Connection string

Many of the EventStoreConnection.Create overloads accept a connection string that you can use to control settings of the connection. A benefit to having these as a connection string instead of using the fluent API is that you can change them between environments without recompiling (i.e. a single node in dev and a cluster in production).

Here are all available overloads for the Create methods of the EventStoreConnection class, which use the connection string:

Method	Description
Create(string connectionString)	Connects to EventStoreDB with settings from connection string
Create(string connectionString, ConnectionSettingsBuilder builder)	Connects to EventStoreDB by merging connection string settings with pre-populated builder for additional settings

The connection string format should look familiar to those who have used connection strings in the past. It consists of a series of key/value pairs separated by semicolons.

You can set the following values using the connection string:

Name	Format	Description
ConnectTo	A URI in format described above to connect to	The URI to connect to
GossipSeeds	Comma separated list of ip:port	A list of seeds to try to discover from
ClusterDns	String	The DNS name of the cluster for discovery
ExternalGossipPort	Integer	The port to try to gossip on
DefaultUserCredentials	String in format username:password	The default credentials for the connection
MaxQueueSize	Integer	Maximum number of outstanding operations
MaxConcurrentItems	Integer	Maximum number of concurrent async operations
MaxRetries	Integer	Maximum number of retry attempts
MaxReconnections	Integer	The maximum number of times to try reconnecting
RequireMaster	True/false	If set the server will only process if it is master
ReconnectionDelay	Integer (milliseconds)	The delay before attempting to reconnect
OperationTimeout	Integer (milliseconds)	The time before considering an operation timed out
OperationTimeoutCheckPeriod	Integer (milliseconds)	The frequency in which to check timeouts
UseSslConnection	True/false	Whether to use SSL for this connection
TargetHost	String	The hostname expected on the certificate
ValidateServer	True/false	Whether to validate the remote server
FailOnNoServerResponse	True/False	Whether to fail on no server response
HeartbeatInterval	Integer (milliseconds)	The interval at which to send the server a heartbeat
HeartbeatTimeout	Integer (milliseconds)	The amount of time to receive a heartbeat response before timing out
MaxDiscoverAttempts	Integer	The maximum number of attempts to try to discover the cluster
GossipTimeout	Integer (milliseconds)	The amount of time before timing out a gossip response
VerboseLogging	True/false	Enables verbose logging

You can specify only one of ConnectTo, ClusterDns and GossipSeeds. Also, you'd only need to define ExternalGossipPort if you connect to the cluster using the DNS name (ClusterDns). The gossip port is usually the external HTTP port. When connecting to the cluster using GossipSeeds, you need to specify the gossip port for each node address in the list of seeds.

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You can also use spacing instead of camel casing in your connection string.

var connectionString = "ConnectTo=tcp://admin:changeit@localhost:1113; HeartBeatTimeout=500"

Sets the connection string to connect to localhost on the default port and sets the heartbeat timeout to 500ms.

var connectionString = "Connect To = tcp://admin:changeit@localhost:1113; HeartBeat Timeout = 500"

Using spaces:

var connectionString = "ConnectTo=discover://admin:changeit@mycluster:3114; HeartBeatTimeout=500"

Tells the connection to try gossiping to a manager node found under the DNS mycluster at port 3114 to connect to the cluster.

var connectionString = "GossipSeeds=192.168.0.2:1111,192.168.0.3:1111; HeartBeatTimeout=500"

Tells the connection to try gossiping to the gossip seeds 192.168.0.2 or 192.168.0.3 on port '1111' to discover information about the cluster.

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You can also use the ConnectionString class to return a ConnectionSettings object.