logging.js

const axios = require('axios');

module.exports = (serviceName, context) => {
    return async (tracingObj) => {
        // Tracing
        const { api, tracer } = tracingObj;

        const toLokiServer = async (details) => {
            const { message, level, job, endpointLabel, endpoint, namespace } = details;
            let error = false;
            let stream = {
                service_name: serviceName,
                level,
                job,
                namespace,
            };
            if (endpoint) {
                stream[endpointLabel] = endpoint;
            }

            try {
                await axios.post(process.env.LOGS_TARGET, {
                    streams: [
                        {
                            stream,
                            'values': [
                                [ `${Date.now() * 1000000}`, message ]
                            ]
                        }
                    ]
                });
            } catch (err) {
                console.log(`Logging error: ${err}`);
                error = true;
            }

            return error;
        };

        // Logging system sends to Loki
        const logEntry = async (details) => {
            let logSpan;
            let error = false;
            if (context === 'requester') {
                // Create a new span
                logSpan = tracer.startSpan("log_to_loki");
            }

            if (process.env.LOGS_TARGET) {
                error = await toLokiServer(details);
            } else {
                console.log(details.message);
            }

            if (context === 'requester') {
                // Set the status code as OK and end the span
                logSpan.setStatus({ code: (!error) ? api.SpanStatusCode.OK : api.SpanStatusCode.ERROR });
                logSpan.end();
            }
        };

        return logEntry;
    };
}