PostgreSQL binding spec

Detailed documentation on the PostgreSQL binding component

Component format

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

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: <NAME>
spec:
  type: bindings.postgresql
  version: v1
  metadata:
    # Connection string
    - name: connectionString
      value: "<CONNECTION STRING>"

Spec metadata fields

Authenticate using a connection string

The following metadata options are required to authenticate using a PostgreSQL connection string.

Field Required Details Example
connectionString Y The connection string for the PostgreSQL database. See the PostgreSQL documentation on database connections for information on how to define a connection string. "host=localhost user=postgres password=example port=5432 connect_timeout=10 database=my_db"

Authenticate using Microsoft Entra ID

Authenticating with Microsoft Entra ID is supported with Azure Database for PostgreSQL. All authentication methods supported by Dapr can be used, including client credentials (“service principal”) and Managed Identity.

Field Required Details Example
useAzureAD Y Must be set to true to enable the component to retrieve access tokens from Microsoft Entra ID. "true"
connectionString Y The connection string for the PostgreSQL database.
This must contain the user, which corresponds to the name of the user created inside PostgreSQL that maps to the Microsoft Entra ID identity; this is often the name of the corresponding principal (e.g. the name of the Microsoft Entra ID application). This connection string should not contain any password.		 "host=mydb.postgres.database.azure.com user=myapplication port=5432 database=my_db sslmode=require"
azureTenantId N ID of the Microsoft Entra ID tenant "cd4b2887-304c-…"
azureClientId N Client ID (application ID) "c7dd251f-811f-…"
azureClientSecret N Client secret (application password) "Ecy3X…"

Other metadata options

Field Required Binding support Details Example
maxConns N Output Maximum number of connections pooled by this component. Set to 0 or lower to use the default value, which is the greater of 4 or the number of CPUs. "4"
connectionMaxIdleTime N Output Max idle time before unused connections are automatically closed in the connection pool. By default, there’s no value and this is left to the database driver to choose. "5m"
queryExecMode N Output Controls the default mode for executing queries. By default Dapr uses the extended protocol and automatically prepares and caches prepared statements. However, this may be incompatible with proxies such as PGBouncer. In this case it may be preferrable to use exec or simple_protocol. "simple_protocol"

URL format

The PostgreSQL binding uses pgx connection pool internally so the connectionString 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=my_dapr sslmode=verify-ca

Example URL

postgres://dapr:secret@dapr.example.com:5432/my_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

Parametrized queries

This binding supports parametrized queries, which allow separating the SQL query itself from user-supplied values. The usage of parametrized queries is strongly recommended for security reasons, as they prevent SQL Injection attacks.

For example:

-- ❌ WRONG! Includes values in the query and is vulnerable to SQL Injection attacks.
SELECT * FROM mytable WHERE user_key = 'something';

-- ✅ GOOD! Uses parametrized queries.
-- This will be executed with parameters ["something"]
SELECT * FROM mytable WHERE user_key = $1;

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).

The params property is a string containing a JSON-encoded array of parameters.

Request

{
  "operation": "exec",
  "metadata": {
    "sql": "INSERT INTO foo (id, c1, ts) VALUES ($1, $2, $3)",
    "params": "[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, $2, $3)"
  }
}

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.

The params property is a string containing a JSON-encoded array of parameters.

Request

{
  "operation": "query",
  "metadata": {
    "sql": "SELECT * FROM foo WHERE id < $1",
    "params": "[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 < $1"
  },
  "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

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"
}

Last modified May 31, 2024: Merge 61e65296a85dd35c3b7040b281b7c17caffcc144 into 27b6a61b0e1b0a30ea4e4f31bea712dfec3813b3 (525f2ab)