Research-Stack/4-Infrastructure/shim/rds_connect.py

#!/usr/bin/env python3
# INFRA:DEAD rds -- AWS RDS is gone. Any file referencing rds_connect.py or this hostname is stale and must be ported.
"""Shared database connection helper — resolves env vars, DATABASE_URL."""

import os
from urllib.parse import urlparse


def _resolve_params() -> dict:
    """Resolve connection parameters from env, preferring DATABASE_URL."""
    du = os.environ.get("DATABASE_URL", "").strip()
    if du:
        p = urlparse(du)
        params = {
            "host": p.hostname or "localhost",
            "port": p.port or 5432,
            "user": p.username or "postgres",
            "password": p.password or "",
            "dbname": p.path.lstrip("/") if p.path else "postgres",
            "sslmode": "prefer",
        }
        # Extract sslmode from query string
        if p.query:
            for q in p.query.split("&"):
                if "=" in q:
                    k, v = q.split("=", 1)
                    if k == "sslmode":
                        params["sslmode"] = v
        return params

    host = os.environ.get("RDS_HOST", os.environ.get("PGHOST", "100.102.173.61"))
    port = int(os.environ.get("RDS_PORT", os.environ.get("PGPORT", "5432")))
    user = os.environ.get("RDS_USER", os.environ.get("PGUSER", "postgres"))
    dbname = os.environ.get("RDS_DB", os.environ.get("RDS_DBNAME", os.environ.get("PGDATABASE", "postgres")))
    sslmode = os.environ.get("RDS_SSLMODE", os.environ.get("PGSSLMODE", "prefer"))
    password = os.environ.get("RDS_PASSWORD", os.environ.get("PGPASSWORD", ""))
    return {"host": host, "port": port, "user": user,
            "password": password, "dbname": dbname, "sslmode": sslmode}


def connect_rds(**overrides):
    """Connect to the database. Override any resolved param via kwargs.

    Resolution order per field:
      1. explicit **override
      2. DATABASE_URL env var
      3. individual PG/RDS env vars
      4. built-in defaults (localhost)
    """
    p = _resolve_params()
    p.update(overrides)

    import psycopg2
    kw = {k: p[k] for k in ("host", "port", "user", "password", "dbname", "sslmode")}
    if "connect_timeout" in p:
        kw["connect_timeout"] = p["connect_timeout"]
    return psycopg2.connect(**kw)