Add snowflake support

README.md

@@ -5,7 +5,7 @@ Database agnostic SQL exporter for [Prometheus](https://prometheus.io).
 ## Overview
 
 SQL Exporter is a configuration driven exporter that exposes metrics gathered from DBMSs, for use by the Prometheus
-monitoring system. Out of the box, it provides support for MySQL, PostgreSQL, Microsoft SQL Server and Clickhouse, but
+monitoring system. Out of the box, it provides support for MySQL, PostgreSQL, Microsoft SQL Server, Clickhouse, and Snowflake, but
 any DBMS for which a Go driver is available may be monitored after rebuilding the binary with the DBMS driver included.
 
 The collected metrics and the queries that produce them are entirely configuration defined. SQL queries are grouped into

sql.go

@@ -9,8 +9,10 @@ import (
 	_ "github.com/ClickHouse/clickhouse-go" // register the ClickHouse driver
 	_ "github.com/denisenkom/go-mssqldb"    // register the MS-SQL driver
 	_ "github.com/go-sql-driver/mysql"      // register the MySQL driver
+	_ "github.com/lib/pq"                   // register the PostgreSQL driver
+	_ "github.com/snowflakedb/gosnowflake"  // register the Snowflake driver
+
 	log "github.com/golang/glog"
-	_ "github.com/lib/pq" // register the PostgreSQL driver
 )
 
 // OpenConnection extracts the driver name from the DSN (expected as the URI scheme), adjusts it where necessary (e.g.
@@ -43,6 +45,12 @@ import (
 // Using the https://github.com/kshvakov/clickhouse driver, DSN format (passed to the driver with the`clickhouse://`
 // prefix replaced with `tcp://`):
 //   clickhouse://host:port?username=username&password=password&database=dbname&param=value
+//
+// Snowflake
+//
+// Using the https://godoc.org/github.com/snowflakedb/gosnowflake driver, DSN format (passed to the driver stripped
+// of the `snowflake://`` prefix):
+//   snowflake://username:password@account/dbname?role=rolename&warehouse=warehousename&param=value
 func OpenConnection(ctx context.Context, logContext, dsn string, maxConns, maxIdleConns int) (*sql.DB, error) {
 	// Extract driver name from DSN.
 	idx := strings.Index(dsn, "://")
@@ -57,6 +65,8 @@ func OpenConnection(ctx context.Context, logContext, dsn string, maxConns, maxId
 		dsn = strings.TrimPrefix(dsn, "mysql://")
 	case "clickhouse":
 		dsn = "tcp://" + strings.TrimPrefix(dsn, "clickhouse://")
+	case "snowflake":
+		dsn = strings.TrimPrefix(dsn, "snowflake://")
 	}
 
 	// Open the DB handle in a separate goroutine so we can terminate early if the context closes.