@lokalise/fastify-extras/dist/plugins/healthcheck/healthcheckMetricsPlugin.js

Opinionated set of fastify plugins, commonly used in Lokalise

import fp from 'fastify-plugin';
const VALID_PROMETHEUS_NAME_REGEX = /[a-zA-Z_:][a-zA-Z0-9_:]*/;
/**
 * Execute healthcheck and calculate the check time
 */
export const wrapHealthCheckForPrometheus = (healthCheck, healthcheckName) => {
    return {
        name: healthcheckName,
        checker: async (app) => {
            const startTime = Date.now();
            const response = await healthCheck(app);
            const checkTimeInMsecs = Date.now() - startTime;
            return {
                checkPassed: !!response.result,
                checkTimeInMsecs,
            };
        },
    };
};
function plugin(app, opts, done) {
    const invalidNames = [];
    for (const healthcheck of opts.healthChecks) {
        if (!VALID_PROMETHEUS_NAME_REGEX.test(healthcheck.name)) {
            invalidNames.push(healthcheck.name);
        }
    }
    if (invalidNames.length > 0) {
        return done(new Error(`Invalid healthcheck names: ${JSON.stringify(invalidNames)}`));
    }
    try {
        const promClient = app.metrics.client;
        if (!promClient) {
            throw new Error('Prometheus client is not registered');
        }
        for (const check of opts.healthChecks) {
            new promClient.Gauge({
                name: `${check.name}_availability`,
                help: `Whether ${check.name} was available at the time`,
                async collect() {
                    const checkResult = await check.checker(app);
                    if (checkResult.checkPassed) {
                        this.set(1);
                    }
                    else {
                        this.set(0);
                    }
                },
            });
            new promClient.Gauge({
                name: `${check.name}_latency_msecs`,
                help: `How long the healthcheck for ${check.name} took`,
                async collect() {
                    const checkResult = await check.checker(app);
                    if (checkResult.checkPassed) {
                        this.set(checkResult.checkTimeInMsecs);
                    }
                    else {
                        this.set(checkResult.checkTimeInMsecs ?? 0);
                    }
                },
            });
        }
    }
    catch (err) {
        return done(err);
    }
    done();
}
export const healthcheckMetricsPlugin = fp(plugin, {
    fastify: '5.x',
    name: 'healthcheck-metrics-plugin',
});
//# sourceMappingURL=healthcheckMetricsPlugin.js.map