whole_func_string: function runJob(uuid, runner_id, callback) {
              var idx = queued_jobs.indexOf(uuid);
              if (idx === -1) {
                  return callback(new e.BackendPreconditionFailedError(
                    'Only queued jobs can be run'));
              } else {
                  queued_jobs.splice(idx, 1);
                  jobs[uuid].runner_id = runner_id;
                  jobs[uuid].execution = 'running';
                  return callback(null, clone(jobs[uuid]));
              }
          }
func_code_string: function runJob(uuid, runner_id, callback) {
              var idx = queued_jobs.indexOf(uuid);
              if (idx === -1) {
                  return callback(new e.BackendPreconditionFailedError(
                    'Only queued jobs can be run'));
              } else {
                  queued_jobs.splice(idx, 1);
                  jobs[uuid].runner_id = runner_id;
                  jobs[uuid].execution = 'running';
                  return callback(null, clone(jobs[uuid]));
              }
          }
func_documentation_string: Lock a job, mark it as running by the given runner, update job status. uuid - the job uuid (String) runner_id - the runner identifier (String) callback - f(err, job) callback will be called with error if something fails, otherwise it'll return the updated job using getJob.