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Backend service

Rafiki’s backend service is the software’s main service for handling business logic and external communication. The service is responsible for:

  • Exposing the endpoints of the Open Payments APIs for public clients to initiate payments and look up information. This is the external communication piece.
  • Exposing an Interledger connector to send and receive STREAM packets with peers.
  • Enabling you to manage accounts and track liquidity.
  • Exposing an internal GraphQL Backend Admin API for service operators to manage accounts, liquidity, and application settings, like peering relationships.

Requirements

The following are required when using the backend service.

  • A Redis database as a cache to share STREAM connection details and total amounts received across processes
  • A Postgres database, separate from the auth service’s database, for Open Payments resources
  • TigerBeetle or a separate Postgres database for accounting liquidity

You must also set the environment variables for the backend service.

Open Payments

The backend service exposes the Open Payments APIs, which are auth-protected using an opinionated version of the Grant Negotiation and Authorization Protocol (GNAP). Review the auth service page for more details about grant authorization and authentication.

The backend service allows you to manage Open Payments incoming payments, quotes, and outgoing payments. Quotes and outgoing payments call the ILP connector, described in the next section, to send ILP packets. Quoting sends unfulfillable probe packets, for example to determine a transaction’s cost before executing the payment. Outgoing payments send packets as part of executing the payment.

Interledger connector

The backend service exposes an ILP connector to send and receive ILP packets between peers.

Some of the responsibilities of a connector include:

  • Authenticating packets against ILP account credentials.
  • Forwarding packets to a sender or receiver.
  • Rejecting a packet for any number of reasons, including expiration, insufficient liquidity, rate limit exceeded, or if the amount exceeds the maxPacketAmount agreed to by the connector and its peer.
  • Converting currencies.
  • Fulfilling packets with an internal STREAM server.

The backend service includes an HTTP server listening on the configured CONNECTOR_PORT. Your connector can receive incoming packets via HTTP and/or direct calls from within the backend service. An incoming packet is only accepted if it’s from a configured peer and accompanied by your peer’s incoming HTTP authToken.

Similarly, if a packet’s destination address corresponds to a peer, your connector will forward the packet to your peer over HTTP, along with your peer’s outgoing HTTP authToken.

A packet can either continue on to your peer via HTTP or terminate at your Rafiki instance’s STREAM server. If the packet terminates at your STREAM server, your connector will attempt to extract and decode the payment tag from the packet’s destination address. When your connector successfully matches the tag with a locally managed wallet address or incoming payment, the connector will not forward the packet. Instead, it will credit the corresponding balance and track the total amount received in Redis to support STREAM receipts. Packets addressed to a wallet address happen via SPSP.

GraphQL Backend Admin API

The backend service exposes a GraphQL Backend Admin API to manage assets, peers, wallet addresses, Open Payments resources, and several types of liquidity.

Environment variables

VariableHelm Value NameDefaultDescription
ADMIN_PORTbackend.port.admin3001Admin API GraphQL Server port
AUTH_SERVER_GRANT_URLundefinedendpoint on the Open Payments Auth Server to request a grant
AUTH_SERVER_INTROSPECTION_URLundefinedendpoint on the Open Payments Auth Server to introspect an access token
AUTO_PEERING_SERVER_PORT3005If auto-peering is enabled, its server will use this port
CONNECTOR_PORTbackend.port.connector3002port of the ILP connector for for sending packets over ILP over HTTP
DATABASE_URLbackend.postgresql.host, backend.postgresql.port, backend.postgresql.username, backend.postgresql.database, backend.postgresql.passwordpostgresql://postgres:password@localhost:5432/developmentPostgres database URL of database storing the resource data; For Helm, these components are provided individually.
ENABLE_AUTO_PEERINGfalseFlag to enable auto peering. View documentation.
ENABLE_SPSP_PAYMENT_POINTERStrueenables SPSP route
EXCHANGE_RATES_LIFETIMEbackend.lifetime.exchangeRate15_000time in milliseconds the exchange rates provided by the ASE via the EXCHANGE_RATES_URL are valid for
EXCHANGE_RATES_URLbackend.serviceUrls.EXCHANGE_RATES_URLundefinedendpoint on the Account Servicing Entity to request exchange rates
GRAPHQL_IDEMPOTENCY_KEY_TTL_MSbackend.idempotencyTTL86400000TTL in milliseconds for idempotencyKey on GraphQL mutations (Admin API). Default: 24hrs
GRAPHQL_IDEMPOTENCY_KEY_LOCK_MS2000TTL in milliseconds for idempotencyKey concurrency lock on GraphQL mutations (Admin API)
ILP_ADDRESSbackend.ilp.addressundefinedILP address of this Rafiki instance
ILP_CONNECTOR_URLundefinedThe ILP connector address where ILP packets are received. Communicated during auto-peering
INCOMING_PAYMENT_EXPIRY_MAX_MS2592000000Maximum milliseconds into the future incoming payments expiry can be set to on creation. Default: 30 days
INCOMING_PAYMENT_WORKERSbackend.workers.incomingPayment1number of workers processing incoming payment requests
INCOMING_PAYMENT_WORKER_IDLEbackend.workerIdle200time in milliseconds that INCOMING_PAYMENT_WORKERS will wait until they check an empty incoming payment request queue again
INSTANCE_NAMEundefinedthis Rafiki instance’s name used to communicate for auto-peering
KEY_IDbackend.key.idundefinedthis Rafiki instance’s client key id
LOG_LEVELbackend.logLevelinfoPino Log Level
NODE_ENVbackend.nodeEnvdevelopmentnode environment, development, test, or production
OPEN_PAYMENTS_PORTbackend.port.openPayments3003port of the Open Payments resource server port
OPEN_PAYMENTS_URLbackend.serviceUrls.OPEN_PAYMENTS_URLundefinedpublic endpoint of this Open Payments Resource Server
OUTGOING_PAYMENT_WORKERSbackend.workers.outgoingPayment4number of workers processing outgoing payment requests
OUTGOING_PAYMENT_WORKER_IDLEbackend.workerIdle200time in milliseconds that OUTGOING_PAYMENT_WORKERS will wait until they check an empty outgoing payment request queue again
PRIVATE_KEY_FILEbackend.key.fileundefinedthe path to this Rafiki instance’s client private key
QUOTE_LIFESPANbackend.lifetime.quote5 * 60_000time in milliseconds an Open Payments quote is valid for
REDIS_TLS_CA_FILE_PATHbackend.redis.tlsCaFile''Redis TLS config
REDIS_TLS_CERT_FILE_PATHbackend.redis.tlsCertFile''Redis TLS config
REDIS_TLS_KEY_FILE_PATHbackend.redis.tlsKeyFile''Redis TLS config
REDIS_URLbackend.redis.host, backend.redis.portredis://127.0.0.1:6379Redis URL of database handling ILP packet data URL; For Helm, these components are provided individually.
SIGNATURE_SECRETbackend.quoteSignatureSecretundefinedsecret to generate request header signatures for webhook event requests
SIGNATURE_VERSION1version number to generate request header signatures for webhook event requests
SLIPPAGEbackend.ilp.slippage0.01accepted ILP rate fluctuation, default 1%
STREAM_SECRETbackend.ilp.streamSecretundefinedseed secret to generate shared STREAM secrets
TIGERBEETLE_CLUSTER_ID0Tigerbeetle cluster ID picked by the system that starts the TigerBeetle cluster to create a Tigerbeetle client
TIGERBEETLE_REPLICA_ADDRESSES3004Tigerbeetle replica addresses for all replicas in the cluster, which are comma separated IP addresses/ports, to create a Tigerbeetle client
TRUST_PROXYfalseflag to use X-Forwarded-Proto header to determine if connections is secure
USE_TIGERBEETLEtrueflag - use TigerBeetle or Postgres for accounting
WALLET_ADDRESS_DEACTIVATION_PAYMENT_GRACE_PERIOD_MS86400000time in milliseconds into the future to set expiration of open incoming payments when deactivating wallet address. Default: 1 days
WALLET_ADDRESS_LOOKUP_TIMEOUT_MS1500time in milliseconds the ASE has to create a missing wallet address until timeout
WALLET_ADDRESS_POLLING_FREQUENCY_MS100frequency of polling while waiting for ASE to create a missing wallet address
WALLET_ADDRESS_URLbackend.serviceUrls.WALLET_ADDRESS_URLhttp://127.0.0.1:3001/.well-known/paythis Rafiki instance’s internal wallet address
WALLET_ADDRESS_WORKERSbackend.workers.walletAddress1number of workers processing wallet address requests
WALLET_ADDRESS_WORKER_IDLEbackend.workerIdle200time in milliseconds that WALLET_ADDRESS_WORKERS will wait until they check an empty wallet address request queue again
WEBHOOK_MAX_RETRYbackend.webhookMaxRetry10maximum number of times Rafiki backend retries sending a certain webhook event to the configured WEBHOOK_URL
WEBHOOK_TIMEOUTbackend.lifetime.webhook2000milliseconds
WEBHOOK_URLbackend.serviceUrls.WEBHOOK_URLundefinedendpoint on the Account Servicing Entity that consumes webhook events
WEBHOOK_WORKERSbackend.workers.webhook1number of workers processing webhook events
WEBHOOK_WORKER_IDLEbackend.workerIdle200time in milliseconds that WEBHOOK_WORKERS will wait until they check an empty webhook event queue again
WITHDRAWAL_THROTTLE_DELAYbackend.withdrawalThrottleDelayundefineddelay in liquidity withdrawal processing
ENABLE_MANUAL_MIGRATIONSbackend.enableManualMigrationsfalseWhen set to true, user needs to run database manually with command npm run knex -- migrate:latest --env production