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Druid connection
Connect a task to an Apache Druid cluster (the DruidDbApiHook) over a
managed Leoflow Connection. The query path goes through the Druid broker.
Declare the provider
# leoflow.yaml
dag_id: druid_smoke
connectors:
- druid
URI shape
druid://<login>:<password>@<host>:<port>/<schema>
The control plane builds this URI from the Connection’s fields. Reserved
characters in the password (e.g. @, :, /) are percent-escaped by the
URI builder; DruidDbApiHook un-escapes them back. The reserved-character
round-trip is pinned by TestDruidConnectionURIShapeIntegration (in
internal/storage/).
Fields the UI asks for
| Field | Required | Notes |
|---|---|---|
| Conn Id | yes | e.g. druid_target. Exported as AIRFLOW_CONN_DRUID_TARGET (uppercased). |
| Conn Type | yes | druid. |
| Host | yes | The Druid broker host. |
| Schema | optional | The schema namespace (commonly druid). |
| Login | yes | The Druid user. |
| Password | yes | Stored encrypted at rest (ADR 0019). |
| Port | optional | Defaults to 8082 (broker). |
| Extra | optional | JSON — e.g. {"endpoint":"druid/v2/sql"}. Encrypted at rest. |
Example DAG
The provider import must live inside the task body — a top-level provider import fails compilation in the parser sidecar.
# dag.py
from airflow.sdk import DAG, task
@task
def query():
from airflow.providers.apache.druid.hooks.druid import DruidDbApiHook
hook = DruidDbApiHook(druid_broker_conn_id="druid_target")
rows = hook.get_records("SELECT 1")
print("druid up:", rows)
with DAG("druid_smoke", schedule=None, catchup=False, tags=["example"]):
query()
# leoflow.yaml
schema_version: "1.0"
dag_id: druid_smoke
python_version: "3.11"
connectors:
- druid
Security notes
- Secrets in logs: never
print()the URI itself — it carries the password. Log host + port + schema only. - TLS in transit: front the broker with HTTPS and set the endpoint in Extra accordingly.
- gRPC channel (agent ↔ control plane): Connections are only served over an authenticated channel (see #58 + ADR 0021).
Related
- ADR 0019 — secret encryption at rest.
- ADR 0021 — agent secret delivery (
AIRFLOW_CONN_<CONN_ID>). - #142 — connector cookbook umbrella.