Fix #60

Basic policy

• Make a module of echo.rs in interledger-service-util crate
• Insert the service into node.rs

Must-learn Specs

• ilp-prepare.ts
• echo.ts

Brief Spec

• echo service responds to the address of the node
  • a sender sends an ILP prepare packet (packet A)
  • a receiver responds with a new ILP prepare packet (packet B) to the sender
  • These packets should be handled before any other actual core services that make funds on-hold
• the packet data of the prepare ILP packets is like below:
  • A type
    • amount arbitrary
    • executionCondition arbitrary
    • expiresAt arbitrary
    • destination the address of the node
    • data
      • ECHOECHOECHOECHO(16 bytes) + 0 + VarOctetString(source address)
  • B type
    • amount the same as the received packet
    • executionCondition the same as the received packet
    • expiresAt arbitrary (tipically the expires of the packet - 1000 (minMessageWindow))
    • destination source address that extracted from the received packet
    • data
      • ECHOECHOECHOECHO(16 bytes) + 1
• the receiver (who receives packet A)
  • responds with a B type packet
  • throws error when the data size of ILP packet is less than 17 bytes
    • 17 bytes = ECHOECHOECHOECHO + type(0)
  • throws error when the data does not start with ECHOECHOECHOECHO
  • these errors should be handled as ILP reject packets
    • F01_INVALID_PACKET

Question

• What happens if a sender sends echo packets to a terminal receiver that does not implement echo server (not a connector)?

ILP Packet handling in ilp-connector

• index.ts
  • creates App and listen
• app.ts
  • createApp loads accounts from env or config, and adds it to Accounts
  • listen
    • adminApi.listen()
    • backend.connect()
    • middlewareManager.setup()
    • accounts.loadIlpAddress()
    • accounts.connect()
    • middlewareManager.startup()
• middleware-manager.ts
  • constructor adds BUILTIN_MIDDLEWARES
    • error-handler, throughput, etc...
    • error-handler is inserted first, and called first covering all the exceptions
  • setup adds plug-ins for each account, and sets up Pipelines
  • startup calls startup handlers of each account

memo

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