Docker映像构建（摆脱依赖关系）

Question

I am building a php docker image from the base image of php:7.2-fpm-alpine , where some custom php extension is needed.

Like the following commands for installing dependencies and some extra extension.

RUN apk upgrade --update && apk add libpng-dev libjpeg-turbo-dev \
 freetype-dev libbz2 libxml2-dev libxml2 bzip2-dev libxslt libxslt-dev \
 && docker-php-ext-install bcmath calendar gd hash zip pdo_mysql

Since I need to manually install dependencies for my extensions, compiled it to get something like bcmath.so gd.so .

I am thinking if I can get rid off those dependencies and just copy the *.so into the new image, Since I am planting to use a multi-stage build in Dockerfile.

The question is can I get rid of the GCC+ compiler and some other dependencies(openssl, curl)? and just grape the compiled result to the new image?

Answer 1

Create a directory on host operating system. Use Docker Volume to mount your directory to Container, to the place where your *.so are supposed to be found.

Answer 2

Once you've compiled the extensions, you should be able to get rid of the -dev packages at least. The -dev packages include things like the c source header files (.h).

So in your example, you install libxml2-dev and libxml2. In this case, the libxml2 package is the files needed to run the code, libxml2-dev is the package needed to compile any code that uses libxml2. When you compile the extension for PHP, the extension doesn't include all of the binaries to run the particular feature, it usually relies on the packages installed on the OS.

You could get rid of gcc, and some of the support stuff, but you may need to go through a process of removing a package and then testing if anything breaks.

It may also be possible to remove some of the modules within PHP, again this depends on your code and what that does. Although this is beyond what I've done and I'm not sure of the benefits of doing this.