mr_show: Display approvals

Currently there is no way to use lab to view the list of contributors that
have approved an MR.  It would be nice if the users that approved an MR
were displayed in the 'mr show' output.

Display the approvers in a 'Approved By:' section of 'mr show'.

Signed-off-by: Prarit Bhargava <prarit@redhat.com>

cmd/mr_show.go

@@ -116,6 +116,7 @@ func printMR(mr *gitlab.MergeRequest, project string, renderMarkdown bool) {
 	assignee := "None"
 	milestone := "None"
 	labels := "None"
+	approvedByUsers := "None"
 	state := map[string]string{
 		"opened": "Open",
 		"closed": "Closed",
@@ -145,6 +146,14 @@ func printMR(mr *gitlab.MergeRequest, project string, renderMarkdown bool) {
 		log.Fatal(err)
 	}
 
+	approvedBys, err := lab.GetMRApprovedBys(project, mr.IID)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if len(approvedBys) > 0 {
+		approvedByUsers = strings.Join(approvedBys, ", ")
+	}
+
 	fmt.Printf(`
 #%d %s
 ===================================
@@ -155,14 +164,15 @@ Branches: %s->%s
 Status: %s
 Assignee: %s
 Author: %s
+Approved By: %s
 Milestone: %s
 Labels: %s
 Issues Closed by this MR: %s
 WebURL: %s
 `,
 		mr.IID, mr.Title, mr.Description, project, mr.SourceBranch,
 		mr.TargetBranch, state, assignee,
-		mr.Author.Username, milestone, labels,
+		mr.Author.Username, approvedByUsers, milestone, labels,
 		strings.Trim(strings.Replace(fmt.Sprint(closingIssues), " ", ",", -1), "[]"),
 		mr.WebURL,
 	)

cmd/mr_show_test.go

@@ -37,6 +37,7 @@ Branches: mrtest->master
 Status: Open
 Assignee: zaquestion
 Author: zaquestion
+Approved By: None
 Milestone: 1.0
 Labels: documentation
 Issues Closed by this MR: 

internal/gitlab/gitlab.go

@@ -1102,3 +1102,23 @@ func MoveIssue(project string, issueNum int, dest string) (string, error) {
 	}
 	return fmt.Sprintf("%s/issues/%d", destProject.WebURL, issue.IID), nil
 }
+
+func GetMRApprovedBys(project string, mrNum int) ([]string, error) {
+	var retArray []string
+
+	p, err := FindProject(project)
+	if err != nil {
+		return retArray, err
+	}
+
+	configuration, _, err := lab.MergeRequestApprovals.GetConfiguration(p.ID, mrNum)
+	if err != nil {
+		return retArray, err
+	}
+
+	for _, approvedby := range configuration.ApprovedBy {
+		retArray = append(retArray, approvedby.User.Username)
+	}
+
+	return retArray, err
+}