add values to spannerDefaults

[j143]

const spannerDefaults = {
  minNodes: 1,
  maxNodes: 3,
  stepSize: 2,
  overloadStepSize: 5,
  scaleOutCoolingMinutes: 5,
  scaleInCoolingMinutes: 30,
  scalingMethod: 'STEPWISE',
  regional_margin: 5,
  multi_regional_margin: 5
};
const metricDefaults = {
  period: 60,
  aligner: 'ALIGN_MAX',
  reducer: 'REDUCE_SUM'
}
const DEFAULT_THRESHOLD_MARGIN = 5;

    // merge in the defaults
    spanners[sIdx] = {...spannerDefaults, ...spanners[sIdx]};

    spanners[sIdx].metrics =
      buildMetrics(spanners[sIdx].projectId, spanners[sIdx].instanceId);

    // merge in the current Spanner state
    spanners[sIdx] = {
      ...spanners[sIdx],
      ...await getSpannerMetadata(spanners[sIdx].projectId, spanners[sIdx].instanceId)
    };

    if (spanner.regional) {
      threshold = metric.regional_threshold;
      if (!metric.hasOwnProperty('regional_margin')) 
        metric.regional_margin = DEFAULT_THRESHOLD_MARGIN;
      margin = metric.regional_margin;
    }

    const metricsObject = {
      name: metric.name,
      threshold: threshold,
      margin: margin,
      value: maxMetricValue
    };

[j143]

cloudspannerecosystem#28