Files
robot-shop/cart/server.js
2020-11-02 13:27:29 +01:00

408 lines
12 KiB
JavaScript

const instana = require('@instana/collector');
// init tracing
// MUST be done before loading anything else!
instana({
tracing: {
enabled: true
}
});
const redis = require('redis');
const request = require('request');
const bodyParser = require('body-parser');
const express = require('express');
const pino = require('pino');
const expPino = require('express-pino-logger');
// Prometheus
const promClient = require('prom-client');
const Registry = promClient.Registry;
const register = new Registry();
const counter = new promClient.Counter({
name: 'items_added',
help: 'running count of items added to cart',
registers: [register]
});
var redisConnected = false;
var redisHost = process.env.REDIS_HOST || 'redis'
var catalogueHost = process.env.CATALOGUE_HOST || 'catalogue'
const logger = pino({
level: 'info',
prettyPrint: false,
useLevelLabels: true
});
const expLogger = expPino({
logger: logger
});
const app = express();
app.use(expLogger);
app.use((req, res, next) => {
res.set('Timing-Allow-Origin', '*');
res.set('Access-Control-Allow-Origin', '*');
next();
});
app.use((req, res, next) => {
let dcs = [
"asia-northeast2",
"asia-south1",
"europe-west3",
"us-east1",
"us-west1"
];
let span = instana.currentSpan();
span.annotate('custom.sdk.tags.datacenter', dcs[Math.floor(Math.random() * dcs.length)]);
next();
});
app.use(bodyParser.urlencoded({ extended: true }));
app.use(bodyParser.json());
app.get('/health', (req, res) => {
var stat = {
app: 'OK',
redis: redisConnected
};
res.json(stat);
});
// Prometheus
app.get('/metrics', (req, res) => {
res.header('Content-Type', 'text/plain');
res.send(register.metrics());
});
// get cart with id
app.get('/cart/:id', (req, res) => {
redisClient.get(req.params.id, (err, data) => {
if(err) {
req.log.error('ERROR', err);
res.status(500).send(err);
} else {
if(data == null) {
res.status(404).send('cart not found');
} else {
res.set('Content-Type', 'application/json');
res.send(data);
}
}
});
});
// delete cart with id
app.delete('/cart/:id', (req, res) => {
redisClient.del(req.params.id, (err, data) => {
if(err) {
req.log.error('ERROR', err);
res.status(500).send(err);
} else {
if(data == 1) {
res.send('OK');
} else {
res.status(404).send('cart not found');
}
}
});
});
// rename cart i.e. at login
app.get('/rename/:from/:to', (req, res) => {
redisClient.get(req.params.from, (err, data) => {
if(err) {
req.log.error('ERROR', err);
res.status(500).send(err);
} else {
if(data == null) {
res.status(404).send('cart not found');
} else {
var cart = JSON.parse(data);
saveCart(req.params.to, cart).then((data) => {
res.json(cart);
}).catch((err) => {
req.log.error(err);
res.status(500).send(err);
});
}
}
});
});
// update/create cart
app.get('/add/:id/:sku/:qty', (req, res) => {
// check quantity
var qty = parseInt(req.params.qty);
if(isNaN(qty)) {
req.log.warn('quantity not a number');
res.status(400).send('quantity must be a number');
return;
} else if(qty < 1) {
req.log.warn('quantity less than one');
res.status(400).send('quantity has to be greater than zero');
return;
}
// look up product details
getProduct(req.params.sku).then((product) => {
req.log.info('got product', product);
if(!product) {
res.status(404).send('product not found');
return;
}
// is the product in stock?
if(product.instock == 0) {
res.status(404).send('out of stock');
return;
}
// does the cart already exist?
redisClient.get(req.params.id, (err, data) => {
if(err) {
req.log.error('ERROR', err);
res.status(500).send(err);
} else {
var cart;
if(data == null) {
// create new cart
cart = {
total: 0,
tax: 0,
items: []
};
} else {
cart = JSON.parse(data);
}
req.log.info('got cart', cart);
// add sku to cart
var item = {
qty: qty,
sku: req.params.sku,
name: product.name,
price: product.price,
subtotal: qty * product.price
};
var list = mergeList(cart.items, item, qty);
cart.items = list;
cart.total = calcTotal(cart.items);
// work out tax
cart.tax = calcTax(cart.total);
// save the new cart
saveCart(req.params.id, cart).then((data) => {
counter.inc(qty);
res.json(cart);
}).catch((err) => {
req.log.error(err);
res.status(500).send(err);
});
}
});
}).catch((err) => {
req.log.error(err);
res.status(500).send(err);
});
});
// update quantity - remove item when qty == 0
app.get('/update/:id/:sku/:qty', (req, res) => {
// check quantity
var qty = parseInt(req.params.qty);
if(isNaN(qty)) {
req.log.warn('quanity not a number');
res.status(400).send('quantity must be a number');
return;
} else if(qty < 0) {
req.log.warn('quantity less than zero');
res.status(400).send('negative quantity not allowed');
return;
}
// get the cart
redisClient.get(req.params.id, (err, data) => {
if(err) {
req.log.error('ERROR', err);
res.status(500).send(err);
} else {
if(data == null) {
res.status(404).send('cart not found');
} else {
var cart = JSON.parse(data);
var idx;
var len = cart.items.length;
for(idx = 0; idx < len; idx++) {
if(cart.items[idx].sku == req.params.sku) {
break;
}
}
if(idx == len) {
// not in list
res.status(404).send('not in cart');
} else {
if(qty == 0) {
cart.items.splice(idx, 1);
} else {
cart.items[idx].qty = qty;
cart.items[idx].subtotal = cart.items[idx].price * qty;
}
cart.total = calcTotal(cart.items);
// work out tax
cart.tax = calcTax(cart.total);
saveCart(req.params.id, cart).then((data) => {
res.json(cart);
}).catch((err) => {
req.log.error(err);
res.status(500).send(err);
});
}
}
}
});
});
// add shipping
app.post('/shipping/:id', (req, res) => {
var shipping = req.body;
if(shipping.distance === undefined || shipping.cost === undefined || shipping.location == undefined) {
req.log.warn('shipping data missing', shipping);
res.status(400).send('shipping data missing');
} else {
// get the cart
redisClient.get(req.params.id, (err, data) => {
if(err) {
req.log.error('ERROR', err);
res.status(500).send(err);
} else {
if(data == null) {
req.log.info('no cart for', req.params.id);
res.status(404).send('cart not found');
} else {
var cart = JSON.parse(data);
var item = {
qty: 1,
sku: 'SHIP',
name: 'shipping to ' + shipping.location,
price: shipping.cost,
subtotal: shipping.cost
};
// check shipping already in the cart
var idx;
var len = cart.items.length;
for(idx = 0; idx < len; idx++) {
if(cart.items[idx].sku == item.sku) {
break;
}
}
if(idx == len) {
// not already in cart
cart.items.push(item);
} else {
cart.items[idx] = item;
}
cart.total = calcTotal(cart.items);
// work out tax
cart.tax = calcTax(cart.total);
// save the updated cart
saveCart(req.params.id, cart).then((data) => {
res.json(cart);
}).catch((err) => {
req.log.error(err);
res.status(500).send(err);
});
}
}
});
}
});
function mergeList(list, product, qty) {
var inlist = false;
// loop through looking for sku
var idx;
var len = list.length;
for(idx = 0; idx < len; idx++) {
if(list[idx].sku == product.sku) {
inlist = true;
break;
}
}
if(inlist) {
list[idx].qty += qty;
list[idx].subtotal = list[idx].price * list[idx].qty;
} else {
list.push(product);
}
return list;
}
function calcTotal(list) {
var total = 0;
for(var idx = 0, len = list.length; idx < len; idx++) {
total += list[idx].subtotal;
}
return total;
}
function calcTax(total) {
// tax @ 20%
return (total - (total / 1.2));
}
function getProduct(sku) {
return new Promise((resolve, reject) => {
request('http://' + catalogueHost + ':8080/product/' + sku, (err, res, body) => {
if(err) {
reject(err);
} else if(res.statusCode != 200) {
resolve(null);
} else {
// return object - body is a string
// TODO - catch parse error
resolve(JSON.parse(body));
}
});
});
}
function saveCart(id, cart) {
logger.info('saving cart', cart);
return new Promise((resolve, reject) => {
redisClient.setex(id, 3600, JSON.stringify(cart), (err, data) => {
if(err) {
reject(err);
} else {
resolve(data);
}
});
});
}
// connect to Redis
var redisClient = redis.createClient({
host: redisHost
});
redisClient.on('error', (e) => {
logger.error('Redis ERROR', e);
});
redisClient.on('ready', (r) => {
logger.info('Redis READY', r);
redisConnected = true;
});
// fire it up!
const port = process.env.CART_SERVER_PORT || '8080';
app.listen(port, () => {
logger.info('Started on port', port);
});