[WIP] Add merge/rebase feature

handler/comment_handler.go

@@ -36,6 +36,7 @@ const (
 	assignReviewerConstant   string = "AssignReviewer"
 	unassignReviewerConstant string = "UnassignReviewer"
 	messageConstant          string = "message"
+	mergePRConstant          string = "Merge"
 
 	noDCO             string = "no-dco"
 	labelLimitDefault int    = 5
@@ -120,16 +121,34 @@ func HandleComment(req types.IssueCommentOuter, config config.Config, derekConfi
 		feedback, err = createMessage(req, command.Type, command.Value, config, derekConfig)
 		break
 
+	case mergePRConstant:
+		merger := merge{
+			Config:     config,
+			RepoConfig: derekConfig,
+		}
+
+		feedback, err = merger.Merge(req, command.Type, command.Value)
+
+		if len(feedback) > 0 {
+			log.Printf("Feedback: %s\n", feedback)
+		}
+
+		if err != nil {
+			log.Println(err)
+		}
+
+		break
+
 	default:
 		feedback = "Unable to work with comment: " + req.Comment.Body
 		err = nil
 		break
 	}
 
-	fmt.Print(feedback)
+	log.Print(feedback)
 
 	if err != nil {
-		fmt.Println(err)
+		log.Println(err)
 	}
 }
 
@@ -434,6 +453,8 @@ func parse(body string, commandTriggers []string) *types.CommentAction {
 			commandTrigger + "clear reviewer: ":   unassignReviewerConstant,
 			commandTrigger + "message: ":          messageConstant,
 			commandTrigger + "msg: ":              messageConstant,
+			commandTrigger + "merge":              mergePRConstant,
+			commandTrigger + "rebase":             mergePRConstant,
 		}
 
 		for trigger, commandType := range commands {

handler/merge.go

@@ -0,0 +1,159 @@
+package handler
+
+import (
+	"context"
+	"fmt"
+	"log"
+
+	"github.com/alexellis/derek/config"
+	"github.com/alexellis/derek/types"
+	"github.com/google/go-github/github"
+)
+
+type merge struct {
+	Config     config.Config
+	RepoConfig *types.DerekRepoConfig
+}
+
+func (m *merge) Merge(req types.IssueCommentOuter, cmdType string, cmdValue string) (string, error) {
+	result := ""
+
+	client, ctx := makeClient(req.Installation.ID, m.Config)
+
+	if req.Issue.PullRequest == nil {
+		return "can't merge a non-PR issue", nil
+	}
+
+	if len(m.RepoConfig.Mergers) == 0 {
+		return "can't merge without at least one merger", nil
+	}
+
+	if mayMerge(req.Comment.User.Login, m.RepoConfig.Mergers) == false {
+		return fmt.Sprintf("user %s, may not merge", req.Comment.User.Login), nil
+	}
+
+	pr, _, err := client.PullRequests.Get(ctx, req.Repository.Owner.Login, req.Repository.Name, req.Issue.Number)
+	if err != nil {
+		return "unable to get pull request", err
+	}
+
+	if pr.GetMerged() == false {
+
+		if pr.GetMergeable() == true {
+
+			if validMergePolicy(req) == false {
+				sendComment(client, req.Repository.Owner.Login, req.Repository.Name, req.Issue.Number,
+					"I am unable to merge this PR due to merge-policy exception(s)")
+
+				return "invalid merge policy", nil
+			}
+
+			mustApprove := []string{}
+
+			// An approver, can't approve their own PRs so must come out
+			// of the list
+			for _, approver := range m.RepoConfig.MustApprove {
+				if approver != pr.GetUser().GetLogin() {
+					mustApprove = append(mustApprove, approver)
+				}
+			}
+
+			if len(mustApprove) > 0 {
+
+				listOpts := &github.ListOptions{}
+				reviews, _, listReviewsErr := client.PullRequests.ListReviews(ctx, req.Repository.Owner.Login,
+					req.Repository.Name, req.Issue.Number, listOpts)
+
+				if listReviewsErr != nil {
+					return fmt.Sprintf("unable to list reviews for %d", pr.GetID()), listReviewsErr
+				}
+
+				mustApproveConfirmed := []github.PullRequestReview{}
+				for _, r := range reviews {
+					fmt.Printf("Review state: %s, commitID: %s, HEADSHA: %s\n", r.GetState(), r.GetCommitID(), pr.GetHead().GetSHA())
+					for _, approver := range mustApprove {
+						if r.GetState() == "APPROVED" &&
+							r.GetUser().GetLogin() == approver &&
+							r.GetCommitID() == pr.GetHead().GetSHA() {
+							mustApproveConfirmed = append(mustApproveConfirmed, *r)
+						}
+					}
+				}
+
+				if len(m.RepoConfig.MustApprove) != len(mustApproveConfirmed) {
+					return fmt.Sprintf("needed %d approvals, but had: %d",
+						len(m.RepoConfig.MustApprove), len(mustApproveConfirmed)), nil
+				}
+			}
+
+			pullRequestOptions := github.PullRequestOptions{
+				MergeMethod: "rebase",
+				CommitTitle: fmt.Sprintf("Merge PR #%d", req.Issue.Number),
+			}
+
+			mergeRes, _, err := client.PullRequests.Merge(ctx,
+				req.Repository.Owner.Login, req.Repository.Name, req.Issue.Number,
+				fmt.Sprintf(`Merging PR #%d by Derek
+
+This is an automated merge by the bot Derek, find more
+https://github.com/alexellis/derek/
+
+Signed-off-by: Derek <[email protected]>`, req.Issue.Number), &pullRequestOptions)
+
+			if err != nil {
+
+				body := fmt.Sprintf(`I have been unable to merge the requested PR: %s`, err.Error())
+
+				sendComment(client, req.Repository.Owner.Login, req.Repository.Name, req.Issue.Number,
+					body)
+
+				return fmt.Sprintf("Merge issue: %s, %t", mergeRes.GetMessage(), mergeRes.GetMerged()), err
+			}
+
+			sendComment(client, req.Repository.Owner.Login, req.Repository.Name, req.Issue.Number,
+				`I have merged the pull request using the rebase strategy.`)
+		} else {
+			sendComment(client, req.Repository.Owner.Login, req.Repository.Name, req.Issue.Number,
+				"This pull request cannot be merged. Rebase your work and try again.")
+		}
+	}
+
+	return result, err
+}
+
+func sendComment(client *github.Client, login string, repo string, issue int, comment string) {
+
+	issueComment := &github.IssueComment{
+		Body: &comment,
+	}
+
+	_, _, err := client.Issues.CreateComment(context.Background(),
+		login, repo, issue, issueComment)
+	if err != nil {
+		log.Printf("Error creating comment %s %s %d\n", login, repo, issue)
+	}
+}
+
+func validMergePolicy(req types.IssueCommentOuter) bool {
+	validDCO := true
+	for _, label := range req.Issue.Labels {
+		if label.Name == "no-dco" {
+			validDCO = false
+			break
+		}
+	}
+
+	return validDCO
+}
+
+func mayMerge(user string, list []string) bool {
+	may := false
+
+	for _, item := range list {
+		if item == user {
+			may = true
+			break
+		}
+	}
+	return may
+}

types/types.go

@@ -56,6 +56,12 @@ type Issue struct {
 	State     string       `json:"state"`
 	Milestone Milestone    `json:"milestone"`
 	URL       string       `json:"url"`
+
+	PullRequest *PullRequestIssueLink `json:"pull_request"`
+}
+
+type PullRequestIssueLink struct {
+	URL string `json:"url"`
 }
 
 type Milestone struct {
@@ -79,21 +85,27 @@ type CommentAction struct {
 type DerekRepoConfig struct {
 
 	// A redirect URL to load the config from another location.
-	Redirect string
+	Redirect string `yaml:"redirect"`
 
 	// Features can be turned on/off if needed.
-	Features []string
+	Features []string `yaml:"features"`
 
 	// Users who are enrolled to make use of Derek
-	Maintainers []string
+	Maintainers []string `yaml:"maintainers"`
 
 	// Curators is an alias for Maintainers and is only used if the Maintainers list is empty.
-	Curators []string
+	Curators []string `yaml:"curators"`
 
 	//ContributingURL url to contribution guide
 	ContributingURL string `yaml:"contributing_url"`
 
 	Messages []Message `yaml:"custom_messages"`
+
+	// Mergers are those who can perform a rebase
+	Mergers []string `yaml:"mergers"`
+
+	// MustApprove are those from whom an approval must be in place for a merge
+	MustApprove []string `yaml:"must_approve"`
 }
 
 type Message struct {