mirror of https://github.com/knative/docs.git
212 lines
6.5 KiB
Markdown
212 lines
6.5 KiB
Markdown
# Hello World - Node.js sample
|
|
|
|
A simple web app written in Node.js that you can use for testing. It reads in an
|
|
env variable `TARGET` and prints "Hello \${TARGET}!". If TARGET is not
|
|
specified, it will use "World" as the TARGET.
|
|
|
|
## Prerequisites
|
|
|
|
- A Kubernetes cluster with Knative installed. Follow the
|
|
[installation instructions](https://github.com/knative/docs/blob/master/install/README.md)
|
|
if you need to create one.
|
|
- [Docker](https://www.docker.com) installed and running on your local machine,
|
|
and a Docker Hub account configured (we'll use it for a container registry).
|
|
- [Node.js](https://nodejs.org/en/) installed and configured.
|
|
|
|
## Recreating the sample code
|
|
|
|
While you can clone all of the code from this directory, hello world apps are
|
|
generally more useful if you build them step-by-step. The following instructions
|
|
recreate the source files from this folder.
|
|
|
|
1. Create a new directory and initalize `npm`. You can accept the defaults, but
|
|
change the entry point to `app.js` to be consistent with the sample code
|
|
here.
|
|
|
|
```shell
|
|
npm init
|
|
|
|
package name: (helloworld-nodejs)
|
|
version: (1.0.0)
|
|
description:
|
|
entry point: (index.js) app.js
|
|
test command:
|
|
git repository:
|
|
keywords:
|
|
author:
|
|
license: (ISC) Apache-2.0
|
|
```
|
|
|
|
1. Install the `express` package:
|
|
|
|
```shell
|
|
npm install express --save
|
|
```
|
|
|
|
1. Create a new file named `app.js` and paste the following code:
|
|
|
|
```js
|
|
const express = require("express");
|
|
const app = express();
|
|
|
|
app.get("/", function(req, res) {
|
|
console.log("Hello world received a request.");
|
|
|
|
const target = process.env.TARGET || "World";
|
|
res.send("Hello " + target + "!");
|
|
});
|
|
|
|
const port = process.env.PORT || 8080;
|
|
app.listen(port, function() {
|
|
console.log("Hello world listening on port", port);
|
|
});
|
|
```
|
|
|
|
1. Modify the `package.json` file to add a start command to the scripts section:
|
|
|
|
```json
|
|
{
|
|
"name": "knative-serving-helloworld",
|
|
"version": "1.0.0",
|
|
"description": "",
|
|
"main": "app.js",
|
|
"scripts": {
|
|
"start": "node app.js"
|
|
},
|
|
"author": "",
|
|
"license": "Apache-2.0"
|
|
}
|
|
```
|
|
|
|
1. In your project directory, create a file named `Dockerfile` and copy the code
|
|
block below into it. For detailed instructions on dockerizing a Node.js app,
|
|
see
|
|
[Dockerizing a Node.js web app](https://nodejs.org/en/docs/guides/nodejs-docker-webapp/).
|
|
|
|
```Dockerfile
|
|
# Use the official Node.js 10 image.
|
|
# https://hub.docker.com/_/node
|
|
FROM node:10
|
|
|
|
# Create and change to the app directory.
|
|
WORKDIR /usr/src/app
|
|
|
|
# Copy application dependency manifests to the container image.
|
|
# A wildcard is used to ensure both package.json AND package-lock.json are copied.
|
|
# Copying this separately prevents re-running npm install on every code change.
|
|
COPY package*.json ./
|
|
|
|
# Install production dependencies.
|
|
RUN npm install --only=production
|
|
|
|
# Copy local code to the container image.
|
|
COPY . .
|
|
|
|
# Configure and document the service HTTP port.
|
|
ENV PORT 8080
|
|
EXPOSE $PORT
|
|
|
|
# Run the web service on container startup.
|
|
CMD [ "npm", "start" ]
|
|
```
|
|
|
|
1. Create a new file, `service.yaml` and copy the following service definition
|
|
into the file. Make sure to replace `{username}` with your Docker Hub
|
|
username.
|
|
|
|
```yaml
|
|
apiVersion: serving.knative.dev/v1alpha1
|
|
kind: Service
|
|
metadata:
|
|
name: helloworld-nodejs
|
|
namespace: default
|
|
spec:
|
|
runLatest:
|
|
configuration:
|
|
revisionTemplate:
|
|
spec:
|
|
container:
|
|
image: docker.io/{username}/helloworld-nodejs
|
|
env:
|
|
- name: TARGET
|
|
value: "Node.js Sample v1"
|
|
```
|
|
|
|
## Building and deploying the sample
|
|
|
|
Once you have recreated the sample code files (or used the files in the sample
|
|
folder) you're ready to build and deploy the sample app.
|
|
|
|
1. Use Docker to build the sample code into a container. To build and push with
|
|
Docker Hub, run these commands replacing `{username}` with your Docker Hub
|
|
username:
|
|
|
|
```shell
|
|
# Build the container on your local machine
|
|
docker build -t {username}/helloworld-nodejs .
|
|
|
|
# Push the container to docker registry
|
|
docker push {username}/helloworld-nodejs
|
|
```
|
|
|
|
1. After the build has completed and the container is pushed to docker hub, you
|
|
can deploy the app into your cluster. Ensure that the container image value
|
|
in `service.yaml` matches the container you built in the previous step. Apply
|
|
the configuration using `kubectl`:
|
|
|
|
```shell
|
|
kubectl apply --filename service.yaml
|
|
```
|
|
|
|
1. Now that your service is created, Knative will perform the following steps:
|
|
|
|
- Create a new immutable revision for this version of the app.
|
|
- Network programming to create a route, ingress, service, and load balance
|
|
for your app.
|
|
- Automatically scale your pods up and down (including to zero active pods).
|
|
|
|
1. To find the IP address for your service, use these commands to get the
|
|
ingress IP for your cluster. If your cluster is new, it may take sometime for
|
|
the service to get asssigned an external IP address.
|
|
|
|
```shell
|
|
# In Knative 0.2.x and prior versions, the `knative-ingressgateway` service was used instead of `istio-ingressgateway`.
|
|
INGRESSGATEWAY=knative-ingressgateway
|
|
|
|
# The use of `knative-ingressgateway` is deprecated in Knative v0.3.x.
|
|
# Use `istio-ingressgateway` instead, since `knative-ingressgateway`
|
|
# will be removed in Knative v0.4.
|
|
if kubectl get configmap config-istio -n knative-serving &> /dev/null; then
|
|
INGRESSGATEWAY=istio-ingressgateway
|
|
fi
|
|
|
|
kubectl get svc $INGRESSGATEWAY --namespace istio-system
|
|
|
|
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
|
|
xxxxxxx-ingressgateway LoadBalancer 10.23.247.74 35.203.155.229 80:32380/TCP,443:32390/TCP,32400:32400/TCP 2d
|
|
```
|
|
|
|
1. To find the URL for your service, use
|
|
|
|
```
|
|
kubectl get ksvc helloworld-nodejs --output=custom-columns=NAME:.metadata.name,DOMAIN:.status.domain
|
|
NAME DOMAIN
|
|
helloworld-nodejs helloworld-nodejs.default.example.com
|
|
```
|
|
|
|
1. Now you can make a request to your app to see the result. Replace
|
|
`{IP_ADDRESS}` with the address you see returned in the previous step.
|
|
|
|
```shell
|
|
curl -H "Host: helloworld-nodejs.default.example.com" http://{IP_ADDRESS}
|
|
Hello Node.js Sample v1!
|
|
```
|
|
|
|
## Removing the sample app deployment
|
|
|
|
To remove the sample app from your cluster, delete the service record:
|
|
|
|
```shell
|
|
kubectl delete --filename service.yaml
|
|
```
|