Wordpress in Azure App Service unable to read files via symbolic link-CodePudding

I have setup a containerized Wordpress project as a Azure App Service based on the official Wordpress Docker image where I have made no modifications to the image itself other than adding a SSH server based on the instructions given by Azure. This is what the Dockerfile looks like:

FROM wordpress:6.0.3-php7.4

########################################## Add SSH support for Azure ##########################################
# Install OpenSSH and set the password for root to "Docker!".
RUN apt update \
    && apt install -y openssh-server \
    && rm -rf /var/lib/apt/lists/*

RUN echo "root:Docker!" | chpasswd

# Copy the sshd_config file to the /etc/ssh/ directory
COPY docker/ssh/sshd_config /etc/ssh/

# Copy and configure the ssh_setup file
RUN mkdir -p /tmp
COPY docker/ssh/ssh_setup.sh /tmp
RUN chmod  x /tmp/ssh_setup.sh \
    && (sleep 1;/tmp/ssh_setup.sh 2>&1 > /dev/null)

# Open port 2222 for SSH access
EXPOSE 80 2222
###############################################################################################################

COPY docker/script.sh script.sh
RUN chmod  x script.sh
CMD []
ENTRYPOINT ["./script.sh"]

And docker/script.sh

#!/bin/bash
exec service ssh start &
exec /usr/local/bin/docker-entrypoint.sh apache2-foreground

On the App Service I have added the WEBSITES_ENABLE_APP_SERVICE_STORAGE=true application setting to enable persistent storage as well as set the WORDPRESS_DB_HOST, WORDPRESS_DB_NAME, WORDPRESS_DB_PASSWORD and WORDPRESS_DB_USER settings to connect to my database running on a another host.

When accessing the app service page in the browser and going through the Wordpress setup I can easily upload new files which are placed in the file system at /var/www/html/wp-content/uploads/<year>/<month>/<filename> which I can then access in my browser at https://my-app-service.azurewebsites.net/wp-content/uploads/<year>/<month>/<filename>.

With Azure only persisting data written in /home I instead tried to move the /var/www/html/wp-content/uploads directory to /home/uploads and then create a symbolic link to this from the expected path like so (the symbolic link creation could then also be added to the Dockerfile to automate this during deployment):

$ cd /var/www/html/wp-content
$ mv uploads /home/uploads
$ ln -s /home/uploads uploads

Now however, when I access https://my-app-service.azurewebsites.net/wp-content/uploads/<year>/<month>/<filename> I just get an empty 400 response.

In order to see if this was some sort of limitation of Azure I decided to try something similar with the most simple Python page instead. Dockerfile:

FROM python:3.10.0
RUN mkdir -p /var/www/html
WORKDIR /var/www/html

########################################## Add SSH support for Azure ##########################################
# Install OpenSSH and set the password for root to "Docker!".
RUN apt update \
    && apt install -y openssh-server \
    && rm -rf /var/lib/apt/lists/*

RUN echo "root:Docker!" | chpasswd

# Copy the sshd_config file to the /etc/ssh/ directory
COPY docker/ssh/sshd_config /etc/ssh/

# Copy and configure the ssh_setup file
RUN mkdir -p /tmp
COPY docker/ssh/ssh_setup.sh /tmp
RUN chmod  x /tmp/ssh_setup.sh \
    && (sleep 1;/tmp/ssh_setup.sh 2>&1 > /dev/null)

# Open port 2222 for SSH access
EXPOSE 80 2222
###############################################################################################################

COPY docker/script.sh script.sh
RUN chmod  x script.sh
CMD []
ENTRYPOINT ["./script.sh"]

And docker/script.sh

#!/bin/bash
exec service ssh start &
exec python -m http.server 80

Doing the same thing here works, so it doesn't seem to be a limitation with Azure. What I don't understand, however, is that the Wordpress docker image with the symbolic link works as expected running on my local machine.

What am I doing wrong? Why does the Python project work but not the Wordpress one?

CodePudding user response：

You have to change the configuration of apache webserver so, that it can follow symbolic links:

<VirtualHost *:80>
    DocumentRoot /var/www
    <Directory />
        Options FollowSymLinks
        AllowOverride None
    </Directory>

CodePudding user response：

Solved it by adding an Alias instead of a symbolic link and disabling MMAP:

docker/extra.conf:

Alias /wp-content/uploads/ "/home/uploads/"
<Directory "/home/uploads/">
        Options Indexes MultiViews
        AllowOverride None
        Require all granted
</Directory>

<Directory "/home/uploads">
  EnableMMAP Off
</Directory>

docker/script.sh

#!/bin/bash
exec service ssh start &
exec /usr/local/bin/docker-entrypoint.sh apache2-foreground

Dockerfile

FROM wordpress:6.0.3-php7.4

########################################## Add SSH support for Azure ##########################################
# Install OpenSSH and set the password for root to "Docker!".
RUN apt update \
    && apt install -y openssh-server \
    && rm -rf /var/lib/apt/lists/*

RUN echo "root:Docker!" | chpasswd

# Copy the sshd_config file to the /etc/ssh/ directory
COPY docker/ssh/sshd_config /etc/ssh/

# Copy and configure the ssh_setup file
RUN mkdir -p /tmp
COPY docker/ssh/ssh_setup.sh /tmp
RUN chmod  x /tmp/ssh_setup.sh \
    && (sleep 1;/tmp/ssh_setup.sh 2>&1 > /dev/null)

# Open port 2222 for SSH access
EXPOSE 80 2222
###############################################################################################################

COPY docker/apache/extra.conf /etc/apache2/extra.conf
RUN cat /etc/apache2/extra.conf >> /etc/apache2/apache2.conf

COPY docker/script.sh /usr/local/bin/script.sh
RUN chmod  x /usr/local/bin/script.sh
CMD []
ENTRYPOINT ["/usr/local/bin/script.sh"]