Safely get global ddev directory, fixes #806 (#878)

* Use GetGlobalDdevDir to ensure ~/.ddev exists before operating on it, fixes #806.

* Replace gohomedir.Dir() with GetGlobalDdevDir() in providerPantheon.go

* Run goimports and gofmt

cmd/ddev/cmd/auth_pantheon.go

@@ -5,7 +5,6 @@ import (
 
 	"github.com/drud/ddev/pkg/util"
 	"github.com/drud/go-pantheon/pkg/pantheon"
-	gohomedir "github.com/mitchellh/go-homedir"
 	"github.com/spf13/cobra"
 )
 
@@ -22,12 +21,12 @@ var PantheonAuthCommand = &cobra.Command{
 		if len(args) != 1 {
 			util.Failed("Too many arguments detected. Please provide only your Pantheon Machine token., e.g. 'ddev auth-pantheon [token]'. See https://pantheon.io/docs/machine-tokens/ for instructions on creating a token.")
 		}
-		userDir, err := gohomedir.Dir()
-		util.CheckErr(err)
-		sessionLocation := filepath.Join(userDir, ".ddev", "pantheonconfig.json")
+
+		ddevDir := util.GetGlobalDdevDir()
+		sessionLocation := filepath.Join(ddevDir, "pantheonconfig.json")
 
 		session := pantheon.NewAuthSession(args[0])
-		err = session.Auth()
+		err := session.Auth()
 		if err != nil {
 			util.Failed("Could not authenticate with pantheon: %v", err)
 		}

pkg/ddevapp/providerPantheon.go

@@ -6,12 +6,11 @@ import (
 	"path/filepath"
 	"strings"
 
+	"fmt"
+
 	"github.com/drud/ddev/pkg/fileutil"
 	"github.com/drud/ddev/pkg/output"
 	"github.com/drud/ddev/pkg/util"
-	gohomedir "github.com/mitchellh/go-homedir"
-
-	"fmt"
 
 	"github.com/drud/go-pantheon/pkg/pantheon"
 	"gopkg.in/yaml.v2"
@@ -133,9 +132,9 @@ func (p *PantheonProvider) prepDownloadDir() {
 }
 
 func (p *PantheonProvider) getDownloadDir() string {
-	userDir, err := gohomedir.Dir()
-	util.CheckErr(err)
-	destDir := filepath.Join(userDir, ".ddev", "pantheon", p.app.Name)
+	ddevDir := util.GetGlobalDdevDir()
+	destDir := filepath.Join(ddevDir, "pantheon", p.app.Name)
+
 	return destDir
 }
 
@@ -304,15 +303,14 @@ func findPantheonSite(name string) (pantheon.Site, error) {
 
 // getPantheonSession loads the pantheon API config from disk and returns a pantheon session struct.
 func getPantheonSession() *pantheon.AuthSession {
-	userDir, err := gohomedir.Dir()
-	util.CheckErr(err)
-	sessionLocation := filepath.Join(userDir, ".ddev", "pantheonconfig.json")
+	ddevDir := util.GetGlobalDdevDir()
+	sessionLocation := filepath.Join(ddevDir, "pantheonconfig.json")
 
 	// Generate a session object based on the DDEV_PANTHEON_API_TOKEN environment var.
 	session := &pantheon.AuthSession{}
 
 	// Read a previously saved session.
-	err = session.Read(sessionLocation)
+	err := session.Read(sessionLocation)
 
 	if err != nil {
 		// If we can't read a previous session fall back to using the API token.