# Hipster Shop: Cloud-Native Microservices Demo Application

This project contains a 10-tier microservices application. The application is a
web-based e-commerce app called **“Hipster Shop”** where users can browse items,
add them to the cart, and purchase them.

**Google uses this application to demonstrate Kubernetes, GKE, Istio,
Stackdriver, gRPC** and similar cloud-native technologies nowadays.

## Screenshots

| Home Page | Checkout Screen |
|-----------|-----------------|
| [![Screenshot of store homepage](./img/hipster-shop-frontend-1.png)](./img/hipster-shop-frontend-1.png) | [![Screenshot of checkout screen](./img/hipster-shop-frontend-2.png)](./img/hipster-shop-frontend-2.png) |

## Service Architecture

**Hipster Shop** is composed of many microservices written in different
languages that talk to each other over gRPC.

[![Architecture of
microservices](./img/architecture-diagram.png)](./img/architecture-diagram.png)

Find **Protocol Buffers Descriptions** at the [`./pb` directory](./pb).

| Service | Language | Description |
|---------|----------|-------------|
| [frontend](./src/frontend) | Go | Exposes an HTTP server to serve the website. Does not require signup/login and generates session IDs for all users automatically. |
| [cartservice](./src/cartservice) |  C# | Stores the items in the user's shipping cart in Redis and retrieves it. |
| [productcatalogservice](./src/productcatalogservice) | Go | Provides the list of products from a JSON file and ability to search products and get individual products. |
| [currencyservice](./src/currencyservice) | Node.js | Converts one money amount to another currency.  Uses real values fetched from European Central Bank. It's the highest QPS service. |
| [paymentservice](./src/paymentservice) | Node.js | Charges the given credit card info (hypothetically😇) with the given amount and returns a transaction ID. |
| [shippingservice](./src/shippingservice) | Go | Gives shipping cost estimates based on the shopping cart. Ships items to the given address (hypothetically😇) |
| [emailservice](./src/emailservice) | Python | Sends users an order confirmation email (hypothetically😇). |
| [checkoutservice](./src/checkoutservice) | Go | Retrieves user cart, prepares order and orchestrates the payment, shipping and the email notification. |
| [recommendationservice](./src/recommendationservice) | Python | Recommends other products based on what's given in the cart. |
| [loadgenerator](./src/loadgenerator) | Python/Locust | Continuously sends requests imitating realistic user shopping flows to the frontend. |


## Features

- **[Kubernetes](https://kubernetes.io)/[GKE](https://cloud.google.com/kubernetes-engine/):**
  The app is designed to run on Kubernetes (both locally on "Docker for
  Desktop", as well as on the cloud with GKE).
- **[gRPC](https://grpc.io):** Microservices use a high volume of gRPC calls to
  communicate to each other.
- **[Istio](https://istio.io):** Application works on Istio service mesh.
- **[OpenCensus](https://opencensus.io/) Tracing:** Most services are
  instrumented using OpenCensus trace interceptors for gRPC/HTTP.
- **[Stackdriver APM](https://cloud.google.com/stackdriver/):** Many services
  are instrumented with **Profiling**, **Tracing** and **Debugging**. In
  addition to these, using Istio enables features like Request/Response
  **Metrics** and **Context Graph** out of the box. When it is running out of
  Google Cloud, this code path remains inactive.
- **[Skaffold](https://github.com/GoogleContainerTools/skaffold):** Application
  is deployed to Kubernetes with a single command using Skaffold.
- **Synthetic Load Generation:** The application demo comes with a background
  job that creates realistic usage patterns on the website using
  [Locust](https://locust.io/) load generator.

## Installation

> **Note:** that the first build can take up to 20-30 minutes. Consequent builds
> will be faster.

### Option 1: Running locally with “Docker for Desktop”

> 💡 Recommended if you're planning to develop the application.

1. Install tools to run a Kubernetes cluster locally:

   - kubectl (can be installed via `gcloud components install kubectl`)
   - Docker for Desktop (Mac/Windows): It provides Kubernetes support as [noted
     here](https://docs.docker.com/docker-for-mac/kubernetes/).
   - [skaffold](https://github.com/GoogleContainerTools/skaffold/#installation)

1. Launch “Docker for Desktop”. Go to Preferences and choose “Enable Kubernetes”.

1. Run `kubectl get nodes` to verify you're connected to “Kubernetes on Docker”.

1. Run `skaffold run` (first time will be slow, it can take ~20-30 minutes).
   This will build and deploy the application. If you need to rebuild the images
   automatically as you refactor he code, run `skaffold dev` command.

1. Run `kubectl get pods` to verify the Pods are ready and running. The
   application frontend should be available at http://localhost:80 on your
   machine.

### Option 2: Running on Google Kubernetes Engine (GKE)

> 💡  Recommended for demos and making it available publicly.

1. Install tools specified in the previous section (Docker, kubectl, skaffold)

1. Create a Google Kubernetes Engine cluster and make sure `kubectl` is pointing
   to the cluster.

1. Enable Google Container Registry (GCR) on your GCP project:

       gcloud services enable containerregistry.googleapis.com

1. Configure docker to authenticate to GCR:

       gcloud auth configure-docker -q

1. Edit `skaffold.yaml`, prepend your GCR registry host (`gcr.io/YOUR_PROJECT/`)
   to all `imageName:` fields (or update the existing project name).

1. Edit the Deployment manifests at `kubernetes-manifests` directory and update
   the `image` fields to match the changes you made in the previous step.

1. Run `skaffold run`. This builds the container
   images, pushes them to GCR, and deploys the application to Kubernetes.

1.  Find the IP address of your application then visit the application on your
    browser to confirm installation.

        kubectl get service frontend-external

### (Optional) Deploying on a Istio-installed cluster

> If you followed steps above, run `skaffold delete` to delete what's deployed.

1. Create a GKE cluster.

2. Install Istio **without mutual TLS** option. (Istio mTLS is not yet supported
   on this demo.)

3. Install the automatic sidecar injection (annotate the `default` namespace
   with the label):

       kubectl label namespace default istio-injection=enabled

4. Deploy the application with `skaffold run`.

5. Apply the manifests in [`./istio-manifests`](./istio-manifests) directory.

       kubectl apply -f ./istio-manifests

    This is required only once.

6. Run `kubectl get pods` to see pods are in a healthy and ready state.

1. Find the IP address of your istio gateway Ingress or Service, and visit the
   application.

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This is not an official Google project.