Thin Clients Overview

Overview

A thin client is a lightweight GridGain client that connects to the cluster via a standard socket connection. It does not become a part of the cluster topology, never holds any data, and is not used as a destination of compute grid calculations. What it does is simply establish a socket connection to a standard GridGain node and perform all operations through that node.

The thin clients are based on binary client protocol making it possible to support GridGain connectivity from any programming language.

GridGain provides the following thin clients:

Thin Client Features

The following table outlines features supported by each client.

Thin Client Feature	Java	.Net	C++	Python	Node.js	PHP
Scan Query	yes	yes	No	yes	yes	yes
Scan Query with a filter	yes	yes	No	No	No	No
SqlFieldsQuery	yes	yes	No	yes	yes	yes
Binary Object API	yes	yes	No	No	yes	yes
Async Operations	No	yes	No	yes	yes	yes
SSL/TLS	yes	yes	yes	yes	yes	yes
Authentication	yes	yes	yes	yes	yes	yes
Best Effort Affinity	No	yes	yes	No	No	No
Failover	yes	No	yes	yes	yes	yes

Thin Client Feature

Java

.Net

C++

Python

Node.js

PHP

Scan Query

yes

Scan Query with a filter

yes

SqlFieldsQuery

yes

Binary Object API

yes

Async Operations

yes

SSL/TLS

yes

Authentication

yes

Best Effort Affinity

yes

Failover

yes

Client Connection Failover

All thin clients (except for .NET thin client) support a connection failover mechanism, whereby the client automatically switches to an available node in case of the current node or connection failure. For this mechanism to work, you need to provide a list of node addresses you want to use for failover purposes in the client configuration. Refer to the specific client documentation for details.

Best Effort Affinity

As explained in the Data Partitioning section, data in the cluster is distributed between the nodes in a balanced manner for scallability and performance reasons. Each cluster node maintains a partition map and uses it to send data requrest directly to the right node.

Unlike a regular cluster node, a thin client maintains connection to one node at a time and is not aware of data distribution in the cluster. All requests that the client sends to the cluster are re-routed to the node or nodes that host the requested data. To eliminate the latency associated with rerouting client requests, we introduce the concept of best effort affinity. With the best effort affinity feature enabled, the client maintains connection to all cluster nodes and requests partition mapping for the caches.

To make use of the best effort affinity feature, you will have to provide the addresses of all nodes in the client connection properties.

Cluster Configuration

Thin client connection parameters are controlled by the client connector configuration. By default, GridGain accepts client connections on port 10800. You can change the port, connection buffer size and timeout, enable SSL/TLS, etc.

Configuring Thin Client Connector

The following example shows how to configure thin client connection parameters:

<bean class="org.apache.ignite.configuration.IgniteConfiguration" id="ignite.cfg">
    <property name="clientConnectorConfiguration">
        <bean class="org.apache.ignite.configuration.ClientConnectorConfiguration">
            <property name="port" value="10000"/>
        </bean>
    </property>
</bean>

ClientConnectorConfiguration clientConnectorCfg = new ClientConnectorConfiguration();
// set a port range from 10000 to 10005
clientConnectorCfg.setPort(10000);
clientConnectorCfg.setPortRange(10);

IgniteConfiguration cfg = new IgniteConfiguration().setClientConnectorConfiguration(clientConnectorCfg);

//Start a node
Ignite ignite = Ignition.start(cfg);

The following table describes some parameters that you may want to change.

Parameter Description Default Value

Parameter	Description	Default Value
`thinClientEnabled`	Enables or disables thin client connectivity.	`true`
`port`	The port for thin client connections.	10800
`portRange`	This parameters sets a range of ports for thin client connections. For example, if `portRange` = 10, thin clients can connect to any port from range 10800–18010. The node will try to bind to each port from the range starting from the `port` until it finds an available one. If all ports are unavailable, the node won’t start.	100
`sslEnabled`	Set this property to `true` to enable SSL for thin client connections.	`false`

thinClientEnabled

Enables or disables thin client connectivity.

true

port

The port for thin client connections.

10800

portRange

This parameters sets a range of ports for thin client connections. For example, if portRange = 10, thin clients can connect to any port from range 10800–18010. The node will try to bind to each port from the range starting from the port until it finds an available one. If all ports are unavailable, the node won’t start.

100

sslEnabled

Set this property to true to enable SSL for thin client connections.

false

See the complete list of parameters in the ClientConnectorConfiguration javadoc.

Enabling SSL/TLS for Thin Clients

To enable SSL/TLS for thin client connections, set the sslEnabled property to true and provide an SslContextFactory in the client connector configuration. You can re-use a global SSLContextFactory if you have configured it for communication between nodes, or you can configure one for thin client connection exclusively. This will enable SSL on the cluster side. Then, configure SSL on the client side in a similar fashion. Refer to the specific client documentation for details.

Below is an example configuration that sets SslContextFactory for thin client connection.

<property name="clientConnectorConfiguration">
    <bean class="org.apache.ignite.configuration.ClientConnectorConfiguration">
        <property name="sslEnabled" value="true"/>
        <property name="useIgniteSslContextFactory" value="false"/>
        <property name="sslContextFactory">
            <bean class="org.apache.ignite.ssl.SslContextFactory">
                <property name="keyStoreFilePath" value="/path/to/server.jks"/>
                <property name="keyStorePassword" value="123456"/>
                <property name="trustStoreFilePath" value="/path/to/trust.jks"/>
                <property name="trustStorePassword" value="123456"/>
            </bean>
        </property>
    </bean>
</property>

IgniteConfiguration igniteCfg = new IgniteConfiguration();

ClientConnectorConfiguration clientCfg = new ClientConnectorConfiguration();
clientCfg.setSslEnabled(true);
clientCfg.setUseIgniteSslContextFactory(false);
SslContextFactory sslContextFactory = new SslContextFactory();
sslContextFactory.setKeyStoreFilePath("/path/to/server.jks");
sslContextFactory.setKeyStorePassword("123456".toCharArray());

sslContextFactory.setTrustStoreFilePath("/path/to/trust.jks");
sslContextFactory.setTrustStorePassword("123456".toCharArray());

clientCfg.setSslContextFactory(sslContextFactory);

igniteCfg.setClientConnectorConfiguration(clientCfg);

If you want to use the global SSLContext, you only need to set the sslEnabled property to true, and ClientConnectorConfiguration will look for the SSLContext configured in IgniteConfiguration:

<property name="clientConnectorConfiguration">
    <bean class="org.apache.ignite.configuration.ClientConnectorConfiguration">
        <property name="sslEnabled" value="true"/>
    </bean>
</property>

ClientConnectorConfiguration clientConnectionCfg = new ClientConnectorConfiguration();
clientConnectionCfg.setSslEnabled(true);

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Last updated on Oct 06, 2021