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playgrounds2

• What is this?
• Assumptions
• What's in here?
• Install requirements
• Project secrets
• Adding a template/view
• Run the project locally
• Editing workflow
• Run Javascript tests
• Run Python tests
• Compile static assets
• Test the rendered app
• Deploy to S3
• Deploy to EC2
• Install cron jobs
• Install web services
• Add fake changelog data
• Run the remote cron
• If cron fails
• DNS Configuration)

What is this?

Describe playgrounds2 here.

Assumptions

The following things are assumed to be true in this documentation.

• You are running OSX.
• You are using Python 2.7. (Probably the version that came OSX.)
• You have virtualenv and virtualenvwrapper installed and working.

What's in here?

The project contains the following folders and important files:

• confs -- Server configuration files for nginx and uwsgi. Edit the templates then fab <ENV> render_confs, don't edit anything in confs/rendered directly.
• data -- Data files, such as those used to generate HTML.
• etc -- Miscellaneous scripts and metadata for project bootstrapping.
• jst -- Javascript (Underscore.js) templates.
• less -- LESS files, will be compiled to CSS and concatenated for deployment.
• templates -- HTML (Jinja2) templates, to be compiled locally.
• tests -- Python unit tests.
• www -- Static and compiled assets to be deployed. (a.k.a. "the output")
• www/live-data -- "Live" data deployed to S3 via cron jobs or other mechanisms. (Not deployed with the rest of the project.)
• www/test -- Javascript tests and supporting files.
• app.py -- A Flask app for rendering the project locally.
• app_config.py -- Global project configuration for scripts, deployment, etc.
• copytext.py -- Code supporting the Editing workflow
• crontab -- Cron jobs to be installed as part of the project.
• fabfile.py -- Fabric commands automating setup and deployment.
• public_app.py -- A Flask app for running server-side code.
• render_utils.py -- Code supporting template rendering.
• requirements.txt -- Python requirements.

Install requirements

Node.js is required for the static asset pipeline. If you don't already have it, get it like this:

brew install node
curl https://npmjs.org/install.sh | sh

Then install the project requirements:

cd playgrounds2
npm install less universal-jst
mkvirtualenv playgrounds2
pip install -r requirements.txt
fab update_copy
fab local_bootstrap

Project secrets

Project secrets should never be stored in app_config.py or anywhere else in the repository. They will be leaked to the client if you do. Instead, always store passwords, keys, etc. in environment variables and document that they are needed here in the README.

Adding a template/view

A site can have any number of rendered templates (i.e. pages). Each will need a corresponding view. To create a new one:

• Add a template to the templates directory. Ensure it extends _base.html.
• Add a corresponding view function to app.py. Decorate it with a route to the page name, i.e. @app.route('/filename.html')
• By convention only views that end with .html and do not start with _ will automatically be rendered when you call fab render.

Run the project locally

A flask app is used to run the project locally. It will automatically recompile templates and assets on demand.

workon playgrounds2
python app.py

Visit localhost:8000 in your browser.

To test playground edits, access playgrounds2 directory from a second command line.

workon playgrounds2
python public_app.py

Editing workflow

The app is rigged up to Google Docs for a simple key/value store that provides an editing workflow.

View the sample copy spreadsheet here. A few things to note:

• If there is a column called key, there is expected to be a column called value and rows will be accessed in templates as key/value pairs
• Rows may also be accessed in templates by row index using iterators (see below)
• You may have any number of worksheets
• This document must be "published to the web" using Google Docs' interface

This document is specified in app_config with the variable COPY_GOOGLE_DOC_KEY. To use your own spreadsheet, change this value to reflect your document's key (found in the Google Docs URL after &key=).

The app template is outfitted with a few fab utility functions that make pulling changes and updating your local data easy.

To update the latest document, simply run:

fab update_copy

Note: update_copy runs automatically whenever fab render is called.

At the template level, Jinja maintains a COPY object that you can use to access your values in the templates. Using our example sheet, to use the byline key in templates/index.html:

{{ COPY.attribution.byline }}

More generally, you can access anything defined in your Google Doc like so:

{{ COPY.sheet_name.key_name }}

You may also access rows using iterators. In this case, the column headers of the spreadsheet become keys and the row cells values. For example:

{% for row in COPY.sheet_name %}
{{ row.column_one_header }}
{{ row.column_two_header }}
{% endfor %}

Run Javascript tests

With the project running, visit localhost:8000/test/SpecRunner.html.

Run Python tests

Python unit tests are stored in the tests directory. Run them with fab tests.

Compile static assets

Compile LESS to CSS, compile javascript templates to Javascript and minify all assets:

workon playgrounds2
fab render

(This is done automatically whenever you deploy to S3.)

Test the rendered app

If you want to test the app once you've rendered it out, just use the Python webserver:

cd www
python -m SimpleHTTPServer

Deploy to S3

To deploy all assets except the playgrounds pages:

fab staging master deploy

To deploy the playgrounds pages:

fab staging remote:deploy_playgrounds

Deploy to EC2

You can deploy to EC2 for a variety of reasons. We cover two cases: Running a dynamic Web application and executing cron jobs.

For running a Web application:

• In fabfile.py set env.deploy_to_servers to True.
• Also in fabfile.py set env.deploy_web_services to True.
• Run fab staging master setup to configure the server.
• Run fab staging master bootstrap to bootstrap the database.
• Run fab staging master deploy to deploy the app.
• Run fab staging master remote:deploy_playgrounds to render and deploy the playgrounds pages.
• Run fab staging master remote:update_search_index to bootstrap Cloudsearch.

For running cron jobs:

• In fabfile.py set env.deploy_to_servers to True.
• Also in fabfile.py, set env.install_crontab to True.
• Run fab staging master setup to configure the server.
• Run fab staging master deploy to deploy the app.

You can configure your EC2 instance to both run Web services and execute cron jobs; just set both environment variables in the fabfile.

Install cron jobs

Cron jobs are defined in the file crontab. Each task should use the cron.sh shim to ensure the project's virtualenv is properly activated prior to execution. For example:

* * * * * ubuntu bash /home/ubuntu/apps/$PROJECT_NAME/repository/cron.sh fab $DEPLOYMENT_TARGET cron_test

Note: In this example you will need to replace $PROJECT_NAME with your actual deployed project name.

To install your crontab set env.install_crontab to True at the top of fabfile.py. Cron jobs will be automatically installed each time you deploy to EC2.

Install web services

Web services are configured in the confs/ folder. Currently, there are two: nginx.conf and uwsgi.conf.

Running fab setup will deploy your confs if you have set env.deploy_to_servers and env.deploy_web_services both to True at the top of fabfile.py.

To check that these files are being properly rendered, you can render them locally and see the results in the confs/rendered/ directory.

fab render_confs

You can also deploy the configuration files independently of the setup command by running:

fab deploy_confs

Add fake changelog data

Call fab create_test_revisions and look at this playground: http://localhost:8000/playground/strong-reach-playground-bowdon-ga.html

Run the remote cron

To manually run the cron job on the remote server (which will also redeploy all playgrounds), use the following command:

fab [staging|production] [master|stable] remote:process_updates

If cron fails

If the overnight cron job fails changes in process may not have been applied. The changes that were in process will have been staged in changes-in-process.json in the root directory of the repository. The accumulating changeset will have been deleted from data/changes.json. Depending on what stage of the cron job failed (processing or rendering) the changes may or may not have been applied in their entirety. It is virtually impossible to automatically handle every case that may arise, so instead you must manually investigate which changes were applied and determine if changes staged in changes-in-process.json need to be copied by into data/changes.json so they will be applied the next time the cron job is run. This can not be done automatically because it could result in duplicate playgrounds being created if, for example, the cron job failed half-way through the processing step.

If you determine that all changes have been successfully applied (even if they were not rendered), simply delete changes-in-process.json, fix the bug and rerun the cron process to render those changes.

DNS Configuration

The www version of this application CNAME'd to S3 as usual. Our internal DNS doesn't support issuing a 301 for the bare domain and S3 doesn't support bare domains unless using Route 53. To work around this we've configured a custom Nginx rule to redirect bare domain traffic to www:

server {
    listen 80;
    server_name playgroundsforeveryone.com;
    return 301 $scheme://www.playgroundsforeveryone.com$request_uri;
}

In order for this to work the default Nginx server must be modified to be the default server:

server {
    listen 80 default_server;
    client_max_body_size 15M;
    root /var/www;
    server_name $hostname "";
    include /etc/nginx/locations-enabled/*;
}