Rob Allen's DevNotes – Developing software in the Real World

Invoking many OpenWhisk actions from another one

I have a project where I need to store a number of items into a data store. I have an OpenWhisk action that stores the items so I wrote an action that takes advantage of the OpenWhisk JS client library to do invoke my store action once for each item in an array that this action receives. This is the code:

"use strict";

const openwhisk = require('openwhisk');

async function main(params) {
    if (!params.items) {
        return {error: "No items"}
    }

    const action = "my_api/store")
    const ow = openwhisk();

    console.log(params.items.length + " items to be invoked")
    let actions = params.items.map(function (item) {
        return ow.actions.invoke({actionName: action, params: {item: item}});
    });

    try {
        const responses = await Promise.all(actions);
    } catch (err) {
        console.error('Error invoking actions', err)
        return Promise.reject({error: err});
    }
    console.log(actions.length + " actions invoked")
    return {number_stored: actions.length}
 }


exports.main = main;

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"use strict";

const openwhisk = require('openwhisk');

async function main(params) {

if (!params.items) {

return {error: "No items"}

}

const action = "my_api/store")

const ow = openwhisk();

console.log(params.items.length + " items to be invoked")

let actions = params.items.map(function (item) {

return ow.actions.invoke({actionName: action, params: {item: item}});

});

try {

const responses = await Promise.all(actions);

} catch (err) {

console.error('Error invoking actions', err)

return Promise.reject({error: err});

}

console.log(actions.length + " actions invoked")

return {number_stored: actions.length}

}

exports.main = main;

This is a NodeJS v8 action (–kind nodejs:8 when creating via wsk) and… continue reading.

Posted on 14 March 2018 in JS, OpenWhisk Leave a comment

Using async/await in OpenWhisk

I'm currently writing an OpenWhisk action in JavaScript that searches Twitter using their API. To do this, I need to get a bearer token from one API endpoint and then call the search endpoint. Disclaimer: I'm in no way a JavaScript expert, so I would love it if you could constructively suggest improvements in the comments! To do this in OpenWhisk, you need to use Promises like this:

Posted on 7 March 2018 in JS, OpenWhisk One comment so far

Automated Testing for PHP training course

I'm delighted to announce my new venture, PHP Training, with my friend Gary Hockin. As you can probably guess from the name, PHP Training is a training organisation where we provide public training courses on topics related to PHP. These courses will be held in person, initially at various venues in the UK, and are taught by Gary and myself. Both of us are experienced trainers and this is the first time we've offered training… continue reading.

Posted on 17 January 2018 in PHP, PHP Training View all 4 comments

Using Composer packages with OpenWhisk

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.

Posted on 3 January 2018 in OpenWhisk, PHP One comment so far

2017 in pictures

Another year has passed which gives me an excuse to to reflect on what's happened. As usual, I look at the photos that I've taken and frame my thoughts around them. January I started the year with one of my favourite pictures of the kids. I also spoke at CodeMash in Ohio. This was a new conference to me and I knew no-one there. Fortunately, I was introduced to Mo, so had at least one… continue reading.

Posted on 31 December 2017 in Me Leave a comment

Run the UniFi Controller headless on Mac

I'm running a UniFi network here with wireless access points, the Security Gateway and a PoE switch. It seems to be a robust system and is almost certainly overkill, but reliability is high on my lists after bad experiences with a NetGear WiFi router. The UniFi system software is called the Controller and runs on a various operating systems. As I have a Mac mini here, I decided to run it on there. Weirdly, however… continue reading.

Posted on 20 December 2017 in Software View all 3 comments

Generating training handouts for printing

When training, I like to provide my attendees with a printed copy of the slides with space next to each one to write notes. This handout has 4 slides to a page, along with a title page and I use pdfjam to create it. Pdfjam is a wonderful command line tool for manipulating PDFs and fits the bill perfectly for converting a PDF with one slide per page into a PDF with 4 slides per… continue reading.

Posted on 6 December 2017 in PDF Leave a comment

Implementing CORS in Zend Expressive

On a recent project, I needed to implement CORS support for my Expressive API. The easiest way to do this is to use Mike Tuupola's PSR-7 CORS Middleware. As this is a standard Slim-Style PSR-7 middleware implementation, we need to wrap it for Expressive, so we make a factory: App/Factory/CorsMiddlewareFactory.php:

<?php declare(strict_types=1);
namespace App\Factory;

use Tuupola\Middleware\Cors;
use Zend\Diactoros\Response;
use Zend\Stratigility\Middleware\CallableMiddlewareWrapper;

class CorsMiddlewareFactory
{
    public function __invoke($container)
    {
        return new CallableMiddlewareWrapper(
            new Cors([
                "origin" => ["*"],
                "methods" => ["GET", "POST", "PUT", "PATCH", "DELETE"],
                "headers.allow" => ["Content-Type", "Accept"],
                "headers.expose" => [],
                "credentials" => false,
                "cache" => 0,
            ]),
            new Response()
        );
    }
}

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<?php declare(strict_types=1);

namespace App\Factory;

use Tuupola\Middleware\Cors;

use Zend\Diactoros\Response;

use Zend\Stratigility\Middleware\CallableMiddlewareWrapper;

class CorsMiddlewareFactory

{

public function __invoke($container)

{

return new CallableMiddlewareWrapper(

new Cors([

"origin" => ["*"],

"methods" => ["GET", "POST", "PUT", "PATCH", "DELETE"],

"headers.allow" => ["Content-Type", "Accept"],

"headers.expose" => [],

"credentials" => false,

"cache" => 0,

]),

new Response()

);

}

We then register this in our App\ConfigProvider::getDependencies() by adding to the factories key so that it looks something like this:

    'factories'  => [
        Action\HomePageAction::class => Action\HomePageFactory::class,
        \Tuupola\Middleware\Cors::class => Factory\CorsMiddlewareFactory::class,
    ],

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'factories' => [

Action\HomePageAction::class => Action\HomePageFactory::class,

\Tuupola\Middleware\Cors::class => Factory\CorsMiddlewareFactory::class,

],

If you don't… continue reading.

Posted on 15 November 2017 in PHP, Zend Expressive View all 3 comments

Customising Whoops in Expressive

I find the Whoops error handler page in Expressive quite hard to read and particularly dislike that the error message displayed in the top left is hidden if it's more than a few words long. To fix this, I discovered that you can provide a custom CSS file to the PrettyPrintHandler and then override to your heart's content! One way to do this is to add a delegator factory to add the additional functionality, so… continue reading.

Posted on 8 November 2017 in PHP, Zend Expressive Leave a comment

Using Docker to create a MySQL server

When working on test code on my computer, I usually use the built-in PHP server (php -S) which works nicely. Every so often, I need access to MySQL and I use Docker to temporarily create a MySQL server for me. This is how I do it. The magic command is:

$ docker run --name mysql \
  -e MYSQL_USER=rob -e MYSQL_PASSWORD=123456 -e MYSQL_DATABASE=bookshelf \
  -p 3306:3306 -d mysql/mysql-server:5.7

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$ docker run --name mysql \

-e MYSQL_USER=rob -e MYSQL_PASSWORD=123456 -e MYSQL_DATABASE=bookshelf \

-p 3306:3306 -d mysql/mysql-server:5.7

This creates a Docker container called "mysql" on port 3306. We pass three environment variables: MYSQL_USER, MYSQL_PASSWORD & MYSQL_DATABASE which are our credentials and… continue reading.

Posted on 1 November 2017 in Development View all 2 comments