Add test functions and instructions to verify installation

**What**
- Add test publisher and receiver functions and instructions for how to
  use them to test the installations of the `nats-connector`. This
  should make the installation easier for users.

Resolves #4

Signed-off-by: Lucas Roesler <[email protected]>

README.md

@@ -15,24 +15,50 @@ make build push
 
 ## Try it out
 
+Test functions have been created to help you verify the installation of `nats-connector`.  See [`contrib/test-functions`](./contrib/test-functions).
+
 ### Deploy on Kubernetes
 
-The following instructions show how to run `kafka-connector` on Kubernetes.
+The following instructions show how to run and test `nats-connector` on Kubernetes.
 
-Deploy a function with a `topic` annotation:
+1. Deploy the receiver functions, the receiver function must have the `topic` annotation:
 
-```bash
-export OPENFAAS_URL="http://localhost:8080" # Set your gateway
+   ```bash
+   export OPENFAAS_URL="http://localhost:8080" # Set your gateway via env variable or the -g flag
+   faas-cli deploy --name receive-message --image openfaas/receive-message:latest --fprocess='./handler' --annotation topic="nats-test"
+   ```
 
-faas store deploy figlet --annotation topic="nats-test"
-```
+   Alternatively, you can deploy with the `stack.yml` provided in this repo
+   ```
+   cd contrib/test-functions
+   faas-cli deploy -f stack.yml
+   ```
 
-Deploy the connector with:
+2. Deploy the connector with:
 
-```bash
-kubectl apply -f ./yaml/kubernetes/connector-dep.yml
-```
+   ```bash
+   kubectl apply -f ./yaml/kubernetes/connector-dep.yml
+   ```
+
+3. Now publish a message on the `nats-test` topic.  We have provided a simple function to help do this
+
+   ```bash
+   faas-cli deploy --name publish-message --image openfaas/publish-message:latest --fprocess='./handler' --env nats_url=nats://nats.openfaas:4222
+   ```
+   If you used the `stack.yml` in step 1, then this function is already deployed.
+
+   Invoke the publisher
+   ```bash
+   faas-cli invoke publish-message <<< "test message"
+   ```
+
+4. Verify that the receiver was invoked by checking the logs
+
+   ```bash
+   faas-cli logs receive-message
 
-Now publish a message on the `nats-test` topic.
+   2019-12-29T19:06:50Z 2019/12/29 19:06:50 received "test message"
+   ```
 
-If you want to configure the topic, then edit ./yaml/kubernetes/connector-dep.yaml
+### Configuring the NATS topics
+If you want to configure the topics that the connector listens to, then edit the `topics` env variable in  [yaml/kubernetes/connector-dep.yaml](./yaml/kubernetes/connector-dep.yaml)

contrib/test-functions/publish-message/go.mod

@@ -0,0 +1,9 @@
+module publish-message
+
+go 1.13
+
+require (
+	github.com/nats-io/nats-server/v2 v2.1.2 // indirect
+	github.com/nats-io/nats.go v1.9.1
+	github.com/openfaas-incubator/go-function-sdk v0.0.0-20191017092257-70701da50a91
+)

contrib/test-functions/publish-message/go.sum

@@ -0,0 +1,27 @@
+github.com/golang/protobuf v1.3.2 h1:6nsPYzhq5kReh6QImI3k5qWzO4PEbvbIW2cwSfR/6xs=
+github.com/golang/protobuf v1.3.2/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
+github.com/nats-io/jwt v0.3.0 h1:xdnzwFETV++jNc4W1mw//qFyJGb2ABOombmZJQS4+Qo=
+github.com/nats-io/jwt v0.3.0/go.mod h1:fRYCDE99xlTsqUzISS1Bi75UBJ6ljOJQOAAu5VglpSg=
+github.com/nats-io/jwt v0.3.2 h1:+RB5hMpXUUA2dfxuhBTEkMOrYmM+gKIZYS1KjSostMI=
+github.com/nats-io/jwt v0.3.2/go.mod h1:/euKqTS1ZD+zzjYrY7pseZrTtWQSjujC7xjPc8wL6eU=
+github.com/nats-io/nats-server/v2 v2.1.2 h1:i2Ly0B+1+rzNZHHWtD4ZwKi+OU5l+uQo1iDHZ2PmiIc=
+github.com/nats-io/nats-server/v2 v2.1.2/go.mod h1:Afk+wRZqkMQs/p45uXdrVLuab3gwv3Z8C4HTBu8GD/k=
+github.com/nats-io/nats.go v1.9.1 h1:ik3HbLhZ0YABLto7iX80pZLPw/6dx3T+++MZJwLnMrQ=
+github.com/nats-io/nats.go v1.9.1/go.mod h1:ZjDU1L/7fJ09jvUSRVBR2e7+RnLiiIQyqyzEE/Zbp4w=
+github.com/nats-io/nkeys v0.1.0 h1:qMd4+pRHgdr1nAClu+2h/2a5F2TmKcCzjCDazVgRoX4=
+github.com/nats-io/nkeys v0.1.0/go.mod h1:xpnFELMwJABBLVhffcfd1MZx6VsNRFpEugbxziKVo7w=
+github.com/nats-io/nkeys v0.1.3 h1:6JrEfig+HzTH85yxzhSVbjHRJv9cn0p6n3IngIcM5/k=
+github.com/nats-io/nkeys v0.1.3/go.mod h1:xpnFELMwJABBLVhffcfd1MZx6VsNRFpEugbxziKVo7w=
+github.com/nats-io/nuid v1.0.1 h1:5iA8DT8V7q8WK2EScv2padNa/rTESc1KdnPw4TC2paw=
+github.com/nats-io/nuid v1.0.1/go.mod h1:19wcPz3Ph3q0Jbyiqsd0kePYG7A95tJPxeL+1OSON2c=
+github.com/openfaas-incubator/go-function-sdk v0.0.0-20191017092257-70701da50a91 h1:18SEXx3EzxO9wdrcO+EKePNM0JCquzyLjiPYbgIfX7w=
+github.com/openfaas-incubator/go-function-sdk v0.0.0-20191017092257-70701da50a91/go.mod h1:F37Kp+hwdHP+o3UKjkGzikQg4weKiMvcegT9vCQjvjE=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20190701094942-4def268fd1a4 h1:HuIa8hRrWRSrqYzx1qI49NNxhdi2PrY7gxVSq1JjLDc=
+golang.org/x/crypto v0.0.0-20190701094942-4def268fd1a4/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20190726091711-fc99dfbffb4e h1:D5TXcfTk7xF7hvieo4QErS3qqCB4teTffacDWr7CI+0=
+golang.org/x/sys v0.0.0-20190726091711-fc99dfbffb4e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

contrib/test-functions/publish-message/handler.go

@@ -0,0 +1,57 @@
+package function
+
+import (
+	"bytes"
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+
+	nats "github.com/nats-io/nats.go"
+	handler "github.com/openfaas-incubator/go-function-sdk"
+)
+
+var (
+	subject        = "nats-test"
+	defaultMessage = "Hello World"
+)
+
+// Handle a serverless request
+func Handle(req handler.Request) (handler.Response, error) {
+	msg := defaultMessage
+	if len(req.Body) > 0 {
+		msg = string(bytes.TrimSpace(req.Body))
+	}
+
+	natsURL := nats.DefaultURL
+	val, ok := os.LookupEnv("nats_url")
+	if ok {
+		natsURL = val
+	}
+
+	nc, err := nats.Connect(natsURL)
+	if err != nil {
+		r := handler.Response{
+			Body:       []byte(fmt.Sprintf("can not connect to nats: %s", err)),
+			StatusCode: http.StatusInternalServerError,
+		}
+		return r, err
+	}
+	defer nc.Close()
+
+	log.Printf("Sending %q to %q\n", msg, subject)
+	err = nc.Publish(subject, []byte(msg))
+	if err != nil {
+		log.Println(err)
+		r := handler.Response{
+			Body:       []byte(fmt.Sprintf("can not publish to nats: %s", err)),
+			StatusCode: http.StatusInternalServerError,
+		}
+		return r, err
+	}
+
+	return handler.Response{
+		Body:       []byte(fmt.Sprintf("Sent %q", msg)),
+		StatusCode: http.StatusOK,
+	}, nil
+}