Délégation de tâches avec ZeroMQ La délégation de tâches en asynchrone est un moyen efficace d’alléger la charge que subissent nos systèmes. En effet, de nombreux cas d’utilisation ne nécessitent pas d’être exécutés de façon synchrone lorsqu’un utilisateur effectue une action ou qu’un événement extérieur intervient. Par exemple, lorsqu’il n’est pas nécessaire de restituer la dernière version des données et que le traitement avant restitution est coûteux en ressources, il est possible de renvoyer des données préalablement mises en cache et de déporter en asynchrone une tâche de rafraîchissement de ce cache. Un autre exemple concerne les systèmes qui mêlent des requêtes fortement consommatrices en ressources (CPU, mémoire, …) et des requêtes peu consommatrices pour lesquelles on va vouloir garantir une latence faible même lorsque des requêtes consommatrices sont en cours de traitement. Pour résoudre cette problématique de délégation de tâches, on utilise habituellement une solution comme ActiveMQ ou RabbitMQ. Conclusion
Python Module of the Week - Python Module of the Week PyMOTW If you find this information useful, consider picking up a copy of my book, The Python Standard Library By Example. Navigation Table of Contents Next: About Python Module of the Week This Page Show Source Now available for Python 3! Buy the book! Python Module of the Week¶ © Copyright Doug Hellmann Apache Qpid™: Open Source AMQP Messaging Bash Reference Manual Table of Contents This text is a brief description of the features that are present in the Bash shell (version 4.4, 7 September 2016). The Bash home page is This is Edition 4.4, last updated 7 September 2016, of The GNU Bash Reference Manual, for Bash, Version 4.4. Bash contains features that appear in other popular shells, and some features that only appear in Bash. This manual is meant as a brief introduction to features found in Bash. 1 Introduction 1.1 What is Bash? Bash is the shell, or command language interpreter, for the GNU operating system. Bash is largely compatible with sh and incorporates useful features from the Korn shell ksh and the C shell csh. While the GNU operating system provides other shells, including a version of csh, Bash is the default shell. 1.2 What is a shell? At its base, a shell is simply a macro processor that executes commands. A Unix shell is both a command interpreter and a programming language. 2 Definitions blank builtin \a
Learn the Basics See more examples... Core Documentation ZeroMQ - The Guide explains how to use ZeroMQ as an intelligent transport layer for your distributed apps. Old version for version 2.2. The ZeroMQ Reference Manual specifies the ZeroMQ API. The ZeroMQ FAQ by the community is the first place to look for answers to frequently asked questions and problems. Slideshows Comparisons In 2011, CERN (the European Organization for Nuclear Research) compared CORBA, Ice, Thrift, ZeroMQ, YAMI4, RTI, and Qpid (AMQP). Who is Using ZeroMQ? Since ZeroMQ is free software we don't track who uses it. Example Code This shows a filter that collects data from two different remote publishers and sends it to local subscribers: Introductions Ilya Grigorik writes: The best way to get started with ZeroMQ is to work through some hands-on examples - the concepts are not new, but the ease with which you can compose them takes some getting use to. Brian Buchanan writes: Andrew Cholakian writes: Nicholas Piël writes: Zed Shaw writes:
Broker vs. Brokerless This article presents different models of how messaging can be done. It discusses drawbacks and advantages of individual approaches. It is meant as a background reading to learn how ØMQ differs from traditional messaging systems. Architecture of most messaging systems is distinctive by the messaging server ("broker") in the middle. There are several advantages to this model. Firstly, applications don't have to have any idea about location of other applications. Secondly, message sender and message receiver lifetimes don't have to overlap. Thirdly, broker model is to some extent resistant to the application failure. Drawbacks of broker model are twofold: Firstly, it requires excessive amount of network communication. To demonstrate the drawbacks of the broker model, let's consider a simple scenario where data have to be processed by four distinct applications in a row. First, let's have a look how this scenario would look like when implemented using SOA (ESB, request/reply) architecture.
dbtools — dbtools 0.4.0 documentation A simple interface to SQLite databases. Overview This module handles simple interfacing with a SQLite database. Inspired by ipython-sql, dbtools returns pandas DataFrame objects from SELECT queries, and can handle basic forms of other SQL statements (CREATE, INSERT, UPDATE, DELETE, and DROP). The goal is not to replicate the full functionality of SQLAlchemy or really to be used for object-relational mapping at all. Installation The easiest way to get dbtools is with pip: Alternately, you can clone the repository and install from source: git clone email@example.com:jhamrick/dbtools.git cd dbtools python setup.py install There is also a Makefile in the root of the repository which is just a convenience wrapper around setup.py. Examples Create and load >>> from dbtools import Table>>> tbl = Table.create("data.db", "People",... If a table already exists, we can just directly create a Table object: Insert Inserting with a list (excluding id, because it autoincrements): >>> tbl.insert(["Alyssa P. Select
Apache ActiveMQ ™ -- Index WindowsDualBoot This page describes how to set up your computer in order to dual boot Ubuntu and Windows. Although this may seem obvious, it is important to back up your files to an external backup medium before attempting a dual-boot installation (or any other hard drive manipulation), in case your hard drive becomes corrupted during the process. External hard drives, USB flash drives, and multiple DVDs or CDs are all useful for this purpose. Some computer manufacturers that pre-install Windows provide a Windows recovery/re-installation CD or DVD with the computer. However, many companies no longer ship a physical disc but instead create a hidden partition on the hard drive in which the recovery-disk information is stored. A utility is then usually provided which allows the user to burn a recovery/re-installation CD or DVD from it. You may need to request a physical recovery/re-installation CD or DVD directly from your computer manufacturer. Install Ubuntu Automatic partition resizing (not recommended)
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