Ballerina Programming Language

V 0.991

Ballerina is an open source programming language and platform for cloud-era application programmers to easily write software that just works.

Prerequisites

• JDK 8 or OpenJDK 8

• Node (v8.9.x) + npm (v5.6.0 or later)

• Docker

• Kubernetes

• Ballerina

• VSC or IntelliJ (see) Ballerina plugin

See more

• Examples
• Ballerina central
• Publishing config

Todo

Validation tests (TDD: warriors & apigw)

When deploy the services on the cluster, verify that the following calls work:

• should succeed only inside the cluster

curl GET http://wiarriors-service/api/v1/warriors

• Outside the cluster with a valid apikey should succeed

curl GET http://techwatch.io/api/v1/apigw/warriors -H "apikey: Z2FtZTpnYW1lMQ==" 

• Outside the cluster with a invalid apikey should fail

curl GET http://techwatch.io/api/apigw/v1/warriors -H "apikey: G02TheBeach==" 

[Step 0] Init project

# use ballerina init command inside the work directory   
ballerina init

[Step 1] Warriors service

• Add the service as a ballerina module New -> Module

• Create the service class New -> New Ballerina File,

• Code the config and logic the service

[Step 2] API Gateway

Add the API Gateway service as a ballerina module, create the service class and code the config and logic of the API Gateway

[Step 3] Add Kubernetes config

The Kubernetes config of the internal service (do the same for warriors service)

@kubernetes:Service {
    name: "Warriors"
}
@kubernetes:Deployment {
    image: "warriors",    // remember the docker image should contain only simple letters
    name: "WarriorsService",
    replicas: 3,
    namespace: "wired-services",
    buildImage: false,
    labels: {team:"WIRED", scope:"SERVICE"},
    dockerHost: "tcp://192.168.99.103:2376",    // IP can be obtained via `minikube ip` command
    dockerCertPath: "~/.minikube/certs",    // Docker cert path should be configure here
    singleYAML: true
}

To build the docker image, add docker expose config, will build the docker image when run the ballerina build command

@docker:Expose{}

[Step 4] Build project

We need a Kubernetes cluster running, in this example we use minikube, install it and start the cluster:

minikube start

• Logs

And then build the project using command ballerina build <module>, will build the specified module or all modules if no specifications.

ballerina build warriors

• Logs:

• Generated files:

• Generated Dockerfile for api-gateway service:

• Generated deployment file for api-gateway service:

[Step 5] Deploy our services

The deployment commands are logged when run ballerina build.

• Docker container

docker run -d -p 9090:9090 warriors:latest

• Kubernetes deployment

kubectl apply -f <path-to-your-projec-dir>/target/kubernetes/warriors

[Step 6] Plugin Tools

The current version of the intellij plugin has bugs, the vsc plugin will be used to continue this work.

• The plugin generates sequence diagrams from the source code in real-time

• The API desiner generates documentation from the source code but also allows the reverse generate a code from the disigner in real time. We can therefore develop services without writing any line of code,only by using the UI

•