func()

in lib/ec2macosinit/userdata.go [23:73]

• 38 lines of code
• 10 McCabe index (conditional complexity)

func (c *UserDataModule) Do(ctx *ModuleContext) (message string, err error) {
	// Get user data from IMDS
	ud, respCode, err := ctx.IMDS.getIMDSProperty("user-data")
	if err != nil {
		return "", fmt.Errorf("ec2macosinit: error getting user data from IMDS: %s\n", err)
	}
	if respCode == 404 { // 404 = no user data provided, exit nicely
		return "no user data provided through IMDS", nil
	}
	if respCode != 200 { // 200 = ok
		return "", fmt.Errorf("ec2macosinit: received an unexpected response code from IMDS: %d - %s\n", respCode, err)
	}

	// Attempt to base64 decode userdata.
	// This maintains consistency alongside Amazon Linux 2's cloud-init, which states:
	//     "Some tools and users will base64 encode their data before handing it to
	//      an API like boto, which will base64 encode it again, so we try to decode."
	decoded, err := decodeBase64(ud)
	if err == nil {
		ud = decoded
	}

	// Write user data to file
	userDataFile := path.Join(baseDir, ctx.IMDS.InstanceID, fileName)
	f, err := os.OpenFile(userDataFile, os.O_CREATE|os.O_WRONLY, 0755)
	if err != nil {
		return "", fmt.Errorf("ec2macosinit: error while opening user data file: %s\n", err)
	}
	defer f.Close()
	if _, err := f.WriteString(ud); err != nil {
		return "", fmt.Errorf("ec2macosinit: error while writing to user data file: %s\n", err)
	}

	// If we don't want to execute the user data, exit nicely - we're done
	if !c.ExecuteUserData {
		return "successfully handled user data with no execution request", nil
	}

	// Execute user data script
	out, err := executeCommand([]string{userDataFile}, "", []string{})
	if err != nil {
		if strings.Contains(err.Error(), "exec format error") {
			contentType := http.DetectContentType([]byte(ud))
			return fmt.Sprintf("provided user data is not executable (detected type: %s)", contentType), nil
		} else {
			return fmt.Sprintf("error while running user data with stdout: [%s] and stderr: [%s]", out.stdout, out.stderr), err
		}
	}

	return fmt.Sprintf("successfully ran user data with stdout: [%s] and stderr: [%s]", out.stdout, out.stderr), nil
}