Introduction

This repository holds the configuration of the PRISM View Server (PVS).

The present README.md holds the architecture, conventions, relevant configuration, installation instructions, as well as canonical references.

Architecture

The PRISM View Server (PVS) uses various Docker images whereas core, cache, client, and preprocessor are build from this repository and the others are pulled from docker hub.

Prerequisites

Object Storage (OBS)

Access keys to store preprocessed items and caches used by all services.

Access key to input items used by preprocessor.

Networks

One internal and one external network per stack.

Volumes

In base stack

• traefik-data

Per collection

• db-data used by database
• redis-data used by redis
• instance-data used by registrar and renderer

Services

The following services are defined via docker compose files.

reverse-proxy

• based on the external traefik image
• data stored in local volume on swarm master
• reads swarm changes from /var/run/docker.sock on swarm master
• provides the endpoint for external access
• configured via docker labels

database

• based on external postgis:10 image
• DB stored in local volume on swarm master
• provides database to all other services

redis

• based on external redis image
• data stored in local volume on swarm master
• holds these keys
  • preprocessing
    • preprocess-md_queue
      • holds metadata in json including object path for image to be preprocessed
      • lpush by ingestor or manually
      • brpop by preprocessor
    • preprocess_queue
      • holds items (tar object path) to be preprocessed
      • lpush by ingestor or manually
      • brpop by preprocessor
    • preprocessing_set
      • holds ids for currently preprocessed items
      • sadd by preprocessor
    • preprocess-success_set
      • holds ids for successfully preprocessed items
      • sadd by preprocessor
    • preprocess-failure_set
      • holds ids for failed preprocessed items
      • sadd by preprocessor
  • registration
    • register_queue
      • holds items (metadata and data objects prefix - same as tar object path above) to be registered
      • lpush by preprocessor or manually
      • brpop by registrar
    • registering_set
      • holds ids for currently registered items
      • sadd by registrar
    • register-success_set
      • holds ids for successfully registered items
      • sadd by registrar
    • register-failure_set
      • holds its for failed registered items
      • sadd by registrar
  • seeding
    • seed_queue
      • time intervals to pre-seed
      • lpush by registrar or manually
      • brpop by seeder
    • seed-success_set
    • seed-failure_set

TODO: ingestor

see new service in #7 (closed)

TODO: seeder

• based on cache image
• connects to DB
• brpop time interval from seed_queue
• for each seed time and extent from DB
  • pre-seed using renderer

preprocessor

• based on preprocessor image (GDAL 3.1)
• connects to OBS
• brpop item from preprocess_queue or preprocess-md_queue
  • sadd to preprocessing_set
  • downloads image or package from OBS
  • translates to COG
  • translates to GSC if needed
  • uploads COG & GSC to OBS
  • adds item (metadata and data object paths) to register_queue
  • sadd to preprocess-{success|failure}_set
  • srem from preprocessing_set

registrar

• based on core image
• connects to OBS & database
• uses instance-data volume
• brpop item from register_queue
  • sadd ...
  • register in DB
  • (optional) store time:start/time:end in seed_queue
  • sadd/srem ...

cache

• based on cache image
• connects to OBS & database
• provides external service for WMS & WMTS
• either serves WMTS/WMS requests from cache or retrieves on-demand from renderer to store in cache and serve

renderer

• based on core image
• connects to OBS & database
• provides external service for OpenSearch, WMS, & WCS
• renders WMS requests received from cache or seeder

TODO: ELK stack

see #9 (closed)

Usage