mirror of https://github.com/knative/docs.git
115 lines
3.6 KiB
Markdown
115 lines
3.6 KiB
Markdown
# Cloud Events - .NET Core
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A simple web app written in ASP.NET and C# 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 the 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-dotnet
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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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1. If you look in `controllers\CloudEventsController.cs`, you will see two key functions for the
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different modes of operation:
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```csharp
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private async Task<IActionResult> ReceiveAndSend(CloudEvent receivedEvent) {
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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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private IActionResult ReceiveAndReply(CloudEvent receivedEvent) {
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// This is called whenever an event is received if $K_SINK is NOT set, and it replies with
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// the new event instead.
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}
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```
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1. If you look in `Dockerfile`, you will see a method for pulling in the
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dependencies and building an ASP.NET container based on Alpine. You can build
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and push this to your registry of choice via:
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```bash
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# Build and push the container on your local machine.
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docker buildx build --platform linux/arm64,linux/amd64 -t "<image>" --push .
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```
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1. If you look in `service.yaml`, take the `<image>` name and insert it
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into the `image:` field.
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```bash
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kubectl apply -f service.yaml
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```
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## Testing the sample
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Get the URL for your Service with:
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```bash
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$ kubectl get ksvc
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NAME URL LATESTCREATED LATESTREADY READY REASON
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cloudevents-dotnet http://cloudevents-dotnet... cloudevents-dotnet-ss5pj cloudevents-dotnet-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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<service-URL>
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```
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Where `<service-URL>` is the URL from the `kubectl get ksvc` command.
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You will get back:
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```json
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{
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"specversion": "1.0",
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"type": "dev.knative.docs.sample",
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"source": "https://github.com/knative/docs/code-samples/serving/cloudevents/cloudevents-dotnet",
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"id": "d662b6f6-35ff-4b98-bffd-5ae9eee23dab",
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"time": "2020-05-19T01:26:23.3500138Z",
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"datacontenttype": "application/json",
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"data": {
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"message": "Hello, Dave"
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}
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}
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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 record:
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```bash
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kubectl delete --filename service.yaml
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```
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