Add prune option

prune option indicate if unmanaged labels should be removed,
by default is set to true

README.md

@@ -29,7 +29,7 @@ By using this workflow, you can sync current labels with labels configured in a
 
 ![](docs/assets/screenshot.png)
 
-The default file path is `.github/labels.yml`, but you can specify any file path with `jobs.<job_id>.steps.with`.
+The default file path is `.github/labels.yml`, but you can specify any file path with `jobs.<job_id>.steps.with.manifest`.
 
 To create manifest of the current labels easily, using [label-exporter](https://github.com/micnncim/label-exporter) is recommended.
 
@@ -57,7 +57,11 @@ jobs:
           manifest: path/to/manifest/labels.yml
 ```
 
-If a label color changes, the same label is updated with the new color. If a label name changes, the previous label is deleted. All issues and PRs that were previously labeled with this label are now unlabeled.
+If a label color changes, the same label is updated with the new color. If a label name changes, the previous label is deleted by default.
+Also all existing labels which not listed in `manifest` will be deleted by default.
+All issues and PRs that were previously labeled with this label are now unlabeled.
+
+You can add `jobs.<job_id>.steps.with.prune: false` in order to preserver all existing labels which is not mentioned in `manifest`, in this case when a label will be renamed old label will be not deleted.
 
 ## Sync labels on another repository
 

action.yml

@@ -12,6 +12,10 @@ inputs:
   token:
     description: "An alternative GitHub token to use instead"
     required: false
+  prune:
+    description: "remove unmanaged labels from repository"
+    required: false
+    default: true
 runs:
   using: "docker"
   image: "Dockerfile"

cmd/action-label-syncer/main.go

@@ -18,6 +18,7 @@ import (
 	"context"
 	"fmt"
 	"os"
+	"strconv"
 	"strings"
 
 	"github.com/micnncim/action-label-syncer/pkg/github"
@@ -48,8 +49,14 @@ func main() {
 	}
 	owner, repo := slugs[0], slugs[1]
 
+	prune, err := strconv.ParseBool(os.Getenv("INPUT_PRUNE"))
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "unable to parse prune: %v\n", err)
+		os.Exit(1)
+	}
+
 	ctx := context.Background()
-	if err := client.SyncLabels(ctx, owner, repo, labels); err != nil {
+	if err := client.SyncLabels(ctx, owner, repo, labels, prune); err != nil {
 		fmt.Fprintf(os.Stderr, "unable to sync labels: %v\n", err)
 		os.Exit(1)
 	}

pkg/github/github.go

@@ -16,6 +16,7 @@ package github
 
 import (
 	"context"
+	"fmt"
 	"io/ioutil"
 
 	"github.com/google/go-github/github"
@@ -56,7 +57,7 @@ func NewClient(token string) *Client {
 	}
 }
 
-func (c *Client) SyncLabels(ctx context.Context, owner, repo string, labels []Label) error {
+func (c *Client) SyncLabels(ctx context.Context, owner, repo string, labels []Label, prune bool) error {
 	labelMap := make(map[string]Label)
 	for _, l := range labels {
 		labelMap[l.Name] = l
@@ -74,19 +75,21 @@ func (c *Client) SyncLabels(ctx context.Context, owner, repo string, labels []La
 	eg := errgroup.Group{}
 
 	// Delete labels.
-	for _, currentLabel := range currentLabels {
-		currentLabel := currentLabel
-		eg.Go(func() error {
-			_, ok := labelMap[currentLabel.Name]
-			if ok {
-				return nil
-			}
-			return c.deleteLabel(ctx, owner, repo, currentLabel.Name)
-		})
-	}
+	if prune {
+		for _, currentLabel := range currentLabels {
+			currentLabel := currentLabel
+			eg.Go(func() error {
+				_, ok := labelMap[currentLabel.Name]
+				if ok {
+					return nil
+				}
+				return c.deleteLabel(ctx, owner, repo, currentLabel.Name)
+			})
+		}
 
-	if err := eg.Wait(); err != nil {
-		return err
+		if err := eg.Wait(); err != nil {
+			return err
+		}
 	}
 
 	// Create and/or update labels.
@@ -100,6 +103,7 @@ func (c *Client) SyncLabels(ctx context.Context, owner, repo string, labels []La
 			if currentLabel.Description != l.Description || currentLabel.Color != l.Color {
 				return c.updateLabel(ctx, owner, repo, l)
 			}
+			fmt.Printf("label: %+v not changed on %s/%s\n", l, owner, repo)
 			return nil
 		})
 	}
@@ -114,6 +118,7 @@ func (c *Client) createLabel(ctx context.Context, owner, repo string, label Labe
 		Color:       &label.Color,
 	}
 	_, _, err := c.githubClient.Issues.CreateLabel(ctx, owner, repo, l)
+	fmt.Printf("label: %+v created on: %s/%s\n", label, owner, repo)
 	return err
 }
 
@@ -149,10 +154,12 @@ func (c *Client) updateLabel(ctx context.Context, owner, repo string, label Labe
 		Color:       &label.Color,
 	}
 	_, _, err := c.githubClient.Issues.EditLabel(ctx, owner, repo, label.Name, l)
+	fmt.Printf("label %+v updated on: %s/%s\n", label, owner, repo)
 	return err
 }
 
 func (c *Client) deleteLabel(ctx context.Context, owner, repo, name string) error {
 	_, err := c.githubClient.Issues.DeleteLabel(ctx, owner, repo, name)
+	fmt.Printf("label: %s deleted from: %s/%s\n", name, owner, repo)
 	return err
 }