Postgres: Switch the datasource plugin from lib/pq to pgx (#103961)

* Create libpqToPGX feature toggle

* Refactor PostgreSQL datasource to support PGX with feature toggle

- Updated `ProvideService` to accept feature toggles for enabling PGX.
- Modified integration tests to use the new PGX connection method.
- Introduced new functions for handling PGX connections and queries.
- Enhanced TLS configuration handling for PostgreSQL connections.
- Updated existing tests to ensure compatibility with PGX and new connection methods.

* Update PostgreSQL datasource to enhance connection pooling and error handling

- Increased `MaxOpenConns` to 10 in integration tests for improved connection management.
- Refactored connection handling in `newPostgresPGX` to return a connection pool instead of a single connection.
- Updated health check error handling to utilize context and feature toggles for better error reporting.
- Adjusted `DisposePGX` method to close the connection pool properly.
- Enhanced query execution to acquire connections from the pool, ensuring efficient resource usage.

* Cleanup

* Revert postgres_test unnecessary changes

* Rename feature toggle from `libpqToPGX` to `postgresDSUsePGX`

* Add null check to dispose method

* Fix lint issues

* Refactor connection string generation

* Address comment in health check file

* Rename p to pool

* Refactor executeQueryPGX and split into multiple functions

* Fix lint issues

* The returning error message from PGX is enough no need to separate the error code.

* Move TLS handling to newPostgresPGX function

* Disable ssl for integration tests

* Use MaxIdleConns option

* Remove old feature toggle

* Rename`generateConnectionConfigPGX` to `generateConnectionStringPGX`

* Add back part of the error messages

* Don't show max idle connections option when PGX enabled

* Address comments from Sriram

* Add back Sriram's changes

* PostgreSQL: Rework tls manager to use temporary files instead (#105330)

* Rework tls manager to use temporary files instead

* Lint and test fixes

* Update pkg/tsdb/grafana-postgresql-datasource/postgres.go

Co-authored-by: Ivana Huckova <30407135+ivanahuckova@users.noreply.github.com>

* Update betterer

---------

Co-authored-by: Ivana Huckova <30407135+ivanahuckova@users.noreply.github.com>

---------

Co-authored-by: Ivana Huckova <30407135+ivanahuckova@users.noreply.github.com>

pkg/tsdb/grafana-postgresql-datasource/sqleng/handler_checkhealth.go

@@ -10,11 +10,17 @@ import (
 
 	"github.com/grafana/grafana-plugin-sdk-go/backend"
 	"github.com/grafana/grafana-plugin-sdk-go/backend/log"
+	"github.com/grafana/grafana/pkg/services/featuremgmt"
 	"github.com/lib/pq"
 )
 
-func (e *DataSourceHandler) CheckHealth(ctx context.Context, req *backend.CheckHealthRequest) (*backend.CheckHealthResult, error) {
-	err := e.Ping()
+func (e *DataSourceHandler) CheckHealth(ctx context.Context, req *backend.CheckHealthRequest, features featuremgmt.FeatureToggles) (*backend.CheckHealthResult, error) {
+	var err error
+	if features.IsEnabled(ctx, featuremgmt.FlagPostgresDSUsePGX) {
+		err = e.PingPGX(ctx)
+	} else {
+		err = e.Ping()
+	}
 	if err != nil {
 		logCheckHealthError(ctx, e.dsInfo, err)
 		if strings.EqualFold(req.PluginContext.User.Role, "Admin") {
@@ -63,6 +69,7 @@ func ErrToHealthCheckResult(err error) (*backend.CheckHealthResult, error) {
 			res.Message += fmt.Sprintf(". Error message: %s", errMessage)
 		}
 	}
+
 	if errors.Is(err, pq.ErrSSLNotSupported) {
 		res.Message = "SSL error: Failed to connect to the server"
 	}
@@ -125,10 +132,10 @@ func logCheckHealthError(ctx context.Context, dsInfo DataSourceInfo, err error)
 		"config_tls_client_cert_length":     len(dsInfo.DecryptedSecureJSONData["tlsClientCert"]),
 		"config_tls_client_key_length":      len(dsInfo.DecryptedSecureJSONData["tlsClientKey"]),
 	}
-	configSummaryJson, marshalError := json.Marshal(configSummary)
+	configSummaryJSON, marshalError := json.Marshal(configSummary)
 	if marshalError != nil {
 		logger.Error("Check health failed", "error", err, "message_type", "ds_config_health_check_error")
 		return
 	}
-	logger.Error("Check health failed", "error", err, "message_type", "ds_config_health_check_error_detailed", "details", string(configSummaryJson))
+	logger.Error("Check health failed", "error", err, "message_type", "ds_config_health_check_error_detailed", "details", string(configSummaryJSON))
 }