Architecture

VARS is a microservices system organized into four layers: orchestration, web, application, and data.

System Diagram

graph TD
    subgraph clients["Client Applications"]
        va["vars-annotation"]
        vq["vars-query"]
        vg["vars-gridview"]
    end

    nginx["nginx\n(reverse proxy + SSL termination)"]

    subgraph services["Microservices"]
        annosaurus["annosaurus"]
        vs["vampire-squid"]
        oni["oni"]
        panoptes["panoptes"]
        raziel["raziel"]
        charybdis["charybdis"]
        beholder["beholder"]
        skimmer["skimmer"]
        pythia["pythia"]
    end

    subgraph db["PostgreSQL Databases"]
        db1[("M3_ANNOTATIONS")]
        db2[("M3_VIDEO_ASSETS")]
        db3[("VARS_KB")]
    end

    clients --> nginx
    nginx --> annosaurus & vs & oni & panoptes & raziel & beholder
    annosaurus --> db1
    vs --> db2
    oni --> db3
    charybdis -.->|"cross-service queries"| annosaurus & vs & oni
    pythia --> annosaurus
    skimmer --> panoptes

Layers

Orchestration

The varsq Bash script is the command-line interface for managing the deployment. It handles environment configuration, SSL certificate generation, service start/stop, database backups, and pass-through to Docker Compose.

Web

An nginx reverse proxy sits in front of all services. It handles SSL termination and routes incoming requests by path prefix:

Application

Nine microservices handle distinct responsibilities. Core services (annosaurus, vampire-squid, oni) own the primary data stores. Support services (raziel, charybdis) provide gateway and cross-service query capabilities. Processing services (beholder, skimmer, pythia) handle media and ML workflows.

See Services for details on each.

Data

Three PostgreSQL databases run within a single container: