MySQLi not found dockerized php

Question

I'm trying to dockerize my website. I've got Nginx and PHP up and running and it's working find except I can't connect to a db. When the page is loaded I get the error:

Fatal error: Uncaught Error: Class 'MySQLi' not found in /private/conn.php:8 Stack trace: #0 /public_html/index.php(2): require() #1 {main} thrown in /private/conn.php on line 8

My connection line on line 8 is:

$db = new mysqli("$host", "$user", "$pass", "$db", "$port");

Now this used to work fine on my old set up but since moving to a new one and installing php7.1.5 I can't get it running. Now, I haven't used the mysqlnd so this may be a misunderstanding on my part but the mysqlnd includes the mysqli driver.

Output of phpinfo:

How can I get this running? Or should I be using a different driver now?

Answer 1

You need to enable the php extension in your Dockerfile:

FROM php:7
RUN docker-php-ext-install mysqli

There is no need to touch php.ini.

Answer 2

i had similar issue with
php:7-apache image, which by default will not have mysqli installed
you can verify this inside the container

$ docker exec -it <phpcontainerid> bash  

inside the docker container bash terminal

# docker-php-ext-enable mysqli

if mysqli is not installed which you will come to know from the output of above command

# docker-php-ext-install mysqli

then i commited this change so the same image

$ docker commit -p <phpcontainerid> <new or same image name>

Answer 3

works for me:

inside php container:

docker-php-ext-install mysqli

apachectl restart

• docker images: mysql, php:7.2.30-apache

https://github.com/docker-library/php/issues/391