Add init command

cmd/init.go

@@ -0,0 +1,85 @@
+package cmd
+
+import (
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/briandowns/spinner"
+	"github.com/mitchellh/cli"
+	"trellis-cli/trellis"
+)
+
+type InitCommand struct {
+	UI      cli.Ui
+	Trellis *trellis.Trellis
+}
+
+func (c *InitCommand) Run(args []string) int {
+	if err := c.Trellis.LoadProject(); err != nil {
+		c.UI.Error(err.Error())
+		return 1
+	}
+
+	switch len(args) {
+	case 0:
+	default:
+		c.UI.Error(fmt.Sprintf("Error: too many arguments (expected 0, got %d)\n", len(args)))
+		c.UI.Output(c.Help())
+		return 1
+	}
+
+	c.UI.Info(fmt.Sprintf("Creating virtualenv in %s", c.Trellis.Virtualenv.Path))
+
+	err := c.Trellis.Virtualenv.Create()
+	if err != nil {
+		c.UI.Error(fmt.Sprintf("Error creating virtualenv: %s", err))
+		return 1
+	}
+
+	c.UI.Info("✓ Virtualenv created\n")
+
+	pip := execCommand("pip", "install", "-r", "requirements.txt")
+
+	s := spinner.New(spinner.CharSets[14], 100*time.Millisecond)
+	s.Suffix = " Installing pip dependencies (pip install -r requirements.txt) ..."
+	s.FinalMSG = "✓ Dependencies installed\n"
+	s.Start()
+
+	err = pip.Run()
+
+	if err != nil {
+		s.Stop()
+		c.UI.Error(fmt.Sprintf("Error installing pip requirements", err))
+		return 1
+	}
+
+	s.Stop()
+
+	return 0
+}
+
+func (c *InitCommand) Synopsis() string {
+	return "Initializes an existing Trellis project"
+}
+
+func (c *InitCommand) Help() string {
+	helpText := `
+Usage: trellis init [options]
+
+Initializes an existing Trellis project to be managed by trellis-cli.
+The initialization process does two things:
+
+1. creates a virtual environment via virtualenv to manage dependencies
+2. installs dependencies via pip (specified by requirements.txt in your Trellis project)
+
+This command is idempotent meaning it can be run multiple times without side-effects.
+
+  $ trellis init
+
+Options:
+  -h, --help  show this help
+`
+
+	return strings.TrimSpace(helpText)
+}

cmd/new.go

@@ -130,6 +130,9 @@ func (c *NewCommand) Run(args []string) int {
 		return 1
 	}
 
+	initCommand := &InitCommand{UI: c.UI, Trellis: c.trellis}
+	initCommand.Run([]string{})
+
 	// Update default configs
 	for env, config := range c.trellis.Environments {
 		c.trellis.UpdateDefaultConfig(config, c.name, c.host, env)

main.go

@@ -56,6 +56,9 @@ func main() {
 		"info": func() (cli.Command, error) {
 			return &cmd.InfoCommand{UI: ui, Trellis: trellis}, nil
 		},
+		"init": func() (cli.Command, error) {
+			return &cmd.InitCommand{UI: ui, Trellis: trellis}, nil
+		},
 		"new": func() (cli.Command, error) {
 			return cmd.NewNewCommand(ui, trellis, c.Version), nil
 		},

trellis/virtualenv.go

@@ -39,6 +39,10 @@ func (v *Virtualenv) Create() (err error) {
 
 	cmd.Args = append(cmd.Args, v.Path)
 
+	if v.Initialized() {
+		return nil
+	}
+
 	err = cmd.Run()
 	if err != nil {
 		return err