Deviser Overview

Deviser is a specialized maintenance service within the Krateo Composable Portal (KCP) backend. Its primary responsibility is to manage the lifecycle, partitions, and data retention of the PostgreSQL databases used by Krateo.

Key Responsibilities

• PostgreSQL Partition Management: Automatically creates and maintains daily partitions for time-series data (e.g., resources and events), ensuring optimal query performance.
• Data Retention & Quotas: Enforces retention policies by dropping expired partitions and managing storage quotas.
• Soft-Delete Purge: Periodically performs hard-deletes of resources marked as soft-deleted in the krateo_resources table.
• Database Readiness: Ensures the database schema is correctly applied and ready for use by other KCP components at startup.

How it works

Deviser runs a scheduled main loop that performs the following routine:

1. DB Connect: Checks connectivity to the PostgreSQL instance.
2. Schema Check: Validates and applies required SQL schemas.
3. Partition Ensure: Creates partitions for a configured number of days ahead.
4. Partition Maintenance: Drops old partitions based on expiration or storage quotas.
5. Soft-Delete Purge: Cleans up resources that have been marked for deletion.

Technical Reference

Environment Variables

Name	Description	Default
PORT	Service port for health probes (/livez, /readyz)	8081
DB_HOST	Database host	localhost
DB_PORT	Database port	5432
DB_NAME	Database name	-
DB_USER	Database username	-
DB_PASS	Database password	-
DB_PARTITIONS_DAYS	Number of days ahead to create partitions	7
PM_MAX_PARTITIONS_SIZE	Maximum allowed total size of all partitions	10GB
PM_RETENTION_DAYS	Number of days to retain partitions	2
PM_TRIGGER_RATIO	Fraction of max size to trigger cleanup	0.75
PM_DRY_RUN	If true, cleanup actions are logged but not executed	false
OTEL_ENABLED	Enable OpenTelemetry metrics exporter	true

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Documentation