fix: ensure the label names are sanitised

packages/opentelemetry-exporter-prometheus/src/PrometheusSerializer.ts

@@ -111,17 +111,19 @@ function stringify(
  let labelsStr = '';
 
  for (const [key, val] of Object.entries(labels)) {
+ const santisedLabelName = sanitizePrometheusMetricName(key);
  hasLabel = true;
- labelsStr += `${labelsStr.length > 0 ? ',' : ''}${key}="${escapeLabelValue(
- val
- )}"`;
+ labelsStr += `${
+ labelsStr.length > 0 ? ',' : ''
+ }${santisedLabelName}="${escapeLabelValue(val)}"`;
  }
  if (additionalLabels) {
  for (const [key, val] of Object.entries(additionalLabels)) {
+ const santisedLabelName = sanitizePrometheusMetricName(key);
  hasLabel = true;
  labelsStr += `${
  labelsStr.length > 0 ? ',' : ''
- }${key}="${escapeLabelValue(val)}"`;
+ }${santisedLabelName}="${escapeLabelValue(val)}"`;
  }
  }
 

packages/opentelemetry-exporter-prometheus/test/PrometheusSerializer.test.ts

@@ -487,6 +487,34 @@ describe('PrometheusSerializer', () => {
  `} 1 ${mockedHrTimeMs}\n`
  );
  });
+
+ it('should sanitise label names', async () => {
+ const serializer = new PrometheusSerializer();
+
+ const meter = new MeterProvider({
+ processor: new ExactProcessor(SumAggregator),
+ }).getMeter('test');
+ const counter = meter.createCounter('test') as CounterMetric;
+ // if you try to use a label name like account-id prometheus will complain
+ // with an error like:
+ // error while linting: text format parsing error in line 282: expected '=' after label name, found '-'
+ counter
+ .bind(({
+ 'account-id': '123456',
+ } as unknown) as Labels)
+ .add(1);
+ const records = await counter.getMetricRecord();
+ const record = records[0];
+
+ const result = serializer.serializeRecord(
+ record.descriptor.name,
+ record
+ );
+ assert.strictEqual(
+ result,
+ `test{account_id="123456"} 1 ${mockedHrTimeMs}\n`
+ );
+ });
  });
  });
 });