Skip to content

Latest commit

 

History

History
180 lines (123 loc) · 8.02 KB

CONTAINERS.md

File metadata and controls

180 lines (123 loc) · 8.02 KB
Raw

Hyrax-in-a-Container

Our goal is to provide a practical, reusable "reference environment for applications. The first step is providing on on-ramp for Hyrax engine development. Then providing help with Hyrax-based application development. Finally, providing better guidance around deployment.

Where are we at? It's complicated. What we have below is experimental support, but one that we want to push towards. We need your help to keep pushing in this direction. So dig in and prepare to get your hands dirty.

The Hyrax Engine Development is further along than the Docker Image for Hyrax-based Applications which is further along than Deploying to Production.

Hyrax Engine Development

We support a docker-compose-based development environment for folks working on the Hyrax engine. This environment is substantially more like a Hyrax production setup than the older fedora_wrapper/solr_wrapper approach.

First, make sure you have installed Docker. Then clone the Hyrax repository.

Within your cloned repository, tell Docker to get started installing your development environment:

docker-compose build
docker-compose up

This starts containers for:

  • a hyrax test application (.dassie);
  • Fedora
  • Solr
  • Postgresql
  • Redis
  • Memcached
  • SideKiq (for background jobs)

It also runs database migrations. This will also bring up a development application on http://localhost:3000.

To stop the containers for the Hyrax-based application, type Ctrl+c. To restart the containers you need only run docker-compose up.

Note: Starting and stopping Docker in this way will preserve your data between restarts.

Note: I (Jeremy) encountered a problem using docker-compose build. I ran bundle update in ./hyrax as well as within ./hyrax/.dassie. That appeared to clear up the problem of a failure to build a gem.

Code Changes and Testing

With docker-compose up running, any changes you make to your cloned Hyrax code-base should show up in http://localhost:3000; There may be cases where you need to restart your test application (e.g. stop the containers and start them up again).

Any changes you make to Hyrax should be tested. You can run the full test suite using the following command:

docker-compose exec -w /app/samvera/hyrax-engine app sh -c "bundle exec rspec"

Let's break down the above command:

docker-compose exec
Tell docker to run the following:
-w /app/samvera/hyrax-engine
In the working directory "/app/samvera/hyrax-engine" (e.g. your cloned Hyrax repository)
app
of the container named "app"
sh -c
run the following shell script
"bundle exec rspec"
run the rspec test suite

Note: The bundle exec rspec portion of the command runs the whole test suite. See the rspec command documentation for how to refine your test runs.

Note: The /app/samvera/hyrax-webapp is analogous to the .internal_test_app that we generate as part of the Hyrax engine Continuous Integration.

The Docker Container Named "app"

As a developer, you may need to run commands against the Hyrax-based application and/or the Hyrax engine. Examples of those commands are rails db:migrate and rspec. You would run rails db:migrate on the Hyrax-based application, and rspec on the Hyrax engine.

In the engine development app container, the .dassie test Hyrax-based application is setup as a docker bind mount to /app/samvera/hyrax-webapp, and your local development copy of Hyrax (eg. the clone samvera/hyrax) is bound to /app/samvera/hyrax-engine. Those directories are defined as part of the Dockerfile configuration. . What does this structure mean? Let's look at an example. The following command will list the rake tasks for the Hyrax-based application running in Docker:

docker-compose exec -w /app/samvera/hyrax-webapp app sh -c "bundle exec rake -T"

And this command lists the rake tasks for the Hyrax engine that is in Docker:

docker-compose exec -w /app/samvera/hyrax-engine app sh -c "bundle exec rake -T"

In the two examples, note the difference in the -w switch. In the first case, it's referencing the Hyrax-based application. In the latter case, it's referencing the Hyrax engine.

Debugging

I (Jeremy) find myself wanting to debug the application. This requires a somewhat different approach than running Hyrax bare-metal. You need to use docker attach to debug the running docker instance.

  1. With docker-compose up running open a new Terminal session.
  2. In that new Terminal session, using docker container ls find the "CONTAINER ID" for the hyrax-engine-dev.
  3. With the "CONTAINER ID", run docker attach <CONTAINER ID>.

This advice comes from Debugging Rails App With Docker Compose: How to use Byebug in a dockerized rails app.

Troubleshooting

Bad Address SOLR

With docker-compose up running, if you see the following, then there may be issues with file permissions:

db_migrate_1  | waiting for solr:8983
db_migrate_1  | nc: bad address 'solr'

Check the Docker application logs and look for permission errors:

Executing /opt/docker-solr/scripts/precreate-core hyrax_test /opt/solr/server/configsets/hyraxconf
cp: cannot create directory '/var/solr/data/hyrax_test': Permission denied

The solution that appears to work is to docker-compose down --volumes; This will tear down the docker instance, and remove the volumes. You can then run docker-compose up to get back to work. Note: the --volumes switch will remove all custom data.

Docker Image for Hyrax-based Applications

We also provide a base image which can be reused for your Hyrax applications: hyrax.

echo "FROM samveralabs/hyrax" > Dockerfile

This is for applications that mount Hyrax and is separate from the docker containers for Hyrax engine development.

Maintaining

We publish several Hyrax images to hub.docker.com under the samveralabs group. To build them, do:

# build an image for an app using Postgresql (`gem 'pg'`)
docker build --target hyrax --tag samveralabs/hyrax:(git rev-parse HEAD) .
docker push samveralabs/hyrax:(git rev-parse HEAD)

# or; build a development image with sqlite
docker build --target hyrax --tag samveralabs/hyrax:(git rev-parse HEAD)-sqlite --build-arg DATABASE_APK_PACKAGE="sqlite" .
docker push samveralabs/hyrax:(git rev-parse HEAD)-sqlite

We also publish an image for the stable test application dassie:

docker build --target hyrax-engine-dev --tag samveralabs/dassie:(git rev-parse HEAD) .

docker tag samveralabs/dassie:(git rev-parse HEAD) samveralabs/dassie:$HYRAX_VERSION

docker push samveralabs/dassie:(git rev-parse HEAD)
docker push samveralabs/dassie:$HYRAX_VERSION

Deploying to Production

Also under development is a Helm chart, which we are developing into a robust, configurable production environment for Hyrax applications.

If you have a Kubernetes cluster configured (kubectl cluster-info), you can deploy the dassie test applications with:

helm dependency update chart/hyrax
helm install -n hyrax --set image.tag=(git rev-parse HEAD) dassie chart/hyrax