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Switch helloworld-go with kn (#2807) 

* Try helloworld-go with kn

* Add kn as a prereq.

* Incorporate Ashleigh's feedback

* Fix @abrennan89 feedback
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1
docs/serving/samples/hello-world/helloworld-go/Dockerfile
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# Use the official Golang image to create a build artifact.
# This is based on Debian and sets the GOPATH to /go.
# https://hub.docker.com/_/golang
FROM golang:1.13 as builder
# Create and change to the app directory.

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docs/serving/samples/hello-world/helloworld-go/README.md
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A simple web app written in Go 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`.
Follow the steps below to create the sample code and then deploy the app to your
cluster. You can also download a working copy of the sample, by running the
following commands:
```shell
git clone -b "{{< branch >}}" https://github.com/knative/docs knative-docs
cd knative-docs/docs/serving/samples/hello-world/helloworld-go
```
## Before you begin
- A Kubernetes cluster with Knative installed and DNS configured. Follow the
[installation instructions](../../../../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).
## Recreating the sample code
1. Create a new file named `helloworld.go` and paste the following code. This
code creates a basic web server which listens on port 8080:
```go
package main
import (
"fmt"
"log"
"net/http"
"os"
)
func handler(w http.ResponseWriter, r *http.Request) {
log.Print("helloworld: received a request")
target := os.Getenv("TARGET")
if target == "" {
target = "World"
}
fmt.Fprintf(w, "Hello %s!\n", target)
}
func main() {
log.Print("helloworld: starting server...")
http.HandleFunc("/", handler)
port := os.Getenv("PORT")
if port == "" {
port = "8080"
}
log.Printf("helloworld: listening on port %s", port)
log.Fatal(http.ListenAndServe(fmt.Sprintf(":%s", port), nil))
}
```
1. In your project directory, create a file named `Dockerfile` and copy the code
block below into it. For detailed instructions on dockerizing a Go app, see
[Deploying Go servers with Docker](https://blog.golang.org/docker).
```docker
# Use the official Golang image to create a build artifact.
# This is based on Debian and sets the GOPATH to /go.
# https://hub.docker.com/_/golang
FROM golang:1.13 as builder
# Create and change to the app directory.
WORKDIR /app
# Retrieve application dependencies using go modules.
# Allows container builds to reuse downloaded dependencies.
COPY go.* ./
RUN go mod download
# Copy local code to the container image.
COPY . ./
# Build the binary.
# -mod=readonly ensures immutable go.mod and go.sum in container builds.
RUN CGO_ENABLED=0 GOOS=linux go build -mod=readonly -v -o server
# Use the official Alpine image for a lean production container.
# https://hub.docker.com/_/alpine
# https://docs.docker.com/develop/develop-images/multistage-build/#use-multi-stage-builds
FROM alpine:3
RUN apk add --no-cache ca-certificates
# Copy the binary to the production image from the builder stage.
COPY --from=builder /app/server /server
# Run the web service on container startup.
CMD ["/server"]
```
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/v1
kind: Service
metadata:
name: helloworld-go
namespace: default
spec:
template:
spec:
containers:
- image: docker.io/{username}/helloworld-go
env:
- name: TARGET
value: "Go Sample v1"
```
1. Use the go tool to create a
[`go.mod`](https://github.com/golang/go/wiki/Modules#gomod) manifest.
```shell
go mod init github.com/knative/docs/docs/serving/samples/hello-world/helloworld-go
```
## 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-go .
# Push the container to docker registry
docker push {username}/helloworld-go
```
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. Run the following command to find the domain URL for your service:
```shell
kubectl get ksvc helloworld-go --output=custom-columns=NAME:.metadata.name,URL:.status.url
```
Example:
```shell
NAME URL
helloworld-go http://helloworld-go.default.1.2.3.4.xip.io
```
1. Now you can make a request to your app and see the result. Replace
the URL below with the URL returned in the previous command.
```shell
curl http://helloworld-go.default.1.2.3.4.xip.io
Hello Go Sample v1!
```
> Note: Add `-v` option to get more detail if the `curl` command failed.
## Removing the sample app deployment
To remove the sample app from your cluster, delete the service record:
```shell
kubectl delete --filename service.yaml
```

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docs/serving/samples/hello-world/helloworld-go/index.md
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@ -5,4 +5,231 @@ weight: 1
type: "docs"
---
{{% readfile file="README.md" %}}
This guide describes the steps required to to create the `helloworld-go` sample app
and deploy it to your cluster.
The sample app reads a `TARGET` environment variable, and prints `Hello ${TARGET}!`.
If `TARGET` is not specified, `World` is used as the default value.
## Prerequisites
You will need:
- A Kubernetes cluster with [Knative installed and DNS configured](../../../../install/README.md).
- [Docker](https://www.docker.com) installed and running on your local machine, and a Docker Hub account configured.
- Optional: You can use the Knative CLI client [`kn`](https://github.com/knative/client/releases) to simplify resource creation and deployment. Alternatively, you can use `kubectl` to apply resource files directly.
## Building
1. Create a basic web server which listens on port 8080, by copying the following code into a new file named `helloworld-go`:
```go
package main
import (
"fmt"
"log"
"net/http"
"os"
)
func handler(w http.ResponseWriter, r *http.Request) {
log.Print("helloworld: received a request")
target := os.Getenv("TARGET")
if target == "" {
target = "World"
}
fmt.Fprintf(w, "Hello %s!\n", target)
}
func main() {
log.Print("helloworld: starting server...")
http.HandleFunc("/", handler)
port := os.Getenv("PORT")
if port == "" {
port = "8080"
}
log.Printf("helloworld: listening on port %s", port)
log.Fatal(http.ListenAndServe(fmt.Sprintf(":%s", port), nil))
}
```
You can also download a working copy of the sample, by running the
following commands:
```shell
git clone -b "{{< branch >}}" https://github.com/knative/docs knative-docs
cd knative-docs/docs/serving/samples/hello-world/helloworld-go
```
1. Navigate to your project directory and copy the following code into a new file named `Dockerfile`:
```docker
# Use the official Golang image to create a build artifact.
# This is based on Debian and sets the GOPATH to /go.
FROM golang:1.13 as builder
# Create and change to the app directory.
WORKDIR /app
# Retrieve application dependencies using go modules.
# Allows container builds to reuse downloaded dependencies.
COPY go.* ./
RUN go mod download
# Copy local code to the container image.
COPY . ./
# Build the binary.
# -mod=readonly ensures immutable go.mod and go.sum in container builds.
RUN CGO_ENABLED=0 GOOS=linux go build -mod=readonly -v -o server
# Use the official Alpine image for a lean production container.
# https://hub.docker.com/_/alpine
# https://docs.docker.com/develop/develop-images/multistage-build/#use-multi-stage-builds
FROM alpine:3
RUN apk add --no-cache ca-certificates
# Copy the binary to the production image from the builder stage.
COPY --from=builder /app/server /server
# Run the web service on container startup.
CMD ["/server"]
```
1. Use the Go tool to create a
[`go.mod`](https://github.com/golang/go/wiki/Modules#gomod) manifest.
```shell
go mod init github.com/knative/docs/docs/serving/samples/hello-world/helloworld-go
```
## Deploying
1. To build the sample code into a container, and push using Docker Hub, enter the following commands and replace `{username}` with your Docker Hub username:
```shell
# Build the container on your local machine
docker build -t {username}/helloworld-go .
# Push the container to docker registry
docker push {username}/helloworld-go
```
1. After the build has completed and the container is pushed to docker hub, you
can deploy the app into your cluster. Choose one of the following methods:
{{< tabs name="helloworld_go" default="kn" >}}
{{% tab name="yaml" %}}
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/v1
kind: Service
metadata:
name: helloworld-go
namespace: default
spec:
template:
spec:
containers:
- image: docker.io/{username}/helloworld-go
env:
- name: TARGET
value: "Go Sample v1"
```
Check that the container image value in the `service.yaml` file matches the container you built in the previous step.
1. Apply the configuration using `kubectl`:
```shell
kubectl apply --filename service.yaml
```
After 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. Run the following command to find the domain URL for your service:
```shell
kubectl get ksvc helloworld-go --output=custom-columns=NAME:.metadata.name,URL:.status.url
```
Example:
```shell
NAME URL
helloworld-go http://helloworld-go.default.1.2.3.4.xip.io
```
{{< /tab >}}
{{% tab name="kn" %}}
Use `kn` to deploy the service:
```shell
kn service create helloworld-go --image=docker.io/{username}/helloworld-go --env TARGET="Go Sample v1"
```
You should see output like this:
```shell
Creating service 'helloworld-go' in namespace 'default':
0.031s The Configuration is still working to reflect the latest desired specification.
0.051s The Route is still working to reflect the latest desired specification.
0.076s Configuration "helloworld-go" is waiting for a Revision to become ready.
15.694s ...
15.738s Ingress has not yet been reconciled.
15.784s Waiting for Envoys to receive Endpoints data.
16.066s Waiting for load balancer to be ready
16.237s Ready to serve.
Service 'helloworld-go' created to latest revision 'helloworld-go-jjzgd-1' is available at URL:
http://helloworld-go.default.1.2.3.4.xip.io
```
You can then access your service through the resulting URL.
{{< /tab >}}
{{< /tabs >}}
## Verifying
1. Now you can make a request to your app and see the result. Replace
the URL below with the URL returned in the previous command.
```shell
curl http://helloworld-go.default.1.2.3.4.xip.io
Hello Go Sample v1!
```
> Note: Add `-v` option to get more detail if the `curl` command failed.
## Removing
To remove the sample app from your cluster, delete the service record:
{{< tabs name="service_url" default="kn" >}}
{{% tab name="kubectl" %}}
```shell
kubectl delete --filename service.yaml
```
{{< /tab >}}
{{% tab name="kn" %}}
```shell
kn service delete helloworld-go
```
{{< /tab >}}
{{< /tabs >}}

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docs/serving/samples/hello-world/helloworld-shell/index.md
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@ -25,9 +25,9 @@ cd knative-docs/docs/serving/samples/hello-world/helloworld-shell
[installation instructions](../../../../install/README.md).
- [Docker](https://www.docker.com) installed and running on your local machine,
and a Docker Hub account configured.
- (optional) The Knatice CLI client [kn](https://github.com/knative/client/releases) that simplifies the deployment. Alternative you can also use [kubectl](https://kubernetes.io/docs/tasks/tools/install-kubectl/) and apply resource files directly.
- Optional: You can use the Knative CLI client [`kn`](https://github.com/knative/client/releases) to simplify resource creation and deployment. Alternatively, you can use `kubectl` to apply resource files directly.
## Build
## Building
1. Create a new file named `script.sh` and paste the script below. This will run netcat (`nc`) in an endless loop, returning a friendly welcome message.