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HotPocket developer kit

Evernode uses HotPocket as its smart contract engine. HotPocket smart contracts can be developed using any POSIX-compliant language/framework. Using the HotPocket developer kit, you can easily develop and test HotPocket smart contracts on your local PC.

Installation

Prerequisites

The HotPocket developer kit requires you to install Docker Engine and NodeJs on your development machine.

Cross-platform support

The HotPocket developer kit is a global npm package which supports both Linux and Windows operating systems.

  1. Install prerequisites.
  2. Run the following command to install hpdevkit on your machine: 
    npm i hpdevkit -g

NOTE: In Linux platforms, installation requires root privileges. Hence, add sudo to the above command.

Creating a HotPocket smart contract

You can use the HotPocket developer kit to generate smart contract projects such that everything is pre-configured. Here, we are creating a NodeJs smart contract (This assumes you have prior experience with developing NodeJs applications):

hpdevkit gen nodejs starter-contract myproj
cd myproj
npm install
npm start

The 'npm start' command will build and deploy the NodeJs smart contract into a HotPocket cluster running on your machine. It will also start printing the console output from the HotPocket instance. You can press Ctrl+C at any time to exit from monitoring the HotPocket console output. However, the HotPocket instance will continue to run even after you exit the monitoring console.

Viewing logs

You can re-enter the monitoring console with the command hpdevkit logs 1, where 1 is the HotPocket instance number you wish to monitor.

Changing the cluster size

In order to resize the HotPocket cluster, you need to delete and re-create it:

  1. Delete the existing cluster using the hpdevkit clean command.

  2. Set the HP_CLUSTER_SIZE environment variable to the size you want.

    # Windows (command prompt)
set HP_CLUSTER_SIZE=5

# Windows (powershell)
$env:HP_CLUSTER_SIZE=5

# Linux (bash)
export HP_CLUSTER_SIZE=5

  3. Deploy your contract again with npm start.

Creating HotPocket client application

You can use the HotPocket developer kit to generate a HotPocket client application such that everything is pre-configured. Here, we are creating a NodeJs client (This assumes you have prior experience with developing NodeJs applications):

hpdevkit gen nodejs blank-client myclient
cd myclient
npm install
node myclient.js

This will start the client application and connect a HotPocket node listening to port 8081. Also note that you need to have HotPocket nodes running on your machine for the client to connect.

Advanced usage

# Deploy contract files directory to the cluster (`npm start` internally uses this command to deploy)
hpdevkit deploy <contract files directory>

# Stop and clean-up everything (required for changing cluster size)
hpdevkit clean

# View a specific node's logs
hpdevkit logs <node number>

# Start/stop all nodes
hpdevkit start
hpdevkit stop

# Start/stop a specific node
hpdevkit start <node number>
hpdevkit stop <node number>

# Add a new node to the cluster
# (The new node will use the existing UNL and become an observer node)
hpdevkit spawn

If the contract files directory also contains a file named hp.cfg.override, it will be used to override the hp.cfg of all nodes. This can be used to set contract-specific parameters like 'bin_path' and 'bin_args'

An example hp.cfg.override file for a NodeJs application (the HotPocket developer kit NodeJs starter contract automatically includes this file for you):

{
    "contract": {
        "bin_path": "/usr/bin/node",
        "bin_args": "app.js"
    }
}

Inspect contract files of all nodes

You can inspect the files of all the nodes of the cluster using Docker Desktop. image

Environment variables

hpdevkit CLI supports the following environment variables:

Name Description Default value
HP_CLUSTER_SIZE The number of nodes in the cluster. This only takes effect with a fresh cluster. 3
HP_DEFAULT_NODE The node which the 'deploy' command uses to display logs. 1
HP_DEVKIT_IMAGE The Docker image to be used for devkit cluster management. evernodedev/hpdevkit
HP_INSTANCE_IMAGE The Docker image to be used for HotPocket instances. evernodedev/hotpocket:latest-ubt.20.04-njs.20
HP_USER_PORT_BEGIN The starting user port number for the cluster. 8081
HP_PEER_PORT_BEGIN The starting peer port number for the cluster. 22861

Updates

Run one of the following commands to update hpdevkit to the latest version, and update the supporting docker images:

  • Using hpdevkit CLI

    hpdevkit update

  • Using npm

    npm update hpdevkit -g

NOTE: You need to re-deploy your contracts for the new changes to take effect.

Uninstall

Run the following command to uninstall hpdevkit and the supporting docker images and containers:

  • Using hpdevkit CLI 
    hpdevkit uninstall

NOTE: Uninstalling from hpdevkit CLI is recommended. If you uninstall using npm, you will have to clean the hpdevkit supporting docker images and containers manually.

NOTE: In Linux platforms, you will need root privileges to execute updates and uninstallations. Hence, add sudo to the above commands.

Reporting issues

Report issues here.