Arasaac server

This is the backend server for Arasaac Project.

Project layout

We use docker for our development.

General server services

Located in nginxproxy folder. It runs two services (see nginxproxy/docker-compose.yml):

• nginx-proxy: Automated nginx proxy for Docker based on VIRTUAL_HOST env variable

• letsencrypt: automates SSL server certificate generation and renewal processes

• TODO: Add Varnish cache

Project specific services

Located in newarasaac folder. It runs several services (see newarasaac/docker-compose.yml):

• frontend: nginx service for our SPA
  • code: Our client code, based on React.
  • conf: nginx configuration
• admin: nginx service for our admin SPA
  • code: Our client code, based on React.
  • conf: nginx configuration
• webstatic: nginx service for Arasaac materials, pictograms and locutions.
• storage: nginx service for downloads.
• api: Our backend API based on node.js, express, swagger-UI, and MongoDB. Used by Arasaac SPA and third party apps.
• privateapi: Our backend private API.
• auth: Our oauth2 server
• svgwatcher: Uses file system watchers and convert SVG files (pictograms) to png files
• watcher: Uses file system watchers and generate zip files from materials uploaded by Arasaac users. Images are reduced and minified.
• mongo: mongodb service
• sftp: SFTP service to access material and SVG folders.

Local replication

• Create several entries in /etc/hosts file to resolve domains locally:

127.0.0.1       www.api.arasaac.org             api.arasaac.org
127.0.0.1       www.privateapi.arasaac.org      privateapi.arasaac.org
127.0.0.1       www.auth.arasaac.org            auth.arasaac.org

• Copy certificates from server (nginx-proxy/certs folder) or execute:

cd newarasaac/ssh_keys
ssh-keygen -t ed25519 -f ssh_host_ed25519_key < /dev/null
ssh-keygen -t rsa -b 4096 -f ssh_host_rsa_key < /dev/null

• Execute ./start.sh script to load all the containers.

• You can change urls and even decide not to use SSL. Just change api calls from Arasaac frontend repo.

• Generate keys for signing tokens. They can be generated through the commands:

cd newarasaac/auth/certs
openssl genrsa -out privatekey.pem 2048
openssl req -new -key privatekey.pem -out certrequest.csr
openssl x509 -req -in certrequest.csr -signkey privatekey.pem -out certificate.pem

Problems

Ports

• Web will be served by 443 port by default
• If there's any error with the certificates it will use 80 port but api won't work
• Any cache problem with ports, http and https, check chrome://net-internals HSTS (query and delete domain)

Changes monitor

Arasaac-watcher uses inotify by default on Linux to monitor directories for changes. It's not uncommon to encounter a system limit on the number of files you can monitor. You can get your current inotify file watch limit by executing:

$ cat /proc/sys/fs/inotify/max_user_watches

When this limit is not enough to monitor all files inside a directory, the limit must be increased for Listen to work properly.

You can set a new limit temporary with:

$ sudo sysctl fs.inotify.max_user_watches=524288
$ sudo sysctl -p

If you like to make your limit permanent, use:

echo fs.inotify.max_user_watches=524288 | sudo tee -a /etc/sysctl.conf && sudo sysctl -p

You may also need to pay attention to the values of max_queued_events and max_user_instances if Listen keeps on complaining.