@Override
  public String getScriptPath(JobInstance jobInstance, String scriptName)
      throws FileNotFoundException {
    String scriptPath;
    InstallationRecord jobInstallation = getInstallationFinder().getAllInstalledJobs().get(jobInstance);
    scriptPath = Paths.get(jobInstallation.getScriptFilePath(), scriptName).toString();

    File scriptFile = new File(scriptPath);
    if (!scriptFile.exists()) {
      throw new FileNotFoundException("Script does not exist: " + scriptPath);
    }
    return scriptPath;
  }
Constructs the path to the specified script within the job installation.

@param jobInstance             the instance of the job.
@param scriptName              the name of the script.
@return                        the full path to the script.
@throws FileNotFoundException  if the job installation path doesn't exist.
samza-rest/src/main/java/org/apache/samza/rest/proxy/job/ScriptJobProxy.java