+				Usage:       "choose an existing runtime - " + strings.Join(fnRuntimes, ", "),
+				Destination: &a.runtime,
+			},
+		},
+	}
+}
+
+func (a *initFnCmd) init(c *cli.Context) error {
+	if !a.force {
+		for _, fn := range validfn {
+			if _, err := os.Stat(fn); !os.IsNotExist(err) {
+				return errors.New("function file already exists")
+			}
+		}
+	}
+
+	entrypoint := c.Args().First()
+	if entrypoint == "" {
+		fmt.Print("Please, specify an entrypoint for your function: ")
+		fmt.Scanln(&entrypoint)
+	}
+	if entrypoint == "" {
+		return errors.New("entrypoint is missing")
+	}
+
+	pwd, err := os.Getwd()
+	if err != nil {
+		return fmt.Errorf("error detecting current working directory: %s\n", err)
+	}
+
+	if a.runtime == "" {
+		rt, err := detectRuntime(pwd)
+		if err != nil {
+			return err
+		}
+		var ok bool
+		a.runtime, ok = fileExtToRuntime[rt]
+		if !ok {
+			return fmt.Errorf("could not detect language of this function: %s\n", a.runtime)
+		}
+	}
+
+	if _, ok := acceptableFnRuntimes[a.runtime]; !ok {
+		return fmt.Errorf("cannot use runtime %s", a.runtime)
+	}
+
+	ff := &funcfile{
+		Runtime:    &a.runtime,
+		Version:    initialVersion,
+		Entrypoint: &entrypoint,
+	}
+
+	if err := encodeFuncfileYAML("function.yaml", ff); err != nil {
+		return err
+	}
+	fmt.Println("function.yaml written")
+	return nil
+}
+
+func detectRuntime(path string) (string, error) {
+	scores := map[string]uint{
+		"": 0,
+	}
+	err := filepath.Walk(path, func(_ string, info os.FileInfo, _ error) error {
+		if info.IsDir() {
+			return nil
+		}
+
+		ext := strings.ToLower(filepath.Ext(info.Name()))
+		if ext == "" {
+			return nil
+		}
+		scores[ext]++
+		return nil
+	})
+	if err != nil {
+		return "", fmt.Errorf("file walk error: %s\n", err)
+	}
+
+	biggest := ""
+	for ext, score := range scores {
+		if score > scores[biggest] {
+			biggest = ext
+		}
+	}
+
+	return biggest, nil
+
+}

fnctl/main.go

@@ -30,6 +30,7 @@ ENVIRONMENT VARIABLES:
 		push(),
 		routes(),
 		run(),
+		initFn(),
 	}
 	app.Run(os.Args)
 }