add pull command

cmd/mg/cmd/pull.go

@@ -2,19 +2,102 @@ package cmd
 
 import (
 	"fmt"
+	"log"
+	"os"
+	"sync"
 
+	git "github.com/go-git/go-git/v5"
 	"github.com/spf13/cobra"
 )
 
 // pullCmd represents the pull command
-var pullCmd = &cobra.Command{
-	Use:   "pull",
-	Short: "pull all git repos",
-	Run: func(cmd *cobra.Command, args []string) {
-		fmt.Println("pull called")
-	},
-}
+var (
+	jobs    int
+	pullCmd = &cobra.Command{
+		Use:   "pull",
+		Short: "add current path to list of repos",
+		Run: func(_ *cobra.Command, args []string) {
+			type RepoError struct {
+				Error error
+				Repo  string
+			}
+			if jobs < 1 {
+				log.Println("jobs must be greater than 0")
+				os.Exit(1)
+			}
+			conf := GetConfig()
+			if len(args) > 0 {
+				log.Println("too many arguments")
+				os.Exit(1)
+			}
+			repoChan := make(chan string, len(conf.Repos))
+			errs := []RepoError{}
+			alreadyUpToDate := 0
+			mutex := sync.Mutex{}
+			wg := sync.WaitGroup{}
+			wg.Add(len(conf.Repos))
+			for i := 0; i < jobs; i++ {
+				go func() {
+					for repo := range repoChan {
+						log.Printf("attempting pull: %s\n", repo)
+						r, err := git.PlainOpenWithOptions(repo, &(git.PlainOpenOptions{DetectDotGit: true}))
+						if err != nil {
+							mutex.Lock()
+							errs = append(errs, RepoError{Error: err, Repo: repo})
+							mutex.Unlock()
+							log.Printf("pull failed for %s: %v\n", repo, err)
+							wg.Done()
+							continue
+						}
+						w, err := r.Worktree()
+						if err != nil {
+							mutex.Lock()
+							errs = append(errs, RepoError{Error: err, Repo: repo})
+							mutex.Unlock()
+							log.Printf("pull failed for %s: %v\n", repo, err)
+							wg.Done()
+							continue
+						}
+						err = w.Pull(&git.PullOptions{})
+						if err == git.NoErrAlreadyUpToDate {
+							mutex.Lock()
+							alreadyUpToDate++
+							mutex.Unlock()
+							fmt.Printf("repo %s: already up to date\n", repo)
+							wg.Done()
+							continue
+						} else if err != nil {
+							mutex.Lock()
+							errs = append(errs, RepoError{Error: err, Repo: repo})
+							mutex.Unlock()
+							log.Printf("pull failed for %s: %v\n", repo, err)
+							wg.Done()
+							continue
+						} else {
+							fmt.Printf("successfully pulled %s\n", w.Filesystem.Root())
+						}
+						wg.Done()
+					}
+				}()
+			}
+			for _, repo := range conf.Repos {
+				repoChan <- repo.Path
+			}
+			close(repoChan)
+			wg.Wait()
+			for _, err := range errs {
+				log.Printf("error pulling %s: %s\n", err.Repo, err.Error)
+			}
+			lenErrs := len(errs)
+			fmt.Println()
+			fmt.Printf("successfully pulled %d/%d repos\n", len(conf.Repos)-lenErrs, len(conf.Repos))
+			fmt.Printf("%d repos already up to date\n", alreadyUpToDate)
+			fmt.Printf("failed to pull %d/%d repos\n", lenErrs, len(conf.Repos))
+		},
+	}
+)
 
 func init() {
 	rootCmd.AddCommand(pullCmd)
+	pullCmd.Flags().IntVarP(&jobs, "jobs", "j", 1, "number of jobs to run in parallel")
 }