To allow the system to keep evolving while we work on modernising it, the better approach is to iteratively replace it piece by piece over time—something we call the Strangler Fig pattern.
No one is going to accept a complete feature freeze for one, two, or even ten years while you rewrite everything from scratch. What you are starting to rewrite today will not be the same system you will be replacing once (if) you finish the rewrite—i.e. you are chasing a moving target.
A lot of rewrites fail because they are cancelled before completion—and a half-finished rewrite is, in most cases, not usable.
(Photo by Sébastien Lavalaye via Unsplash )
A close-up photo of a blue necktie with flowers on it. The necktie is tied in a knot meant to resemble a tulip flower.
A bearded man (Raniz) is standing in a stairwell with books on shelves in the background. He is wearing a brown Oxford shirt and a blue necktie with flowers on it. The necktie is tied in a knot resembling a tulip flower
A flowery knot for a flowery tie.
Tulip knot.
Happy #tieday!
Straight-up bugs are probably fine to fix, but what about behaviour that doesn't exactly meet your specifications?
Changing behaviour that has been in place for many years—even if it was _wrong_—comes with the risk of breaking your customers' workflows and integrations. Tread carefully!
How do you treat your existing bugs when replacing your ageing software systems?
Your legacy system most likely has bugs—probably lots of them. How do you treat them when modernising or rewriting (parts of) it?
(image credit: XKCD 1172, "Workflow", CC-BY SA 2.5)
This means you can continue working on the rest of the system, and any improvements made are immediately beneficial.
Iteratively replacing parts of an active system like this is called the Strangler Fig Pattern.
Iteratively taking a small part of the larger system, breaking it out and either rewriting that part or modernising it, continuing until the whole system (or, at least, the major parts that need it) is modernised,.
A half-finished rewrite is useless.
When modernising a legacy system, it is (most often) better to gradually replace parts of the system rather than do a complete rewrite from scratch.
Final #tieday of February. Trying on a new knot today - an "Arabian knot" by Mr C. I have no idea why it's called that. Tell me your theories!
Would you look at that. It's another #tieday.
Just one this week! Eldredge knot.
Three #tieday in a row. Today with a Trinity knot and a view.
Day two of ContainerDays London. Time for me to present. Talking about working with minimal container images (starting in 2 minutes!) and then pipeline patterns and anti-patterns later today.
Day one at ContainerDays London. Sporting a Haddon knot today.
You here? Come listen to me tomorrow when I talk about working with minimal container images (after lunch) or pipeline patterns and anti-patterns (last slot).
Or just come say hi! Look for a beard and a necktie 😁
I was at JFokus last week, talking about how to modernise legacy software systems.
If you weren't there or went to see someone else (what a betrayal, how could you?!), the recording is available now.
Watch it, then talk to me if you need help getting started!
#tieday at the JFokus speaker conference. Lots of interesting discussions here today.
Sporting a Trinity knot
Day 2 of JFokus. Today I'm talking about modernising legacy software systems with the Strangler Fig pattern in A2 at 13:00, come listen or just check out the Haddon knot!
Day 1 of JFokus in Stockholm. Sporting a Vidalia knot for today. Come say hi if you're here! Or come listen to me talk about modernising legacy software systems with the Strangler Fig pattern tomorrow at 13!
I got a comment about the tie when donating blood this morning so naturally had to explain about #tieday for the nurses 🙂
Went with a Harlequin knot today. Tricky to tie, but I kinda like it. It's a bit better with a thicker tie though - the edges hold their points better with more material.
Back at work after holidays and a refreshing skip trip.
What a better way to start the Tieyear than an Eldredge?
Last day of work before the holidays. Celebrating with my most festive tie and a Double Eldredge knot.
Happy holidays, see you in January
Would you look at that, it's #tieday again. In the right light, the shirt looks like gingerbread.
I didn't really know what knot to pick this morning, and sort of just started tying something and it ended up as a Truelove knot.
This delayed #tieday post brought to you by Cloudflare - proving that sticking about a fifth of all the eggs in the same basket isn't a good idea at all.
Cape knot. I rather like how the tail seam ended up right at the center.
Yet another #tieday today. Third time with a tie this week due to CLC conference in Mannheim.
Apparently you can wear a smartwatch through the airport security check, but not a tie clip 🙂
Tulip knot
Use them with care and remember to second-guess and inspect everything that comes out of them and you'll not only get good results, you'll hopefully learn and improve your own skills at the same time.
Full blog post: buff.ly/fjUnYRd
I caught Claude Code "lying" to me this morning.
This is a gentle reminder that while these kinds of tools are both capable and useful, they are also incredibly flawed and lack any kind of actual intelligence.
Day two of Newcrafts, a proper #tieday!
Started the day with a morning run around the Eiffel Tower and now I'm at the conference sporting a Trinity knot.
Last day in Paris before I go home to Sweden tomorrow.
In Paris today for Newcrafts where I held a TDD-workshop in the morning slot.
Good times and now I get to enjoy the rest of the conference in peace 😁
I think this tie is still my absolute favourite and it really shines in the Haddon knot.
Time for another #tieday. Went a bit advanced with an Intrinity knot today. It's essentially a Penrose knot tied on top of a Trinity knot - long ties only 😅
Neon Oni's latest new album Nihilism is blasting out of the speakers today.
Bonus pics from TDC in Trondheim where I was on Monday.
Time for another#tieday again. The beard is getting a bit long so I'm off to trim it (and the hair) in an hour.
Tie is tied in a Rachel knot, named after the inventor's wife.
Have a nice day!
