How to run cron and web application in same container? - php

Question

I am new to docker. Hardly I have containerized my php application to run it in the web interface. But I have some cron to run with it. I learnt how to create separate cron image and run it from How to run a cron job inside a docker container?. But my use case is different. I need to use the php files from my php application container which seems not possible from my way. I tried creating the docker-compose.yml as follow to see if it would work
docker-compose.yml:
version: "3"
services:
app:
build:
context: ./docker/php
container_name: 'app'
restart: 'always'
ports:
- "80:80"
- "443:443"
links:
- db
volumes:
- ${DOCUMENT_ROOT-./src}:/var/www/html
- ${PHP_INI-./docker/php/php.ini}:/usr/local/etc/php/php.ini
- ${VHOSTS_DIR-./docker/apache2/vhosts}:/etc/apache2/sites-enabled
- ${LOG_DIR-./docker/logs/apache2}:/var/log/apache2
extra_hosts:
- "test.local:127.0.0.1"
hostname: cloudservice.local
domainname: local
#entrypoint: sh /var/www/html/cron.sh
As I have commented entry point here and if I do docker-compose up, everything works perfectly fine, My Dockerfile is as under
Dockerfile:
FROM php:7.2.27-apache
RUN apt-get update
RUN apt-get install -y cron
RUN apt-get -y update --fix-missing
RUN apt-get upgrade -y
# Install useful tools
RUN apt-get -y install apt-utils nano wget dialog
# Install important libraries
RUN apt-get -y install --fix-missing apt-utils build-essential git curl libcurl4 libcurl4-openssl-dev zip
# Composer
RUN curl -sS https://getcomposer.org/installer | php -- --install-dir=/usr/local/bin --filename=composer
# Install xdebug
#RUN pecl install xdebug-2.5.0
#RUN docker-php-ext-enable xdebug
# Other PHP7 Extensions
RUN apt-get -y install libsqlite3-dev libsqlite3-0 default-mysql-client
RUN docker-php-ext-install pdo_mysql
RUN docker-php-ext-install pdo_sqlite
RUN docker-php-ext-install mysqli
RUN docker-php-ext-install curl
RUN docker-php-ext-install tokenizer
RUN docker-php-ext-install json
RUN apt-get -y install zlib1g-dev
RUN docker-php-ext-install zip
RUN apt-get -y install libicu-dev
RUN docker-php-ext-install -j$(nproc) intl
RUN docker-php-ext-install mbstring
RUN apt-get install -y libfreetype6-dev libjpeg62-turbo-dev libpng-dev
RUN docker-php-ext-configure gd --with-freetype-dir=/usr/include/ --with-jpeg-dir=/usr/include/
RUN docker-php-ext-install -j$(nproc) gd
RUN pecl install redis-5.1.1 \
&& docker-php-ext-enable redis
# Enable apache modules
RUN a2enmod rewrite headers
My cron.sh file is as under
#!/usr/bin/env bash
# Ensure the log file exists
touch /var/www/html/logs/crontab.log
# Ensure permission on the command
chmod a+x /var/www/html/cron-local/hn-shc-rapid-daily.sh
# Added a cronjob in a new crontab
echo "* * * * * bash /var/www/html/cron-local/hn-shc-rapid-daily.sh >> /var/www/html/logs/crontab.log 2>&1" > /etc/crontab
# Registering the new crontab
crontab /etc/crontab
# Starting the cron
/usr/sbin/service cron start
# Displaying logs
# Useful when executing docker-compose logs mycron
tail -f /var/www/html/logs/crontab.log
But with the entry point commented, i cannot run cron. If i don't comment entrypoint, then cron runs, my web application doesn't. Is there any possibility to fix this?
Thanks

Answer 1

At the end of the docker file i added the following code after removing
RUN a2enmod rewrite headers
# Copy hello-cron file to the cron.d directory
COPY hello-cron /etc/cron.d/hello-cron #just any name
# Give execution rights on the cron job
RUN chmod 0644 /etc/cron.d/hello-cron
# Apply cron job
RUN crontab /etc/cron.d/hello-cron
# Create the log file to be able to run tail
RUN touch /var/log/cron.log
# Enable apache modules
RUN a2enmod rewrite headers
CMD cron && /usr/sbin/apache2ctl -D FOREGROUND
and cron.sh was changed to
* * * * * echo "hello world" >> /var/www/html/logs/crontab.log 2>&1
This worked for me. I need not have to add entry neither on docker-compose nor on docker file, but I guess entry also would work.
I don't know if this is the right way to do. If anyone would give me more advance idea, I would be happy to give it a try.
Thanks

Answer 2

I think it's better if you specify the entry point in the docker-compose file without "sh" in front of it. Remember that declaring a new entrypoint in the docker-compose file overwrites the entrypoint in the dockerfile. Link
I would advise you to create your own Entrypoint Script which will execute your crons in the container CMD ["/entrypoint.sh"]
Example:
Create an file and named "entrypoint.sh" or whatever and save it in the same folder where your Dockerfile is located. In this file push your Content from your cron.sh.
RUN apt-get install -y libfreetype6-dev libjpeg62-turbo-dev libpng-dev
RUN docker-php-ext-configure gd --with-freetype-dir=/usr/include/ --with-jpeg-dir=/usr/include/
RUN docker-php-ext-install -j$(nproc) gd
RUN pecl install redis-5.1.1 \
&& docker-php-ext-enable redis
# Enable apache modules
RUN a2enmod rewrite headers
COPY entrypoint.sh /
RUN chmod +x /entrypoint.sh
CMD ["/entrypoint.sh"]
But you could also just add your cron directly in the docker file.
...
# Enable apache modules
RUN a2enmod rewrite headers
COPY your-cron.cron /
RUN crontab /your-cron.cron
...