Pendulum

Pendulum is a quorum based Tangle implementation designed towards reliable timekeeping and high-throughput messaging.

• Latest release: 1.0.7 release
• License: GPLv3

Special thanks to all of the IOTA Contributors!

Hardware requirements

Minimal (~t2.small AWS instance)

• 2GB RAM
• 1 GHz CPU
• 10 GB storage
• 10Mbit/s WAN, static IP

Optimal (~t2.medium AWS instance)

• 4GB RAM or more
• 2 or more 2GHz CPU cores (~ t2.medium AWS instance)
• 50GB SSD
• 1Gbit/s WAN, static IP

Enterprise-grade

• Four or more instances with Optimal specs
  • two or more instances with --remote API enabled
  • two or more "relayer" instances connected to multiple peers
• For validators: additional dedicated instance with Optimal specification for the validator node
• HA loadbalancer proxing API instances. Can be hardware or software based (e.g. Nginx cluster sample config below)

Developers

• Please read CONTRIBUTING.md for details on our code of conduct, and the process for submitting pull requests to us.
• Please read the pendulum-1.0-specifications before contributing.

Installing

Make sure you have Maven and Java 8 installed on your computer.

Download

$ git clone https://github.com/HelixNetwork/pendulum.git

Build

Build an executable jar at the target directory using maven.

$ cd pendulum
$ mvn clean package

Launch Full node

java -jar target/pendulum-<VERSION>.jar -p 8085

Launch Validator node

Launching a node as a validator first requires to generate a 64 character hex string, that is used as a seed for key generation. You will find the public key in the last line of the validator.key file contained in the resources directory. If you wish to act as a validator, please send a request to dt@hlx.ai containing your public key.

java -jar target/pendulum-<VERSION>.jar -p 8085 --validator <pathToValidatorSeed>

Nginx cluster sample config

For production-level applications we recommend exposing a single public API endpoint reverse-proxing multiple fullnode instances. Additionally, we highly recommend obtaining an SSL certificate from a trusted authority (e.g. from Let’s Encrypt).

Below is a sample configuration file for the popular Nginx webserver (typically put into /etc/nginx/conf.d/ ). For more information please consult the official Nginx documentation

upstream pendulum {
        ip_hash;
        Server fullnode1.ip.address:8085;
        Server fullnode2.ip.address:8085;
}

server {
        listen 443 ssl;
        listen [::]:443 ssl;
        server_name my.api.endpoint.com;

        server_tokens off;

        ssl_certificate /path/to/cert.pem;
        ssl_certificate_key /path/to/key.pem;
        ssl_session_timeout 5m;
        ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
        ssl_ciphers 'EECDH+AESGCM:EDH+AESGCM:AES256+EECDH:AES256+EDH';
        ssl_prefer_server_ciphers on;

        ssl_ecdh_curve secp384r1;
        ssl_session_tickets off;

        # OCSP stapling
        ssl_stapling on;

        ssl_stapling_verify on;
        resolver 8.8.8.8;

        location / {
                ## CORS
                proxy_hide_header Access-Control-Allow-Origin;
                add_header 'Access-Control-Allow-Origin' '*' always;
                add_header 'Access-Control-Allow-Credentials' 'true';
                add_header 'Access-Control-Allow-Headers' 'Authorization,Accept,Origin,DNT,X-HELIX-API-Version,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range';
                add_header 'Access-Control-Allow-Methods' 'GET,POST,OPTIONS,PUT,DELETE,PATCH';

                if ($request_method = 'OPTIONS') {
                        add_header 'Access-Control-Allow-Origin' '*';
                        add_header 'Access-Control-Allow-Credentials' 'true';
                        add_header 'Access-Control-Allow-Headers' 'Authorization,Accept,Origin,DNT,X-HELIX-API-Version,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range';
                        add_header 'Access-Control-Allow-Methods' 'GET,POST,OPTIONS,PUT,DELETE,PATCH';
                        add_header 'Access-Control-Max-Age' 1728000;
                        add_header 'Content-Type' 'text/plain charset=UTF-8';
                        add_header 'Content-Length' 0;
                        return 204;
                }

                proxy_redirect off;
                proxy_set_header host $host;
                proxy_set_header X-real-ip $remote_addr;
                proxy_set_header X-forward-for $proxy_add_x_forwarded_for;
                proxy_set_header X-Forwarded-Proto $scheme;
                proxy_pass http://pendulum;
        }
}

Configuration

INI

You can also provide an ini file to store all of your command line options and easily update (especially neighbors) if needed. You can enable it via the --config flag. Here is an example INI file:

[HLX]
PORT = 8085
UDP_RECEIVER_PORT = 4100
NEIGHBORS = udp://my.favorite.com:5100
HXI_DIR = XI
DB_PATH = db
ZMQ_ENABLED = true

MessageQ

MessageQ is a small zmq wrapper for streaming gathered metrics and statistics of topics, enabling targeted event streams from subscribing clients to processes of the node. A client interested in real time state updates and notifications could use any desired zmq-client to start listening to topics.

Currently the following topics are covered: