lex-node

Node identity and cluster management for LegionIO. Handles heartbeat broadcasting, dynamic configuration distribution, cluster secret exchange, Vault token management, and RSA public key distribution between nodes.

Version: 0.3.2

This is a core LEX installed by default with LegionIO.

Installation

Installed automatically as a dependency of legionio. To disable:

{
  "extensions": {
    "node": {
      "enabled": false
    }
  }
}

Runners

Beat

Periodic heartbeat broadcast to the cluster.

• beat(status:) - Publishes a heartbeat message with the node hostname, PID, timestamp, and status. Interval is controlled by the beat_interval setting.

Crypt

RSA keypair and cluster secret exchange.

• push_public_key - Broadcasts this node's RSA public key to all peers
• update_public_key(name:, public_key:) - Stores a received public key in cluster settings
• delete_public_key(name:) - Removes a stored public key from cluster settings
• request_public_keys - Broadcasts a request for all nodes to send their public keys
• push_cluster_secret(public_key:, queue_name:) - Encrypts the cluster secret with a peer's RSA public key and delivers it to their queue
• request_cluster_secret - Requests the cluster secret from peers
• receive_cluster_secret(message:) - Decrypts and stores the cluster secret received from a peer

Node

Dynamic configuration distribution and node management.

• message(**hash) - Merges arbitrary key/value pairs into Legion::Settings at runtime
• update_settings(settings:, restart: false) - Merges a settings hash into Legion::Settings; optionally restarts Legion. Publishes an UpdateResult message on completion.
• update_gem(extension:, version: nil, reload: true) - Installs or upgrades a LEX gem via Gem.install, then reloads Legion. Publishes an UpdateResult message on completion.
• push_public_key - Broadcasts this node's RSA public key (raw string form)
• update_public_key(name:, public_key:) - Stores a received public key in cluster settings
• push_cluster_secret(public_key:, queue_name:) - Encrypts and delivers the cluster secret to a peer
• receive_cluster_secret(message:) - Decrypts and stores the received cluster secret
• receive_vault_token(message:, routing_key:, public_key:) - Delegates to the Vault runner

Vault

Vault token lifecycle management.

• request_token - Checks if Vault is enabled but not connected, then calls request_vault_token
• request_vault_token - Broadcasts a request for a Vault token from peers
• receive_vault_token(message:) - Decrypts the received Vault token, stores it, and calls Legion::Crypt.connect_vault
• push_vault_token(public_key:, node_name:) - Encrypts the local Vault token with a peer's RSA public key and delivers it to their queue

How It Works

Each node periodically calls beat to broadcast its presence. On startup, nodes exchange RSA public keys, then use them to securely distribute the cluster shared secret (AES encryption key) and Vault tokens - all encrypted peer-to-peer so no secrets traverse the bus in plaintext.

Dynamic config changes (update_settings) and gem upgrades (update_gem) can be pushed to individual nodes or broadcast to all nodes at runtime. Both operations publish an UpdateResult message to node.<name>.update_result so the outcome can be observed cluster-wide.

Transport

• Exchange: node (topic exchange)
• Queues: node.<name> (node-specific, exclusive, auto-delete), crypt, vault, health
• Messages: Beat, PublicKey, RequestPublicKeys, PushClusterSecret, RequestClusterSecret, RequestVaultToken, PushVaultToken, UpdateResult

Requirements

• Ruby >= 3.4
• LegionIO framework

License

MIT