Tuesday, 10 March 2015

My inspiring afternoon at Number 10

In the middle of last week I received an email informing me that I'd been chosen to attend an event organsied by Girls in Tech to meet some of the Inspiring Fifty - inspiring women in tech of Europe.  The surprising part was that it would be hosted at Number 10 Downing Street!

The first question I asked myself was "what did I do to get picked?" closely followed by "what the hell am I going to wear?".  I mentally perused my wardrobe of jeans and geek t-shirts and figured I'd best go out and buy a trouser suit.

Upon passing through multiple levels of security to enter 10 Downing Street, our phones and other electronics had to be left at the entrance and so sadly I have no pictures from inside.

The event started with sparkling elderflower juice in a room with the Ada Lovelace portrait watching over us - I tickles me to think this was a deliberate decision. Drinks were followed by a tour around the building.

The best way I can describe the house is as a "living museum".  The building is filled with precious furniture, art and relics of its history, with none locked away behind glass or a red rope.  One of the staff members who guided us quite proudly stated that he felt such furniture should be enjoyed and I agree with him.  We were filed into a plain boardroom which turned out to be the Cabinet Office and discovered we'd been sat in the chairs from Disraeli's time.  The simple room belies its lengthy history.

After the tour the mentees filed into another boardroom and were sat around the edges.  The attending members of the Inspiring Fifty had been partaking in a round table with Baroness Joanna Shields, chair of TechCityUk, regarding initiatives they believe the government could undertake to improve Europe's digital economy.

Half of the mentors - the Inspiring Fifty - stood up in turn and and introduced themselves with a short 2 minute speech.  Some spoke about how they see tech as a growing area which more women need to take advantage of.  Some spoke of how they defied sexist assumptions in their youth to become founders and board members of tech companies. Others spoke about how young women need to be informed that tech is not just for the boys.  A few others spoke about the gender imbalance in tech, from developers to founders.  Each had something inspiring to say.

Sarah Wood, co-founder and COO of Unruly Media, stated that we need to do more to bring the older generation closer to tech. As technology becomes more central to our lives those who did not grow up with it may find themselves becoming isolated.

Neelie Kroes, Ex-Vice President of the European Commission, spoke about how Europe must come together more and embrace its burgeoning tech startup culture, in particular supporting women.

A few of them used words to the effect of being in tech is not just about "sitting in a dark room coding", which of course it isn't, but I couldn't help feeling like my chosen career was being deemed as insufficient and something I should strive my way out of via entrepreneurship.  I felt myself unwittingly sinking into my chair feeling like some kind of interloper at this prestigious event.

Afterwards we headed back out for more elderflower and mingling in a format loosely based on 'speed networking'.  I managed to speak with Sue Black, Sarah Wood and Sherry Coutu.  I asked for advice on career building as an Engineer and received a few tips, for which I'm grateful, although I couldn't shake the feeling that I didn't belong there.

Finally, there were photos outside number 10, where even I could not resist the temptation to take a selfie!

The event was about women leadership, and that is definitely something I wish to learn more about and harness in myself, but the way it was presented felt that it would need to be at the expense of my Software Engineering career - I like coding and we could certainly do with more women Software Engineers.

Leadership isn't confined to entrepreneurs; from Grace Hopper and Molly Holzschlag to Anna Shipman, engineers have demonstrated such qualities.  These are skills and traits that need to be nurtured in people at every level and chosen career path.  I would like to see the encouragement of role models in tech include all aspects of tech and not made to feel like a race to the boardroom.

The event has inspired me to be on the look out for mentorships aimed at women software engineers, preferably by women.  Senior Engineers, Architects, Tech Leads, CTOs, etc.  I follow the idea that it's difficult to believe you can be something if you can't see other people like yourself already being it.  If it doesn't already exist, well, I may have to make it myself.

The event was a wonderful opportunity for entrepreneurs now can we have one for engineers?

Saturday, 3 January 2015

2014 Retrospective

At the end of 2012 I performed a simple Retrospective of the year.  I seem to have neglected to do one at the end of 2013 but it shall be a yearly habit from now on.

Conferences attended:



This is a big achievement for me personally.  Thank you to those that made it happen.

  • Joint Contributor with Paul Shannon in More Agile Testing by Lisa Crispin and Janet Gregory
  • Contributed a chapter to Build Quality In - the collection of Continuous Delivery and DevOps stories edited by Steve Smith and Matthew Skelton


  • Co-organised my first conference - PIPELINE 2014!
  • Went skiing for the first time
  • Started Portuguese lessons
  • Took Cycling Classes and Bicycle Maintenance classes
  • Continued my Cello lessons (aiming for Grade 3 this spring)
  • Attempted the Computer Networks Coursera course and achieved a grade of 47%. I'm proud of this score as it was a pretty intense course.
  • Stepped down from the ACCU committee as I could no longer devote the proper time to it.
  • Only managed to finish reading 6 books when I'd hoped to read 18.
  • Donated blood 3 times before being temporarily suspended to investigate anaemia :(
  • Sadly, I still have limited proficiency with the Portuguese language

Changed Jobs
In August I left my role at 7digital, I job and company I loved and spoke about, after 4 years of being with them.  I wanted to try a new challenge.  I know it sounds corny, but I really did.  I wanted to see if I could take all the things I'd learned there to somewhere new, share my knowledfe and learn even more.

I took up a Senior Engineer role at JUST EAT and it's been great.  I've had much to learn and as a result have been battling my own Imposter Syndrome, but I hope I've been making a difference, even a small one.

Next Year

I plan to get back on top of my reading, blogging and neglected fitness - the usual stuff.

Having left 7digital in August I now longer feel comfortable presenting about the experience report about their journey towards Continuous Delivery.  Change happens there every day and I am no longer able to 'finish' the presentation with details of what is currently being achieved.  There are still many things I could talk about from that time though, possibly distil the learnings into something more transferable, but I believe the audiences enjoyed hearing a real life experience report.

Creating a new presentation is top of the list and I'm open to ideas and suggestions.


Once again I've achieved more than I thought - a year is a long time and we regularly fail to remember anything other than recent events.  This feeling has been compounded by my focus in the latter half of the year being centred almost exclusively on my new role at JUST EAT, which is to be expected.  A new role is challenging with a new codebase, domain, terminology and people to learn about, which is exactly what I was seeking, so I'm happy!

Here's to 2015!

Thursday, 1 January 2015

Frequent releases reduce risk

This post expands on a train of thought initiated by Dan North in his talk "Kicking the Complexity Habit" at NDC London 2014.

"Frequent releases reduce risk" - this is something you hear all the time in conversations about Continuous Delivery.  How exactly is this the case?  It sounds counter-intuitive.  Surely releasing more often is introducing more volatility into Production? Isn't it less risky to hold off releasing as long as possible and take your time with testing to guarantee confidence in the package?

Let's think about what we mean by risk.

What is risk?

Risk is a factor of the likelihood of a failure happening combined with the worst case impact of that failure:

Risk = Likelihood of failure x Worst case impact of failure

Therefore an extremely low risk activity is when failure is incredibly unlikely to happen and the impact of the failure is negligible.  Low risk activities also include those where either of these factors is remarkably low such that it severely reduces the effect of the other.

Playing the lottery is low risk - the chance of failing (i.e. not winning) is very high, but the impact of failing (i.e. losing the cost of the ticket) is minimal, hence why many people play the lottery.

Flying is also low risk due to the factors being balanced the opposite way. The chance of a failure is extremely low - flying has a very high safety record - but the impact of a failure is extremely high.  We fly often as we consider the risk to be very low.

High risk activities are when both sides of the ratio are high - high likelihood of failure and high impact, for example extreme sports such as free solo climbing and cave diving.

Large, infrequent releases are riskier

Rolling a set of changes into a single release package increases the likelihood of a failure occurring - a lot of change is happening all at once.   

The worst case impact of a failure includes the release causing an outage and severe data loss.  Each change in a release could cause this to happen.  

The reaction to try and test for every failure is a reasonable one, but it is impossible.  We can test for the known scenarios but we can't test for scenarios we don't know about until they are encountered ("unknown unknowns").   This is not to say that testing is pointless, on the contrary it provides confidence that the changes have not broken expected, known, behaviour.  The tricky part is balancing the desire for thorough testing against the likelihood of them finding a failure and the time taken to perform and maintain them.

Build up an automated suite of tests which protect against the failure scenarios you know about, and each time a new one is encountered add it to the test suite.  Increase your suite of regressions tests, but keep them light, fast and repeatable.  

No matter how much you test, Production is the only place where it counts.

Small, frequent releases reduce the likelihood of a failure

Releasing often, containing as small a change as possible, reduces the likelihood that the release will contain a failure.

There's no way to reduce the impact of a failure - the worst case is still that the release could bring the whole system down and incur severe data loss, but we lower the overall risk with the smaller releases.

Release small changes often and reduce the likelihood of a failure and therefore the risk.

Saturday, 14 June 2014

Book - "Build Quality In"

I'm extremely happy to announce that I've been asked to contribute to a new book about Continuous Delivery and DevOps called "Build Quality In".  The book is being collated and edited by my LondonCD and PIPELINE conf colleagues Steve Smith and Matthew Skelton.  We're going to be donating 70% of author royalties to the awesome initiative Code Club as our way of giving back.
It's going to be a collection of experience reports, including the successes and failures of many teams and projects - there will be much to share and learn!  
The book will be released continuously (hah!) via LeanPub and you can register your interest here: https://leanpub.com/buildqualityin

Sunday, 4 May 2014


Versioning is hard, so why do we do it?  To enable consuming apps to resist change.

What if these apps were built to be tolerant of change? What if you built your API or library in such a way that you avoided breaking the contract, but added to it? What if you constantly push changes and consumers constantly consume them?

What would you need versioning for now?

Tuesday, 18 February 2014

Gotcha when downgrading ServiceStack.Redis to version 3


It turns out that this is caused by a change of the default behaviour in NuGet 2.8 whereby it now picks the lowest patch version of a package dependency.


You're probably aware of the announcement that ServiceStack is no longer free from version 4, but if you've already installed it, and reflexively clicked the licence agreement, then you probably need to downgrade to the latest of v3.

I discovered the hard way that there's a mismatch in the versions pulled down from NuGet.  Cryptically, this gives the following error message:

System.TypeLoadException : Method 'get_Db' in type 'ServiceStack.Redis.RedisNativeClient' from assembly 'ServiceStack.Redis, Version=, Culture=neutral, PublicKeyToken=null' does not have an implementation.

If you run the command Install-Package ServiceStack.Redis -Version 3.9.71 then along with ServiceStack.Redis v3.9.71 NuGet pulls down ServiceStack.Common version 3.9.11, which is not compatible (I've confirmed this behaviour in a fresh solution).

To solve it, you need to explicitly install version 3.9.71 of ServiceStack.Common:

Install-Package ServiceStack.Common -Version 3.9.71

P.s. don't forget to set the version constraints in your package.config file.

Wednesday, 13 November 2013

Islington STEM Event

We're constantly hearing about the skills shortage for IT roles in the UK Technology Industry and how more female role models are needed to encourage young women to consider IT careers.  Last year I decided I would get involved and signed myself up to be a STEM Ambassador.  STEM is an acronym for Science Technology Engineering and Maths which is generally used in the world of education.

On Monday I took part in a STEM Careers event for Year 9 pupils (13-14 year olds) held at the City and Islington Sixth Form College.  I was a Speed Networker, along with Ambassadors from other STEM fields.  The format entails having the Ambassadors sit at separate tables and the pupils get to spend 5 minutes at each one before moving onto another table.

It was suggested that I bring a prop with me from my job, so I grabbed a laptop.  Now this is the second time I've done an event like this and I learned the hard way that showing a screen of code to young people does not impress them, rather it frightens them.  They find the code impenetrable, they assume it's complex and don't even look at it.  I did have some success showing HTML to students and saw the lights go on when they discovered it was easily understandable.

This time I loaded up my presentation for A Day in the Life of a 7digital Developer so that I could show the images of the office, the daily standup, people pair programming and other pictures.  I also showed my spike I did with WebGL a couple of years ago as I discovered that something visual can capture their imaginations.

Almost all of the pupils had no knowledge of what a Software Developer does, or even what the role is.  I tried to get across the feeling of creativity and exploration that comes with being able to develop software whilst  also emphasising the need for teamwork inherent in the role.  In the space of 5 minutes it was impossible, but I hope that my enthusiasm came across and that  alone will inspire them to look into it as a choice.

It was an interesting day, and very tiring, but I feel that we made a difference in giving the pupils a chance to meet real people in different STEM roles and expand their knowledge of the opportunities out there.