README

tigerbeetle-node

TigerBeetle client for Node.js.

Installation

The following steps will install the tigerbeetle-node module to your current working directory.

Prerequisites

NodeJS >= 14.0.0. (If the correct version is not installed, an installation error will occur)

Your operating system should be Linux (kernel >= v5.6) or macOS. Windows support is not yet available but is in the works.

Ensure you are not currently in the project (tigerbeetle-node) directory, but the parent directory instead;

YARN Package Manager

yarn add tigerbeetle-node

NPM Package Manager

npm install tigerbeetle-node

Development

Follow these steps to get up and running when cloning the repo:

git clone --recurse-submodules https://github.com/coilhq/tigerbeetle-node.git
yarn

Usage

A client needs to be configured with a cluster_id and replica_addresses. This instantiates the client where memory is allocated to internally buffer events to be sent. For the moment, only one client can be instantiated globally per process. Future releases will allow multiple client instantiations.

import { createClient } from 'tigerbeetle-node'

const client = createClient({
  cluster_id: 1,
  replica_addresses: ['3001', '3002', '3003']
})

One of the ways TigerBeetle achieves its performance is through batching. This is reflected in the below function interfaces where each one takes in an array of events.

Account Creation

const account = {
    id: 137n, // u128
    user_data: 0n, // u128, opaque third-party identifier to link this account (many-to-one) to an external entity:
    reserved: Buffer.alloc(48, 0), // [48]u8
    unit: 1,   // u16, unit of value
    code: 718, // u16, a chart of accounts code describing the type of account (e.g. clearing, settlement)
    flags: 0,  // u32
    debits_reserved: 0n,  // u64
    debits_accepted: 0n,  // u64
    credits_reserved: 0n, // u64
    credits_accepted: 0n, // u64
    timestamp: 0n, // u64, Reserved: This will be set by the server.
}

const errors = await client.createAccounts([account])

Successfully executed events return an empty array whilst unsuccessful ones return an array with errors for only the ones that failed. An error will point to the index in the submitted array of the failed event.

  const errors = await client.createAccounts([account1, account2, account3])

  // errors = [{ index: 1, code: 1 }]
  const error = errors[0]
  switch (error.code) {
    case CreateAccountError.exists: {
      console.error(`Batch event at ${error.index} already exists.`)
    }
  }

The example above shows that the event in index 1 failed with error 1. This means that account1 and account3 were created successfully but not account2.

The flags on an account provide a way for you to enforce policies by toggling the bits below. | bit 0 | bit 1 | bit 2 | |----------|----------------------------------|-----------------------------------------| | linked | debits_must_not_exceed_credits | credits_must_not_exceed_debits |

The creation of an account can be linked to the successful creation of another by setting the linked flag (see linked events). By setting debits_must_not_exceed_credits, then any transfer such that debits_accepted + debits_reserved + amount > credit_accepted will fail. Similarly for credits_must_not_exceed_debits.

  enum CreateAccountFlags {
    linked = (1 << 0),
    debits_must_not_exceed_credits = (1 << 1),
    credits_must_not_exceed_debits = (1 << 2)
  }

  let flags = 0
  flags |= CreateAccountFlags.debits_must_not_exceed_credits

Account lookup

The id of the account is used for lookups. Only matched accounts are returned.

  // account 137n exists, 138n does not
  const accounts = await client.lookupAccounts([137n, 138n])

  /**
   * const accounts = [{
   *   id: 137n,
   *   user_data: 0n,
   *   reserved: Buffer,
   *   unit: 1,
   *   code: 718,
   *   flags: 0,
   *   debits_reserved: 0n,
   *   debits_accepted: 0n,
   *   credits_reserved: 0n,
   *   credits_accepted: 0n,
   *   timestamp: 1623062009212508993n,
   * }]
   */

Creating a transfer

This creates a journal entry between two accounts.

const transfer = {
    id: 1n, // u128
    debit_account_id: 1n,  // u128
    credit_account_id: 2n, // u128
    user_data: 0n, // u128, opaque third-party identifier to link this transfer (many-to-one) to an external entity 
    reserved: Buffer.alloc(32, 0), // two-phase condition can go in here
    timeout: 0n, // u64, in nano-seconds. 
    code: 1,  // u32, a chart of accounts code describing the reason for the transfer (e.g. deposit, settlement)
    flags: 0, // u32
    amount: 10n, // u64
    timestamp: 0n, //u64, Reserved: This will be set by the server.
}

const errors = await client.createTransfers([transfer])

Two-phase transfers are supported natively by toggling the appropriate flag. TigerBeetle will then adjust the credits_reserved and debits_reserved fields of the appropriate accounts. A corresponding commit transfer then needs to be sent to accept or reject the transfer. | bit 0 | bit 1 | bit 2 | |----------|--------------------|------------------| | linked | two_phase_commit | condition |

The condition flag signals to TigerBeetle that a 256-bit cryptographic condition will be supplied in the reserved field. This will be validated against a supplied pre-image when the transfer is committed. Transfers within a batch may also be linked (see linked events).

  enum CreateTransferFlags {
    linked = (1 << 0>>),
    two_phase_commit = (1 << 1),
    condition = (1 << 2)
  }

// two-phase transfer
  let flags = 0n
  flags |= TransferFlags.two_phase_commit

  // two-phase transfer with condition supplied in `reserved`
  let flags = 0n
  flags |= TransferFlags.two_phase_commit
  flags |= TransferFlags.condition

Committing a transfer

This is used to commit a two-phase transfer. | bit 0 | bit 1 | bit 2 | |----------|----------|------------| | linked | reject | preimage |

By default (flags = 0), it will accept the transfer. TigerBeetle will atomically rollback the changes to debits_reserved and credits_reserved of the appropriate accounts and apply them to the debits_accepted and credits_accepted balances. If the preimage bit is set then TigerBeetle will look for it in the reserved field and validate it against the condition from the associated transfer. If this validation fails, or reject is set, then the changes to the reserved balances are atomically rolled back.

const commit = {
    id: 1n,   // u128, must correspond to the transfer id
    reserved: Buffer.alloc(32, 0), // [32]u8
    code: 1,  // u32, accounting system code to identify type of transfer
    flags: 0, // u32
    timestamp: 0n, // u64, Reserved: This will be set by the server.
}
const errors = await client.commitTransfers([commit])

Linked events

When the linked flag is specified for the createAccount, createTransfer, commitTransfer event, it links an event with the next event in the batch, to create a chain of events, of arbitrary length, which all succeed or fail together. The tail of a chain is denoted by the first event without this flag. The last event in a batch may therefore never have the linked flag set as this would leave a chain open-ended. Multiple chains or individual events may coexist within a batch to succeed or fail independently. Events within a chain are executed within order, or are rolled back on error, so that the effect of each event in the chain is visible to the next, and so that the chain is either visible or invisible as a unit to subsequent events after the chain. The event that was the first to break the chain will have a unique error result. Other events in the chain will have their error result set to linked_event_failed.

let batch = []
let linkedFlag = 0
linkedFlag |= CreateTransferFlags.linked

// An individual transfer (successful)
batch.push({ id: 1n, ... })

// A chain of 4 transfers (the last transfer in the chain closes the chain with linked=false)
batch.push({ id: 2n, ..., flags: linkedFlag }) // Commit/rollback.
batch.push({ id: 3n, ..., flags: linkedFlag }) // Commit/rollback.
batch.push({ id: 2n, ..., flags: linkedFlag }) // Fail with exists
batch.push({ id: 4n, ..., flags: 0 })          // Fail without committing.

// An individual transfer (successful):
// This should not see any effect from the failed chain above.
batch.push({ id: 2n, ..., flags: 0 })

// A chain of 2 transfers (the first transfer fails the chain)
batch.push({ id: 2n, ..., flags: linkedFlag })
batch.push({ id: 3n, ..., flags: 0 })

// A chain of 2 transfers (successful)
batch.push({ id: 3n, ..., flags: linkedFlag })
batch.push({ id: 4n, ..., flags: 0 })

const errors = await client.createTransfers(batch)

/**
 * [
 *  { index: 1, error: 1 }, // linked_event_failed
 *  { index: 2, error: 1 }, // linked_event_failed
 *  { index: 3, error: 2 }, // exists
 *  { index: 4, error: 1 }, // linked_event_failed
 * 
 *  { index: 6, error: 7 }, // exists_with_different_flags
 *  { index: 7, error: 1 }, // linked_event_failed
 * ]
 */

Usage no npm install needed!