These are some notes for working on the OpenWhisk PHP Runtime, but are probably applicable to the other runtimes too. Setting up I have a clone of the runtimes I'm interested in and core side-by-side in a directory. You then need various tools for development, which are documented here for macOS & Ubuntu in the Prerequites section. Build the container The PHP runtime creates two containers, one for PHP 7.1 and one for PHP 7.2.… continue reading.
When writing an API, it's common to produce an output that conforms to a known media type such as JSON API or HAL, etc. I'm a strong believer that even though I'm writing an API, my application has a view layer. It's not the same as building an HTML page, but you still need to separate out the code that creates the structured output from your model layer. For a couple of APIs that I've… continue reading.
Any non-trivial PHP applications use various components to do its work, from PDO though to classes from Packagist. It's fairly common in a standard PHP application to use Dependency Injection to configure and load these classes when necessary. How do we do this in a serverless environment such as OpenWhisk? This question comes up because we do not have a single entry point into our application, instead we have one entry point per action. If… continue reading.
As with all serverless offerings OpenWhisk offers an API Gateway to provide HTTP routing to your serverless actions. This provides a number of advantages over web actions, the most significant of which are routing based on HTTP method, authentication and custom domains (in IBM Cloud). Creating routes with the wsk CLI To route to an action using API Gateway, you first need to make your action a web action first: $ wsk action update todo-backend/listTodos… continue reading.
Every PHP project I write has dependencies on components from Packagist and my Serverless OpenWhisk PHP projects are no different. It turns out that adding Composer dependencies is trivial. Let's create a simple action that converts a number to it's string form. e.g. 123 becomes one hundred and twenty three. We'll start with our simple ow-php-hello project from my earlier article and add a new function to serverless.yml: functions: n2w: handler: n2w.main Our handler is… continue reading.
Serverless Framework is a toolkit to help you mange and deploy a serverless application. (Personally, I'm not a fan of the name as the word "Serverless" already has a meaning in the same space!) It's a useful tool and supports all the major providers, though AWS Lambda seems to be first-among-equals. The OpenWhisk plugin for Serverless is maintained by the rather excellent James Thomas, so if you have any questions, ping him! As I build… continue reading.
When creating new OpenWhisk actions in PHP, It's likely that you'll want to take advantage of the rich ecosystem of Composer packages on Packagist.org. The OpenWhisk PHP runtime has you covered with some pre-installed Composer packages and also the ability to upload your own using a zip file. Pre-installed Composer packages The PHP runtime ships with two Composer packages by default: Guzzle and ramsey/uuid. This is handy as if you need to make an API… continue reading.
By default, OpenWhisk will handle the relevant responses for CORS. Specifically, it will respond to an OPTIONS request with these headers: Access-Control-Allow-Origin: * Access-Control-Allow-Methods: OPTIONS, GET, DELETE, POST, PUT, HEAD, PATCH Access-Control-Allow-Headers: Authorization, Content-Type If you need to change what is sent or you don't want to send these headers at all, then you need to do set the annotation web-custom-options to true and handle the OPTIONS header yourself. Note that if you don't set… continue reading.