AWS CLI, Serverless Framework and Terraform
Install AWS CLI according to your operating system using this link.
If you don’t have an IAM user follow step A, otherwise if you need to create only access keys for an existing user follow step B.
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Sign in to the AWS Management Console and open the IAM console.
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In the navigation pane, choose Users and then choose Add user.
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Type the user name for the new user, select Programmatic access and AWS Management Console access
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For Console password, choose Autogenerated password. You can view or download the passwords when you get to the Final page.
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Select Require password reset.
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Click Next: Require password reset.
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Select Attach existing policies directly, choose AdministratorAccess,
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Click Next: Tags, Next: Review and Create User.
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To view the users' access keys (access key IDs and secret access keys), choose Show next to each password and access key that you want to see. To save the access keys, choose Download .csv and then save the file to a safe location.
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Sign in to the AWS Management Console and open the IAM console.
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In the navigation pane, choose Users and then choose the existing user you want to create the access keys.
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Under the Security credentials pane, in the section Access keys click Create access key
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Type the user name for the new user, select Programmatic access and AWS Management Console access
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To view the users' access keys (access key IDs and secret access keys), choose Show next to Secret access key. To save the access key, choose Download .csv and then save the file to a safe location.
After installing AWS CLI and getting your access keys run this command to quickly set your AWS credentials, region and output format (default:json)
$ aws configure
Serverless is a Node.js CLI tool so the first thing you need to do is to install Node.js on your machine.
Go to the official Node.js website, download and follow the installation instructions to install Node.js on your local machine.
Note: Serverless runs on Node v6 or higher.
You can verify that Node.js is installed successfully by running node --version in your terminal. You should see the corresponding Node version number printed out.
Next, install the Serverless Framework via npm which was already installed when you installed Node.js.
Open up a terminal and type npm install -g serverless to install Serverless.
$ npm install -g serverless
Once the installation process is done you can verify that Serverless is installed successfully by running the following command in your terminal:
$ serverless
To see which version of serverless you have installed run:
$ serverless --version
$ brew install terraform
The messaging-infrastructure directory contains the necessary Terraform files for provisioning the topics and the Queues.
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To have publishers and consumers fully decoupled from each other, ideally the publisher should know only about the topic (not the queues), and the consumers should know only about the queues (not the topic). Therefore, creating the topic and queues should not be responsibility of publishers and consumers. In that case, topic and queues will be created beforehand using Terraform. |
The messaging-infrastructure directory is divided into folders of resource owners. In this example, Order Service is responsible for publishing messages to orderCreated topic, therefore, the creation of this topic is in a Terraform file inside order folder.
The same applies for the stockConsumerForOrderCreated queue. Stock Service is responsible for consuming messages from stockConsumerForOrderCreated queue, therefore, the creation of this queue is in a Terraform file inside stock folder.
Inside /messaging-infrastructure/order/topics/ run the following commands to create a Terraform Workspace and a new topic orderCreated
$ terraform init $ terraform workspace new qa-order-topics $ terraform apply
Inside /messaging-infrastructure/stock/order-consumers/ run the following commands to create a Terraform Workspace and a new queue stockConsumerForOrderCreated
$ terraform init $ terraform workspace new qa-stock-order-consumers $ terraform apply
Fill the stock with itens to approve the order
$ curl --location --request PUT 'http://localhost:8081/stock' \
--header 'Content-Type: application/json' \
--data-raw '{
"sku": "123_aspirin",
"amount": "100",
"branchId": "1212"
}'
$ curl --location --request PUT 'http://localhost:8081/stock' \
--header 'Content-Type: application/json' \
--data-raw '{
"sku": "456_ibuprofen",
"amount": "200",
"branchId": "1212"
}'
Create and order
$ curl --location --request POST 'http://localhost:8080/orders' \
--header 'Content-Type: application/json' \
--data-raw '{
"orderId": "3333",
"customerId": "11111",
"walletId": "101010",
"orderItems":[
{
"sku": "123_aspirin",
"amount": "10",
"branchId": "1212",
"cost": "100"
},{
"sku": "456_ibuprofen",
"amount": "10",
"branchId": "1212",
"cost": "50"
}
]
}'
Check the CloudWatch log events of the lambda functions to see the printed order.
Check that the stock of ibuprofen is 190, since the order reserved 10 itens (it is possible to see in the logs of stock service that the order was processed and the stock was updated):
$ curl --location --request GET 'http://localhost:8081/stock/456_ibuprofen'
Edit the Class OrderCreatedConsumer int the Stock Service and add:
throw new Exception("Problem consuming the message");
Create and order
$ curl --location --request POST 'http://localhost:8080/orders' \
--header 'Content-Type: application/json' \
--data-raw '{
"orderId": "4444",
"customerId": "11111",
"walletId": "101010",
"orderItems":[
{
"sku": "123_aspirin",
"amount": "10",
"branchId": "1212",
"cost": "100"
},{
"sku": "456_ibuprofen",
"amount": "10",
"branchId": "1212",
"cost": "50"
}
]
}'
AWS SNS wont be able to deliver the message to its consumer since the service is not running. Therefore, after the configured retries, the message will be delivered to its deadletter queue (it is possible to check the message in the AWS console in stockConsumerForOrderCreated_DLQ)
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