Add option to start SQL Runner from a given step (closes #32)

main.go

@@ -40,7 +40,7 @@ func main() {
 		log.Fatalf("Could not parse playbook (YAML): %s", err.Error())
 	}
 
-	statuses := run.Run(pb, options.sqlroot)
+	statuses := run.Run(pb, options.sqlroot, options.fromStep)
 	code, message := review(statuses)
 
 	log.Printf(message)

options.go

@@ -40,6 +40,7 @@ type Options struct {
 	version   bool
 	playbook  string
 	sqlroot   string
+	fromStep  string
 	variables CLIVariables
 }
 
@@ -55,6 +56,7 @@ func (o *Options) GetFlagSet() *flag.FlagSet {
 	fs.StringVar(&(o.playbook), "playbook", "", "Playbook of SQL scripts to execute")
 	fs.StringVar(&(o.sqlroot), "sqlroot", SQLROOT_PLAYBOOK, fmt.Sprintf("Absolute path to SQL scripts. Use %s and %s for those respective paths", SQLROOT_PLAYBOOK, SQLROOT_BINARY))
 	fs.Var(&(o.variables), "var", "Variables to be passed to the playbook, in the key=value format")
+	fs.StringVar(&(o.fromStep), "fromStep", "", "Starts from a given step defined in your playbook")
 	// TODO: add format flag if/when we support TOML
 
 	return fs

run/run.go

@@ -26,6 +26,7 @@ const (
 	POSTGRESQL_TYPE = "postgresql"
 
 	ERROR_UNSUPPORTED_DB_TYPE = "Database type is unsupported"
+	ERROR_FROM_STEP_NOT_FOUND = "The fromStep argument did not match any available steps"
 )
 
 // Reports on any errors from running the
@@ -55,7 +56,34 @@ type QueryStatus struct {
 //
 // Handles dispatch to the appropriate
 // database engine
-func Run(pb playbook.Playbook, sqlroot string) []TargetStatus {
+func Run(pb playbook.Playbook, sqlroot string, fromStep string) []TargetStatus {
+
+	// Check fromStep argument to ensure that it actually matches a step and to get the
+	// index to start from
+	stepIndex := 0
+	if fromStep != "" {
+		exists := false
+		for i := 0; i < len(pb.Steps); i++ {
+			if pb.Steps[i].Name == fromStep {
+				exists = true
+				stepIndex = i
+				break;
+			}
+		}
+
+		// Process failure case
+		if exists == false {
+			allStatuses := make([]TargetStatus, 0)
+			for _, tgt := range pb.Targets {
+				status := fromStepNotFound(tgt.Name, fromStep)
+				allStatuses = append(allStatuses, status)
+			}
+			return allStatuses
+		}
+	}
+
+	// Trim skippable steps from the array
+	pb.Steps = pb.Steps[stepIndex:]
 
 	targetChan := make(chan TargetStatus, len(pb.Targets))
 
@@ -77,6 +105,16 @@ func Run(pb playbook.Playbook, sqlroot string) []TargetStatus {
 	return allStatuses
 }
 
+// Helper for a fromStep not found error
+func fromStepNotFound(targetName string, fromStep string) TargetStatus {
+	errs := []error{fmt.Errorf("%s: %s", ERROR_FROM_STEP_NOT_FOUND, fromStep)}
+	return TargetStatus{
+		Name:   targetName,
+		Errors: errs,
+		Steps:  nil,
+	}
+}
+
 // Route to correct database client and run
 func routeAndRun(target playbook.Target, sqlroot string, steps []playbook.Step, variables map[string]interface{}, targetChan chan TargetStatus) {
 	switch strings.ToLower(target.Type) {