🐶 Datadog Custom Metrics
Helpers for sending Datadog custom metrics via hot-shots.
yarn add seek-datadog-custom-metrics
Tagging convention
All custom metrics are prefixed by AppConfig.name
.
Two global tags are also added to every custom metric:
AppConfig.environment
becomes env:${value}
AppConfig.version
becomes version:${value}
These tags are consistent with tags sent by Gantry via Datadog's AWS integration.
API reference
createStatsDClient
createStatsDClient
creates a hot-shots client configured with our tagging convention.
This is intended for containerized services, particularly those deployed with Gantry.
import { StatsD } from 'hot-shots';
import { createStatsDClient } from 'seek-datadog-custom-metrics';
import config from '../config';
import { rootLogger } from '../logger';
const errorHandler = (err: Error) => {
rootLogger.error('StatsD error', err);
};
const metricsClient = createStatsDClient(StatsD, config, errorHandler);
createLambdaExtensionClient
createLambdaExtensionClient
creates a Lambda extension client.
This is intended for AWS Lambda functions and is a replacement for createCloudWatchClient
.
This client will only submit metrics as a distribution which enables globally accurate aggregations for percentiles (p50, p75, p90, etc).
import { createLambdaExtensionClient } from 'seek-datadog-custom-metrics';
import config from '../config';
const { metricsClient, withLambdaExtension } =
createLambdaExtensionClient(config);
export const handler = withLambdaExtension((event, _ctx) => {
try {
logger.info('request');
await lambdaFunction(event);
} catch (err) {
logger.error({ err }, 'request');
metricsClient.increment('invocation_error');
throw new Error('invoke error');
}
});
createNoOpClient
createNoOpClient
returns a no-op client.
This is intended for use where a MetricsClient interface is expected but you do not wish to provide one, e.g in tests.
import { createNoOpClient } from 'seek-datadog-custom-metrics';
const metricsClient = createNoOpClient();
createTimedSpan
createTimedSpan
wraps an asynchronous closure and records custom Datadog metrics about its performance.
This is intended as a lightweight alternative to APM where nested spans aren't required.
import { createTimedSpan } from 'seek-datadog-custom-metrics';
const timedSpan = createTimedSpan(metricsClient);
const loadPrivateKey = async (): Promise<PrivateKey> =>
await timedSpan(
'secrets.load_private_key',
() => client.getSecretValue({ SecretId }).promise(),
);
httpTracingConfig
The dd-trace package can instrument your application and trace its outbound HTTP requests.
However, its emitted trace.http.request
metric only captures the HTTP method against the resource.name
tag,
which is not useful if your application makes HTTP requests to multiple resources and you want to inspect latency by resource.
This configuration object adds a hook to replace the resource.name
with a HTTP method and semi-normalised URL.
For example, if your application makes the following HTTP request:
PUT https://www.example.com/path/to/123?idempotencyKey=c1083fb6-519c-42bf-8619-08dfd6229954
The trace.http.request
metric will see the following tag change:
- resource_name:put
+ resource_name:put_https://www.example.com/path/to/number?idempotencyKey=uuid
Apply the configuration object where you bootstrap your application with the Datadog tracer:
import { httpTracingConfig } from 'seek-datadog-custom-metrics';
datadogTracer?.use('http', httpTracingConfig);
This configuration may be superseded in future if the underlying dd-trace implementation is corrected.
DataDog/dd-trace-js#1118