Puppet Communications Protocol (PCP)

This document describes the PCP framework and its communications protocol.

Index

Introduction - overview of the PCP framework
Terminology - definitions used by the Puppet communications protocol

Syntax

Message - JSON-based message format
URI - PCP URI format

Semantics

Session - initialise connections
Inventory - inventory service and transaction
Message Delivery - how the fabric processes and delivers client messages
Error Handling - error handling
Delivery Authorization - how the fabric reports message delivery authorization failures
Delivery Guarantees - how the fabric guarantees the delivery of messages
Message Versioning - how the fabric handles message versions

Implementations

The following projects follow the PCP specifications described here, using WebSockets as the underlying wire protocol.

pcp-broker provides a PCP broker implementation in Clojure
cpp-pcp-client is a PCP client library written in C++
pxp-agent is a PXP agent based on cpp-pcp-client, that offers a Puppet module
clj-pcp-client is a PCP client library written in Clojure