PostgreSQL to Elasticsearch/OpenSearch sync

• PGSync is a middleware for syncing data from Postgres to Elasticsearch/OpenSearch or OpenSearch.
• It allows you to keep Postgres as your source of truth data source and expose structured denormalized documents in Elasticsearch/OpenSearch.

Requirements

• Python 3.7+
• Postgres 9.6+
• Redis 3.1.0
• Elasticsearch 6.3.1+ or OpenSearch 1.3.7+
• SQlAlchemy 1.3.4+

Postgres setup

Enable logical decoding in your Postgres setting.

• You also need to set up two parameters in your Postgres config postgresql.conf

  wal_level = logical

  max_replication_slots = 1

Installation

You can install PGSync from PyPI:

$ pip install pgsync

Config

Create a schema for the application named e.g schema.json

Example schema

Example spec

.. code-block::

[
    {
        "database": "[database name]",
        "index": "[Elasticsearch or OpenSearch index]",
        "nodes": {
            "table": "[table A]",
            "schema": "[table A schema]",
            "columns": [
                "column 1 from table A",
                "column 2 from table A",
                ... additional columns
            ],
            "children": [
                {
                    "table": "[table B with relationship to table A]",
                    "schema": "[table B schema]",
                    "columns": [
                      "column 1 from table B",
                      "column 2 from table B",
                      ... additional columns
                    ],
                    "relationship": {
                        "variant": "object",
                        "type": "one_to_many"
                    },
                    ...
                },
                {
                    ... additional children
                }
            ]
        }
    }
]

Environment variables

Setup environment variables required for the application

SCHEMA='/path/to/schema.json'

ELASTICSEARCH_HOST=localhost
ELASTICSEARCH_PORT=9200

PG_HOST=localhost
PG_USER=i-am-root # this must be a postgres superuser or replication user
PG_PORT=5432
PG_PASSWORD=*****

REDIS_HOST=redis
REDIS_PORT=6379
REDIS_DB=0
REDIS_AUTH=*****

Running

Bootstrap the database (one time only)

• $ bootstrap --config schema.json

Run pgsync as a daemon

• $ pgsync --config schema.json --daemon