The hello-world composite contains one component hello. The hello component is defined by a container image which is written in Node.js and it is a simple webapp.
Now let's look at the steps required to try this hello-world cell.
- Clone the wso2/cellery-samples repository
- Navigate to the hello-world Sample.
cd <SAMPLES_ROOT>/composite/hello-world
In this section let us focus on build, run and push a hello-world composite.
The helloComposite contains one component hello. The hello component is defined by a container image wso2cellery/samples-hello-world-webapp:latest-dev
which is written in Node.js and it is a simple webapp. An input variable HELLO_NAME is expected by the hello component with default value Cellery to render the webpage.
These input parameters can be supplied when starting up the compositeto modify the runtime behaviour.
import ballerina/config;
import celleryio/cellery;
public function build(cellery:ImageName iName) returns error? {
// Hello Component
// This Components exposes the HTML hello world page
cellery:Component helloComponent = {
name: "hello",
src: {
image: "wso2cellery/samples-hello-world-webapp:latest-dev"
},
ingresses: {
webUI: <cellery:HttpPortIngress>{
port: 80
}
},
envVars: {
HELLO_NAME: { value: "Cellery" }
}
};
// Composite Initialization
cellery:Composite helloComposite = {
components: {
helloComp: helloComponent
}
};
return <@untainted> cellery:createImage(helloComposite, iName);
}
public function run(cellery:ImageName iName, map<cellery:ImageName> instances, boolean startDependencies,
boolean shareDependencies) returns (cellery:InstanceState[]|error?) {
cellery:CellImage|cellery:Composite helloComposite = cellery:constructImage(iName);
string helloName = config:getAsString("HELLO_NAME");
if (helloName !== "") {
helloComposite.components["helloComp"]["envVars"]["HELLO_NAME"].value = helloName;
}
return <@untainted> cellery:createInstance(helloComposite, iName, instances, startDependencies, shareDependencies);
}Follow below instructions to build, run and push the hello world composite.
-
Build the composite image for hello-world project by executing the
cellery buildcommand as shown below. NoteCELLERY_HUB_ORGis your organization name in cellery hub.$ cellery build hello-world-composite.bal <CELLERY_HUB_ORG>/hello-world-composite:latest Hello World Cell Built successfully. ✔ Building image <CELLERY_HUB_ORG>/hello-world-composite:latest ✔ Saving new Image to the Local Repository ✔ Successfully built image: <CELLERY_HUB_ORG>/hello-world-composite:latest What's next? -------------------------------------------------------- Execute the following command to run the image: $ cellery run <CELLERY_HUB_ORG>/helloworld:latest -------------------------------------------------------- -
As mentioned above in the hello-world.bal,
HELLO_NAMEare used as input parameters to thehellocomponent. Therefore, run the hello-world composite image with ‘cellery run’ command with input parameters your name forHELLO_NAMEas shown below to change the hello-world components's default behaviour.$ cellery run <CELLERY_HUB_ORG/hello-world-composite:latest -e HELLO_NAME=WSO2 -n hello ✔ Extracting Cell Image <CELLERY_HUB_ORG/hello-world-composite:latest Main Instance: hello ✔ Reading Cell Image <CELLERY_HUB_ORG/hello-world-composite:latest ✔ Validating environment variables ✔ Validating dependencies Instances to be Used: INSTANCE NAME CELL IMAGE USED INSTANCE SHARED ---------------- ----------------------------------------------- ------------------- -------- hello <CELLERY_HUB_ORG>/hello-world-composite:latest To be Created - Dependency Tree to be Used: No Dependencies ✔ Starting main instance my-hello-world ✔ Successfully deployed image: <CELLERY_HUB_ORG>/hello-world-composite:latest What's next? -------------------------------------------------------- Execute the following command to list running cells: $ cellery list instances -------------------------------------------------------- -
Now hello-world composite is deployed, execute
cellery list instancesto see the status of the deployed cell.$ cellery list instances Composite Instances: INSTANCE IMAGE STATUS COMPONENTS AGE ---------- ------------------------------------------ -------- ------------ ----------------------- hello wso2cellery/hello-world-composite:latest Ready 1 10 minutes 45 seconds -
Execute
cellery viewto see the components of the cell. This will open a webpage in a browser that allows to visualize the components and dependent cells/components of the composite image.$ cellery view <CELLERY_HUB_ORG>/hello-world-composite:latest
-
Execute below command to create an ingress. Please note this ingress is created to direct the traffic to kubernetes service
hello--hello-serviceand this name is depends on the instance name of the composite (as we have started the composite instance ashello, the service name will behello--hello-service). Therefore, in case if you have started the composite instance with different name (e.g.my-hello), you will have to modify the ingress service name, and create it accordingly (e.g.my-hello--hello-service).$ kubectl apply -f hello-world-ingress.yaml -
Check the ingress rules are correctly applied by getting the list of ingresses as shown below.
$ kubectl get ingress NAME HOSTS ADDRESS PORTS AGE hello-web-ingress hello-world-composite.com localhost 80 25m -
Add the IP address shown in the ingress to your /etc/hosts, therefore you can invoke the service.
127.0.0.1 hello-world-composite.com -
Now access the web page by accessing to http://hello-world-composite.com.
-
As a final step, let us push your first composite project to your cellery hub account as shown below.
$ cellery push <CELLERY_HUB_ORG>/hello-world-composite:latest ✔ Connecting to registry-1.docker.io ✔ Reading image <CELLERY_HUB_ORG>/hello-world-composite:latest from the Local Repository ✔ Checking if the image <CELLERY_HUB_ORG>/hello-world-composite:latest already exists in the Registry ✔ Pushing image <CELLERY_HUB_ORG>/hello-world-composite:latest Image Digest : sha256:8935b3495a6c1cbc466ac28f4120c3836894e8ea1563fb5da7ecbd17e4b80df5 ✔ Successfully pushed image: <CELLERY_HUB_ORG>/hello-world-composite:latest What's next? -------------------------------------------------------- Execute the following command to pull the image: $ cellery pull <CELLERY_HUB_ORG>/hello-world-composite:latest --------------------------------------------------------
Congratulations! You have successfully created your own cell!
Please feel free to checkout this repository and play around with the sample as explained here