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Function: createCounter()

@arolariu/website

@arolariu/website / instrumentation.server / createCounter

Function: createCounter()

createCounter(name, description?, unit?): Counter<Attributes>

Defined in: instrumentation.server.ts:1165

Create a counter metric instrument.

Counters are monotonically increasing values used to track totals. They can only go up (or reset to zero). Use for counting events or operations.

Parameters​

name​

MetricName

Metric name following semantic conventions (e.g., "http.server.requests")

description?​

string

Human-readable description of what the metric measures

unit?​

string

Optional unit of measurement (e.g., "1", "requests", "bytes")

Returns​

Counter<Attributes>

Counter instrument for recording values with type-safe attributes

Remarks​

  • Counter values should only increase
  • Use add() with positive values only
  • Include units in the name (e.g., "requests", "bytes", "errors")
  • Keep attribute cardinality low to avoid metric explosion
  • Counters are aggregated as sums in backends

Examples​

const requestCounter = createCounter(
  'http.server.requests',
  'Total number of HTTP requests received',
  '1'
);

// Record a request with type-safe attributes
requestCounter.add(1, {
  'http.method': 'GET',
  'http.status_code': 200,
  'next.render_context': 'api',
});
// User action counter
const userActionCounter = createCounter('user.actions', 'Total user actions');
userActionCounter.add(1, {
  'user.authenticated': true,
  'user.role': 'admin',
});

See​

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