A concise, fast-paced guide to orchestrating and deploying scalable services with Docker About This Book Explore the new features added to the core Docker Engine to make multi-container orchestration easy Leverage tools such as Docker Machine, Swarm, Compose, and third-party tools such as Kubernetes, Mesosphere, and CoreOS to orchestrate containers Use Docker Compose with Swarm and apply rolling updates for zero downtime deployments Who This Book Is For This book is aimed at Sysadmins and DevOps engineers who know what Docker does and are now looking to manage multiple containers on multiple hosts using the orchestration feature. What You Will Learn Build scalable, reliable services with Docker See how to manage a service in Docker using Docker Swarm, Kubernetes, and Mesosphere Discover simpler orchestration tools such as CoreOS/Fleet and Rancher Cattle Understand cluster-wide logging, system monitoring, and troubleshooting Build, test, and deploy containers using Continuous Integration Deploy cluster hosts on cloud services and automate your infrastructure In Detail Docker orchestration is what you need when transitioning from deploying containers individually on a single host to deploying complex multi-container apps on many machines. This book covers the new orchestration features of Docker 1.12 and helps you efficiently build, test, and deploy your application using Docker. You will be shown how to build multi-container applications using Docker Compose. You will also be introduced to the building blocks for multi-host Docker clusters such as registry, overlay networks, and shared storage using practical examples. This book gives an overview of core tools such as Docker Machine, Swarm, and Compose which will enhance your orchestration skills. You’ll learn how to set up a swarm using the decentralized building block. Next, you’ll be shown how to make the most out of the in-built orchestration feature of Docker engine and you’ll use third-party tools such as Kubernetes, Mesosphere, and CoreOS to orchestrate your existing process. Finally, you will learn to deploy cluster hosts on cloud services and automate your infrastructure. Style and approach This comprehensive guide will take you through the orchestration feature of Docker. Using practical examples, you will discover various tools that can be used to manage multiple containers with ease.

Build customized themes to make your Moodle courses engaging and interactive About This Book Leverage the power of Moodle 3 to create interactive and engaging themes for your courses Experience and integrate the power of Bootstrap and CSS into your Moodle app Implement your plans with illustrative examples to become a top notch designer Who This Book Is For If you are a Moodle administrator, developer, or designer and wish to enhance your Moodle site to make it visually attractive, then this book is for you. You should be familiar with web design techniques such as HTML and further experience with CSS would be helpful. What You Will Learn Plan a personalized Moodle theme from start to finish Install a Moodle theme in different operating systems and change Moodle’s theme settings Add your own customized logo and test your changes in several web browsers Customize the Moodle site to fit in with other elements such as websites and social networks, among others Create a design mock-up using graphics software Design themes that are capable of working with a huge number of different resolutions, screen sizes, screen orientations, and pixel densities Work with code to adjust the theme to users requirements Create new custom icons for your theme In Detail Theming is one of the main features of Moodle, and it can be used to customize your online courses and make them look exactly how you want them to,according to your target audience. If you have been looking for a book that will help you develop Moodle themes that you are proud of, and that your students will enjoy, then this is the book for you. We start off by introducing Moodle 3 and explaining what it is, how it works, and what tools you might need to create a stunning Moodle theme. We then show you how to choose and change the pre-installed Moodle themes in detailed steps, and explain what Moodle themes are and how they work. Next, we show you how to change an existing theme and test the changes that you have made. You can not only plan the customization of theme, but also tailor it using advanced Moodle theming processes; this book is your one-stop guide to creating your own personalized Moodle 3 theme. Style and approach This book acts as a comprehensive guide which helps you to create visually stunning and responsive themes to add that extra edge to your Moodle apps.

Master application development by writing succinct, robust, and reusable code with Qt 5 About This Book Unleash the power of Qt 5 with C++14 Integrate useful third-party libraries such as OpenCV Package and deploy your application on multiple platforms Who This Book Is For This book will appeal to developers and programmers who would like to build GUI-based applications. Knowledge of C++ is necessary and the basics of Qt would be helpful. What You Will Learn Create stunning UIs with Qt Widget and Qt Quick Develop powerful, cross-platform applications with the Qt framework Design GUIs with the Qt Designer and build a library in it for UI preview Handle user interaction with the Qt signal/slot mechanism in C++ Prepare a cross-platform project to host a third-party library Build a Qt application using the OpenCV API Use the Qt Animation framework to display stunning effects Deploy mobile apps with Qt and embedded platforms In Detail Qt 5.7 is an application development framework that provides a great user experience and develops full-capability applications with Qt Widgets, QML, and even Qt 3D. This book will address challenges in successfully developing cross-platform applications with the Qt framework. Cross-platform development needs a well-organized project. Using this book, you will have a better understanding of the Qt framework and the tools to resolve serious issues such as linking, debugging, and multithreading. Your journey will start with the new Qt 5 features. Then you will explore different platforms and learn to tame them. Every chapter along the way is a logical step that you must take to master Qt. The journey will end in an application that has been tested and is ready to be shipped. Style and approach This is an easy-to-follow yet comprehensive guide to building applications in Qt. Each chapter covers increasingly advanced topics, with subjects grouped according to their complexity as well as their usefulness. Packed with practical examples and explanations, Mastering Qt contains everything you need to take your applications to the next level.

Master the capabilities of RethinkDB and implement them to develop efficient real-time web applications. The way to better database development is here! About This Book Master the powerful ReQL queries to manipulate your JSON data, Learn how to develop scalable, real-time web applications using RethinkDB and Node.js and deploy them for production, A detailed, step-by-step guide to help you master the concepts of RethinkDB programming with ease Who This Book Is For This book caters to all the real-time application developers looking forward to master their skills using RethinkDB. A basic understanding of RethinkDB and Node.js is essential to get the most out of this book. What You Will Learn Master the web-based management console for data-center configuration (sharding, replication, and more), database monitoring, and testing queries. Run queries using the ReQL language Perform Geospatial queries (such as finding all the documents with locations within 5km of a given point). Deal with time series data, especially across various times zones. Extending the functionality of RethinkDB and integrate it with third party libraries such as ElasticSearch to enhance our search In Detail RethinkDB has a lot of cool things to be excited about: ReQL (its readable,highly-functional syntax), cluster management, primitives for 21st century applications, and change-feeds. This book starts with a brief overview of the RethinkDB architecture and data modeling, and coverage of the advanced ReQL queries to work with JSON documents. Then, you will quickly jump to implementing these concepts in real-world scenarios, by building real-time applications on polling, data synchronization, share market, and the geospatial domain using RethinkDB and Node.js. You will also see how to tweak RethinkDB's capabilities to ensure faster data processing by exploring the sharding and replication techniques in depth. Then, we will take you through the more advanced administration tasks as well as show you the various deployment techniques using PaaS, Docker, and Compose. By the time you have finished reading this book, you would have taken your knowledge of RethinkDB to the next level, and will be able to use the concepts in RethinkDB to develop efficient, real-time applications with ease. Style and approach This book is a unique blend of comprehensive theory and real-world examples to help you master RethinkDB.

Deploy, configure, and run clusters of Docker containers with Swarm About This Book Get to grips with Docker Swarm, one of the key components of the Docker ecosystem. Optimize Swarm and SwarmKit features for scaling massive applications through containers. Learn about Docker’s scheduling tricks, high availability, security, and platform scalability. Who This Book Is For If you are a Linux admin or a Docker user who wants to natively manage Docker clusters, then this is the book for you. What You Will Learn Create and manage Swarm Mode clusters of any size Get a backstage view of the biggest Swarms ever built : Swarm2k and Swarm3k, with their 2,300 and 4,700 nodes Discovery mechanisms and Raft Deploy your containerized app on Swarm Administer Swarm clusters on AWS, Azure, and DigitalOcean Integrate Flocker volumes with Swarm Create and manage Swarms on OpenStack Magnum In Detail Docker Swarm serves as one of the crucial components of the Docker ecosystem and offers a native solution for you to orchestrate containers. It’s turning out to be one of the preferred choices for Docker clustering thanks to its recent improvements. This book covers Swarm, Swarm Mode, and SwarmKit. It gives you a guided tour on how Swarm works and how to work with Swarm. It describes how to set up local test installations and then moves to huge distributed infrastructures. You will be shown how Swarm works internally, what’s new in Swarmkit, how to automate big Swarm deployments, and how to configure and operate a Swarm cluster on the public and private cloud. This book will teach you how to meet the challenge of deploying massive production-ready applications and a huge number of containers on Swarm. You'll also cover advanced topics that include volumes, scheduling, a Libnetwork deep dive, security, and platform scalability. Style and approach A comprehensive guide that covers all aspects of Docker Swarm from setup to customization.

This book gets you started with essential software development easily and quickly, guiding you through Java's different facets. By adopting this approach, you can bridge the gap between learning and doing immediately. You will learn the new features of Java 9 quickly and experience a simple and powerful approach to software development. You will be able to use the Java runtime tools, understand the Java environment, and create Java programs. We then cover more simple examples to build your foundation before diving to some complex data structure problems that will solidify your Java 9 skills. With a special focus on modularity and HTTP 2.0, this book will guide you to get employed as a top notch Java developer. By the end of the book, you will have a firm foundation to continue your journey towards becoming a professional Java developer. What you will learn ?Compile, package and run a trivial program using a build management tool ?Get to know the principles of test-driven development and dependency management ?Separate the wiring of multiple modules from the application logic into an application using dependency injection ?Benchmark Java execution using Java 9 microbenchmarking ?See the workings of the Spring framework

Practical Computer Vision Projects About This Book ?Updated for OpenCV 3, this book covers new features that will help you unlock the full potential of OpenCV 3 ?Written by a team of 7 experts, each chapter explores a new aspect of OpenCV to help you make amazing computer-vision aware applications ?Project-based approach with each chapter being a complete tutorial, showing you how to apply OpenCV to solve complete problems Who This Book Is For This book is for those who have a basic knowledge of OpenCV and are competent C++ programmers. You need to have an understanding of some of the more theoretical/mathematical concepts, as we move quite quickly throughout the book. What You Will Learn ?Execute basic image processing operations and cartoonify an image ?Build an OpenCV project natively with Raspberry Pi and cross-compile it for Raspberry Pi.text ?Extend the natural feature tracking algorithm to support the tracking of multiple image targets on a video ?Use OpenCV 3's new 3D visualization framework to illustrate the 3D scene geometry ?Create an application for Automatic Number Plate Recognition (ANPR) using a support vector machine and Artificial Neural Networks ?Train and predict pattern-recognition algorithms to decide whether an image is a number plate ?Use POSIT for the six degrees of freedom head pose ?Train a face recognition database using deep learning and recognize faces from that database In Detail As we become more capable of handling data in every kind, we are becoming more reliant on visual input and what

"Create real-time hybrid applications with the leader of HTML5 frameworks: Ionic Framework About This Book ?Step into the world of amazingly interactive and real-time app development using Ionic 2 ?Leverage the powerful Angular 2 along with Ionic to develop cutting edge apps ?Detailed code examples and explanations will help you get up and running with Ionic quickly and easily Who This Book Is For This book is for JavaScript developers with basic skills. No previous knowledge of Ionic is required for this book. What You Will Learn ?Understanding the world of the mobile hybrid architecture ?Scaffolding and working with Ionic templates ?Transforming a single page app to a multi-page app using Navigation Controller ?Integrating Ionic components, decorators, and services and rapidly developing complex applications ?Theming Ionic apps as well as customizing components using SCSS ?Working with Ionic Native to interface with device features, such as camera, notifications, and battery ?Building a production grade app using Ionic and Uber API to let users book a ride ?Migrating an Ionic 1 app to Ionic 2 or Ionic 3 ?Performing unit testing, end-to-end testing, and device testing on your apps ?Deploying Ionic apps to store and manage their subsequent releases In Detail Ionic makes it incredibly easy to build beautiful and interactive mobile apps using HTML5, SCSS, and Angular. Ionic also makes app development easier, faster, and more fun. This hands-on guide will help you understand the Ionic framework and how you can leverage it to create amazing real-time applications. We begin by covering the essential features of Angular 2, and then dive straight into how Ionic fits in today's world of hybrid app development and give you a better understanding of the mobile hybrid architecture along the way. Further on, you will learn how to work with Ionic decorators, services, and components, which will allow you to build complex apps using the Ionic framework. We will take a look at theming Ionic apps using the built-in SCSS setup. After that, we will explore Ionic Native, and you will learn how to integrate device-specific features, such as notifications, with the Ionic app. To complete our learning, we will be building a Rider app, using Ionic and Uber API, to book a ride. Next, you will learn how to unit test, end-to-end test, monkey test, and execute device testing on AWS Device farm. Then, we will take a look at migrating the existing Ionic 1 apps to Ionic 2 and deploy them to the App Store. The final chapter on Ionic 3 wraps up this book by explaining the new features of Ionic 3 at the time of writing this book. By the end of this book, you will be able to develop, deploy, and manage hybrid mobile applications built with Cordova, Ionic, and Angular. All the examples in this book are valid for both Ionic 2 and Ionic 3. Style and approach A step-by-step, practical approach to learning Ionic using the example of designing an online course app. Each topic is explained sequentially in the process of creating a course. This includes explanations of both basic and advanced features of Ionic. "

"Key Features ?Understand and use Vue's reactivity system, data binding, and computed properties ?Create fluid transitions in your application with Vue's built-in transition system ?Use Vuex and Webpack to build medium-to-large scale SPAs and enhance your development workflow Book De*ion Vue.js is an open source JavaScript library for building modern, interactive web applications. With a rapidly growing community and a strong ecosystem, Vue.js makes developing complex single page applications a breeze. Its component-based approach, intuitive API, blazing fast core, and compact size make Vue.js a great solution to craft your next front-end application. From basic to advanced recipes, this book arms you with practical solutions to common tasks when building an application using Vue. We start off by exploring the fundamentals of Vue.js: its reactivity system, data-binding syntax, and component-based architecture through practical examples. After that, we delve into integrating Webpack and Babel to enhance your development workflow using single file components. Finally, we take an in-depth look at Vuex for state management and Vue Router to route in your single page applications, and integrate a variety of technologies ranging from Node.js to Electron, and Socket.io to Firebase and HorizonDB. This book will provide you with the best practices as determined by the Vue.js community. What you will learn ?Understand the fundamentals of Vue.js through numerous practical examples ?Piece together complex web interfaces using theVue.js component system ?Use Webpack and Babel to enhance your development workflow ?Manage your "

Gain essential knowledge and keep your NetScaler environment in top form About This Book Learn how the main features - Load Balancing, Content Switching, GSLB, SSL offloading, AAA, AppFirewall, and Gateway work under the hood using vividly explained flows and traces Explore the NetScaler layout and the various logs, tools and methods available to help you when it’s time to debug An easy-to-follow guide, which will walk you through troubleshooting common issues in your NetScaler environment Who This Book Is For This book is aimed at NetScaler administrators who have a basic understanding of the product but are looking for deeper exposure and guidance in identifying and fixing issues to keep their application environment performing optimally. What You Will Learn Troubleshoot traffic management features such as load balancing, SSL, GSLB and content switching Identify issues with caching and compression Deal with authentication issues when using LDAP, RADIUS, certificates, Kerberos and SAML Diagnose NetScaler high availability and networking issues Explore how application firewall protections work and how to avoid false positives Learn about NetScaler Gateway integration issues with XenApp, XenDesktop, and XenMobile Deal with NetScaler system-level issues Discover the NetScaler troubleshooting tools In Detail NetScaler is a high performance Application Delivery Controller (ADC). Making the most of it requires knowledge that straddles the application and networking worlds. As an ADC owner you will also likely be the first person to be solicited when your business applications fail. You will need to be quick in identifying if the problem is with the application, the server, the network, or NetScaler itself. This book provides you with the vital troubleshooting knowledge needed to act fast when issues happen. It gives you a thorough understanding of the NetScaler layout, how it integrates with the network, and what issues to expect when working with the traffic management, authentication, NetScaler Gateway and application firewall features. We will also look at what information to seek out in the logs, how to use tracing, and explore utilities that exist on NetScaler to help you find the root cause of your issues. Style and approach This helpful guide to troubleshooting NetScaler is delivered in a comprehensive and easy-to-follow manner. The topics in the book adopt a step-by-step approach.

Design efficient machine learning systems that give you more accurate results About This Book Gain an understanding of the machine learning design process Optimize machine learning systems for improved accuracy Understand common programming tools and techniques for machine learning Develop techniques and strategies for dealing with large amounts of data from a variety of sources Build models to solve unique tasks Who This Book Is For This book is for data scientists, scientists, or just the curious. To get the most out of this book, you will need to know some linear algebra and some Python, and have a basic knowledge of machine learning concepts. What You Will Learn Gain an understanding of the machine learning design process Optimize the error function of your machine learning system Understand the common programming patterns used in machine learning Discover optimizing techniques that will help you get the most from your data Find out how to design models uniquely suited to your task In Detail Machine learning is one of the fastest growing trends in modern computing. It has applications in a wide range of fields, including economics, the natural sciences, web development, and business modeling. In order to harness the power of these systems, it is essential that the practitioner develops a solid understanding of the underlying design principles. There are many reasons why machine learning models may not give accurate results. By looking at these systems from a design perspective, we gain a deeper understanding of the underlying algorithms and the optimisational methods that are available. This book will give you a solid foundation in the machine learning design process, and enable you to build customised machine learning models to solve unique problems. You may already know about, or have worked with, some of the off-the-shelf machine learning models for solving common problems such as spam detection or movie classification, but to begin solving more complex problems, it is important to adapt these models to your own specific needs. This book will give you this understanding and more. Style and approach This easy-to-follow, step-by-step guide covers the most important machine learning models and techniques from a design perspective.

Get up and running with ReactJS by developing five cutting-edge and responsive projects About This Book Create pragmatic real-world applications while learning React and its modern developer tools Build sustainable user interfaces by transforming data into components of UI Learn how to generate reusable ReactJS components effectively Who This Book Is For If you are a web developer and wish to learn ReactJS from scratch, then this book is tailor-made for you. Good understanding of Java*, HTML, and CSS is expected. What You Will Learn Create, reuse, and compose React components using JSX Share data between various React components and techniques for data flow within a React app Handle user interactions with the help of event handlers and dynamic components Set up and use various next generation ES2015/ES6 features with React Understand the performance and immutability features of React using React add-ons Learn the techniques of Animation in React Use data stores to store model-related data and information Create a flux-based React application by using Reflux library In Detail ReactJS is an open-source JavaScript library that brings the power of reactive programming to web applications and sites. It aims to address the challenges encountered in developing single-page applications, and is intended to help developers build large, easily scalable and changing web apps. Starting with a project on Open Library API, you will be introduced to React and JSX before moving on to learning about the life cycle of a React component. In the second project, building a multi-step wizard form, you will learn about composite dynamic components and perform DOM actions. You will also learn about building a fast search engine by exploring server-side rendering in the third project on a search engine application. Next, you will build a simple frontpage for an e-commerce app in the fourth project by using data models and React add-ons. In the final project you will develop a complete social media tracker by using the flux way of defining React apps and know about the best practices and use cases with the help of ES6 and redux. By the end of this book, you will not only have a good understanding of ReactJS but will also have built your very own responsive frontend applications from scratch. Style and approach An easy-to-follow program to learn ReactJS with the help of real world projects. Each topic is explained within the context of a project and provides plenty of tips and tricks for using ReactJS.

Build real-world applications for the Apple Watch platform using the WatchKit framework and Swift 2.0 About This Book Find out how to download and install the Xcode development tools before learning about Xcode playgrounds and the Swift programming language Discover everything you need to know about the WatchKit platform architecture, its classes, as well its limitations This book introduces you to the very latest mobile platform with hands-on instructions so you can build your very own Apple Watch apps Who This Book Is For This book is for developers who are interested in creating amazing apps for the Apple Watch platform. Readers are expected to have no prior experience of programming. What You Will Learn Navigate within the WatchKit interface using the page-based, modal, and hierarchical navigation techniques Work with context menus to allow your users to interact with the Apple Watch and respond to their actions to perform a task Use the MapKit framework to display a map within the WatchKit interface to track the user's current location Build effective user interfaces for the WatchKit platform and integrate iCloud capabilities to synchronize data between the iOS app and the WatchKit UI Design your apps for the Apple Watch platform by adhering to the set of User Interface design guidelines set out by Apple Reinforce image caching to display animations within the Apple Watch user interface Explore WatchKit tables, which allow your users to purchase groceries and pay for them using Apple Pay Analyze the new layout system to ensure that your Apple Watch apps work with various screen sizes In Detail Wearable are the next wave of mobile technology and with the release of Apple’s WatchKit SDK, a whole new world of exciting development possibilities has opened up. Apple Watch App Development introduces you to the architecture and possibilities of the Apple Watch platform, as well as an in-depth look at how to work with Xcode playgrounds. Benefit from a rapid introduction to the Swift programming language so you can quickly begin developing apps with the WatchKit framework and the Xcode Development IDE. Get to grips with advanced topics such as notifications, glances, iCloud, Apple pay, closures, tuples, protocols, delegates, concurrency, and using Swift Playgrounds, with each concept is backed up with example code that demonstrates how to properly execute it. Finally, discover how to package and deploy your Watch application to the Apple AppStore. By the end of this book, you will have a good understanding of how to develop apps for the Apple Watch platform, and synchronize data using iCloud between the wearable and the iOS device. Style and approach This book takes a step-by-step approach to developing applications for the Apple Watch using the Swift programming language and the WatchKit UI. Each topic is explained in a conversational and easy-to-follow style.

As a user, you will learn, using real-world scenarios and tasks, exactly how to use all the features of Sametime. Beginning with how to install Sametime, we've included step-by-step de*ions and screen prints for each topic area in a clear easy-to-follow format. Each chapter builds on what you learn in earlier chapters and guides you into using the more advanced features of Sametime, but if you only want to develop your skills in one particular area, each chapter acts as a stand-alone module. If you want to learn how to use IBM Lotus Sametime, then this book is for you. No matter if you're new to Sametime or want to become a Sametime power user, this book contains something for you. The focus is on using Sametime as a user and does not include information about development or administration of a Sametime environment; but any user of Sametime in an organization will be able to take this book, sit down at their computer, and learn how to use each feature of Sametime from start to finish.

An example-based approach leads you step-by-step through the implementation and customization of each library component and its associated resources in turn. To emphasize the way that jQuery UI takes the difficulty out of user interface design and implementation, each chapter ends with a 'fun with' section that puts together what you've learned throughout the chapter to make a usable and fun page. In these sections you'll often get to experiment with the latest associated technologies like AJAX and JSON. This book is for front-end designers and developers who need to quickly learn how to use the jQuery UI User Interface Library. To get the most out of this book you should have a good working knowledge of HTML, CSS, and JavaScript, and will need to be comfortable using jQuery, the underlying foundation of jQuery UI.

This book is a step-by-step tutorial that will teach you to customize VirtueMart templates and themes. It includes all the essential screenshots and code with exhaustive explanations accompanied by exercises to ensure good pickup.You may be the owner of a Joomla! VirtueMart web store or a designer working with Joomla! VirtueMart. If you want to customize VirtueMart to unleash its enormous potential and elevate your store to the next level, this book is for you. You must have some experience with VirtueMart and understand its basic features. You also need to know HTML and should be comfortable taking up some challenges in PHP and JavaScript programming.

This is a cookbook, with practical recipes providing tips and tricks to the most common problems and scenarios faced with CMS Made Simple Development. If you are a CMS Made Simple user wanting to expand your skill set, or a programmer who wants to develop for CMS Made Simple, this book is for you. You will need working knowledge of PHP, HTML, and SQL. Some experience with CMS Made Simple is recommended.

This is a cookbook with over 80 recipes offering solutions to common game development problems with Panda3D with explained sample code and screenshots added in. If you are a developer with experience in Python, Panda3D, and optionally C++ and shading languages and you are looking for quick and easy to integrate solutions to common game development problems with Panda3D, this book is for you.

This book is written in a cookbook style. Each chapter consists of recipes, each of which is composed of step-by-step instructions to complete a particular task. Each recipe also includes tips, alternatives, and references to other recipes or appropriate external sources. The book can be explored chapter by chapter or in no particular order. This book is intended for all levels of network administrators. If you are an advanced user of pfSense, then you can flip to a particular recipe and quickly accomplish the task at hand, while if you are new to pfSense, you can read chapter by chapter and learn all of the features of the system from the ground up.

Packed with fully explained examples, LaTeX Beginner's Guide is a hands-on introduction quickly leading a novice user to professional-quality results. If you are about to write mathematical or scientific papers, seminar handouts, or even plan to write a thesis, then this book offers you a fast-paced and practical introduction. Particularly during studying in school and university you will benefit much, as a mathematician or physicist as well as an engineer or a humanist. Everybody with high expectations who plans to write a paper or a book will be delighted by this stable software.

Create and customize your own website with the Concrete5 Beginner's Guide