Zato—Agile ESB, SOA, REST and Cloud Integrations in Python

Dariusz Suchojad — Tue, 14 Jan 2014 18:50:32 +0000

Zato is a Python-based platform for integrating applications and exposing back-end services to front-end clients. It's an ESB (Enterprise Service Bus) and an application server focused on data integrations. The platform doesn't enforce any limits on architectural style for designing systems and can be used for SOA (Service Oriented Architecture), REST (Representational State Transfer) and for building systems of systems running in-house or in the cloud.

At its current version of 1.1 (at the time of this writing), Zato supports HTTP, JSON, SOAP, SQL, AMQP, JMS WebSphere MQ, ZeroMQ, Redis NoSQL and FTP. It includes a browser-based GUI, CLI, API, security, statistics, job scheduler, HAProxy-based load balancer and hot-deployment. Each piece is extensively documented from the viewpoint of several audiences: architects, admins and programmers.

Zato servers are built on top of gevent and gunicorn frameworks that are responsible for handling incoming traffic using asynchronous notification libraries, such as libevent or libev, but all of that is hidden from programmers' views so they can focus on their job only.

Servers always are part of a cluster and run identical copies of services deployed. There is no limit on how many servers a single cluster can contain.

Each cluster keeps its configuration in Redis and an SQL database. The former is used for statistics or data that is frequently updated and mostly read-only. The latter is where the more static configuration shared between servers is kept.

Users access Zato through its Web-based GUI, the command line or API.

Zato promotes loose coupling, reusability of components and hot-deployment. The high-level goal is to make it trivial to access or expose any sort of information. Common integration techniques and needs should be, at most, a couple clicks away, removing the need to reimplement the same steps constantly, slightly differently in each integration effort.

Everything in Zato is about minimizing the interference of components on each other, and server-side objects you create can be updated easily, reconfigured on fly or reused in other contexts without influencing any other.

This article guides you through the process of exposing complex XML data to three clients using JSON, a simpler form of XML and SOAP, all from a single code base in an elegant and Pythonic way that doesn't require you to think about the particularities of any format or transport.

To speed up the process of retrieving information by clients, back-end data will be cached in Redis and updated periodically by a job-scheduled service.

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