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AshishAnand
Employee
Employee
Cloud foundry marketplace is one stop shop to explore all cloud foundry service offering. This blog discusses the procedure to make your own service available in Cloud foundry marketplace also I'll discuss how to manage that exposed custom service.

What are we building?


We are implementing something called service broker to expose our service in cloud foundry marketplace. A service broker in cloud foundry is a special type of application which manages the complete life cycle of a cloud foundry service like service instance creation, deletion and update and binding and unbinding of service with an application.

We will implement this service broker in NodeJS using Express, but you can use any other language of your choice which cloud foundry runtime supports.

Few jargons for better understanding


Application: An application is any deployed code in cloud foundry

Service: Service in cloud foundry is a managed software offering which can be used by an application.

Service broker: Service broker is an application which manages the complete lifecycle of a service.

Service broker API: service broker API is an HTTP interface which allows communication between cloud foundry marketplace and service broker.

Service instance: service instance is an instantiation of serice.

Service binding: service binding is a relationship between application and service.

Service catalog: Service catalog contains metadata about service like name, plans, quota etc

Writing your own service broker implementation


When we say implementing service broker, it means we are just implementing service broker API so that operation like creation, deletion and update of service instance and binding and unbinding of service can take place from cloud foundry service marketplace. We will implement this in NodeJs with

We will implement this in NodeJs with Express so it will be helpful if you have a prior knowledge of Node and Express. You can refer to one of my prior blog https://blogs.sap.com/2014/11/15/integrate-sap-ui5-or-open-ui5-with-nodejs/

In the below section I have explained different components of my service broker application

app.js


In app.js we are just configuring our application and starting a basic HTTP server.
/**
* External Module dependencies.
*/

var express = require('express'),
http = require('http'),
path = require('path'),
bodyParser = require("body-parser"),
validate = require("express-validation");

/**
* Internal module dependencies.
*/
var serviceBrokerRoute = require('./routes/route');

/**
* Application configuration
*/
var app = express();
app.use(bodyParser.urlencoded({
extended : true
}));
app.use(bodyParser.json());

/**
* Route registration
*/
app.use("/v2", serviceBrokerRoute);

/**
* error handler
*/
app.use(function(err, req, res, next) {
if (err instanceof validate.ValidationError)
return res.status(err.status).json(err);
return res.status(500);
});

/**
* start server
*/
http.createServer(app).listen(process.env.PORT || 3000, function() {
console.log('Express server listening on port ' + process.env.PORT || 3000);
});

 

Package.json


package.json contains metadata of the project with dependencies. One important thing is to specify the script attribute to start the application else cloud foundry will not be able to start it.
{
"name": "service-broker-node-implementation",
"version": "0.0.1",
"private": true,
"scripts": {
"start": "node app.js"
},
"dependencies": {
"express": "~4.13.4",
"body-parser": "1.18.1",
"express-basic-auth": "~1.1.2",
"express-validation": "~1.0.2",
"joi": "~10.6.0"
}
}

route.js


route.js contains actual API endpoint for service broker implementation.

Managing authorization


Service broker API specification says all the endpoint should be protected via basic authorization. I have hard coded the credential but you should store in the system provided variable in cloud foundry. You need to tell this credential to cloud controller while registering your application as a service broker. I have used express-basic-auth NPM package for authorization check, not used Passport as it's a very simple basic auth implementation and to keep it light.
/**
* Middleware for authorization check
*/
router.use(basicAuth({
users: { 'admin': 'supersecret' },
challenge: true,
realm: 'Imb4T3st4pp'
}));

/v2/catalog


This endpoint gives the cloud controller complete metadata about the service broker like name, id, description, plans, dependencies etc.
/**
* end point for service catalog
*/
router.get('/catalog', function(req,res){
res.send(catalogJSON);
});

Following is the catalog.JSON file which the above endpoint is serving. This is a dummy metadata, you need to change it to cater to your requirments:
{
"services": [{
"name": "fake-service",
"id": "acb56d7c-XXXX-XXXX-XXXX-feb140a59a66",
"description": "fake service",
"tags": ["no-sql", "relational"],
"requires": ["route_forwarding"],
"bindable": true,
"metadata": {
"provider": {
"name": "The name"
},
"listing": {
"imageUrl": "http://example.com/cat.gif",
"blurb": "Add a blurb here",
"longDescription": "A long time ago, in a galaxy far far away..."
},
"displayName": "The Fake Broker"
},
"dashboard_client": {
"id": "398e2f8e-XXXX-XXXX-XXXX-19a71ecbcf64",
"secret": "277cabb0-XXXX-XXXX-XXXX-7822c0a90e5d",
"redirect_uri": "http://localhost:1234"
},
"plan_updateable": true,
"plans": [{
"name": "fake-plan-1",
"id": "d3031751-XXXX-XXXX-XXXX-a42377d3320e",
"description": "Shared fake Server, 5tb persistent disk, 40 max concurrent connections",
"max_storage_tb": 5,
"metadata": {
"costs":[
{
"amount":{
"usd":99.0
},
"unit":"MONTHLY"
},
{
"amount":{
"usd":0.99
},
"unit":"1GB of messages over 20GB"
}
],
"bullets": [
"Shared fake server",
"5 TB storage",
"40 concurrent connections"
]
}
}, {
"name": "fake-plan-2",
"id": "0f4008b5-XXXX-XXXX-XXXX-dace631cd648",
"description": "Shared fake Server, 5tb persistent disk, 40 max concurrent connections. 100 async",
"max_storage_tb": 5,
"metadata": {
"costs":[
{
"amount":{
"usd":199.0
},
"unit":"MONTHLY"
},
{
"amount":{
"usd":0.99
},
"unit":"1GB of messages over 20GB"
}
],
"bullets": [
"40 concurrent connections"
]
}
}]
}]
}

v2/service_instances/:instance_id


These are the endpoint for service instance provisioning, deprovisonig and update. It just sends status code with {} response object, you need to enhance it to cater to your requirements.
/**
* end point for service instance create
*/
router.put('/service_instances/:instance_id',validate(validator.serviceInstanceCreateRequestValidator), function(req,res){
res.status(201).send({});
});

/**
* end point for service instance update
*/
router.patch('/service_instances/:instance_id',validate(validator.serviceInstanceUpdateRequestValidator), function(req,res){
res.status(200).send({});
});

/**
* end point for service instance delete
*/
router.delete('/service_instances/:instance_id',validate(validator.deleteRequestValidator), function(req,res){
res.status(200).send({});
});

v2/service_instances/:instance_id/service_bindings/:binding_id


These are the endpoint for service instance binding and un-binding. It just sends status code with {} response object, you need to enhance it to cater to your requirements.
/**
* end point for service instance binding
*/
router.put('/service_instances/:instance_id/service_bindings/:binding_id',validate(validator.bindServiceInstanceRequestValidator), function(req,res){
res.status(201).send({});
});

/**
* end point for service instance unbinding
*/
router.delete('/service_instances/:instance_id/service_bindings/:binding_id',validate(validator.deleteRequestValidator), function(req,res){
res.status(200).send({});
});

Polling for asynchronous operations


Cloud foundry waits for very little time for service broker for processing, it's 30 seconds if I remember correctly. Anything more than that is a time out. If you need more time you can use tell cloud controller to poll for your operation progress by adding the query parameter accepts_incomplete=true to the request. Then the cloud controller will keep polling at regular interval of time via below endpoint:
/**
* end point for operation status polling
*/
router.get('/service_instances/:instance_id/last_operation', function(req,res){
res.status(200).send({});
});

Validation


I have used express-validation NPM for validation of query parameters and body:
var joi = require('joi');

this.serviceInstanceCreateRequestValidator={
body: {
service_id: joi.required(),
plan_id: joi.required(),
space_guid: joi.required()
}
};
this.serviceInstanceUpdateRequestValidator={
body: {
service_id: joi.required()
}
};
this.deleteRequestValidator={
query: {
service_id: joi.required(),
plan_id: joi.required()
}
};
this.bindServiceInstanceRequestValidator={
body: {
service_id: joi.required(),
plan_id: joi.required()
}
};
module.exports = this;

Deploying your service broker application to cloud foundry


Now since you have your implementation code ready, you can now deploy that application using below command in cloud foundry CLI:

cf push cloud-foundry-service-broker-node-implementation


where cloud-foundry-service-broker-node-implementation is the name of your application. You can give any name to your baby 🙂

Registering your service broker


Now since you have your service broker implementation up and running in cloud foundry, you can register it as a service broker by using the following command in cloud foundry CLI:

cf create-service-broker custom-service-broker admin supersecret https://cloud-foundry-service-broker-node-implementation.cfapps.eu10.hana.ondemand.com --space-scoped


Where custom-service-broker admin is the name of your service broker

admin supersecret is the name and password which via which you have protected your endpoints

https://cloud-foundry-service-broker-node-implementation.cfapps.eu10.hana.ondemand.com is the URL of your service broker implementation application

I have registered it at space level, hence it will be available with in the space. You can registering ot globallly also so that it will be available across all ORGs and spaces. You need appropiate credentials to do so.

after executing the above command successfully your service will be available in cloud foundry marketplace.


Making changes to your deployed code


in case you need to make some code changes to your registered service broker, you just need to make the changes locally and push it again to cloud foundry using push command, no need to re-register it unless you have changed the name of the application while pushing which will eventually change the URL of the application.

Creating service instance (Provisioning)



  1. Click on the service title

  2. Go to instances tab from the side menu

  3. click on create instance button

  4. Fill mandatory inputs and finish



Deleting service instance (De-provisioning)



  1. Click on the delete button

  2. Confirm the confirm box


Conclusion


Now we have implemented, deployed, registered and tested our custom service broker in cloud platform. You can find complete code for re-use at the below Git repository

https://github.com/ashishcorg/cloud-foundry-service-broker-node-implementation

Feedbacks welcome as always !!! 🙂 🙂
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