Update the blog to address review comments

Signed-off-by: Vivek Singh <[email protected]>

Author: viveksyngh

_posts/2020-07-08-event-driven-functions-with-openfaas-and-nats.md

@@ -12,7 +12,7 @@ dark_background: true
 ---
 
 In this blog post, I will show how you can invoke OpenFaaS function in response to messages sent on NATS topics in publish-subscribe model.
-OpenFaaS functions are accessible over HTTP endpoints via gateway service but OpenFaaS provides several other way to invoke OpenFaaS functions with help of [connector-sdk](https://github.com/openfaas-incubator/connector-sdk). 
+OpenFaaS functions are accessible over HTTP endpoints via gateway service but OpenFaaS provides several other way to invoke OpenFaaS functions with help of the [connector-sdk](https://github.com/openfaas-incubator/connector-sdk).The connector sdk provides a reusable and tested interface and implementation that allows developers to quickly create a new event source. The code that is unique to OpenFaaS is standardized so that the develop can focus on the details of the receiving message from the event source.
 
 * [kafka-connector](https://github.com/openfaas-incubator/kafka-connector) connects OpenFaaS functions to Kafka topics.
 * [nats-connector](https://github.com/openfaas-incubator/nats-connector) an OpenFaaS event-connector to trigger functions from NATS. 
@@ -24,17 +24,14 @@ There are several other connectors which allows you to trigger OpenFaaS function
 
 ## NATS
 
-[NATS](https://nats.io) is a simple, secure and high performance open source messaging system for cloud native applications, IoT messaging, and microservices architectures. In this blog post, I will be using NATS publish-subscribe concept where publishers publishes a message on a topic/subject and subscribers consumes that message by subscribing to that topic/subject.
+[NATS](https://nats.io) is a simple, secure and high performance open source messaging system for cloud native applications, IoT messaging, and microservices architectures. In this blog post, I will be using NATS publish-subscribe concept where publishers publishes a message on a topic/subject and subscribers consumes that message by subscribing to that subject (sometimes called topics in other event systems).
 
 ![NATS Publish Subscribe](/images/2020-openfaas-nats/nats-publish-subscribe.png "https://docs.nats.io/nats-concepts/pubsub")
 
 ## Pre-requisite Installation
 
 * [k3d](https://github.com/rancher/k3d) to create a [k3s](https://github.com/rancher/k3s) cluster. k3s is lightweight distribution of kubernetes from Rancher Labs.
-* `kubectl` to manage kubernetes cluster.
-* `helm` to install `nats-connector` using helm chart
-* [arkade](https://github.com/alexellis/arkade) to install OpenFaaS. `arkade` is simple CLI tool to install helm charts and apps to your cluster in one command.
-* [faas-cli](https://github.com/openfaas/faas-cli) CLI tool to manage OpenFaaS functions.
+* [arkade](https://github.com/alexellis/arkade) to install OpenFaaS, nats-connector, kubectl and faas-cl. `arkade` is simple CLI tool to install helm charts and apps to your cluster in one command.
 
 > Please make sure you have these tools installed before you proceed next.
 
@@ -57,19 +54,26 @@ Install OpenFaaS using `arkade`
 arkade install openfaas --set basic_auth=true --set functionNamespace=openfaas-fn
 ```
 
-Follow instructions printed to obtain the gateway password and login with `faas-cli`
-
-#### Install NATS connector using helm chart
+#### Install NATS connector using arkade
 `nats-connector` is connector which invokes OpenFaaS function when a message is sent to a NATS topic.
 
 ```
-helm repo add nats-connector  https://openfaas.github.io/faas-netes
+arkade install nats-connector 
+```
+
+> NATS comes with OpenFaaS installation, so we are not setting up NATS here
+
+#### Install kubectl and faas-cli
 
-helm install nats-connector openfaas/nats-connector --namespace=openfaas
+install `kubectl` and `faas-cli` using `arkade` if they are not already installed.   
 
+```
+arkade get kubectl
 ```
 
-> NATS comes with OpenFaaS installation, so we are not setting up NATS here
+```
+arkade get faas-cli
+```
 
 #### Login to OpenFaaS gateway using CLI
 
@@ -102,29 +106,30 @@ echo -n $PASSWORD | faas-cli login --username admin --password-stdin
 Deploy `receive-message` function
 
 ```
-faas-cli deploy --name receive-message --image openfaas/receive-message:latest --fprocess='./handler' --annotation topic="nats-test"
+faas-cli deploy --name receive-message --image openfaas/receive-message:latest \
+        --fprocess='./handler' --annotation topic="nats-test"
 ```
 
 Deploy `publish-message` function
 ```
-faas-cli deploy --name publish-message  --image openfaas/publish-message:latest  --fprocess='./handler' --env nats_url=nats://nats.openfaas:4222
+faas-cli deploy --name publish-message  --image openfaas/publish-message:latest  \
+         --fprocess='./handler' --env nats_url=nats://nats.openfaas:4222
 ```
 
 > Note: You can also build and deploy this function using the stack.yml and code present in nats-connector repository. But for simplicity, I am using pre built and published images of  these functions.
 
+## Verify the installation
 Invoke `publish-message` function to publish a test message
 
 ```
-faas-cli invoke publish-message <<< "test message"
+echo  "test message" | faas-cli invoke publish-message
 ```
 
 When `publish-message` was invoked, it would have pushed `test-message` to the `nats-test` topic on NATS, which would have invoked `receive-message`. We can verify that by checking logs of `receive-message` function.
 
 ```
 faas-cli logs receive-message
 
-ARNING! Communication is not secure, please consider using HTTPS. Letsencrypt.org offers free SSL/TLS certificates.
-Handling connection for 8080
 2020-05-29T15:41:17Z 2020/05/29 15:41:17 Started logging stderr from function.
 2020-05-29T15:41:17Z 2020/05/29 15:41:17 Started logging stdout from function.
 2020-05-29T15:41:17Z Forking - ./handler []
@@ -137,10 +142,11 @@ Handling connection for 8080
 2020-05-29T15:42:24Z 2020/05/29 15:42:24 POST / - 200 OK - ContentLength: 28
 ```
 
-### What Next ?
+## What Next ?
+* Do you have a cool "event driven" use case you want to share? Let us know and become a guest blogger!
 
-If you are new to OpenFaaS, I would recommend you trying [OpenFaaS workshop](https://github.com/openfaas/workshop) .
+* If you are new to OpenFaaS, I would recommend you trying [OpenFaaS workshop](https://github.com/openfaas/workshop) .
 
-If you don't find connector for messaging platform you are using, checkout the [connector-sdk](https://github.com/openfaas-incubator/connector-sdk) which allows you to build event-connectors for OpenFaaS.
+* If you don't find connector for messaging platform you are using, checkout the [connector-sdk](https://github.com/openfaas-incubator/connector-sdk) which allows you to build event-connectors for OpenFaaS.
 
-If you are looking to contribute to open source project, please join OpenFaaS community [slack channel](https://docs.openfaas.com/community/) and start contributing.
+* If you are looking to contribute to open source project, please join OpenFaaS community [slack channel](https://docs.openfaas.com/community/) and start contributing.