Environment Variables

注意

This page is intended for the engineering team deploying and maintaining the application. Environment variable values should never be shared outside of your secure secrets management system.

Required variables

Variable	Format	Description
POSTGRES_USER	string	Database user name
POSTGRES_PASSWORD	string	Database user password
POSTGRES_DB	string	Database name
CLOUD_SQL_INSTANCE_CONNECTION_NAME	project:region:instance	Full Cloud SQL connection identifier
GOOGLE_SERVICE_ACCOUNT_BASE64	base64 string	GCP service account JSON, base64-encoded

How GOOGLE_SERVICE_ACCOUNT_BASE64 works

The service account JSON is stored as a base64-encoded string to allow single-line storage in Vercel’s environment variable system. At runtime, lib/db.ts decodes this string, writes the JSON to a temporary file, passes it to the Cloud SQL connector, then deletes the temporary file immediately. The credential never persists on disk between requests.

To generate the base64 value from a service account key file:

base64 -i service-account.json | tr -d '\n'

GCP service account requirements

The service account must have:

• Cloud SQL Client IAM role on the GCP project
• SELECT privilege on all five bwts_iot_* tables in PostgreSQL

No write access or superuser privileges are required.

Setting variables on Vercel

Variables are configured in the Vercel project dashboard under Settings → Environment Variables. Set each variable for the Production, Preview, and Development scopes as appropriate. Re-deploy after any variable change.

CLOUD_SQL_INSTANCE_CONNECTION_NAME format

{GCP_PROJECT_ID}:{REGION}:{INSTANCE_NAME}

Troubleshooting

Symptom	Likely cause	Fix
invalid client credentials	Base64 value truncated or has line breaks	Re-generate with `base64 -i key.json \
ECONNREFUSED / connection timeout	Wrong CLOUD_SQL_INSTANCE_CONNECTION_NAME	Verify format matches GCP Cloud SQL console
statement_timeout errors	Missing index on timestamp column	Add index: CREATE INDEX ON bwts_iot_telemetry (timestamp);