Add-on Environment Variables

When you attach an add-on, Watasu injects connection details into your app as config vars. This page lists them per add-on. Read these like any other config var (watasu config --app my-app), but don’t overwrite them — the add-on resets them on its next reconcile.

PostgreSQL

Variable	Purpose
`DATABASE_URL`	Full Postgres connection string
`PGHOST`	Hostname
`PGPORT`	Port
`PGDATABASE`	Database name
`PGUSER`	Username
`PGPASSWORD`	Password

DATABASE_URL is what most ORMs and frameworks read. The discrete PG* variables are for tools (psql, pg_dump) and code that builds connections programmatically.

Valkey

Variable	Purpose
`REDIS_URL`	Redis-protocol connection URL
`REDIS_HOST`	Hostname
`REDIS_PORT`	Port
`REDIS_PASSWORD`	Password

The REDIS_* names are intentional — Valkey speaks the Redis protocol, and existing libraries that look for REDIS_URL work unchanged.

ClickHouse

Variable	Purpose
`CLICKHOUSE_URL`	Full connection URL
`CLICKHOUSE_HOST`	Hostname
`CLICKHOUSE_PORT`	Native protocol port
`CLICKHOUSE_DATABASE`	Database name
`CLICKHOUSE_USER`	Username
`CLICKHOUSE_PASSWORD`	Password

Redpanda

Redpanda exports both REDPANDA_* and KAFKA_* names so Kafka client libraries find what they expect:

Variable	Purpose
`REDPANDA_BROKERS`, `KAFKA_BROKERS`, `KAFKA_BOOTSTRAP_SERVERS`	Broker address list
`REDPANDA_USERNAME`, `KAFKA_USERNAME`	SASL username
`REDPANDA_PASSWORD`, `KAFKA_PASSWORD`	SASL password

Object Storage

Object storage exports a wide set of S3-compatible variables so that whichever name your SDK looks for, it finds:

Variable	Purpose
`S3_BUCKET`, `AWS_S3_BUCKET`	Bucket name
`S3_ACCESS_KEY_ID`, `AWS_ACCESS_KEY_ID`	Credential ID
`S3_SECRET_ACCESS_KEY`, `AWS_SECRET_ACCESS_KEY`	Credential secret
`S3_ENDPOINT`, `AWS_ENDPOINT_URL`, `AWS_ENDPOINT_URL_S3`	Endpoint (this isn’t AWS — it’s the Watasu-managed S3-compatible endpoint)
`S3_REGION`, `AWS_REGION`, `AWS_DEFAULT_REGION`, `AWS_S3_REGION`	Region label expected by AWS SDKs
`S3_FORCE_PATH_STYLE`	Whether the SDK should use path-style addressing
`S3_PUBLIC_BUCKET_URL`, `AWS_S3_URL`	Convenience URLs combining bucket + endpoint

Most SDKs (boto3, aws-sdk-*, rclone, minio, etc.) pick these up automatically.

Metrics

Variable	Purpose
`METRICS_PORT`	Port your app should serve Prometheus metrics on (default `9464`)
`OTEL_EXPORTER_OTLP_METRICS_ENDPOINT`	OTLP metrics push endpoint
`OTEL_EXPORTER_OTLP_METRICS_PROTOCOL`	`http/protobuf`
`PROMETHEUS_REMOTE_WRITE_URL`	Prometheus remote-write endpoint

Serve your metrics endpoint on $METRICS_PORT and Watasu scrapes it — see Metrics.

Traces

Variable	Purpose
`OTEL_EXPORTER_OTLP_ENDPOINT`	OTLP ingest endpoint
`OTEL_EXPORTER_OTLP_TRACES_ENDPOINT`	The same endpoint with the `/v1/traces` path
`OTEL_EXPORTER_OTLP_PROTOCOL`	`http/protobuf`

Standard OpenTelemetry SDKs read these automatically.

Logs and Grafana

The logs and Grafana add-ons collect from the platform side and don’t inject any env vars into your app.

Aliases

When you attach an add-on with --as <ALIAS>, every variable that add-on would normally export gets prefixed with ALIAS_:

watasu addons:attach reporting-db --app my-app --as REPORTING

Now your app sees both:

DATABASE_URL — the original primary
REPORTING_DATABASE_URL — the new alias

This is how you give one app multiple databases of the same kind, and it’s how PostgreSQL CLI commands target a specific database (watasu pg:psql REPORTING_DATABASE_URL, or just watasu pg:psql reporting).