I do declare: consensus in a logic language

Abstract

The Paxos consensus protocol can be specified concisely, but is notoriously difficult to implement in practice. We recount our experience building Paxos in Overlog, a distributed declarative programming language. We found that the Paxos algorithm is easily translated to declarative logic, in large part because the primitives used in consensus protocol specifications map directly to simple Overlog constructs such as aggregation and selection. We discuss the programming idioms that appear frequently in our implementation, and the applicability of declarative programming to related application domains.