libgd没有安装在php：5.6-cli docker中

Question

I have a project inside a container and Im trying to use the gd lib for image create.

I do inside the bash of the container this command:

apt-get install php5-gd

Nothing changes after restart and execute php -m

What should I do?

Edit:

I added to my Dockerfile:

RUN apt-get -qq update && apt-get -qq install libpng-dev
RUN docker-php-ext-install gd

I execute docker build -t [name]

But when I execute the bash and type : php -m

[PHP Modules]
Core
ctype
curl
date
dom
ereg
fileinfo
filter
ftp
hash
iconv
json
libxml
mbstring
mysql
mysqli
mysqlnd
openssl
pcntl
pcre
PDO
pdo_mysql
pdo_sqlite
Phar
posix
readline
Reflection
session
SimpleXML
SPL
sqlite3
standard
tokenizer
xml
xmlreader
xmlwriter
zip
zlib

Answer 1

Don't install gd manually. There's the docker-php-ext-install for that.

Inside the dockerfile, add:

RUN docker-php-ext-install gd

There is a bit of an annoyance with docker-php-ext-install that you have to figure out manually what dependencies you'll need. They don't resolve automatically. Due to this, the command will crash on its own, with:

configure: error: png.h not found.

If you look for the error, you will realize that you need libpng-dev.

Hence finally, the whole Dockerfile should look something like this:

FROM php:5.6-cli
RUN apt-get -qq update && apt-get -qq install libpng-dev
RUN docker-php-ext-install gd > /dev/null

docker-php-ext-install is a bit verbose in its output, hence I like to pipe its output to /dev/null. Errors and warnings will still be printed.

You can check that the image has the proper extension by running the image:

docker build -t php-gd .
docker run php-gd /bin/bash -c "php -m | grep gd"

Will print:

gd

---

Same within a docker-compose stack:

docker-compose.yml:

gd-example:
    build: .
    tty: true

docker-compose up --build -d
docker ps // to find container's name. You may also set in the config
docker exec -it docker_gd-example_1 php -m | grep gd      

---

Two sidenotes:

1. From your question is was not clear if you built your container and then run apt-get install php5-gd from it. If so, then that would only instal php5-gd within that container and everytime you recreate it, it will be gone. Always add stuff to a container from within the Dockerfile.

2. Give php:7.1-cli a try. Do you really need to support php 5.6? ;)