A NodeJS implementation of a gRPC client logging interceptor

TracingClientInterceptor.js

'use strict';

const bunyan = require('bunyan');
const grpc = require('grpc');

const log = bunyan.createLogger({name: 'TracingClientInterceptor'});

module.exports = function(options, nextCall) {
    return new grpc.InterceptingCall(nextCall(options), {
        start: function(metadata, listener, next) {
            log.trace('Sending metadata', metadata);
            next(metadata, {
                onReceiveMetadata: function(metadata, next) {
                    log.trace('Receiving metadata', metadata);
                    next(metadata);
                },
                onReceiveMessage: function(message, next) {
                    log.trace('Receiving message', message);
                    next(message);
                },
                onReceiveStatus: function(status, next) {
                    log.trace('Receiving status', status);
                    next(status);
                },
            });
        },
        sendMessage: function(message, next) {
            log.trace('Sending message', message);
            next(message);
        },
        halfClose: function(next) {
            log.trace('Sending close');
            next();
        },
        cancel: function(message, next) {
            log.trace('Sending cancel', message);
            next();
        },
    });
};