# Princeton Geniza Project

Princeton Geniza Project (PGP or Geniza for short) is a custom
Python/Django web application. Version 4.0-4.x developed by CDH.

- Production site: https://geniza.princeton.edu/en/
- software: https://github.com/Princeton-CDH/geniza/

The public site is accessed through the PUL load balancer (NGINX+).

There are two VMs for each environment (production, staging) running in
parallel with the same content and application code. The load balancer
routes traffic between the two VMs; redundancy allows for one host to
be taken down for maintenance without taking the site down.

Both instances of the application connect to the same PostgreSQL
database and Solr collection. User-uploaded content is stored on a
shared NFS drive accessible to both machines.

```mermaid
flowchart TD
    nginxplus[NGINX+ ] -- proxies --> nginx
    nginxplus[NGINX+ ] -- proxies --> nginx2
    subgraph genizavm1 [Geniza VM1]
     nginx[NGINX] -- runs --> Django1
     nginx -- serves --> static1[static assets]
    end
    subgraph genizavm2 [Geniza VM2]
     nginx2[NGINX] -- runs --> Django2
     nginx2 -- serves --> static2[static assets]
    end
    Django1 --> db[(PostgreSQL)]
    Django1 --> solr[(Solr)]
    Django2 --> db[(PostgreSQL)]
    Django2 --> solr[(Solr)]
    genizavm1 --> nfs[/NFS\]
    genizavm2 --> nfs[/NFS\]
```


## Related playbooks

- The Geniza application can be deployed to staging or production with
  the `geniza` playbook.
- Production data can be replicated to staging with the `replicate`
  playbook (does not currently include Solr data; requires reindexing
  after replicate)

## Other details

Load balancer proxy configuration is managed in
[PUL princeton_ansible](https://github.com/pulibrary/princeton_ansible)

- [production config](https://github.com/pulibrary/princeton_ansible/blob/main/roles/nginxplus/files/conf/http/cdh_prod_geniza.conf)
- [staging config](https://github.com/pulibrary/princeton_ansible/blob/main/roles/nginxplus/files/conf/http/cdh_test_geniza.conf)