PostgreSQL binding spec

Detailed documentation on the PostgreSQL binding component

Component format

To setup PostgreSQL binding create a component of type bindings.postgres. See this guide on how to create and apply a binding configuration.

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: <NAME>
  namespace: <NAMESPACE>
spec:
  type: bindings.postgres
  version: v1
  metadata:
  - name: url # Required
    value: <CONNECTION_STRING>

Warning

The above example uses secrets as plain strings. It is recommended to use a secret store for the secrets as described here.

Spec metadata fields

URL format

The PostgreSQL binding uses pgx connection pool internally so the url parameter can be any valid connection string, either in a DSN or URL format:

Example DSN

user=dapr password=secret host=dapr.example.com port=5432 dbname=dapr sslmode=verify-ca

Example URL

postgres://dapr:secret@dapr.example.com:5432/dapr?sslmode=verify-ca

Both methods also support connection pool configuration variables:

• pool_min_conns: integer 0 or greater
• pool_max_conns: integer greater than 0
• pool_max_conn_lifetime: duration string
• pool_max_conn_idle_time: duration string
• pool_health_check_period: duration string

Binding support

This component supports output binding with the following operations:

• exec
• query
• close

exec

The exec operation can be used for DDL operations (like table creation), as well as INSERT, UPDATE, DELETE operations which return only metadata (e.g. number of affected rows).

Request

{
  "operation": "exec",
  "metadata": {
    "sql": "INSERT INTO foo (id, c1, ts) VALUES (1, 'demo', '2020-09-24T11:45:05Z07:00')"
  }
}

Response

{
  "metadata": {
    "operation": "exec",
    "duration": "294µs",
    "start-time": "2020-09-24T11:13:46.405097Z",
    "end-time": "2020-09-24T11:13:46.414519Z",
    "rows-affected": "1",
    "sql": "INSERT INTO foo (id, c1, ts) VALUES (1, 'demo', '2020-09-24T11:45:05Z07:00')"
  }
}

query

The query operation is used for SELECT statements, which returns the metadata along with data in a form of an array of row values.

Request

{
  "operation": "query",
  "metadata": {
    "sql": "SELECT * FROM foo WHERE id < 3"
  }
}

Response

{
  "metadata": {
    "operation": "query",
    "duration": "432µs",
    "start-time": "2020-09-24T11:13:46.405097Z",
    "end-time": "2020-09-24T11:13:46.420566Z",
    "sql": "SELECT * FROM foo WHERE id < 3"
  },
  "data": "[
    [0,\"test-0\",\"2020-09-24T04:13:46Z\"],
    [1,\"test-1\",\"2020-09-24T04:13:46Z\"],
    [2,\"test-2\",\"2020-09-24T04:13:46Z\"]
  ]"
}

close

Finally, the close operation can be used to explicitly close the DB connection and return it to the pool. This operation doesn’t have any response.

Request

{
  "operation": "close"
}

Note, the PostgreSql binding itself doesn’t prevent SQL injection, like with any database application, validate the input before executing query.

Related links

• Basic schema for a Dapr component
• Bindings building block
• How-To: Trigger application with input binding
• How-To: Use bindings to interface with external resources
• Bindings API reference

Last modified August 2, 2021 : Fix Java SDK link (#1695) (2c67fd1)