Merge pull request #26 from screwdriver-cd/mergePR

Add checkIfPR, Fetch, and Merge functions

git/git.go

@@ -9,6 +9,29 @@ import (
 )
 
 var execCommand = exec.Command
+var clone = Clone
+var setConfig = SetConfig
+var mergePR = MergePR
+var fetchPR = FetchPR
+var merge = Merge
+
+// command executes the git command
+func command(arguments ...string) error {
+	cmd := execCommand("git", arguments...)
+
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	err := cmd.Start()
+	if err != nil {
+		return fmt.Errorf("starting git command: %v", err)
+	}
+
+	err = cmd.Wait()
+	if err != nil {
+		return fmt.Errorf("running git command: %v", err)
+	}
+	return nil
+}
 
 // Clone clones a git repo into a destination directory
 func Clone(scmURL, destination string) error {
@@ -20,36 +43,60 @@ func Clone(scmURL, destination string) error {
 
 	repo := parts[0]
 	branch := parts[1]
-	cmd := execCommand("git", "clone", "--quiet", "--progress", "--branch", branch, repo, destination)
+	return command("clone", "--quiet", "--progress", "--branch", branch, repo, destination)
+}
 
-	cmd.Stdout = os.Stdout
-	cmd.Stderr = os.Stderr
-	err := cmd.Start()
+// SetConfig sets up git configuration
+func SetConfig(setting, name string) error {
+	return command("config", setting, name)
+}
+
+// FetchPR fetches a pull request into a specified branch
+func FetchPR(prNumber string, branch string) error {
+	return command("fetch", "origin", "pull/"+prNumber+"/head:"+branch)
+}
+
+// Merge merges changes on the specified branch
+func Merge(branch string) error {
+	return command("merge", "--no-edit", branch)
+}
+
+// MergePR calls FetchPR and Merge
+func MergePR(prNumber string, branch string) error {
+	err := fetchPR(prNumber, branch)
 	if err != nil {
-		return fmt.Errorf("starting git clone command: %v", err)
+		return fmt.Errorf("fetching pr: %v", err)
 	}
-
-	err = cmd.Wait()
+	err = merge(branch)
 	if err != nil {
-		return fmt.Errorf("cloning git repo: %v", err)
+		return fmt.Errorf("merging pr: %v", err)
 	}
 	return nil
 }
 
-//SetConfig sets up git configuration
-func SetConfig(setting, name string) error {
-	cmd := execCommand("git", "config", setting, name)
-	cmd.Stdout = os.Stdout
-	cmd.Stderr = os.Stderr
+// Setup clones a repository, sets the local config, and merges a PR if necessary
+func Setup(scmURL, destination, pr string) error {
+	err := clone(scmURL, destination)
+	if err != nil {
+		return fmt.Errorf("cloning repository: %v", err)
+	}
 
-	err := cmd.Start()
+	err = setConfig("user.name", "sd-buildbot")
 	if err != nil {
-		return fmt.Errorf("starting git config command: %v", err)
+		return fmt.Errorf("setting username: %v", err)
 	}
 
-	err = cmd.Wait()
+	err = setConfig("user.email", "dev-null@screwdriver.cd")
 	if err != nil {
-		return fmt.Errorf("setting git config: %v", err)
+		return fmt.Errorf("setting email: %v", err)
+	}
+
+	if pr != "" {
+		err = mergePR(pr, "_pr")
+		if err != nil {
+			return fmt.Errorf("merging pr: %v", err)
+		}
 	}
+
 	return nil
 }