docker-cloudsql-proxy 
Cloud SQL Proxy with Docker
Environment Variables
| Environment | Variables |
|---|---|
GCLOUD_SERVICE_KEY |
Base64 encoded Google Cloud Service Account credential file. |
GCLOUD_INSTANCE |
The Instance connection name of Google Cloud SQL |
You'll need to encode it in base64 format. To do so, on Linux or macOS, type:
base64 credentials.json