[bengl]

Backends group and filter spans by resource attributes such as service.version and deployment.environment.name, and microtel had no way to set them. This adds a resourceAttributes option:

microtel.init({
  resourceAttributes: {
    'service.version': '1.4.2',
    'deployment.environment.name': 'production',
  },
});

What changed. Values are strings, booleans, or finite numbers, encoded the way span attributes are. A value replaces microtel's own value for the same key, so each key appears once, and the object is copied at init. service.name, telemetry.sdk.name, and telemetry.sdk.version are refused with an error naming the option that sets them, serviceName, sdkName, or sdkVersion, so each has one place to be set. The other telemetry.sdk.* keys are refused because microtel sets them, and so are empty keys.

Number encoding. Integers export as intValue, which OTLP writes as a decimal string. Only safe integers fit that exactly, so larger ones such as 1e21 now export as doubleValue instead of a string like "1e+21" that a collector could reject. Span attributes share the encoder, so they get the same fix.

New defaults. The resource gains service.instance.id, a random UUID made once per process, as the semantic conventions suggest, and host.name from os.hostname(). Both can be replaced through resourceAttributes.

Not taken.

• Array values and resource detectors. Neither is needed for the attributes above.
• An environment variable such as OTEL_RESOURCE_ATTRIBUTES. All configuration goes through init().

Tests. A table in test/test-init.js covers each way the option can be wrong. A child process checks the exported resource: the defaults, with service.instance.id the same across two exports, each value type and its encoding, including false, 0, and integers past the safe range, user values replacing host.name and process.pid, one entry per key, and the copy at init.