Die Komplexität und Größe von verteilten Systemen nehmen stetig zu. Steht nun ein einzelner Service nicht oder nur eingeschränkt zur Verfügung, kann sich dies schnell auf die Verfügbarkeit des ganzen und auf benachbarte Systeme auswirken. Mit Hilfe der Bibliothek Hystrix von Netflix hat man die Möglichkeit auf solche Ereignisse mit wenig Aufwand geeignet zu reagieren.
Der Vortrag zeigt, an welchen Stellen Hystrix eingesetzt werden sollte und welche Stolpersteine es geben kann. U.a. kann das Zusammenspiel mit anderen Bibliotheken für Querschnittsfunktionalitäten wie z.B. Logging und Transaktionshandling für einige Überraschungen sorgen. Auch der deklarative Einsatz von Hystrix kann einen vor neue Herausforderungen stellen.
Speaker: Gerrit Brehmer, inovex GmbH
Event: inovex Meetup (http://www.meetup.com/de-DE/inovex-karlsruhe/)
Datum: 20.10.2016
Mehr Vorträge: https://www.inovex.de/de/content-pool/vortraege/
Fault tolerance in general is a challenging topic. Yet we need fault toleranct designs more badly than ever in order to provide robust, highly available systems - especially in times of scale out systems becoming more and more popular.
Unfortunately, most developers do not care too much about a fault tolerant design, either because they are scared by the complexity of the realm or because they do not care enough. One of the problems is that a lack of fault tolerant design does not hurt a lot in development or in QA, but it hurts a lot in production - as Michael Nygard said: "It's all about production!" (at least figuratively).
In this presentation I do *not* try to give a general introduction to fault tolerant design. Instead I pick a few generic case studies that demonstrate the results of missing fault tolerant design, try to sensitize a bit about the production relevance of fault tolerant design and then go along with a few selected patterns. I picked a few patterns which are surprisingly easy to implement and help to mitigate the problems of the former case studies.
This way I try to show two things:
1. A piece of architecture or design as a pattern is not necessarily hard to implement. Sometimes the code is written quicker than it takes to explain the pattern beforehand.
2. Even if fault tolerant design as a general topic might be hard, some parts of it can be implemented very easily and it's more than worth the coding effort if you look how much better your system behaves in production just from adding those few lines of code.
Die Komplexität und Größe von verteilten Systemen nehmen stetig zu. Steht nun ein einzelner Service nicht oder nur eingeschränkt zur Verfügung, kann sich dies schnell auf die Verfügbarkeit des ganzen und auf benachbarte Systeme auswirken. Mit Hilfe der Bibliothek Hystrix von Netflix hat man die Möglichkeit auf solche Ereignisse mit wenig Aufwand geeignet zu reagieren.
Der Vortrag zeigt, an welchen Stellen Hystrix eingesetzt werden sollte und welche Stolpersteine es geben kann. U.a. kann das Zusammenspiel mit anderen Bibliotheken für Querschnittsfunktionalitäten wie z.B. Logging und Transaktionshandling für einige Überraschungen sorgen. Auch der deklarative Einsatz von Hystrix kann einen vor neue Herausforderungen stellen.
Speaker: Gerrit Brehmer, inovex GmbH
Event: inovex Meetup (http://www.meetup.com/de-DE/inovex-karlsruhe/)
Datum: 20.10.2016
Mehr Vorträge: https://www.inovex.de/de/content-pool/vortraege/
Fault tolerance in general is a challenging topic. Yet we need fault toleranct designs more badly than ever in order to provide robust, highly available systems - especially in times of scale out systems becoming more and more popular.
Unfortunately, most developers do not care too much about a fault tolerant design, either because they are scared by the complexity of the realm or because they do not care enough. One of the problems is that a lack of fault tolerant design does not hurt a lot in development or in QA, but it hurts a lot in production - as Michael Nygard said: "It's all about production!" (at least figuratively).
In this presentation I do *not* try to give a general introduction to fault tolerant design. Instead I pick a few generic case studies that demonstrate the results of missing fault tolerant design, try to sensitize a bit about the production relevance of fault tolerant design and then go along with a few selected patterns. I picked a few patterns which are surprisingly easy to implement and help to mitigate the problems of the former case studies.
This way I try to show two things:
1. A piece of architecture or design as a pattern is not necessarily hard to implement. Sometimes the code is written quicker than it takes to explain the pattern beforehand.
2. Even if fault tolerant design as a general topic might be hard, some parts of it can be implemented very easily and it's more than worth the coding effort if you look how much better your system behaves in production just from adding those few lines of code.
Tempest is an Openstack test suite which runs against all the OpenStack service endpoints. It makes sure that all the OpenStack components work together properly and that no APIs are changed. Tempest is a "gate" for all commits to OpenStack repositories and will prevent merges if tests fail.
So we're running Apache ZooKeeper. Now What? By Camille Fournier Hakka Labs
The ZooKeeper framework was originally built at Yahoo! to make it easy for the company’s applications to access configuration information in a robust and easy-to-understand way, but it has since grown to offer a lot of features that help coordinate work across distributed clusters. Apache Zookeeper became a de-facto standard for coordination service and used by Storm, Hadoop, HBase, ElasticSearch and other distributed computing frameworks.
Design patterns - Common Solutions to Common Problems - Brad WoodOrtus Solutions, Corp
How unique is the problem you’re coding for right now? What’s the chance it’s been solved hundreds, maybe thousands of times? Is your solution the best way? You’ve no doubt heard other developers talk about using “design patterns”. These are reusable solutions to the problems that we all face as developers. The best thing is that most patterns can carry over from one language to another. It’s a great idea to familiarize yourself with these common solutions so you identify them and know when you plug them into your apps.
Let’s take a pragmatic look at exactly what design pattern are – and aren’t! The more you learn, the bigger toolbox you’re building that you can dip into to solve problems. You’ll also start to notice these familiar designs in frameworks and other people’s apps. Learning to recognize common patterns, their names, and when to use them will grow you as a developer, stretch your thinking outside the box, and make you better at what you do. A solid OO background will really help you, and most of what we cover will be generic to any language. Expect to cover some of the most common design patterns along with examples and their pros and cons with examples in CFML.
ZooKeeper - wait free protocol for coordinating processesJulia Proskurnia
ZooKeeper is a service for coordinating processes within distributed systems. Stress test of the tool was applied. Reliable Multicast and Dynamic LogBack system Configuration management were implemented with ZooKeeper.
More details: http://proskurnia.in.ua/wiki/zookeeper_research
Build a Complex, Realtime Data Management App with Postgres 14!Jonathan Katz
Congratulations: you've been selected to build an application that will manage reservations for rooms!
On the surface, this sounds simple, but you are building a system for managing a high traffic reservation web page, so we know that a lot of people will be accessing the system. Therefore, we need to ensure that the system can handle all of the eager users that will be flooding the website checking to see what availability each room has.
Fortunately, PostgreSQL is prepared for this! And even better, we will be using Postgres 14 to make the problem even easier!
We will explore the following PostgreSQL features:
* Data types and their functionality, such as:
* Data/Time types
* Ranges / Multirnages
Indexes such as:
* GiST
* Common Table Expressions and Recursion (though multiranges will make things easier!)
* Set generating functions and LATERAL queries
* Functions and the PL/PGSQL
* Triggers
* Logical decoding and streaming
We will be writing our application primary with SQL, though we will sneak in a little bit of Python and using Kafka to demonstrate the power of logical decoding.
At the end of the presentation, we will have a working application, and you will be happy knowing that you provided a wonderful user experience for all users made possible by the innovation of PostgreSQL!
Nonblocking (NB) algorithms are something of a Holy Grail of concurrent programming--typically very fast, even under heavy load, they come with hard guarantees about forward progress. The downside is that they are very hard to get right. This presentations authors worked on writing some nonblocking utilities (open sourced on SourceForge in the high-scale-lib project) and have made some progress toward a coding style that can be used to build a variety of NB data structures: hash tables, sets, work queues, and bit vectors. These data structures scale much better than even the concurrent JDK™ software utilities while providing the same correctness guarantees. They usually have similar overheads at the low end while scaling incredibly well on high-end hardware. The coding style is still very immature but shows clear promise. It stems from a handful of basic premises: You don't hide payload during updates; any thread can complete (or ignore) any in-progress update; use flat arrays for quick access and broadest-possible striping; and use parallel, concurrent, incremental array copy. At the core is a simple state-machine description of the update logic.
За последние годы разными специалистами и компаниями (от Google до Сноудена) был проделан колоссальный объём работы с целью популяризации протокола SSL, а позже и TLS. Дорабатывались протоколы и шифры, обнаруживались десятки уязвимостей, криптографические библиотеки форкались и проводили аудиты, правозащитные фонды выдавали сотни миллионов сертификатов "забесплатно". В конце концов, TLS явочным порядком, в обход стандарта, стал обязательным для HTTP/2-серверов. Так много сил было приложено, что просто-напросто уже невежливо всё это игнорировать.
Однако процесс внедрения TLS за это время, как это ни удивительно, не стал проще ни на йоту. Сисадмины, приступающие к развёртыванию TLS, вынуждены столкнуться с классификацией типов сертификатов, с множеством центров сертификации (которые непонятно, чем друг друга лучше) и с великим множеством дополнительных заголовков и "ручек", каждую из которых можно подёргать с непредсказуемым результатом. В результате даже крупные компании при внедрении TLS допускают ошибки той или иной степени серьёзности (включая, но не ограничиваясь масштабным даунтаймом клиентов GlobalSign), а небольшие стартапы предпочитают, вообще, обходить криптографию стороной.
За отведённые на доклад 45 минут мы постараемся дать описание каждой из пресловутых "ручек" и рекомендации по их [не]применению, а также дадим рекомендации по развёртыванию TLS на крупной инфраструктуре.
Enemy at the gates: vulnerability research in embedded appliances Chris Hernandez
Slides from a presentation I did on hunting for vulnerabilities in network appliances and virtual appliances. Includes information on cryoserver exploit and mail piler exploit.
You can find the first part of this presentation here: https://www.slideshare.net/secret/pAvK8Qd9f07oa
This presentation takes a deep dive into how the Million Song Library, a microservices-based application, was built using the Netflix Stack, Cassandra and Datastax.
To learn more about Million Song Library and its components visit the project on GitHub: https://github.com/kenzanlabs/million-song-library
Lea
Tempest is an Openstack test suite which runs against all the OpenStack service endpoints. It makes sure that all the OpenStack components work together properly and that no APIs are changed. Tempest is a "gate" for all commits to OpenStack repositories and will prevent merges if tests fail.
So we're running Apache ZooKeeper. Now What? By Camille Fournier Hakka Labs
The ZooKeeper framework was originally built at Yahoo! to make it easy for the company’s applications to access configuration information in a robust and easy-to-understand way, but it has since grown to offer a lot of features that help coordinate work across distributed clusters. Apache Zookeeper became a de-facto standard for coordination service and used by Storm, Hadoop, HBase, ElasticSearch and other distributed computing frameworks.
Design patterns - Common Solutions to Common Problems - Brad WoodOrtus Solutions, Corp
How unique is the problem you’re coding for right now? What’s the chance it’s been solved hundreds, maybe thousands of times? Is your solution the best way? You’ve no doubt heard other developers talk about using “design patterns”. These are reusable solutions to the problems that we all face as developers. The best thing is that most patterns can carry over from one language to another. It’s a great idea to familiarize yourself with these common solutions so you identify them and know when you plug them into your apps.
Let’s take a pragmatic look at exactly what design pattern are – and aren’t! The more you learn, the bigger toolbox you’re building that you can dip into to solve problems. You’ll also start to notice these familiar designs in frameworks and other people’s apps. Learning to recognize common patterns, their names, and when to use them will grow you as a developer, stretch your thinking outside the box, and make you better at what you do. A solid OO background will really help you, and most of what we cover will be generic to any language. Expect to cover some of the most common design patterns along with examples and their pros and cons with examples in CFML.
ZooKeeper - wait free protocol for coordinating processesJulia Proskurnia
ZooKeeper is a service for coordinating processes within distributed systems. Stress test of the tool was applied. Reliable Multicast and Dynamic LogBack system Configuration management were implemented with ZooKeeper.
More details: http://proskurnia.in.ua/wiki/zookeeper_research
Build a Complex, Realtime Data Management App with Postgres 14!Jonathan Katz
Congratulations: you've been selected to build an application that will manage reservations for rooms!
On the surface, this sounds simple, but you are building a system for managing a high traffic reservation web page, so we know that a lot of people will be accessing the system. Therefore, we need to ensure that the system can handle all of the eager users that will be flooding the website checking to see what availability each room has.
Fortunately, PostgreSQL is prepared for this! And even better, we will be using Postgres 14 to make the problem even easier!
We will explore the following PostgreSQL features:
* Data types and their functionality, such as:
* Data/Time types
* Ranges / Multirnages
Indexes such as:
* GiST
* Common Table Expressions and Recursion (though multiranges will make things easier!)
* Set generating functions and LATERAL queries
* Functions and the PL/PGSQL
* Triggers
* Logical decoding and streaming
We will be writing our application primary with SQL, though we will sneak in a little bit of Python and using Kafka to demonstrate the power of logical decoding.
At the end of the presentation, we will have a working application, and you will be happy knowing that you provided a wonderful user experience for all users made possible by the innovation of PostgreSQL!
Nonblocking (NB) algorithms are something of a Holy Grail of concurrent programming--typically very fast, even under heavy load, they come with hard guarantees about forward progress. The downside is that they are very hard to get right. This presentations authors worked on writing some nonblocking utilities (open sourced on SourceForge in the high-scale-lib project) and have made some progress toward a coding style that can be used to build a variety of NB data structures: hash tables, sets, work queues, and bit vectors. These data structures scale much better than even the concurrent JDK™ software utilities while providing the same correctness guarantees. They usually have similar overheads at the low end while scaling incredibly well on high-end hardware. The coding style is still very immature but shows clear promise. It stems from a handful of basic premises: You don't hide payload during updates; any thread can complete (or ignore) any in-progress update; use flat arrays for quick access and broadest-possible striping; and use parallel, concurrent, incremental array copy. At the core is a simple state-machine description of the update logic.
За последние годы разными специалистами и компаниями (от Google до Сноудена) был проделан колоссальный объём работы с целью популяризации протокола SSL, а позже и TLS. Дорабатывались протоколы и шифры, обнаруживались десятки уязвимостей, криптографические библиотеки форкались и проводили аудиты, правозащитные фонды выдавали сотни миллионов сертификатов "забесплатно". В конце концов, TLS явочным порядком, в обход стандарта, стал обязательным для HTTP/2-серверов. Так много сил было приложено, что просто-напросто уже невежливо всё это игнорировать.
Однако процесс внедрения TLS за это время, как это ни удивительно, не стал проще ни на йоту. Сисадмины, приступающие к развёртыванию TLS, вынуждены столкнуться с классификацией типов сертификатов, с множеством центров сертификации (которые непонятно, чем друг друга лучше) и с великим множеством дополнительных заголовков и "ручек", каждую из которых можно подёргать с непредсказуемым результатом. В результате даже крупные компании при внедрении TLS допускают ошибки той или иной степени серьёзности (включая, но не ограничиваясь масштабным даунтаймом клиентов GlobalSign), а небольшие стартапы предпочитают, вообще, обходить криптографию стороной.
За отведённые на доклад 45 минут мы постараемся дать описание каждой из пресловутых "ручек" и рекомендации по их [не]применению, а также дадим рекомендации по развёртыванию TLS на крупной инфраструктуре.
Enemy at the gates: vulnerability research in embedded appliances Chris Hernandez
Slides from a presentation I did on hunting for vulnerabilities in network appliances and virtual appliances. Includes information on cryoserver exploit and mail piler exploit.
You can find the first part of this presentation here: https://www.slideshare.net/secret/pAvK8Qd9f07oa
This presentation takes a deep dive into how the Million Song Library, a microservices-based application, was built using the Netflix Stack, Cassandra and Datastax.
To learn more about Million Song Library and its components visit the project on GitHub: https://github.com/kenzanlabs/million-song-library
Lea
Talking about java for ultra low latency apps on The Developers Conference 2017
http://www.thedevelopersconference.com.br/tdc/2017/saopaulo/trilha-java
Hystrix provides us a fault tolerant mechanism using which we can isolate the interaction of our service with other remote systems, services, and third-party libraries. It provides a fallback mechanism to handle the service response whenever something goes wrong. This presentation gives an overview oh how hystrix works.
Nelson: Rigorous Deployment for a Functional WorldTimothy Perrett
Functional programming finds its roots in mathematics - the pursuit of purity and completeness. We functional programmers look to formalize system behaviors in an algebraic and total manner. Despite this, when it comes time to deploy ones beautiful monadic ivory towers to production, most organizations cast caution to the wind and use a myriad of bash scripts and sticky tape to get the job done. In this talk, the speaker will introduce you to Nelson, an open-source project from Verizon that looks to provide rigor to your large distributed system, whilst offering best-in-class security, runtime traffic shifting and a fully immutable approach to application lifecycle. Nelson itself is entirely composed of free algebras and coproducts, and the speaker will show not only how this has enabled development, but also how it provided a frame with which to reason about solutions to fundamental operational problems.
Lateral Movement: How attackers quietly traverse your NetworkEC-Council
After successfully attacking an endpoint and gaining a foothold there, sophisticated attackers know that to get to the valuable data within an organization they must quietly pivot. From reconnaissance to escalation of privileges to stealing credentials, learn about the tactics and tools that attackers are using today.
Lions, Tigers and Deers: What building zoos can teach us about securing micro...Sysdig
How to secure microservices running in containers? Strategies for Docker, Kubernetes, Openshift, RancherOS, DC/OS Mesos.
Privileges, resources and visibility constrains with capabilities, cgroups and namespaces. Image vulnerability scanning and behaviour security monitoring with Sysdig Falco.
Security regarding NoSQL Databases Still remain a question.Not much research done these databases,this paper concentrates on some of the major NoSQL databases and their flaws
Next Generation DevOps in Drupal: DrupalCamp London 2014Barney Hanlon
In this talk, Barney will be discussing and demonstrating how to:
- Use nginx, Varnish and Apache together in a "SPDY sandwich" to support HTTP 2.0
- Setting up SSL properly to mitigate against attack vectors
- Performance improvements with mod_pagespeed and nginx
- Deploying Drupal sites with Docker containers
Barney is a Technical Team Leader at Inviqa, a Drupal Association member and writes for Techportal on using technologies to improve website performance. He first started using PHP professionally in 2003, and has over seventeen years experience in software development. He is an advocate of Scrum methodology and has an interest in performance optimization, researching and speaking on various techniques to improve user experience through faster load times.
Python has a complex past with cryptography. There are half a dozen major frameworks built on at least three separate C implementations, each with their own strengths and weaknesses and in various states of maintenance. In our development of an open source key management system for OpenStack (Barbican), our team has spent time investigating the major options. This presentation will review the current state of the art and discuss the future of crypto in Python including a new library being developed by a group of Python devs aimed at unifying and expanding the support for modern crypto in the Python ecosystem.
Microservice Performance Metrics
Challenges and requirements
Tools and techniques available
(anti)patterns
Analyzing services with
Dashboard, Hystrix, DynaTrace
Setting up your services in the Dashboards and working through real and simulated problems
Attendees will learn the best web application security practices used by major US government entities. The presentation will cover network configuration, caching, replication, common web application vulnerabilities, and how making these changes will result in better web site performance and user satisfaction. The five most common types of web application attacks will be explained, along with simple ways to prevent them.
Encryption in Microsoft 365 - ExpertsLive Netherlands 2024Albert Hoitingh
In this session I delve into the encryption technology used in Microsoft 365 and Microsoft Purview. Including the concepts of Customer Key and Double Key Encryption.
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
Software Delivery At the Speed of AI: Inflectra Invests In AI-Powered QualityInflectra
In this insightful webinar, Inflectra explores how artificial intelligence (AI) is transforming software development and testing. Discover how AI-powered tools are revolutionizing every stage of the software development lifecycle (SDLC), from design and prototyping to testing, deployment, and monitoring.
Learn about:
• The Future of Testing: How AI is shifting testing towards verification, analysis, and higher-level skills, while reducing repetitive tasks.
• Test Automation: How AI-powered test case generation, optimization, and self-healing tests are making testing more efficient and effective.
• Visual Testing: Explore the emerging capabilities of AI in visual testing and how it's set to revolutionize UI verification.
• Inflectra's AI Solutions: See demonstrations of Inflectra's cutting-edge AI tools like the ChatGPT plugin and Azure Open AI platform, designed to streamline your testing process.
Whether you're a developer, tester, or QA professional, this webinar will give you valuable insights into how AI is shaping the future of software delivery.
GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
Securing your Kubernetes cluster_ a step-by-step guide to success !KatiaHIMEUR1
Today, after several years of existence, an extremely active community and an ultra-dynamic ecosystem, Kubernetes has established itself as the de facto standard in container orchestration. Thanks to a wide range of managed services, it has never been so easy to set up a ready-to-use Kubernetes cluster.
However, this ease of use means that the subject of security in Kubernetes is often left for later, or even neglected. This exposes companies to significant risks.
In this talk, I'll show you step-by-step how to secure your Kubernetes cluster for greater peace of mind and reliability.
Transcript: Selling digital books in 2024: Insights from industry leaders - T...BookNet Canada
The publishing industry has been selling digital audiobooks and ebooks for over a decade and has found its groove. What’s changed? What has stayed the same? Where do we go from here? Join a group of leading sales peers from across the industry for a conversation about the lessons learned since the popularization of digital books, best practices, digital book supply chain management, and more.
Link to video recording: https://bnctechforum.ca/sessions/selling-digital-books-in-2024-insights-from-industry-leaders/
Presented by BookNet Canada on May 28, 2024, with support from the Department of Canadian Heritage.
Elevating Tactical DDD Patterns Through Object CalisthenicsDorra BARTAGUIZ
After immersing yourself in the blue book and its red counterpart, attending DDD-focused conferences, and applying tactical patterns, you're left with a crucial question: How do I ensure my design is effective? Tactical patterns within Domain-Driven Design (DDD) serve as guiding principles for creating clear and manageable domain models. However, achieving success with these patterns requires additional guidance. Interestingly, we've observed that a set of constraints initially designed for training purposes remarkably aligns with effective pattern implementation, offering a more ‘mechanical’ approach. Let's explore together how Object Calisthenics can elevate the design of your tactical DDD patterns, offering concrete help for those venturing into DDD for the first time!
2. What ?
• https://github.com/Netflix/Hystrix
• Hystrix is a latency and fault tolerance library
designed to isolate points of access to remote
systems, services and 3rd party libraries, stop
cascading failure and enable resilience in
complex distributed systems where failure is
inevitable.
11. Command Group
• Group together commands such as for
reporting, alerting, dashboards, or team/library
ownership.
• By default Hystrix group key to define the
command thread-pool unless a separate one is
defined.
18. Request Collapsing
(defcollapser search
"Collapsing single-term search command"
(collapse [arg-lists]
; Create a multi-search command, passing individual terms as a seq of args
(instantiate multi-search (map first arg-lists)))
(map [arg-lists batch-result]
; Map from input args to results. Here we assume order is preserve by
; multi-search so we can return the result list directly
batch-result))
(search “Something1”)
(search “Something2")
19. Circuit Breaker
• Tripping a circuit-breaker to stop all requests to
a particular service for a period of time, either
manually or automatically if the error percentage
for the service passes a threshold.
