@betsys-nestjs/health-check v4.0.0

Health Check Library

Library for implementation of standardized health endpoint in NestJS applications.

Dependencies

Usage

Import HealthCheckModule to your health module with using .forRoot function and register all your health indicators:

@Module({
    imports: [
        HealthCheckModule.forRoot({
            imports: [
                PostgresqlModule.forFeature(connectionPostgresFeatureConfig()),
                MongoModule.forFeature(connectionMongoFeatureConfig()),
                RedisModule.forFeature(connectionRedisFeatureConfig()),
                ElasticModule.forFeature(connectionElasticFeatureConfig()),
            ],
            indicators: [
                {
                    factory: (connection: PostgresConnection) => new PostgresqlHealthIndicator(connection, 'postgres'),
                    inject: [getPostgresConnectionToken()],
                },
                {
                    factory: (connection: MongoConnection) => new MongoHealthIndicator(connection, 'mongo'),
                    inject: [getMongoConnectionToken()],
                },
                {
                    factory: (connection: ElasticConnection) => new ElasticHealthIndicator(connection, 'elastic'),
                    inject: [getElasticConnectionToken()],
                },
                {
                    factory: (client: RedisClient) => new RedisHealthIndicator(client, 'redis'),
                    inject: [getRedisClientToken()],
                    probeType: ProbeTypes.Liveness,
                },
            ],
            kubernetesProbesStyle: true,
        }),
    ],
})
export class HealthModule {
}

• probeType - type of health indicator probe. Default is Readiness.
• kubernetesProbesStyle - if true, health check will be registered as Kubernetes probes endpoints and divided by their probeType (/health/readiness, /health/liveness, and /health/startup). If false, single health check endpoint will be registered (/health) containing all indicators of Readiness type.

Creating your own indicator

To create custom health indicator, you need to create a new class that extends from HealthIndicator and implement getHealth method.

import { Injectable } from '@nestjs/common';
import { HealthCheckError, HealthIndicator, HealthIndicatorResult } from '@betsys/nestjs-health-check';

@Injectable()
export class SimpleHealthIndicator extends HealthIndicator {
    constructor(
        private readonly someThirdPartyOperation: SomeThirdPartyOperation,
        private readonly key: string,
    ) {
        super();
    }

    async isHealthy(): Promise<HealthIndicatorResult> {
        let isHealthy = false;

        try {
            const result = await this.someThirdPartyOperation.execute();

            isHealthy = result.isValid();
        } catch (error) {
            const typesError = error as Error;
            const status = this.getStatus(this.key, false, { error: typesError.message || error });

            throw new HealthCheckError(typesError.message || 'Unknown error', status);
        }
        if (!isHealthy) {
            const status = this.getStatus(this.key, false);
            throw new HealthCheckError('Simple service check failed!', status);
        }

        return this.getStatus(this.key, true);
    }
}