Server architecture for PeriodO

Fly.io

PeriodO is deployed on Fly. Fly hosts apps, which may be distributed over multiple machines. Each kind of machine is defined by a Dockerfile. These Dockerfiles can be found in the linked repositories for the various apps listed below.

Apps are grouped into organizations. Machines that are parts of apps within the same organization can communicate using unencrypted HTTP via a private network. All the apps listed below are in the ‘periodo‘ organization.

For each of the apps listed below, there is -dev version reachable on the staging.perio.do subdomain. For example, periodo-client-dev is reachable at client.staging.perio.do.

Publicly reachable apps

The machines running these apps have public IPv6 and shared IPv4 addresses.

Currently these apps run only in the IAD (Ashburn, Virginia, USA) region, but in the future they may run in multiple regions (e.g. AMS, NRT).

1. periodo-client (client.perio.do)

   • Nginx server serving JavaScript, images, maptiles, etc. for the PeriodO web client.

2. periodo-proxy (data.perio.do)

   • Nginx server that acts as a caching reverse for periodo-server (see below), which it accesses via IPv6 on the private network.
   • Has an attached volume for the HTTP cache.
   • In addition to the primary nginx process, there is an HTTP cache purging service reachable at <region>.periodo-proxy.internal:8081 on the private network.

3. periodo-corsproxy (corsproxy.perio.do)

   • Nginx server proxying requests to and responses from linked data servers that do not properly implement CORS.

4. periodo-legacy-subdomain (test.perio.do)

   • Nginx server redirecting requests to legacy PeriodO URLs.

Internally reachable apps

The machines running these apps only have private IPv6 addresses, and no public domain names or HTTPS certificates.

These apps run only in the IAD region.

1. periodo-server (periodo-server.flycast)

   • Flask HTTP server implementing PeriodO versioning and submission management.
   • Accesses periodo-translator (see below) and the cache purging service (see periodo-proxy above) via IPv6 on the private network.
   • Has an attached volume for the database.

2. periodo-translator (periodo-translator.flycast)

   • Java HTTP server implementing long-running and memory-hungry serializations of the PeriodO dataset to Turtle and CSV.
   • This server stops running when not in use, which should be most of the time.