Tag Archives: solution

Wait for AWS region to become available

AWS CLI has a nifty useful command to enable/opt-in a region on your account – account enable-region e.g.

aws account enable-region --region-name af-south-1

There is a caveat though – this command only begins to enable the region. The process could take a while, but the command exits right away. But what if you need do something with the region when it becomes available? Say you’re running a script and you need to bootstrap the region when its enabled. You need some way to wait for the enablement to finish. Luckily there is another AWS CLI command that lets you check the status of the region – ec2 describe-regions, e.g.

aws ec2 describe-regions --region-names af-south-1

One of the properties it return is whether the region is enabled/opted-in or not. Combining this with a little of bash magic – we can come up with a waiting routine:

aws account enable-region --region-name af-south-1
until [ "$state" = "opted-in" ]
   echo Waiting for af-south-1...
   sleep 5
   state=$(aws ec2 describe-regions --region-names af-south-1 --query "Regions[0].OptInStatus" --output text)

Here on the Line 1 we execute command that initiates enabling region. And the rest is a loop: wait 5 seconds, and check the status of the region. Loop exits when the status becomes “opted-in”. At this point we know that the region has been enabled, and can proceed with using it.

CDK pipeline won’t restart after mutation.

CDK Pipeline is a clever construct that makes continuously deploying your application and infrastructure super easy. The pipeline even has the ability to update itself or “mutate” if your commits include changes to the pipeline itself. This behavior is controlled by selfMutation property of the pipeline constructor and is true by default. Once the pipeline updates itself – it also restarts itself, so that new changes can take effect.

But if you create your CDK pipeline with regular AWS Pipeline as a base e.g.

const rawPipeline = new Pipeline(this, 'RawPipeline', {

const pipeline = new CodePipeline(this, 'Pipeline', {
   codePipeline: rawPipeline,

suddenly the pipeline won’t auto-restart after the mutation. What is happening? Continue reading →

Share node_modules between CDK CodeBuildSteps

CDK makes it pretty easy and straightforward to create CodePipelines – define the pipeline, add build steps as needed, add deployment stages and you’re done. But imagine a scenario where you install Node dependencies in one step and then need to run some NPM scripts in another down the line. In order to avoid reinstalling the dependencies every time you can pass output of one step as an input of another:

const installStep = new CodeBuildStep("install-step", {
   input: sourceStep,
   commands: ["npm ci"],
   primaryOutputDirectory: ".",

const testStep = new CodeBuildStep("test-step", {
   input: installStep,
   commands: ["npm run test"],
   primaryOutputDirectory: ".",

Passing output of the installStep as input of the testStep copies everything created in the installStep – files, directory structure – including all dependencies installed into node_modules folder to the testStep, so any npm command in theory should work. But in reality they’d fail, telling you that some module or other is not found. The reason is that in addition to installing dependencies npm ci command also creates symlinks between some of them. Copying files from one step to another loses those symlinks. In order to rebuild them you need to run npm rebuild before running any npm commands in the consecutive steps. So the test step becomes

const testStep = new CodeBuildStep("test-step", {
   input: installStep,
   commands: ["npm rebuild", "npm run test"],
   primaryOutputDirectory: ".",

And this will throw no errors.

Keep animated images after uploading to WordPress

Haven’t written in a while. Not that nothing interesting happened, but never got around to. But I finally moved my blogs to AWS Lightsail (very smooth process, by the way) and experienced only one hurdle I wanted to write about (surprisingly, not related to AWS).

After the migration, I noticed that all images on my site lost their animation. When I inspected an image – I found that it’s source goes thru some kind of a proxy “i1.wp.com”. After digging a bit I found that it is used by JetPack site acceleration service – it caches images to serve them faster. Unfortunately cached copies seem to lose some of their properties (like animation).

To fix it – go to JetPack settings and turn “Speed up image load times” off

Happy blogging!

SSRS and HTML rendering of ordered list

Microsoft’s SQL Server Reporting Services supports rendering of HTML tags, but for some reason that support stuck in 1990s – only very limited set is supported. And even using that set is problematic.

Case in point – ordered list. While officially supported – the way it is rendered is the stuff nightmares are made off. Jumble of original tags generously intermixed with DIVs and SPANs – it’s a wonder it renders at all.

And sometimes it doesn’t. If you try to view a report in Internet Explorer (especially from older, but still actively used versions of SSRS like 2008) numbering get screwed.
Continue reading →

Full control of your Limitless LED/Milight bulbs from Amazon Echo

Limitless LED Limitless LED offers full color RGBW light bulbs that you can control over Wi-Fi/4G from your computer, phone or smartwatch. They’re an inexpensive alternative to Philips Hue and they look really cool.
But I, being lazy ass that I am, was wondering if you can control the lights from Amazon Echo by voice commands alone. Out of the box Echo and Limitless LED don’t recognize each other. Amazon can see and control Hue, but not Limitless LED. Fortunately geniuses of BWS Systems came up with a really cool piece of software – home automation bridge “HA-Bridge”. It’s free and written in Java so it can run pretty much in any environment under any OS. What it does – it emulates Philips Hue API so other devices on your network – like Echo – can see and interact with it. Continue reading →

Flicker-Free IFRAME refresh

One of our projects consists of single parent page and “widgets” that display secondary (classic ASPX webform) pages. A recent feature request was to auto-refresh widget information at given intervals. On the surface it was pretty straghtforward:

<iframe id="xIfrWidget0"></iframe>
var ifr = document.getElementById('xIfrWidget');

setInterval(function () {
   ifr.src = 'widget.aspx';
}, 2000)

The problem with this approach – there’s an ugly flicker of white between page refresh and the goal was to keep displaying current IFRAME content up until refreshed content is ready. Yes, there’re various AJAX-ified methods (including ASP.NET UpdatePanel) – but they add unnecessary overhead and may cause other issues.

The solution was suggested by this Stack Overflow post. The idea is to have secondary, hidden IFRAME into which perform actual load. Once load complete – switch IFRAMES – currently visible with old content becomes hidden, and hidden one with new content becomes visible. It goes something like this: Continue reading →

Pebbles, rectangles and stack overflow

UntitledWhile working on my Pebble watchface “Future Time” I have encountered persistent annoying problem – watchface would run for a while and then crash – and not only crash, but actually restart the watch. What made this even more frustrating – after 3 restarts in a row Pebble would revert to recovery mode and complete firmware reinstall was required (did I accidentally write a Pebble virus?).
When I dug into device logs I found out that every restart was given reason: “Dangerous Stack Overflow”. Which is kinda strange – I don’t have any recursions nor deeply nested function calls nor large local variables. I tried lots of things – including extreme ones like declaring all local function variables as global or static – nothing helped.
Finally Christian form Pebble developers forum shed a light. He pointed out that I use a lot of GRect constructs which is basic rectangle building block for pretty much anything from defining layers to graphics functions. I used GRect inline directly inside function calls, which I thought wasn’t a big deal, after all “everybody does that” – including Pebble in its examples. Well, as Christian pointed out those GRects are kind of local variables, and either memory is not reclaimed fast enough when they go out of scope or they spring memory leak.
Keeping this in mind I created a global GRect variable and when needed to use a GRect in local function, first I’d assign it’s value to the variable and then use variable in the function.
So something like this:

static void layer_update(Layer *layer, GContext *ctx) {
   graphics_draw_rect(ctx, GRect(10, 10, 30, 30));
   graphics_draw_bitmap_in_rect(ctx, bitmap, GRect(20, 20, 40, 40));

Becomes thus:

GRect temp_rect;

static void layer_update(Layer *layer, GContext *ctx) {
   temp_rect = GRect(10, 10, 30, 30);
   graphics_draw_rect(ctx, temp_rect);
   temp_rect = GRect(20, 20, 40, 40);
   graphics_draw_bitmap_in_rect(ctx, bitmap, temp_rect);

That’s it. This simple change cured the plague, no more crashes, restarts or recovery – just smooth sailing.

TSQL ISNUMERIC and “String or binary data would be truncated” error

If you’re using TSQL ISNUMERIC function in a query, e.g.


You may receive unexpected error:

String or binary data would be truncated.

ISNUMERIC must truncate string data, and if you experienced the above error, some of your data is over the limit. But you can augment the above query:


But cutting only 8000 chars you will avoid the error, and I seriously doubt you will have number over 8000 digits long so it’s a safe bet as well

Restore natural picture look on Samsung smart TV

I really like my new smart TV from Samsung it has tons of bells and whistles. But one thing I noticed – no matter what I watch – series or movies, streaming or broadcast – picture has a “teleplay” feeling – like the action is happening on stage in the theater. If you recall what later Twilight Zone episodes look like you’d know what I am talking about. Maybe it’s supposed to look like this, but I like “film” feeling more. So I found a setting that restores natural picture look:

Go to your TV menu, then select Picture -> Picture Options -> Auto Motion Plus and turn it off.