--dry_run flag (#115)

* --dry_run flag

* more info on dry run

* doc

Author: apesternikov

README.md

@@ -461,6 +461,8 @@ As a result of the setup above the `create_gitops_prs` tool will open up to 2 po
 
 The GitOps pull request is only created (or new commits added) if the `gitops` target changes the state for the target deployment branch. The source pull request will remain open (and keep accumulation GitOps results) until the pull request is merged and source branch is deleted.
 
+`--dry_run` parameter can be used to test the tool without creating any pull requests. The tool will print the list of the potential pull requests. It is recommended to run the tool in the dry run mode as a part of the CI test suite to verify that the tool is configured correctly.
+
 <a name="multiple-release-branches-gitops-workflow"></a>
 ## Multiple Release Branches GitOps Workflow
 

gitops/prer/create_gitops_prs.go

@@ -68,6 +68,7 @@ var (
 	gitopsKind             SliceFlags
 	gitopsRuleName         SliceFlags
 	gitopsRuleAttr         SliceFlags
+	dryRun                 = flag.Bool("dry_run", false, "Do not create PRs, just print what would be done")
 )
 
 func init() {
@@ -236,9 +237,18 @@ func main() {
 	close(targetsCh)
 	wg.Wait()
 
-	workdir.Push(updatedGitopsBranches)
+	if *dryRun {
+		log.Println("dry-run: updated gitops branches: ", updatedGitopsBranches)
+		log.Println("dry-run: skipping push")
+	} else {
+		workdir.Push(updatedGitopsBranches)
+	}
 
 	for _, branch := range updatedGitopsBranches {
+		if *dryRun {
+			log.Println("dry-run: skipping PR creation: branch ", branch, "into ", *prInto)
+			continue
+		}
 		err := gitServer.CreatePR(branch, *prInto, fmt.Sprintf("GitOps deployment %s", branch))
 		if err != nil {
 			log.Fatal("unable to create PR: ", err)