mirror of https://github.com/knative/docs.git
121 lines
3.4 KiB
Markdown
121 lines
3.4 KiB
Markdown
# Cloud Events - Node.js
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A simple web app written in Node.js that can receive and send Cloud Events that you
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can use for testing. It supports running in two modes:
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1. The default mode has the app reply to your input events with the output
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event, which is simplest for demonstrating things working in isolation, but
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is also the model for working for the Knative Eventing `Broker` concept.
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2. `K_SINK` mode has the app send events to the destination encoded in
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`$K_SINK`, which is useful to demonstrate how folks can synthesize events to
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send to a Service or Broker when not initiated by a Broker invocation (e.g.
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implementing an event source)
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The application will use `$K_SINK`-mode whenever the environment variable is
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specified.
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Do the following steps to create the sample code and then deploy the app to your
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cluster. You can also download a working copy of the sample, by running the
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following commands:
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```bash
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git clone https://github.com/knative/docs.git knative-docs
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cd knative-docs/code-samples/serving/cloudevents/cloudevents-nodejs
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```
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## Before you begin
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- A Kubernetes cluster with Knative installed and DNS configured. See
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[Install Knative Serving](https://knative.dev/docs/install/serving/install-serving-with-yaml).
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- [Docker](https://www.docker.com) installed and running on your local machine,
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and a Docker Hub account configured (we'll use it for a container registry).
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## The Sample Code
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In the `index.js` file, you will see two key functions for the different modes
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of operation:
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```js
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const receiveAndSend = (cloudEvent, res) => {
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// This is called whenever an event is received if $K_SINK is set, and sends a new event
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// to the url in $K_SINK.
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}
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const receiveAndReply = (cloudEvent, res) => {
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// This is called whenever an event is received if $K_SINK is NOT set, and it replies with
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// the new event instead.
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}
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```
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## Build and Deploy the Application
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In the `Dockerfile`, you can see how the dependencies are installed using npm.
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You can build and push this to your registry of choice via:
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```bash
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# Build and push the container on your local machine.
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docker buildx build --platform linux/arm64,linux/amd64 -t "<image>" --push .
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```
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### yaml
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To deploy the Knative service, edit the `service.yaml` file and replace `<registry/repository/image:tag>` with the image you have just created.
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```bash
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kubectl apply -f service.yaml
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```
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### kn
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To deploy using the `kn` CLI:
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```bash
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kn service create cloudevents-nodejs --image=<image>
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```
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## Testing the sample
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Get the URL for your Service with:
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```bash
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$ kubectl get ksvc
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NAME URL LATESTCREATED LATESTREADY READY REASON
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cloudevents-nodejs http://cloudevents-nodejs.default.1.2.3.4.sslip.io cloudevents-nodejs-ss5pj cloudevents-nodejs-ss5pj True
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```
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Then send a cloud event to it with:
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```bash
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$ curl -X POST \
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-H "content-type: application/json" \
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-H "ce-specversion: 1.0" \
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-H "ce-source: curl-command" \
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-H "ce-type: curl.demo" \
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-H "ce-id: 123-abc" \
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-d '{"name":"Dave"}' \
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http://cloudevents-nodejs.default.1.2.3.4.sslip.io
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```
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You will get back:
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```bash
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{"message":"Hello, Dave"}
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```
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## Removing the sample app deployment
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To remove the sample app from your cluster, delete the service.
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### yaml
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```bash
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kubectl delete --filename service.yaml
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```
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### kn
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```bash
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kn service delete cloudevents-nodejs
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```
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