Sunday, 7. August 2022Week 31
.: How to Exit Vim

How to Exit Vim


22:19 | Linux | Permalink
Wednesday, 6. July 2022Week 27
.: Add node to MongoDB cluster

To add a new node to an existing MongoDB cluster, login to the mongo shell on the primary node and run the following command:


Similar to remove a node from the cluster, use:


22:14 | Linux | Permalink
Sunday, 19. June 2022Week 24
.: Custom nginx error pages

For quite some time I've been using custom nginx error pages on this site.
My approach so far was to generate a bunch of static HTML with the various error messages and then configure them for each corresponding HTTP status codes in nginx.
As there are quite a number of HTTP errors, I used a little shell script to generate the whole config and HTML, in the end I had a huge file with snippets like the one below.

error_page 429 @custom_error_429;
location @custom_error_429 {
	more_set_headers 'Content-Type: text/html';
	echo '<html>...</html>';

Now while implementing custom error pages for a different project, I tried to see if there is an easier way to do this.
Some searching lead to the One NGINX error page to rule them all article which describes an alternative approach leveraging the nginx SSI module to generate the error pages on the fly.

Instead of generating and defining a specific error page for each error, a single error page is used for all errors.

error_page 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414
           415 416 417 418 421 422 423 424 425 426 428 429 431 451 500
           501 502 503 504 505 506 507 508 510 511 /error.html;

location = /error.html {
	ssi on;
	root /var/www/default;

nginx provides the status code as variable to our error page, but we also need the error message to make it more userfriendly.
For this we define a mapping of status codes to the error messages.

map $status $status_text {
  400 'Bad Request';
  401 'Unauthorized';
  402 'Payment Required';
  403 'Forbidden';
  404 'Not Found';
  405 'Method Not Allowed';
  406 'Not Acceptable';
  407 'Proxy Authentication Required';
  408 'Request Timeout';
  409 'Conflict';
  410 'Gone';
  411 'Length Required';
  412 'Precondition Failed';
  413 'Payload Too Large';
  414 'URI Too Long';
  415 'Unsupported Media Type';
  416 'Range Not Satisfiable';
  417 'Expectation Failed';
  418 'I\'m a teapot';
  421 'Misdirected Request';
  422 'Unprocessable Entity';
  423 'Locked';
  424 'Failed Dependency';
  425 'Too Early';
  426 'Upgrade Required';
  428 'Precondition Required';
  429 'Too Many Requests';
  431 'Request Header Fields Too Large';
  451 'Unavailable For Legal Reasons';
  500 'Internal Server Error';
  501 'Not Implemented';
  502 'Bad Gateway';
  503 'Service Unavailable';
  504 'Gateway Timeout';
  505 'HTTP Version Not Supported';
  506 'Variant Also Negotiates';
  507 'Insufficient Storage';
  508 'Loop Detected';
  510 'Not Extended';
  511 'Network Authentication Required';
  default 'Something went wrong';

Now we have the status and the status_text variables available in our error.html page.

<h1><!--# echo var="status" default="" --> 
<!--# echo var="status_text" default="Something went wrong" --></h1>

09:48 | Webdesign | Permalink
Wednesday, 15. June 2022Week 24
.: nitter

nitter provides a free and open source alternative front-end to Twitter. It talks with the API and does not show any JavaScript or ads (thus no 'forced-login' overlay after reading 5 tweets or similar nastiness).
The source code for it is available on GitHub.

It does a direct mapping of the profile URLs, thus becomes

21:08 | Misc | Permalink
Saturday, 4. June 2022Week 22
.: Blogging like 2002

On the occasion of the 20th anniversary of this blog, I've used to reconstruct the original HTML layout from back in the time and applied it to the Jekyll templates.

Enjoy the blog in all the (<table> based) glory from 2002 :-)

11:32 | Webdesign | Permalink
Thursday, 2. June 2022Week 22
.: Happy 20th Birthday x-log

On June 2nd 2002 I published the first (test) entry in this weblog. The first entry has disappeared since (thus making the second entry the first one in the archive of June 2002).

Screenshot of the first (test) entry

Compared to 20 years ago, the about page no longer needs to explain what a weblog is.
Interesting though that the linked definition of a weblog from back then already did foresee the rise and fall in popularity of weblogs which happend during the last two decades.
To me it seems in the last 1-2 years there has been an increase again in activity around personal weblogs; curious to see if this revival trend continues.

Also the weblog here has changed quite a bit. Initially its content was more on the pure web-logging side (commenting on interesting links I encountered during my daily Internet surfing) mixed with some kind of a journal/commentary of my day-to-day life. Later on it moved more towards a 'knowledge dump' on technical topics mixed with some music discoveries and random personal post from festivals and travels. And lately it has been rather sparse again with posts, still mostly on technical topics around coding, networking, security mixed with some personal posts commenting on the current world situation.
The frequency of posts also followed the changes in content where early on there sometimes were multiple posts per day, nowadays there can be multiple months without any post and there were even entire years where nothing new was posted; let's see how this goes in the future :-)

From the list of linked Blogs in 2002, only deep-resonance aka mk is still active, special shout-out to Markus for the continuous persistence.
To the next twenty years :-)

22:54 | Misc | Permalink
Saturday, 26. March 2022Week 12
.: mt-set-time

A while ago I wrote a little tool to set the time on MikroTik devices. It takes the current time from the local machine and does set it on the device through the API (while respecting the timezone configured on it).
I mostly use it to set the proper time when the device time was completely off (when setting up a new device or when it has been powered off for a long time). Afterwards NTP should take care of keeping the time in sync.

The tool is now available on GitHub together with installation and usage instructions: mt-set-time

16:15 | Networking | Permalink
Tuesday, 15. March 2022Week 11
.: Fight Putin - Ride a Bike

Fight Putin - Ride a Bike

12:55 | Misc | Permalink
Sunday, 27. February 2022Week 08
.: Dr Putin isch


11:53 | Music | Permalink
Saturday, 26. February 2022Week 08
.: Non à la guerre! Nein zum Krieg!

Today I went to Bern to the rally for peace.
My motivation was to show support for the people suffering in this war and to send a signal to our swiss government that the population wants clear participation in sanctions (while remaining neutral, the two in my view are not exclusive!).

Swiss media reported that this was the largest rally for peace in Switzerland since the rallies against the war in Iraq in 2003. That I can link to my own blog entry regarding the rally for peace from 19 years ago, makes me sad.
Clearly we as human species did not progress enough on this topic :-(

Besides showing up to the rally, I also did donate to the ICRC to provide humanitarian aid and I do encourage you to do the same.

21:22 | Misc | Permalink