Added socket keep alive option to Cassandra plugin. (#6201)

plugins/database/cassandra/connection_producer.go

@@ -30,12 +30,14 @@ type cassandraConnectionProducer struct {
 	InsecureTLS        bool        `json:"insecure_tls" structs:"insecure_tls" mapstructure:"insecure_tls"`
 	ProtocolVersion    int         `json:"protocol_version" structs:"protocol_version" mapstructure:"protocol_version"`
 	ConnectTimeoutRaw  interface{} `json:"connect_timeout" structs:"connect_timeout" mapstructure:"connect_timeout"`
+	SocketKeepAliveRaw interface{} `json:"socket_keep_alive" structs:"socket_keep_alive" mapstructure:"socket_keep_alive"`
 	TLSMinVersion      string      `json:"tls_min_version" structs:"tls_min_version" mapstructure:"tls_min_version"`
 	Consistency        string      `json:"consistency" structs:"consistency" mapstructure:"consistency"`
 	PemBundle          string      `json:"pem_bundle" structs:"pem_bundle" mapstructure:"pem_bundle"`
 	PemJSON            string      `json:"pem_json" structs:"pem_json" mapstructure:"pem_json"`
 
 	connectTimeout  time.Duration
+	socketKeepAlive time.Duration
 	certificate     string
 	privateKey      string
 	issuingCA       string
@@ -71,6 +73,14 @@ func (c *cassandraConnectionProducer) Init(ctx context.Context, conf map[string]
 		return nil, errwrap.Wrapf("invalid connect_timeout: {{err}}", err)
 	}
 
+	if c.SocketKeepAliveRaw == nil {
+		c.SocketKeepAliveRaw = "0s"
+	}
+	c.socketKeepAlive, err = parseutil.ParseDurationSecond(c.SocketKeepAliveRaw)
+	if err != nil {
+		return nil, errwrap.Wrapf("invalid socket_keep_alive: {{err}}", err)
+	}
+
 	switch {
 	case len(c.Hosts) == 0:
 		return nil, fmt.Errorf("hosts cannot be empty")
@@ -178,6 +188,7 @@ func (c *cassandraConnectionProducer) createSession() (*gocql.Session, error) {
 	}
 
 	clusterConfig.Timeout = c.connectTimeout
+	clusterConfig.SocketKeepalive = c.socketKeepAlive
 	if c.TLS {
 		var tlsConfig *tls.Config
 		if len(c.certificate) > 0 || len(c.issuingCA) > 0 {

website/source/api/secret/databases/cassandra.html.md

@@ -56,6 +56,9 @@ has a number of parameters to further configure a connection.
 
 - `connect_timeout` `(string: "5s")` – Specifies the connection timeout to use.
 
+- `socket_keep_alive` `(string: "0s")` – the keep-alive period for an active
+	network connection. If zero, keep-alives are not enabled.
+
 TLS works as follows:
 
 - If `tls` is set to true, the connection will use TLS; this happens