PostgreSQL

Detailed information on the PostgreSQL configuration store component

Component format

To set up an PostgreSQL configuration store, create a component of type configuration.postgresql

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: <NAME>
spec:
  type: configuration.postgresql
  version: v1
  metadata:
    # Connection string
    - name: connectionString
      value: "host=localhost user=postgres password=example port=5432 connect_timeout=10 database=config"
    # Name of the table which holds configuration information
    - name: table
      value: "[your_configuration_table_name]" 
    # Timeout for database operations, in seconds (optional)
    #- name: timeoutInSeconds
    #  value: 20
    # Name of the table where to store the state (optional)
    #- name: tableName
    #  value: "state"
    # Name of the table where to store metadata used by Dapr (optional)
    #- name: metadataTableName
    #  value: "dapr_metadata"
    # Cleanup interval in seconds, to remove expired rows (optional)
    #- name: cleanupIntervalInSeconds
    #  value: 3600
    # Maximum number of connections pooled by this component (optional)
    #- name: maxConns
    #  value: 0
    # Max idle time for connections before they're closed (optional)
    #- name: connectionMaxIdleTime
    #  value: 0
    # Controls the default mode for executing queries. (optional)
    #- name: queryExecMode
    #  value: ""
    # Uncomment this if you wish to use PostgreSQL as a state store for actors (optional)
    #- name: actorStateStore
    #  value: "true"

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

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	Details	Example
`table`	Y	Table name for configuration information, must be lowercased.	`configtable`
`maxConns`	N	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	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	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”`

Set up PostgreSQL as Configuration Store

Start the PostgreSQL Database

Connect to the PostgreSQL database and setup a configuration table with following schema:

Field	Datatype	Nullable	Details
KEY	VARCHAR	N	Holds `“Key”` of the configuration attribute
VALUE	VARCHAR	N	Holds Value of the configuration attribute
VERSION	VARCHAR	N	Holds version of the configuration attribute
METADATA	JSON	Y	Holds Metadata as JSON

CREATE TABLE IF NOT EXISTS table_name (
  KEY VARCHAR NOT NULL,
  VALUE VARCHAR NOT NULL,
  VERSION VARCHAR NOT NULL,
  METADATA JSON
);

Create a TRIGGER on configuration table. An example function to create a TRIGGER is as follows:

CREATE OR REPLACE FUNCTION notify_event() RETURNS TRIGGER AS $$
    DECLARE 
        data json;
        notification json;
    BEGIN
        IF (TG_OP = 'DELETE') THEN
            data = row_to_json(OLD);
        ELSE
            data = row_to_json(NEW);
        END IF;
        notification = json_build_object(
                          'table',TG_TABLE_NAME,
                          'action', TG_OP,
                          'data', data);
        PERFORM pg_notify('config',notification::text);
        RETURN NULL; 
    END;
$$ LANGUAGE plpgsql;

Create the trigger with data encapsulated in the field labeled as data:

notification = json_build_object(
  'table',TG_TABLE_NAME,
  'action', TG_OP,
  'data', data
);

The channel mentioned as attribute to pg_notify should be used when subscribing for configuration notifications

Since this is a generic created trigger, map this trigger to configuration table

CREATE TRIGGER config
AFTER INSERT OR UPDATE OR DELETE ON configtable
    FOR EACH ROW EXECUTE PROCEDURE notify_event();

In the subscribe request add an additional metadata field with key as pgNotifyChannel and value should be set to same channel name mentioned in pg_notify. From the above example, it should be set to config

Note

When calling subscribe API, metadata.pgNotifyChannel should be used to specify the name of the channel to listen for notifications from PostgreSQL configuration store.

Any number of keys can be added to a subscription request. Each subscription uses an exclusive database connection. It is strongly recommended to subscribe to multiple keys within a single subscription. This helps optimize the number of connections to the database.

Example of subscribe HTTP API:

curl -l 'http://<host>:<dapr-http-port>/configuration/mypostgresql/subscribe?key=<keyname1>&key=<keyname2>&metadata.pgNotifyChannel=<channel name>'

Last modified March 21, 2024: Merge pull request #4082 from newbe36524/v1.13 (f4b0938)

PostgreSQL

PostgreSQL

Component format

Warning

Spec metadata fields

Authenticate using a connection string

Authenticate using Microsoft Entra ID

Other metadata options

Set up PostgreSQL as Configuration Store

Note

Related links