Postgres components: Adds `queryExecMode` option (#3103)

Signed-off-by: Bernd Verst <github@bernd.dev>

bindings/postgres/metadata.yaml

@@ -79,3 +79,16 @@ metadata:
     sensitive: true
     example: |
       "user=dapr password=secret host=dapr.example.com port=5432 dbname=dapr sslmode=verify-ca"
+  - name: queryExecMode
+    required: false
+    description: |
+      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`.
+    allowedValues:
+      - "cache_statement"
+      - "cache_describe"
+      - "describe_exec"
+      - "exec"
+      - "simple_protocol"
+    example: "cache_describe"
+    default: ""

configuration/postgres/metadata.yaml

@@ -67,4 +67,17 @@ metadata:
     description: |
       Deprecated alias for 'connectionMaxIdleTime'.
     example:  "5m"
-    type: duration
+    type: duration
+  - name: queryExecMode
+    required: false
+    description: |
+      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`.
+    allowedValues:
+      - "cache_statement"
+      - "cache_describe"
+      - "describe_exec"
+      - "exec"
+      - "simple_protocol"
+    example: "cache_describe"
+    default: ""

internal/authentication/postgresql/metadata.go

@@ -32,6 +32,7 @@ type PostgresAuthMetadata struct {
 	ConnectionMaxIdleTime time.Duration `mapstructure:"connectionMaxIdleTime"`
 	MaxConns              int           `mapstructure:"maxConns"`
 	UseAzureAD            bool          `mapstructure:"useAzureAD"`
+	QueryExecMode         string        `mapstructure:"queryExecMode"`
 
 	azureEnv azure.EnvironmentSettings
 }
@@ -42,6 +43,7 @@ func (m *PostgresAuthMetadata) Reset() {
 	m.ConnectionMaxIdleTime = 0
 	m.MaxConns = 0
 	m.UseAzureAD = false
+	m.QueryExecMode = ""
 }
 
 // InitWithMetadata inits the object with metadata from the user.
@@ -81,6 +83,21 @@ func (m *PostgresAuthMetadata) GetPgxPoolConfig() (*pgxpool.Config, error) {
 		config.MaxConns = int32(m.MaxConns)
 	}
 
+	if m.QueryExecMode != "" {
+		queryExecModes := map[string]pgx.QueryExecMode{
+			"cache_statement": pgx.QueryExecModeCacheStatement,
+			"cache_describe":  pgx.QueryExecModeCacheDescribe,
+			"describe_exec":   pgx.QueryExecModeDescribeExec,
+			"exec":            pgx.QueryExecModeExec,
+			"simple_protocol": pgx.QueryExecModeSimpleProtocol,
+		}
+		if mode, ok := queryExecModes[m.QueryExecMode]; ok {
+			config.ConnConfig.DefaultQueryExecMode = mode
+		} else {
+			return nil, fmt.Errorf("invalid queryExecMode metadata value: %s", m.QueryExecMode)
+		}
+	}
+
 	// Check if we should use Azure AD
 	if m.UseAzureAD {
 		tokenCred, errToken := m.azureEnv.GetTokenCredential()

state/postgresql/metadata.yaml

@@ -93,3 +93,16 @@ metadata:
       database driver to choose.
     example:  "5m"
     type: duration
+  - name: queryExecMode
+    required: false
+    description: |
+      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`.
+    allowedValues:
+      - "cache_statement"
+      - "cache_describe"
+      - "describe_exec"
+      - "exec"
+      - "simple_protocol"
+    example: "cache_describe"
+    default: ""