Tuesday, August 29, 2023

Solving Wordpress Critical Error on WP Admin's Login

If you get a "Critical Error" white screen when accessing your WP admin, look into the server's logs. Some hosting companies and software like CPanel make accessing logs quite an easy task.

My logs showed the following PHP error:

 [Tue Aug 29 11:53:45.667499 2023] [proxy_fcgi:error] [pid 592:tid 139914188318464] [client 1.2.3.4:0] AH01071: Got error 'PHP message: PHP Fatal error: Uncaught Error: Class "Elementor\\Core\\Schemes\\Color" not found in /home/user............quire_once('/home/user...')\n#6 /home/user/public_html/wp-admin/upgrade.php(18): require('/home/user...')\n#7 {main}\n thrown in /home/user...', referer: https://www.my.site/wp-admin/ 

The biggest challenge was to find what exactly is the path to the file which refers this "Elementor\\Core\\Schemes\\Color"  class. It appeared to be in /public_html/wp-content/mu-plugins/typography.php

I commented out all PHP content and tried to login again. This time there were no error and the WP offered me to complete the DB upgrade. Once the "Upgrade" button was pressed I instantly got the WP Dashboard back. The only thing that was left was to uncomment the code in /public_html/wp-content/mu-plugins/typography.php

Monday, June 05, 2023

Speeding up Ubuntu guest (23.04) on Windows 11 Home host with VirtualBox

I run VirtualBox v7.0.8 on an updated Windows 11 Home. 

Ubuntu 22.04 simply declined to work once installed on a VM. Even the "guest Additions" CD did not run automatically. Once Guest Addition ran manually, the VM still refused to open reasonably quickly. I tried installing 22.04 twice and then switched to the next in line.

Ubuntu 23.04 simply worked out of the box, but it had issues supporting a 4K monitor. Trying to enlarge the desktop to the full size of a 4K monitor caused blackouts. It was solved by adding more Display memory and increasing general VM RAM. 

Another glitch was that moving a window over a desktop left visual traces - copies of the same window that were living in the background forever. This issue was gone by switching "3D Acceleration" off.


The VBox's VM settings look this way:



KVM Acceleration is selected for Linux guest




Display needs maximum RAM while "3D Acceleration" is better kept off


SATA Controller uses I/O Cache



And the disk is marked as SSD





And yet, switching off "Virtual Machine Platform" feature in Control Panel -> Programs and Features + Restart probably was one single game changer, speeding up the VM a few times.



Tuesday, September 27, 2022

AWS SAM fails on Windows 11 Home while trying to create an AWS Serverless project in PyCharm with AWS Toolkit

PyCharm shows an exception like this: 

java.lang.RuntimeException: Could not execute `sam init`!: [Cloning from https://github.com/aws/aws-sam-cli-app-templates (process may take a moment), Error: Unstable state when updating repo. Check that you have permissions to create/delete files in C:\Users\user\AppData\Roaming\AWS SAM directory or file an issue at https://github.com/aws/aws-sam-cli/issues] at software.aws.toolkits.jetbrains.services.lambda.wizard.SamInitRunner.execute$lambda-1(SamInitRunner.kt:55) 


This happens because the PATH variable on Windows 11 is limited to 260 chars (no idea why).

The fix is easy: Open Registry Editor (type "regedit" in Windows Search box)

and go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem



then change the value for "LongPathsEnabled" from 0 to 1.


You need a Docker on your computer to run a Local SAM build. Install it and run Docker Desktop at least once to accept T&C's and to start the docker service.

Unfortunately, the latest v4.12.0 Docker for Windows  (as of 2022-09-27) does not work well with the latest AWS SAM 1.57.0. 
AWS SAM "Local" build throughs an error. Downgrading to Docker 4.11.1 solves this issue as discussed here.

Python 3.9 is the latest version currently supported by AWS Lambda. Assuming this is what you have selected for your AWS Lambda project, you need to make sure that SAM can find in your path python 3.9 executable' folder. SAM refuses to continue if it knows the path to e.g. python 3.10 but not to python 3.9.

Monday, August 29, 2022

Runing Ubuntu with full GUI on Windows 10 WSL

 While I did not find the way to run a full-blown ubuntu-desktop I ended up with a nice lightweight LXDE Ubuntu GUI.


If Ubuntu app is not already installed on your computer download it from Microsoft Store.

Run the app and type in the terminal:

sudo apt update

sudo apt upgrade -y

sudo apt install lxde


Now you have to install X server for Windows to make it work. Install VcXsrv freeware.

Set DISPLAY and LIBGL_ALWAYS_INDIRECT values in your Ubuntu terminal. You can later add them both to ~/.bashrc to make this change permanent:

export DISPLAY="$(grep nameserver /etc/resolv.conf | sed 's/nameserver //'):0"

export LIBGL_ALWAYS_INDIRECT=1


DISPLAY=:0 is not enough! (here is some more info) Ubuntu app and Windows have different IP addresses so we have to specify the correct IP for the X-server.


Run X-server on Windows: VcSrv installs as XLaunch. Select "One Large Window" and "Display": 0.


Keep the default "No client"


IMPORTANT: Select "Disable access control" checkbox


Click Next and then Finish buttons. You should get a blank window. Now in your Ubuntu terminal run:

startlxde &


You will get a "No session" dialog. It is fine, just hit "OK" button. And voila! - the full desktop appears



You can now run a terminal, Firefox, and install any Ubuntu app you want.



Thursday, June 03, 2021

Define Cloudflare DNS for a AWS S3 bucket

 It's quite a straightforward procedure if you know what to do.

1. Bucket name should exactly match your subdomain name, e.g. mycdn.mysite.com

2. Subdomains should be in one level. Buckets named like part1.mycdn.mysite.com won't work via DNS

3. Define a bucket policy granting Cloudflare servers access. See the JSON here, replace 'www.example.com' with your bucket name (mycdn.mysite.com)

4. Login to Cloudflare and in DNS section add a CNAME record:

mycdn.mysite.com => mycdn.mysite.com.s3.amazonaws.com


That's it!