REST API for GridGain

This chapter explains system requirements for running GridGain, including how to install GridGain, start a cluster, and run a simple Hello World example using GridGain’s thin client REST API.

Thin Client is a lightweight GridGain connection mode. It does not participate in the cluster, never holds any data, or performs computations. All it does is establish a socket connection to an individual GridGain node and perform all operations through that node.

Since GridGain is built on top of Apache Ignite, GridGain reuses Ignite’s system properties, environment properties, startup scripts, etc. wherever possible.

Prerequisites

GridGain was officially tested on:

JDK

Oracle JDK 8, Open JDK 8, IBM JDK 8

Linux (any flavor), Mac OSX (10.6 and up), Windows (XP and up), Windows Server (2008 and up), Oracle Solaris

ISA

x86, x64, SPARC, PowerPC

Network

No restrictions (10G recommended)

Installing GridGain

GridGain is available in three editions: Community Edition (CE), Enterprise Edition (EE) and Ultimate Edition (UE). For this example, we’ll use the GridGain CE, which is distributed as binary, docker, and cloud images, and via RPM/DEB. This chapter explains how to install the GridGain CE binary distribution.

To get started with the GridGain CE binary distribution:

Download the GridGain binary as a zip archive.
Unzip the zip archive into the installation folder in your system.
Move the ignite-rest-http folder from {gridgain}/libs/optional to {gridgain}/libs to enable the Ignite REST library for the cluster. The library is used by GridGain Web Console for cluster management and monitoring needs.
(Optional) Enable required modules.
(Optional) Set the IGNITE_HOME environment variable or Windows PATH to point to the installation folder and make sure there is no trailing / (or \ for Windows) in the path.

Once that’s done, you will need to enable HTTP connectivity by putting the ignite-rest-http module in the classpath of your application. To do this, copy the ignite-rest-http module from {gridgain_dir}/libs/optional/ to the `{gridgain_dir}/libs' folder.

Starting a GridGain Node

Before connecting to GridGain via the REST API, you must start at least one GridGain cluster node.

You can start a GridGain node from the command line using the default configuration or by passing a custom configuration file. You can start as many nodes as you like and they will all automatically discover each other.

Navigate into the bin folder of GridGain installation directory from the command shell. Your command might look like this:

$ cd {gridgain}/bin/

$ cd {gridgain}\bin\

Start a GridGain node with a custom configuration file that is passed as a parameter to ignite.sh|bat like this:

$ ./ignite.sh examples/config/example-ignite.xml

$ ignite.bat examples\config\example-ignite.xml

You will see output similar to this:

[08:53:45] Ignite node started OK (id=7b30bc8e)
[08:53:45] Topology snapshot [ver=1, locNode=7b30bc8e, servers=1, clients=0, state=ACTIVE, CPUs=4, offheap=1.6GB, heap=2.0GB]

Open another tab from your command shell and run the same command again:

$ ./ignite.sh examples/config/example-ignite.xml

$ ignite.bat examples\config\example-ignite.xml

Check the Topology snapshot line in the output. Now you have a cluster of two server nodes with more CPUs and RAM available cluster-wide:

[08:54:34] Ignite node started OK (id=3a30b7a4)
[08:54:34] Topology snapshot [ver=2, locNode=3a30b7a4, servers=2, clients=0, state=ACTIVE, CPUs=4, offheap=3.2GB, heap=4.0GB]

Running Your First GridGain Application

Once the cluster is started, you can use the GridGain REST API to perform cache operations.

You don’t need to explicitly configure anything because the connector is initialized automatically, listening on port 8080.

To verify the connector is ready, use curl:

curl "http://localhost:8080/ignite?cmd=version"

You should see a message like this:

curl "http://localhost:8080/ignite?cmd=version"
{"successStatus":0,"error":null,"sessionToken":null,"response":"8.5.13"}

You can see in the result that GridGain version is 8.5.13.

Request parameters may be provided as either a part of URL or in a form data:

curl 'http://localhost:8080/ignite?cmd=put&cacheName=myCache' -X POST -H 'Content-Type: application/x-www-form-urlencoded' -d 'key=testKey&val=testValue'

Assuming that the server node is running locally, here is a simple example that creates a cache (myCache) and then puts and gets the string "Hello_World!" from the cache via the REST API:

Create a cache:

curl "http://localhost:8080/ignite?cmd=getorcreate&cacheName=myCache"

Put data into the cache. The default type is "string" but you can specify a data type via the keyType parameter.

curl "http://localhost:8080/ignite?cmd=put&key=1&val="Hello_World!"&cacheName=myCache"

Get the data from the cache

curl "http://localhost:8080/ignite?cmd=get&key=1&cacheName=myCache"

Now that you’ve seen a very basic example of accessing GridGain clusters via the REST API, you should probably keep the following in mind:

This is a very basic example. You will want to read more on the REST API here. That page includes a listing of the various API calls and also covers important subjects like Authentication.
The REST interface may not be suitable for all tasks. For example, you should use one of the language clients instead if you’re trying to load bulk data, or perform mission critical tasks with millisecond latency.

Next Steps

From here, you may want to:

Read more about using GridGain
Use GridGain Web Console to monitor your cluster

Using GridGain Web Console

GridGain Web Console is an interactive configuration, management, and monitoring tool, built on top of Apache Ignite Web Console.

Go to https://console.gridgain.com and create an account.
Log in with your new account and go to the "Monitoring Dashboard" screen. Click the three horizontal lines at the top in order to expand the left-hand menu:
Click the "Download Agent" button as shown in the screenshot below:
Extract the web agent into a separate folder.
Navigate to the folder where you extracted the web agent files, and execute the ignite-web-agent.sh (or ignite-web-agent.bat) script.
Ensure that the agent can connect to both console.gridgain.com and your single node cluster started earlier. Look for messages similar to the following in the agent’s log:
Go back to the console.gridgain.com Monitoring Dashboard and refresh it. Confirm that the tool successfully displays metrics for your local single node cluster.