heitorganzeli/docker-w3c-html5-validator repository overview

⁠docker-w3c-html5-validator

Docker image for W3C HTML 5 validator to be used with top-sites/brsites site analysis

⁠Building

to build this image run

$ docker build -t heitorganzeli/docker-w3c-html5-validator .

This will take some time (lots to download), performing the following tasks:

• Install Ubuntu base (16.04), Apache HTTP server, OpenJDK 8, supervisord and a few others.
• Download W3C validator and Validator.nu vnu.jar portable HTML5 validator jar (version 17.x.x).
• Install and configure W3C validator (including Validator.nu setup).
• Start Apache and Validator.nu under supervisord.

⁠Running

To start the image run:

$ docker run -d -p 45000:80 --name w3c_validator heitorganzeli/docker-w3c-html5-validator

this will start the image in a new container and expose the w3c-checker to be used on port 45000 URL is http://localhost:45000/w3c-validator/

To view IP address of the container:

$ docker ps
$ docker inspect w3c_validator

⁠Deploy

To make sure the image starts with system startup systemd can be used.

Create the following script at /etc/systemd/system/docker-w3c_validator.service

[Unit]
Description=W3C validator container
Requires=docker.service
After=docker.service

[Service]
Restart=always
ExecStart=/usr/bin/docker start -a w3c_validator
ExecStop=/usr/bin/docker stop -t 2 w3c_validator

[Install]
WantedBy=default.target

run:

$ systemctl enable docker-w3c_validator.service

⁠Health Check

The validator checker server tends to fail and stop executing checks under high load.

To prevent those performance issues to affect page validation results, the health_checker.py script was created. It try to access the local validator instance and if any exception is raised, it uses the reboot_validator.sh to restart the service.

Because a simple docker stop docker start doesn't always make the service work again, the restart script deletes the old docker image and creates a new one withe the same parameters.

⁠Maintenance

The Dockerfile should be updated whenever there is a new release on https://github.com/validator/validator/releases⁠

⁠Credits

This image is builded on top of:

• https://github.com/setelis/docker-w3c-html5-validator⁠