Global database connection pool (for monolith mode) (#2411)

* Allow monolith components to share a single database pool

* Don't yell about missing connection strings

* Rename field

* Setup tweaks

* Fix panic

* Improve configuration checks

* Update config

* Fix lint errors

* Update comments

2 files changed, 51 insertions, 44 deletions

diff --git a/internal/sqlutil/sqlutil.go b/internal/sqlutil/sqlutil.go
new file mode 100644
index 00000000..0cdae6d3
--- /dev/null
+++ b/internal/sqlutil/sqlutil.go
@@ -0,0 +1,51 @@
+package sqlutil
+
+import (
+	"database/sql"
+	"fmt"
+	"regexp"
+
+	"github.com/matrix-org/dendrite/setup/config"
+	"github.com/sirupsen/logrus"
+)
+
+// Open opens a database specified by its database driver name and a driver-specific data source name,
+// usually consisting of at least a database name and connection information. Includes tracing driver
+// if DENDRITE_TRACE_SQL=1
+func Open(dbProperties *config.DatabaseOptions, writer Writer) (*sql.DB, error) {
+	var err error
+	var driverName, dsn string
+	switch {
+	case dbProperties.ConnectionString.IsSQLite():
+		driverName = "sqlite3"
+		dsn, err = ParseFileURI(dbProperties.ConnectionString)
+		if err != nil {
+			return nil, fmt.Errorf("ParseFileURI: %w", err)
+		}
+	case dbProperties.ConnectionString.IsPostgres():
+		driverName = "postgres"
+		dsn = string(dbProperties.ConnectionString)
+	default:
+		return nil, fmt.Errorf("invalid database connection string %q", dbProperties.ConnectionString)
+	}
+	if tracingEnabled {
+		// install the wrapped driver
+		driverName += "-trace"
+	}
+	db, err := sql.Open(driverName, dsn)
+	if err != nil {
+		return nil, err
+	}
+	if driverName != "sqlite3" {
+		logrus.WithFields(logrus.Fields{
+			"MaxOpenConns":    dbProperties.MaxOpenConns(),
+			"MaxIdleConns":    dbProperties.MaxIdleConns(),
+			"ConnMaxLifetime": dbProperties.ConnMaxLifetime(),
+			"dataSourceName":  regexp.MustCompile(`://[^@]*@`).ReplaceAllLiteralString(dsn, "://"),
+		}).Debug("Setting DB connection limits")
+		db.SetMaxOpenConns(dbProperties.MaxOpenConns())
+		db.SetMaxIdleConns(dbProperties.MaxIdleConns())
+		db.SetConnMaxLifetime(dbProperties.ConnMaxLifetime())
+	}
+	return db, nil
+}
diff --git a/internal/sqlutil/trace.go b/internal/sqlutil/trace.go
index 51eaa1b4..c1673861 100644
--- a/internal/sqlutil/trace.go
+++ b/internal/sqlutil/trace.go
@@ -16,19 +16,16 @@ package sqlutil
 
 import (
 	"context"
-	"database/sql"
 	"database/sql/driver"
 	"fmt"
 	"io"
 	"os"
-	"regexp"
 	"runtime"
 	"strconv"
 	"strings"
 	"sync"
 	"time"
 
-	"github.com/matrix-org/dendrite/setup/config"
 	"github.com/ngrok/sqlmw"
 	"github.com/sirupsen/logrus"
 )
@@ -96,47 +93,6 @@ func trackGoID(query string) {
 	logrus.Warnf("unsafe goid %d: SQL executed not on an ExclusiveWriter: %s", thisGoID, q)
 }
 
-// Open opens a database specified by its database driver name and a driver-specific data source name,
-// usually consisting of at least a database name and connection information. Includes tracing driver
-// if DENDRITE_TRACE_SQL=1
-func Open(dbProperties *config.DatabaseOptions) (*sql.DB, error) {
-	var err error
-	var driverName, dsn string
-	switch {
-	case dbProperties.ConnectionString.IsSQLite():
-		driverName = "sqlite3"
-		dsn, err = ParseFileURI(dbProperties.ConnectionString)
-		if err != nil {
-			return nil, fmt.Errorf("ParseFileURI: %w", err)
-		}
-	case dbProperties.ConnectionString.IsPostgres():
-		driverName = "postgres"
-		dsn = string(dbProperties.ConnectionString)
-	default:
-		return nil, fmt.Errorf("invalid database connection string %q", dbProperties.ConnectionString)
-	}
-	if tracingEnabled {
-		// install the wrapped driver
-		driverName += "-trace"
-	}
-	db, err := sql.Open(driverName, dsn)
-	if err != nil {
-		return nil, err
-	}
-	if driverName != "sqlite3" {
-		logrus.WithFields(logrus.Fields{
-			"MaxOpenConns":    dbProperties.MaxOpenConns(),
-			"MaxIdleConns":    dbProperties.MaxIdleConns(),
-			"ConnMaxLifetime": dbProperties.ConnMaxLifetime(),
-			"dataSourceName":  regexp.MustCompile(`://[^@]*@`).ReplaceAllLiteralString(dsn, "://"),
-		}).Debug("Setting DB connection limits")
-		db.SetMaxOpenConns(dbProperties.MaxOpenConns())
-		db.SetMaxIdleConns(dbProperties.MaxIdleConns())
-		db.SetConnMaxLifetime(dbProperties.ConnMaxLifetime())
-	}
-	return db, nil
-}
-
 func init() {
 	registerDrivers()
 }