Thursday, January 27, 2022

Percona Monitoring and Management (PMM) update server address

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Problem

Your PMM server address has changed (IP, hostname or port). The pmm-agent running on the monitored servers can't connect anymore. This guide assumes that you are on a Linux server (Ubuntu).
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Friday, October 22, 2021

MySQL/MariaDB can not grant privileges [email protected]

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Problem

You can not grant MySQL table access to any users, getting the error: "access denied grant *.* root localhost".
The suggested fixes should fix any of those problems

  • mariadb can not grant access denied for user 'root'@'localhost'
  • MySQL grant access dennied root%localhost
  • create remote mysql users, can not grant access
  • grant identified via mysql_native_password
 

Solution

First, make sure the MySQL users table looks ok:
SELECT host,user,plugin,password,Grant_priv,Super_priv FROM mysql.user
Grant_priv - should be 'Y'
Super_priv - should be 'Y
plugin - should be 'mysql_native_password'

Fixing Grant_priv and Super_priv

UPDATE mysql.user SET Grant_priv='Y', Super_priv='Y' WHERE User='root';
FLUSH PRIVILEGES;
exit;
service mysql restart;

Update grants or reset root password

GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' IDENTIFIED BY '<password>';
GRANT ALL ON *.* TO 'root'@'localhost';
FLUSH PRIVILEGES;
exit;
service mysql restart;

Fixing plugin:

UPDATE user SET plugin='mysql_native_password' WHERE User='root';
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Thursday, March 5, 2020

Parcel building with relative asset paths when using react-router

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Problem:

You want to create a production build that can be uploaded in any folder, so it will work whether you upload it to site.com or site.com/app.

You use react-router in your app, so you also have to make sure that when you refresh a page, let's say site.com/contact-us it will still load the index.html from the correct location. The solution for this is usually to have a .htaccess file to load index.html whenever we try to load a path that doesn't exist:
RewriteEngine on

# Don't rewrite files or directories
RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]

# Rewrite everything else to index.html to allow html5 state links
RewriteRule ^ index.html [L]

Solution:

Step 1: Build parcel with relative asset paths, using --public-url ./:
parcel build src/index.html --no-source-maps --public-url ./

Step 2: The above rewrite only fixes loading the index.html file from the correct location, we still have to make sure all the other assets are loaded relative to your .htaccess file path. To do that, we load any missing file to our target folder:
# If we try to load a missing resource file, load it from folder root
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_URI} ^.*\.(jpg|css|js|gif|png|ico|mp3)$ [NC]
RewriteRule .+?([^\/]*\.*)$ $1 [L]

Step 3: Unforunately so far I don't have a solution for setting a relative path for react-router, so you still have to manually set the public url:
export const browserHistory = createBrowserHistory({
    basename: '/app'
});
This makes sure that when you have a router link to /contact-us it will actually link to /app/contact-us.
The good part is this path will only be referenced once in your build code, so you can easily change it by replacing that string even after the build was done.

Final .htaccess:

Those are the rewrites that make sure your index.html and assets are loaded correctly, even when you move your built app into a different folder.
RewriteEngine on
# Don't rewrite files or directories
RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]

# If we try to load a missing resource file, load it from folder root
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_URI} ^.*\.(jpg|css|js|gif|png|ico|mp3)$ [NC]
RewriteRule .+?([^\/]*\.*)$ $1 [L]

# Rewrite everything else to index.html to allow html5 state links
RewriteRule ^ index.html [L]

I am still thinking of a solution for using a relative basename in react-router, so that way links will also be correct when placed in any subfolder or subdomain.
Let me know if you know a way to use a relative basename for browserHistory.

Later edit: A hacky solution for relative basename

I did manage to figure out a dynamic solution for having a relative basename. It's based on the idea that once our app loads, we could detect the base folder based on the current location.pathname.
I know all the possible start values for all my Routes, which in my case are /sites or /settings. Once we know this, we can safely say that anything that is before those strings in the URL is the base path of our app.

const possibleStartPaths = ['/sites', '/settings'];
// Select everything in the pathname that appears before those strings.
// For example /subfolder/myapp/sites returns /subfolder/myapp
const baseMatch = window.location.pathname.match(
    new RegExp(`(.+?)(?:${possibleStartPaths.map((x) => x.replace('/', '\\/')).join('|')})`)
);
const basename = baseMatch ? baseMatch [1] + '/' : window.location.pathname;
export const browserHistory = createBrowserHistory({ basename });
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Monday, March 2, 2020

Detect Locale Change in React i18next

2 comments
I was looking for a way to re-render Chart.js charts when the react-i18next locale was changed. Looking through their documentation at https://react.i18next.com/ I didn't see any hook that could be used to detect current locale.

Problem

When the translation language is changed I also change the moment.js locale for my time-series charts in Chart.js. I need a way to detect language changes so I can rerender the charts.

Solution

Add the locale ISO code into the translation files and use that.
What I did was:
  1. Add a new translation key in my translation files: 'current_locale': 'en' for the English translation, 'current_locale': 'ro' for Romanian.
  2. Use the useTranslation() hook:
    const { t } = useTranslation();
    
  3. Rerender the chart when language is changed:
    useEffect(() => {
       // This will be now called when the locale is changed
    }, [t('current_locale')])
    

Improvements

You can also create a custom hook if you want:
export const useLocale = () => {
    const { t } = useTranslation();
    return t('current_locale');
};
Now you can use the locale value directly:
const locale = useLocale();
useEffect(() => {
   // This will be now called when the locale is changed
}, [locale])

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Friday, February 28, 2020

Finally switched to HTTPS!

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Switching this blog to HTTPS took a lot longer a was harder than expected due to some Blogger bugs. The Google rankings were hit hard because the blog was not served over HTTPS, this made me spend more time and look for a solution.


Blogger: Whoops, that's an error! (bX-2kvjq7)

I have tried switching this Blogger site to HTTPS multiple times, but it never worked because whenever I switched HTTPS Availability to Yes in the settings I got this error: Whoops, that's an error! (bX-2kvjq7).




The actual problem: domain validation

The solution in my case was to remove the custom domain name, add it again and complete the DNS  validation process using the CNAME and TXT entries.
To remove your domain name go to Settings -> Basic -> Publishing -> Edit and delete the domain name and save.


After that I could enable HTTPS Availability without any error.

While writing this post things broke again

While taking the above screenshots I disabled HTTPS availability, after turning it on again the blog was stuck in a permanent 301 redirect loop, leading to ERR_TOO_MANY_REDIRECTS.
I do use Cloudflare on top of my Blogger blog, but this happens probably because of some Blogger bug and compatibility with Cloudflare.

I was not able to fix this redirect loop while keeping HTTPS availability to Yes, but after switching it to No I just enforced the Always Use HTTPS rule in Cloudflare and now it seems to work.

This solution might also work for other error codes such as bX-aa1bde or bX-gtb2wc.


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Monday, June 19, 2017

Why LiveCoding (now LiveEdu) failed

9 comments

Inception

For those who don't know livecoding.tv first started as a live streaming platform for software development (think of it as twitch for programmers). Initially, I was really excited about this idea and I have even been streaming on the site for 111 hours gathering approximately 100 followers. I wasn't the best streamer, my mic was bad, I seldom talked but the projects I showed were interesting to create and watch.

No one was earning money at the beginning (not streamers, nor livecoding), but if I recall correctly they soon added a "recruiter" plan which might have lead to some earnings for the platform. 

Time to make money!

So far so good, the community was growing, more and more streamers came to the site (even though they weren't earning anything) and viewers were interested in this idea.

It then all went downhill.

They soon added a "PRO" plan so that streamers could stream "premium content" that only PRO users could watch. It was good on paper, but they made two big mistakes:
  • The price of $25/mo was way too high in my opinion and they were referring to it as a "no-brainer". 
  • The percentage that the streamers got from those $25 was not that great. It was zero. This is where probably a lot of streamers (even though they were not earning anything until then) felt used as they were the ones providing the content but they were not receiving anything in exchange.
I recommend reading this discussion in the comment section where they announced the PRO plan. The main issue that I see in their attitude is that they thought it was fine to put themselves above the streamers. Deciding that a source of income is needed while ignoring the content creators was justified by saying "don't worry, we will care about you in the future!".

Why pivot if it's going well?

After they reduced the PRO plan to $9.99 and genuinely seemed interested about the streamers, they made the bold move of rebranding livecoding.tv to liveedu.tv. If you ask me, this is by far the biggest mistake they made. I don't know their reasoning, but it was probably related to making the platform more general, an educational platform not necessarily for coding. They seem to try turning the platform more into a directory of premium videos (udemy?). If that's the case, why keep the live in the name? 

The name livecoding was actually a good website name: memorable, easy to pronounce, easy to write and it was accurately describing what the site was about.

Current issues

I will name a few issues that really stop me from using or recommending liveedu.tv anymore, but first let's see how friendly is it for new users.

I tried today accessing liveedu.tv to see if it's worth going back.  I clicked to watch the stream featured on the homepage.


Most users leave when they see this, but I added the site to the ad-blocker exceptions. 


If I were a new user I might have left immediately not wanting to waste time creating a new account. Luckily I was an old user so I logged into my existing account (well, it wasn't that easy, because they changed their domain and my password manager did not autofill my credentials and I had to go search for it).
After I logged in I got the same screen as above but saying "SOMETHING WENT WRONG",  message which seems to show on some streams.

Now, a list of other issues that just makes me wonder how a good idea turned out so bad:
  • The interface is a mess. The site is very "jumpy", meaning that the entire layout is recalculated several times during page load as some elements are dynamically added but without having their space allocated beforehand. They are still updating it, but it seems to be for the worse. For example, I let you judge the way white space is used in the new chat section...

  • You can't really watch content if you are not a PRO member. There are 15s ads before starting to watch any stream and too many banners, sections and pages asking you to go "PRO".
  • At the time of writing this post, there are only 4 streamers online and I can't even get to load two of them.
  • Twitch now has a programming community.

Conclusion

I have only described the bad parts that I see, feel and felt from my perspective, the perspective of a streamer and occasional viewer. Let me know if you think I have been to harsh judging this site , site behind which is probably an amazing team of developers.

In conclusion, for me LiveEdu.tv is a platform that is too bulky, difficult to use and lacks enough good content to be worth using. I really wanted to see again and interact with the old spirit of LiveCoding.tv, a lean platform on which both the viewer and streamer are respected, but that spirit seems to have been stolen by the Greed Monster.

PS: LiveEdu might actually be a success and their premium projects directory might have a bigger community than I expect, but I have not yet had any contact with that side of the platform.

Later edit (20 June): LiveEdu just released a blog post introducing the new subscriber plans AND limiting the amount of content you can watch for free. I don't understand why they keep focusing on pricing instead of the content.

Date: 19 June 2017
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