common shell provisioner: define a ValidExitCode func

common/shell/exit_code.go

@@ -0,0 +1,39 @@
+package shell
+
+import "fmt"
+
+func (p *Provisioner) ValidExitCode(code int) error {
+	// Check exit code against allowed codes (likely just 0)
+	validCodes := p.ValidExitCodes
+	if len(validCodes) == 0 {
+		validCodes = []int{0}
+	}
+	validExitCode := false
+	for _, v := range validCodes {
+		if code == v {
+			validExitCode = true
+			break
+		}
+	}
+	if !validExitCode {
+		return &ErrorInvalidExitCode{
+			Code:    code,
+			Allowed: validCodes,
+		}
+	}
+	return nil
+}
+
+type ErrorInvalidExitCode struct {
+	Code    int
+	Allowed []int
+}
+
+func (e *ErrorInvalidExitCode) Error() string {
+	if e == nil {
+		return "<nil>"
+	}
+	return fmt.Sprintf("Script exited with non-zero exit status: %d."+
+		"Allowed exit codes are: %v",
+		e.Code, e.Allowed)
+}