Published at DZone with permission of Len DiMaggio, DZone MVB. The screenshot shows that Im performing fault injection testing on a dummy .NET WinForm application named TwoCardPokerGame.exe. I will explain whats in the download and where to place the fault injection binaries shortly. Next, I added four class-scope static objects to my application: Object h1 is the Hand for the user, and h2 is the Hand for the computer. The testing method of fault injection can simply be compared to chaos engineering. Source code fault injection is best performed automatically, as an efficient fault injection process can involve hundreds of modifications, each requiring a rebuild of the target system. Implementing resilient applications with API Gateway (Circuit breaker). The overall structure of the library is presented in Figure 2. The technique can be used to inject delays and abort requests with user-specified error codes, thereby providing the ability to stage different failure scenarios such as service failures, service overloads, high network latency, network partitions, etc. Limit available system resources, such as RAM or number of threads. Once I had the underlying TwoCardPokerLib library code finished, I created a dummy UI component. "name": "Route for Fault Injection with the abort". Using the compile-time injection technique, software testers can simulate software system errors by altering the source code. The TestApi download has two key components. signature of the soSomething method, Line 7 - Our rule will fire when the PrintStream.println method is invoked, Line
Modern applications are built with an increasing number of dependencies; on infrastructure, platform, network, 3rd party software or APIs, etc. So this feature must be used only for debugging or testing purpose. If you followed the previous blog post about Manage .NET Microservices APIs with Apache APISIX API Gateway, make sure you have read it and completed the steps to set up APISIX, etcd and ASP.NET WEB API before continuing with a demo session. You can test the fault tolerance of your Aurora PostgreSQL DB cluster by using fault injection queries. Throughout the post, we get to know the types of possible failure injections with the Fault Injection Plugin and simulate failures on our existing Product backend service (developed by using ASP.NET Core WEB API). Following are the tools used for fault injection purposes: Enjoy unlimited access on 5500+ Hand Picked Quality Video Courses. Find out the Software testing training institute in Kochi for your better start. As youve seen in this article, the primary purpose of fault injection testing is to determine whether the system under test correctly handles errors. Verify that failures don't cascade and are handled in an isolated way. Verify how the end-to-end workload performs under intermittent failure conditions. The TestApi fault injection system has a neat set of trigger conditions including TriggerIfCalledBy(method), TriggerOnEveryCall, and others. Lets suppose that we have an online shopping sample application that consists of many microservices such as Catalog, Product, Order and etc. Fault injection can better identify the nature and cause of production failures. When FaultHarness.exe is launched from the command shell, behind the scenes the harness prepares profiling code that will intercept the normal code execution of TwoCardPokerGame.exe. rule body - in our example, the recipient of the doSomething method
They simulate increased network latency or an overloaded upstream service. Perform testing on both key test environments with the production environment. You can notice that we set the delay injection in the plugin settings: Below we confirm the rule was created by running another curl command with the time measurement: After you run the cmd, you will see there is some delay was introduced: The result of fault injection is as we expected.. Here are some strategies to induce failures: Your test plan should incorporate possible failure points identified during the design phase, in addition to common failure scenarios: Load testing is crucial for identifying failures that only happen under load, such as the back-end database being overwhelmed or service throttling. AWS Fault Injection Simulator (FIS) is a fully managed service for running fault injection experiments to improve an applications performance, observability, and resiliency. Simulations demonstrate the effectiveness of the solutions in the recovery plan and highlight any issues that weren't adequately addressed. Simulation testing involves creating small, real-life situations. Your goal is to see how the application behaves under real-world conditions. My dummy application under test is a simplistic but representative C# WinForm application that simulates a hypothetical card game called Two Card Poker. Automate common testing tasks and integrate them into your build processes. The best way for you to see where Im headed in this column is to take a look at the screenshot in Figure 1. Conduct simulations in a manner that doesn't disrupt actual business but feels like a real situation. API Security with OIDC by using Apache APISIX and Microsoft Azure AD. Fault injection is a software testing technique by introducing faults into the code for improving the coverage and usually used with stress testing for robustness of the developed software. Aborts: Aborts are crash failures. What are your availability requirements? Fault injection testing is used, like stress testing, to find specific flaws in a hardware or software system, so they can be rectified or avoided. In depth knowledge of syllabus and practical gives more confidence. I copied the entire FaultInjectionEngine folder into the folder holding my FaultHarness executable, in my case C:\FaultInjection\FaultHarness\bin\Debug\. I assume that you have the demo project apisix-dotnet-docker up and running. Automate testing where possible to ensure consistent test coverage and reproducibility. Siemens EDA promotes a three-step flow that reduces the overall scope and execution time of the campaign. See a pricing summary and outline of pricing tiers and examples. this line as "METHOD doSomething", the rule would have matched any
These adjustments can be made by updating the existing code, such as by changing a line of code to reflect a different value. A software testing technique called fault injection testing introduces mistakes into a system on purpose to see if it can survive them and recover. Being able to measure availability and resiliency can answer questions like, How much downtime is acceptable? I named the application FaultHarness and I added some minimal code to the program template (see Figure 4). Fault injection Methods: Compile-Time Injections - It is Prior to deployment, fault injection testing is frequently performed to find any potential flaws that might have been introduced during production. Hes worked on several Microsoft products, including Internet Explorer and MSN Search. Prior to deployment, fault See the original article here. Also, we want to be sure that any resilience mechanisms we have in place such as error handling code, circuit breaker, health checks, retry, fallback, redundant instances, and so on. In this case, something might go wrong due to any number of reasons. Improve resiliency and performance with controlled experiments. Once tooling decisions are made, the next step is establishing the execution methodology of the fault campaign. Second, it analyzes the behavior of not-fault-tolerant functionalities in case of failure due to a Test and production are rarely identical, so it's important to validate your application in production using a blue-green or canary deployment. Apache APISIX Fault Injection Plugin also offers a mechanism to inject some errors into our APIs and ensures that our resilience measures are effective. Fault Injection Testing with TESSY. Then I pass those two cards to the Hand constructor and display the value of the hand in a TextBox control. ;-). In code fault injection (also called mutation testing) the source code is modified to trigger failures in the target sys-tem. The first is TestApiCore.dll, which was located in the Binaries folder of the unzipped download. () (). with the These DLLs are part of a collection of .NET libraries named TestApi and can be found at testapi.codeplex.com. How to use the fault injection feature in TESSY, the IEC 61508, IEC 62304, ISO 26262 and EN 50128 certified unit testing tool for safety related embedded C/C++ code. The difference with fault injection is that it needs a particular strategy to test a single condition. The idea is that, if you can anticipate the situations when an exception can occur, you can in theory often programmatically guard against that exception and test for the correct behavior of that guarding behavior. Run Apache APISIX on Microsoft Azure Container Instance. Benefits to fault injection testing include: Although tools can be used to aid automate the process, fault injection can be done manually and doesnt need them. An application-oriented question on the topic along with responses can be seen below. Here I target a method thats located in the application under test, but I could have also targeted a method in the underlying TwoCardPokerLib.dll, such as: After specifying the trigger method, the next step is to specify the condition under which the fault will be injected into the application under test. At this point I right-clicked on the TwoCardPokerGame project in the Solution Explorer window, selected the Add Reference option from the context menu, and pointed to the file TwoCardPokerLib.dll. Fault injection can be limited to a specific set of requests based on the (destination) upstream cluster of a request and/or a set of pre-defined request headers. The primary goal of performance testing is to validate benchmark behavior for the application. Agree For a streaming giant like Netflix, the migration to a complex cloud-based microservices architecture would not have been possible without a revolutionary testing method known as fault injection . Implementing resilient applications with API Gateway (Health Check). Learning from a scratch in a short period is also very important in the learning process. Run-Time Injections This technique uses a software trigger to introduce a bug into a running software system. "name": "Route for Fault Injection with the delay", Content-Type: application/json; charset=utf-8, [{"name":"Macbook Pro","price":1500.9},{"name":"SurfaceBook 3","price":1599.9}]. In our demo case, we made it 100% to easily test the delay in time. Overview of Apache APISIX API Gateway Plugins. Note that since if we had written
Signal processing and optimization using SciPy (Part 1). The fault injection session uses a DLL to start watching for calls to the applications button2_Click method, which is the event handler for the button labeled Evaluate. The fault injection approach at the API Gateway level can be used to test the resiliency of application or microservices APIs against various forms of failures to build Opinions expressed by DZone contributors are their own. I used BuiltInFaults.ThrowExceptionFault. Test how your applications handle CPU stress and whether CPU utilization exceeds your specified threshold. ", Manage .NET Microservices APIs with Apache APISIX API Gateway, Implementing resilient applications with API Gateway (Circuit breaker), Implementing resilient applications with API Gateway (Health Check), Manage .NET Microservice API with Apache APISIX API Gateway, Overview of Apache APISIX API Gateway Plugins, Run Apache APISIX on Microsoft Azure Container Instance, API Security with OIDC by using Apache APISIX and Microsoft Azure AD, API Observability with Apache APISIX Plugins, Here is a quick overview of what we cover , Experiment with the Fault Injection Plugin . By using this website, you agree with our Cookies Policy. Supported browsers are Chrome, Firefox, Edge, and Safari. Imagine software that controls a medical device or a flight system. API Observability with Apache APISIX Plugins. Fault injection can better identify the nature and cause of production failures. It is usually completed before deployment to identify potential flaws in the running software . In this months column, I explain how you can introduce faults into .NET applications at run time using a component of the TestApi library. Application is resilient if it can go back to normal after a disruption. Fault Injection is a technique for enhancing the testing quality by involving the intentional faults in the software. The 0.4 version of the fault injection system I was using requires the FaultInjectionEngine folder to be in the same location as the harness executable. Fault Injection Testing with TESSY. A pre-requisite for an effective fault injection testing is to look at the System "with an open mind" and think "what are all the various faults I can inject in this System?" Version 0.4 supports fault injection testing for applications created using the .NET Framework 3.5. They mimic failures in upstream services. Using the TestApi fault injection system requires that you specify the application under test, the method in the application under test that will trigger a fault, the condition that will trigger a fault, and the kind of fault that will be triggered: Notice that, because the system requires the application under test to be in the same folder as the harness executable, the name of the application under test executable does not need the path to its location. To test resiliency, you should verify how the end-to-end workload performs under intermittent failure conditions. Notice in Figure 1 that the first two application Deal-Evaluate click pairs work properly, but the third click generated an exception. In this paper, we present an approach called service-level fault injection testing and a prototype implementation called Filibuster, that can be used to systematically identify resilience issues early in the development of microservice applications. Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support. If you run curl cmd to hit the APISIX route, now it quickly responds with HTTP 503 error which in turn very comfortable to test catalog service how it reacts to such kind of server errors from downstream services. To identify this in the kernel oops message, add a new taint flag for the fault injection. Shut down the DNS service on domain controllers. While the fault session is running, information about the session is logged into the current directorythat is, the directory that holds the fault harness executable and the application under test executable. Next, in the Visual Studio designer window I double-clicked on the button2 control to auto-generate the controls event handler This part shows you how to inject faults to test the resiliency of your application. In the case of some applications, the effort required to create fault injection testing may not be worthwhile, but there are many testing scenarios where fault injection testing is critically important. As we learned, by using the fault injection method, engineers can build better and more stable systems. How much do you invest in making your application highly available? The fault injection session has been configured so that the first two times a user clicks on the Evaluate button, the application behaves as coded, but on the third click the fault session causes the application to throw an exception of type System.ApplicationException. Step 2 Fault Injection. Test Run - Fault Injection Testing with TestApi. What is the risk versus the cost? Test your application in an environment as close to production as possible. Find performance bottlenecks or other unknown weaknesses missed by traditional software tests. Fault injection is a software testing technique by introducing faults into the code for improving the coverage and usually used with stress testing for robustness of the developed software. This holds 32-bit and 64-bit versions of FaultInjectionEngine.dll. Run tests in production using both synthetic and real user data. Hardware emulation-based fault injection is based on the use of large Field Programmable Gate Arrays (FPGAs) circuits. Thanks to the following technical experts for reviewing this article: Bill Liu and Paul Newson, More info about Internet Explorer and Microsoft Edge, blogs.msdn.com/b/ivo_manolov/archive/2009/11/25/9928447.aspx. I downloaded the latest fault injection APIs release, which in my case was version 0.4, and unzipped the download. Use prebuilt templates to set up and run high-quality experiments in minutes. Availability describes the amount of time when an application runs in a healthy state without significant downtime. In my example I used TriggerEveryOnNthCall(3), which as youve seen injects a fault every third time the trigger method is called. Next, I added a using statement for Microsoft.Test.FaultInjection to the top of my fault harness code so my harness code could directly access the functionality in TestApiCore.dll. Fault injection testing is the process of deliberately inserting an error into an application This tutorial It is an alternative to From the special Visual Studio tools command shell I launch ildasm.exe, point to the application under test, then double-click on the target method. Get superior insights by generating real-world failure conditions, such as impaired performance of different resources. Figure 1 Fault Injection Testing in Action. Another automated tool for injecting errors into memory and disk access is the Fault Tolerance and Performance Evaluator (FTAPE). For fault injection testing, check the resiliency of the system during failures, either by triggering actual failures or by simulating them. Here are some strategies to induce failures: Shut down virtual machine (VM) instances. Crash processes. Expire certificates. Change access keys. Shut down the DNS service on domain controllers. For detailed instructions on how to configure delays and aborts, see Fault Injection. The following text on this line is not executed, Line 5 - Reference to the class of the application to receive the injection, Line
As an interrupt-based trigger, this is what it is. The TestApi library is under active development, so you should check the CodePlex site for updates to the techniques I present in this article. Apache APISIX works in two different modes, both configured using the fault-injection plugin attributes: Delays: Delays are timing failures. You can examine these log files to help resolve any problems that might occur while youre developing your fault injection harness. Learn more, Software Development Processes (SDLC Models), Creo Parametric-3D Modelling Software (Professional). http://127.0.0.1:9080/apisix/admin/routes/1, 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1'. In the following example, we will introduce an HTTP abort to the product microservice to check how our imaginary Catalog service respondsimmediately to the failures introduced by the dependent service. Allows developers to make changes to previously unknown issues before release. After reviewing the state-of-the-art of SFI, we address the challenge of integrating it deeper into software development practice. This blog post describes how an API Gateway like Apache APISIX is useful for testing the robustness and resilience of microservices APIs. http://www.jboss.org/index.html?module=bb&op=viewforum&f=310, https://jira.jboss.org/jira/browse/BYTEMAN, http://en.wikipedia.org/wiki/Fault_injection, Ultra-Fast Microservices: The Enterprise Integration Makes It Easy, Developing Cloud-Native Applications With Containerized Databases, Data Streaming for Data Ingestion Into the Data Warehouse and Data Lake, Fault Injection Testing - First Steps with JBoss Byteman, Line 4 - RULE defines the start of the RULE. To create the game DLL I launched Visual Studio 2008 and selected the C# Class Library template from the File | New Project dialog box. Make sure that simulated scenarios are completely controllable. In this situation, the Two Card Poker application does not handle the application exception gracefully and the result is the system-generated message box. Such systems increase the risk of impact fro API7 Cloud provides a fully managed chaos engineering service with the dashboard to configure the Fault Injection policy easily. Included in the TestApi library is a set of Managed Code Fault Injection APIs. Step 3 Work Product Generation. It is critical to handle failures in service-to-service calls gracefully. Fault injection testing has been around for well over 30 years, and tests the dependability or robustness of a system in the presence of faults in the systems environment (e.g. The code for TwoCardPokerLib is too long to present in its entirety in this article. ( : fault injection) [1] . Once my design was in place, I double-clicked on the button1 control to have Visual Studio generate an event handler skeleton for the button and load file Form1.cs into the code editor. randomizes the order of the cards in the deck. Define specific conditions to stop an experiment or roll back to the pre-experiment state. a faulty power supply, badly-formed input messages) and faults in the system itself (e.g. In mutation testing, you deliberately insert errors into the system under test, but then execute an existing test suite against the faulty system in order to determine whether the test suite catches the new errors created. Using the Visual Studio designer, I dragged a Label control from the Toolbox collection onto the application design surface, and modified the controls Text property from textBox1 to Two Card Poker. Next I added two more Label controls (Your Hand and Computers Hand), two TextBox controls, two Button controls (Deal and Evaluate), and a ListBox control. Affordable solution to train a team and make them project ready. Fault injection testing can take several different forms. Note that you can also specify the percentage of requests to be delayed in numbers. Specifying the name of the method that will trigger the injected fault is a common source of trouble for TestApi fault injection beginners. $0, Line 9 - A rule has to include an IF clause - in our example, it's always true, Line 10 - When the rule is triggered, we throw an exception - note that we supply a string to the exception constructor, Each RULE needs an IF clause - even if you want the rule to always fire, The methods referenced in a RULE cannot be static - if they are static, then there is no $0 (aka this) to reference, Yes, I had several errors and some typos the first few times I tried this. How much does potential downtime cost your business? I copied this DLL into the root directory of the FaultHarness application. You can also try out a centralized platform API7 Cloud to use more advanced API Gateway features. Fault-injection tests involve the deliberate introduction of faults to test system robustness and error-handling capabilities. skeleton. Regular testing should be performed as part of each major change and if possible, on a regular basis to validate existing thresholds, targets and assumptions. Dr. James McCaffreyworks for Volt Information Sciences Inc., where he manages technical training for software engineers working at the Microsoft Redmond, Wash., campus. We can verify this with the help of the testing method Fault Injection . The tests are performed manually here, but you can also run test automation in a fault session. There is a certain irony involved with fault injection testing. Copyright 2019-2022 The Apache Software Foundation. To create the fault injection harness I started a new project in Visual Studio 2008 and selected the C# Console Application template. To test the shopping applications microservices for resiliency, we are going to simulate the product service misbehaving as a faulty service: In the first example, we introduce a 5-second delay for every request to the product service to test if we correctly set a connection timeout for calls to the product service from the Catalog service. In the ASP.NET Core project, there is a simple API to get all products list from the service layer in ProductsController.cs file. AWS Fault Injection Simulator (AWS FIS) is a fully managed service for running fault injection experiments on AWS that makes it easier to improve an applications performance, observability, and resiliency. Fault injection queries are issued as SQL commands to an Amazon Aurora instance. Join Slack channel to discuss, API monetization using an API Management and a billing provider. The Trigger can be of two types, Time Based triggers and Interrupt Based Triggers. A software testing technique called fault injection testing introduces mistakes into a system on purpose to see if it can survive them and recover. When specifying the trigger method signature, you do not use the method return type, and you do not use parameter names. Shut down virtual machine (VM) instances. AWS Fault Injection Simulator (FIS) is a fully managed service for running fault injection experiments to improve an applications performance, observability, and resiliency. Im confident youll find the discussion of fault injection an interesting and possibly useful addition to your toolset. For fault injection testing, check the resiliency of the system during failures, either by triggering actual failures or by simulating them. Benefits to fault injection testing include: FIS simplifies the process of setting up and running controlled fault injection experiments across a range of AWS services, so teams can build confidence in their application behavior. The complete source code for the TwoCardPokerLib library and the FaultHarness fault injection harness is available in the code download that accompanies this article. Additionally, the system requires that the application under test binaries be located in the same folder as the harness executable, so I copied files TwoCardPokerGame.exe and TwoCardPokerLib.dll into C:\FaultInjection\FaultHarness\bin\Debug\. Figure 5 shows an example of using ildasm.exe to examine the signature for the button2_Click method. Create an experiment template and run an experiment. Plan a 1:1 parity of key test environments with the production environment. We make use of First and third party cookies to improve our user experience. Fault injection testing. Injecting faults will imitate hardware failures like circuit board shorts; hence fault injection testing can also be used on hardware. Fault injection testing is related to and sometimes confused with mutation testing. Although these types of faults can be injected by hand the possibility of introducing an unintended fault is high, so tools exist to parse a program automatically and insert faults. Familiarize yourself with the fault injection concept. a flipped bit caused by cosmic radiation, poor design and bad coding). Resiliency describes how quickly an application recovers from failure. In addition to exception faults, the TestApi fault injection system has built-in return type faults that allow you to inject erroneous return values into your application under test at run time. And open source projects like Apache APISIX make it more accessible for us to some fault injection testing techniques and helps you to plan for unknown failures in the distributed architecture. Fault injection different types of failures. Or you can see the complete source code on Github and the instruction on how to build a multi-container APISIX via Docker CLI. Using the TestApi fault injection system requires that you specify the application under test, the method in the application under test that will trigger a fault, the condition that will trigger a fault, and the kind of fault that will be triggered: Learn how to quickly set up experiments using prebuilt templates. There are two different sorts of triggers: interrupt-based triggers and time-based triggers. I added some simple code to compare the two Hand objects and display a message in the ListBox control. Conduct load testing with expected peak volumes to test scalability and performance under load. Distributed systems such as microservices have led to an increase in the complexity of the systems we work with. After specifying the trigger condition, the next step is to specify the type of fault that will be injected into the system under test. Over 2 million developers have joined DZone. Additionally, its possible to inject faults that are very difficult to anticipate, such as System.OutOfMemoryException. Then I added some initialization code to the Form constructor: The Deck constructor creates a deck of 52 cards, in order from the ace of clubs to the king of spades, and the Shuffle method Picking up the right one is significant. Application is correct if it acts as specified. When we do fault injection testing, we deliberately introduce errors to a system/application to make sure that the application can withstand and recover from that condition. Notice that the button2_Click method does not directly handle any exceptions: Before creating the fault injection harness shown in Figure 1, I downloaded the key DLLs to my test host machine. This way, you're testing the application under real conditions, so you can be sure that it will function as expected when fully deployed. "body": "The product service is currently unavailable. Stress testing involves various activities to overload existing resources and remove components to understand overall resiliency and how the application responds to issues. Step 1 Fault List Generation. Load testing validates application scalability by rapidly and/or gradually increasing the load on the application until it reaches a threshold/limit. I also added a using statement for System.Diagnostics because, as youll see shortly, I want to access the Process and ProcessStartInfo classes from that namespace. I hit the
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