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federation

README.md

federation server

Go implementation of Federation protocol server. This federation server is designed to be dropped in to your existing infrastructure. It can be configured to pull the data it needs out of your existing DB.

Downloading the server

Prebuilt binaries of the federation server are available on the releases page.

Config

By default this server uses a config file named federation.cfg in the current working directory. This configuration file should be TOML and the following fields are supported:

  • port - server listening port

  • database

    • type - database type (sqlite3, postgres)
    • dsn - The DSN (data source name) used to connect to the database connection. This value should be appropriate for the database type chosen.
      • for postgres: postgres://user:password@host/dbname?sslmode=sslmode (more info)

  • queries

    • federation - Implementation dependent query to fetch federation results, should return either 1 or 3 columns. These columns should be labeled id,memo,memo_type. Memo and memo_type are optional - see Federation docs for more detail). When executed, this query will be provided with two input parameters, the first will be the name portion of a stellar address and the second will be the domain portion of a stellar address. For example, a request for scott*stellar.org would trigger a query with two input parameters, scott and stellar.org respectively.

    • reverse-federation - A SQL query to fetch reverse federation results that should return two columns, labeled name and domain. When executed, this query will be provided with one input parameter, a stellar account ID used to lookup the name and domain mapping.

      If reverse-lookup isn't supported (e.g. you have a single Stellar account for all users), leave this entry out.

  • tls (only when running HTTPS server)

    • certificate-file - a file containing a certificate
    • private-key-file - a file containing a matching private key

memo_type should be one of the following:

  • id - then memo field should contain unsigned 64-bit integer, please note that this value will be converted to integer so the field should be an integer or a string representing an integer,
  • text - then memo field should contain string, up to 28 characters.
  • hash - then memo field should contain string that is 32bytes base64 encoded.

Example federation.cfg

In this section you can find config examples for the two main ways of setting up a federation server.

#1: Every user has their own Stellar account

In the case that every user owns a Stellar account, you don't need memo. You can simply return id based on the username. Your queries section could look like this:

port = 8000

[database]
type = "postgres"
dsn = "postgres://user:password@host/dbname?sslmode=sslmode"

[queries]
federation = "SELECT account_id as id FROM Users WHERE username = ? AND domain = ?"
reverse-federation = "SELECT username as name, domain FROM Users WHERE account_id = ?"

#2: Single Stellar account for all incoming transactions

If you have a single Stellar account for all incoming transactions you need to use memo to check which internal account should receive the payment.

Let's say that your Stellar account ID is: GD6WU64OEP5C4LRBH6NK3MHYIA2ADN6K6II6EXPNVUR3ERBXT4AN4ACD and every user has an id and username in your database. Then your queries section could look like this:

port = 8000

[database]
type = "postgres"
dsn = "postgres://user:password@host/dbname?sslmode=sslmode"

[queries]
federation = "SELECT username as memo, 'text' as memo_type, 'GD6WU64OEP5C4LRBH6NK3MHYIA2ADN6K6II6EXPNVUR3ERBXT4AN4ACD' as id FROM Users WHERE username = ? AND domain = ?"
# No entry for `reverse-federation` since a reverse-lookup isn't possible

Providing federation for a single domain

In the event that your organization only wants to offer federation for a single domain, a little bit of trickery can be used to configure your queries to satisfy this use case. For example, let's say you own acme.org and want to provide only results for that domain. The following example config illustrates:

federation = "SELECT username as memo, 'text' as memo_type, 'GD6WU64OEP5C4LRBH6NK3MHYIA2ADN6K6II6EXPNVUR3ERBXT4AN4ACD' as id FROM Users WHERE username = ? AND ? = 'acme.org'"
reverse-federation = "SELECT username as name, 'acme.org' as domain FROM Users WHERE account_id = ?"

Notice that SQL fragment ? = 'acme.org" on the federation query: It ensures the incoming query is for the correct domain. Additionally, the reverse-federation query always returns acme.org for the domain.

Postgresql sample

Bundled with the source code of this project is a sample configuration file and a shell script that can be used to populate a sample database. These two items can be used to play around with the service. See (./federation.cfg) and (./build_sample.sh).

Usage

./federation [-c=CONFIGPATH]

Building

This service can built from source, provided you have installed the go tools, by issuing the following command in a terminal:

Given you have a running golang installation, you can build the server with:

go get -u github.com/stellar/go/services/federation

After successful completion, you should find bin/federation is present in your configured GOPATH.

Running tests

go test