Azure Function Logger Dependency Injection

DO use the Logger. Azure Functions - Manage Application Settings via ARM One of the most common task when working with deployments is the need to handle is application settings. Serilog Dependency Injection and Easy IP Logging. Dependency injection is a great tool for creating unit tests. Fancy learning dependency injection? Chief Technology Officer (CTO) Simon Gilbert discusses the art of decoupling Azure Table Storage in C# Asp. When we talk about checking bottlenecks in Magento backend implementations we often mention the built in profiler that allows to see loading time of particular backend functional elements. The following example shows a class TextEditor that can only be dependency-injected with constructor injection. Functions supports built-in logging features using TraceWriter instance. This is the third part in a series demonstrating how to setup continuous deployment of an Azure Functions App using Azure DevOps build and release pipelines. The method takes an IFunctionsHostBuilder interface, which is used to declare the dependencies for DI. Now it's no longer necessary to create static methods, instance methods can be used, and dependency injection using Microsoft. Tag: angularjs,dependency-injection,angular-services. Tracing and logging with Application Insights 07 September 2015 on Azure Application Insights, Azure Services. You don’t connect your components and services together in the code directly, but describe which services are needed by which components in the configuration file. Generally, we create a concrete class object in the class where we require the object, and bind it in the dependent class. The latest update to Azure Functions v2 now has support for registering. These are just some of the reasons why support for dependency injection was added to serverless functions targeting. Do not include occurrences of self-healing events (for example, when a request will be automatically retried). the problem is when other things depend on the function and become tightly coupled to it – Ewan Nov 9 '17 at 18:37 2 What if the function changes in 6 months and isn't so pure, but it's already used in lots of places. If such a module metadata file exists, it is parsed and the artifacts of this module (e. If I misrepresent some of these ideas, the fault is all mine! So, here are three common reasons for using dependency injection:. The built-in dependency injection engine in the functions host would pass an appropriate instance, and logging looked like this: log. Out of the box Azure Functions does not come with dependency injection support you can use in your functions. An injector can create a new service instance from a provider. Now you can use dependency injection to create a factory class that can return a validated principal from an Http request. Inversion of Control and Dependency Injection aren't brand new, but they date back to the late 80s. This blog post shows how to use dependency injection in Azure Functions. Getting started with Swift Language. NET can use the ASP. MassTransit supports several dependency injection containers. Registering services. NET 5, and dependency injection is no different. Dependency Injection in services and actors. Now there’s one more issue you need to be aware of when using the dependency injection service. NET Core Dependency Injection Integration; Audit Filter Pipeline Extension; Autofac Dependency Injection Usage; Azure Blob Storage DataBus; Azure Blob Storage DataBus; Azure Blob Storage DataBus Cleanup with Azure Functions; Azure Service Bus Native Integration; Azure Service Bus Send/Reply Sample; Azure Storage Persistence. To configure elmah. Services , directives , filters , and animations are defined by an injectable factory method or constructor function, and can be injected with "services", "values", and "constants" as dependencies. Posted on September 2, 2019 by admin. IntroductionA Visual Studio 2015 project which shows how to use the Dependancy Injection in an ASP. But what is Dependency Injection? The answers to the question seem to cause more confusion than help. Functions SDK 1. writeline() (because we are in a 'kind of' console app): public class Functions { // This function will get triggered/executed when a new message is written on an Azure Queue called 'queue'. NET stack including: MVC, SignalR and Web API, etc. Most DI providers allow you to register open generic types that will have their generic arguments set based on the requested generic type arguments. py that holds a module-level dictionary and provides a function to add to that dict and read from that dict. You can then create a new Azure Function from. The injector is the main mechanism. io, open the Startup. Wiring up your applications (ASP. This blog post shows how to use dependency injection in Azure Functions. When you're done, remember to run the command Azure Functions: Stop Streaming Logs to disable logging for the function app. While some people employ them daily in their work,. the fancy solution. Injecting the Logger However, for more complex applications, you can use dependency injection  (DI) to handle injection of your logger. This makes it possible to configure which code to use at runtime. Since we are storing our users on DocumentDB, this means we can also store other object types in the same collection without their interfering with each other. Check out their Sample Code and Docs. Logging; it will happily pass an ILogger to your function, which you can then use for writing logs. Dependency injection in Azure Functions on function level This solution only supports transient and singleton scoped services. Azure Functions V2 supports ASP. Create logs. MassTransit supports several dependency injection containers. Durable Functions use Azure Storage queues, tables and blobs to manage state and messages. Most of the time the implementation depends on the services of other classes. brettsam changed the title Allow custom ILoggerProviders Allow custom dependency injection Jun 23, 2017 This was referenced Jun 23, 2017 Replace TraceWriter with an Interface to improve code testability Azure/Azure-Functions#293. We first fetch an instance of ILoggerFactory from our newly constructed serviceProvider, and add a console logger. A Dependency Manager for PHP. For now we will need to do Dependency Injection in Azure Function. Usually he's clear and concise. I wanted to make an Azure Function that could return a result from a database, and as you can imagine, this was a total breeze with lot's of examples available. Configuring Microsoft Dependency Injection. So you can think a container as a higher level of abstraction, wrapping around all the objects that needs dependency injection and resolves each of them internally. NET Core 依赖项注入功能。. Since Azure Function v2 still does not yet has support for dependency injection and this is still a hot topic, I decided to upgrade my soluton for this to Azure Function v2 and provide a nuget package!. If we have a Serilog ILogger that we want to use throughout our function at runtime, how would that work today? The ideal "scenario" is that the ILogger that comes into our function does all the things which it does today (logging to azure log files, and the live debugger in the portal), but also executes custom logging behavior. Here is the definition of the interf. AzureAppServices package, and exposed it as a logging provider in it's own right. However, I am dissatisfied that the Dependency Injection environment at Azure Functions is incomplete, I searched Github’s Issue and found the next Issue…. Azure Functions V2 is now on public preview and I'm going to write another post for DI on Azure Functions V2, by taking advantage of the simple dependency injection feature that ASP. When you use the Web Bot App, the project is based on the Bot. rely on a built-in minimalistic DI container. In my previous blog post, WebJobs in Azure with. NET Search for: Search Skip to content. Slim Framework v2. Upload the zipped folder to the Azure blob storage; The above mentioned tasks will be running daily, weekly, monthly. It introduces the concept of scope and the role it plays in application design. The Node Dependency Injection component allows you to standardize and centralize the way objects are constructed in your application. This might be an issue as Dependency Injection is imperative to unit testing in C#. Functions supports built-in logging features using TraceWriter instance. Dependency Injection with Unity (Microsoft patterns & practices) - Kindle edition by Grigori Melnik, Fernando Simonazzi, Mani Subramanian, Dominic Betts, Chris Tavares. Dependency injection is a feature we've come to expect in any framework. Services , directives , filters , and animations are defined by an injectable factory method or constructor function, and can be injected with "services", "values", and "constants" as dependencies. py that holds a module-level dictionary and provides a function to add to that dict and read from that dict. AngularJS Backend C# Cassandra Component CoR DataStax Design Patterns Extensions FileSystemWatcher Installation IoC Java JavaScript Linux Logging Resharper TSQL Ubuntu Unity Visual Studio Twitter feed. Lets look at the two most important classes in the Durable Functions family; Durable Orchestration Client & Durable Orchestration Context. The required resource, which is often a component of the application itself, is called a dependency. Trigger your functions in Azure. DependencyInjection. There are a lot of ways in which dependency Injection can be done. For example, the IOrderRepository interface defines the methods needed to interact with Order data. The smallest possible way is to create functions and call them several times in the same code. Dependency Injection with Azure Mobile Services. The next step is to have a set of functions in a file and use those functions in several other files. Autofac nuget package, and would like to use this as my DI library. This articles explains the Transient Lifestyle: what it is and when you might want to use it. Points to remember about dependency injection: Dependency injection is wired into the Angular framework and used everywhere. ! Cross-cutting concerns are conceptually separate from the. To configure elmah. getGame() , it is commonly obtained through an injection. NET Azure Functions. Dependency Injection using Ninject. Azure Functions Dependency Injection One of the most requested building blocs for Azure Functions has been support for Dependency Injection. NET Core 依赖项注入功能。. Unfortunately it is not possible to generate a nuget package from these sources. Service Locator Comments (2) | Share The Service Locator pattern and Dependency Injection clearly take a much different approach to achieving Inversion of Control and these differences often lead to philosophical discussions about which is better. The injector is the main mechanism. Can Azure Functions do that? Well, I'm always getting surprised by its power and flexibility. Dependency Injection has always been an integral part of all the web frameworks under the umbrella of the ASP. And on top of it the whole framework is DI friendly and allows us to inject dependency in different ways. This is an issue as DI is imperative to unit testing in C#. I know I shouldn’t have implemented a provider myself, but I wanted to see how the sausage was made. Since learning (and loving) automated testing I have found myself using the dependency injection pattern in almost every project. Use a clean fluent API to create functions with all the boilerplate taken care of and runtime support for authorization and dependency injection. First dependency Inversion Principle(DIP) and second Inversion of Controls(IoC). In this episode, Fabio Cavalcante from the Azure Functions team joins us to showcase how this. In this post, I'm going to show how to inject dependency in Azure Webjob using Unity. During Microsoft Build 2019 Dependency Injection (DI) Support for Azure Functions was released. NET Core in Azure Functions v2. L'uscita della versione 2 del runtime delle Azure Function rappresenta un passo molto importante perché sposta tutta l'implementazione su ASP. NET Core is injectable through the same mechanism, which I think is a good thing. cs in the azure-functions-host. GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together. Search for “Function App” and create one. NET Core dependency injection framework. Dependency Injection in Angularlink. The main difference is that for this project Autofac isn't used and ILogger is implemented. Hidden under all the major unveilings was the news that a mechanism for handling dependency injection in Azure Functions is now available. Dependency Injection (DI) DI is a software design pattern that allow us to develop loosely coupled code. Which DI Layer? First question is whether the built-in dependency injection should be used at all. I've also found the Microsoft. Or, rather than inject a specific type of the service ( EmailSender or MockEmailSender or ExchangeEmailSender) you inject an abstraction that represents the service. Durable Functions. However, we still use existing private assemblies as long as we introduce the service locator pattern for dependency management. Dependency Injection (DI) is a design pattern used to achieve loosely coupled classes in object-oriented programming. Officium is a suite of tools for rapid development of Azure Http triggered functions using existing IoC frameworks. Currently 1. FWIW - The azure functions team has been aware of this issue for a while. NET Core encourages the use of dependency injection by the built-in DI container. 0 releases (still in milestone phase) we decided to change the programming model a bit. DependencyInjection. The package I'm going to use in this post is called AzureFunctions. Since we are storing our users on DocumentDB, this means we can also store other object types in the same collection without their interfering with each other. Hopefully, they'll add this support in their coming sprints. NET Core applications, but also with WPF, UWP, and Xamarin. 0 For projects that support PackageReference , copy this XML node into the project file to reference the package. Instead, I could use an Azure function that runs on a timer to trigger that build for me. When it comes to deciding between the two, you might forgo the benchmark comparison and choose the third-party candidate: dependency injection. Justin on Introducing Swagger UI on Azure Functions; Indulis Misiņš on Introducing Swagger UI on Azure Functions. However, some of these changes will cause breaks to existing apps deployed with the v2 runtime. Out of the box Microsoft. Out of the box Microsoft. NET Core Razor views, dependency injection (DI) and Entity Framework (EF Core) according to UI layouts and business requirements. Returning HTTP Status Codes Manually. By injecting a factory, you get total control of the creation of your dependencies. Adding an extra constructor argument for a Printer so you can output diagnostics is tedious, but you don't need to because Delight has built-in support for logging:. Tracing and logging with Application Insights 07 September 2015 on Azure Application Insights, Azure Services. 2014-09-24T14:39:21-07:00 2014-09-24T14:39:21-07:00 StructureMap is a Dependency Injection / Inversion of Control tool for. However, some of these changes will cause breaks to existing apps deployed with the v2 runtime. Any sample unit test for httptrigger azure function to overcome above issue (Ilogger injection) is helpful. Extensions Microsoft. NET Core is built-in dependency injection. Lots of developers and companies have had long-winded meetings and discussions how a specific DI layer is marginally better than all the rest. The junit5-samples repository hosts a collection of sample projects based on JUnit Jupiter, JUnit Vintage, and other testing frameworks. I'm using a sortish of an Service Locator anti pattern which feels dirty, where say, ServiceConfigurator (the locator) class has static access to service objects configured into ServiceCollection and those are accessed via IServiceProvider contained services lazily after the provider has built up itself. warn logging level when a function fails to perform its intended task. to my mind this is one of the most fascinating things in the Azure platform offerings. This, with the IWidgetRepository are part of the main IRepository, which is declared in the API Controllers. And they have an API to do it. It doesn't have a ready to use integration with Azure Functions, but it has a ready to use integration with ASP. many dependencies. Node Dependency Injection. This makes it possible to configure which code to use at runtime. Leveraging the Dependency Injection support in Azure Functions. But now, Microsoft has released the support for using ASP. Using dependency injection. In these examples we see how to do that with simple functions and methods of classes. js - simple dependency injection. In a web app or hosted service, get an ILogger from dependency injection (DI). To use EF, simply include it as a NuGet package using the project. However, we still use existing private assemblies as long as we introduce the service locator pattern for dependency management. NET Azure Functions. Logging for. Azure Functions 2. There are quite a lot of ways to add dependency injection, but most of them rely on the Service Locator (anti-)pattern. using Constructors or properties. Dependency Injection (DI) has been available in. Entity Framework Core (EF Core) is the newest version of Microsoft's object to relational mapping technology. Why Dependency Injection? Dependency Injection (DI) is a fundamental practice used to manage the dependences between application objects in medium to large-scale applications. [!!!][FEATURE] Lazy Dependency Injection. The only identical feature seems to be constructor injection, and it is understandable, since it’s what most people should be using anyway. Today, we're very pleased to announce the general availability of Azure Functions 2. Now in the scenario we just covered there is place for. 1, working on 2. 0 flavor, but also supports 2. We are using Nlog for logging the details of our tasks. This new Dependency Injection feature will help us write cleaner, better abstracted and easier to test Azure Functions. 依赖注入(DI)是一种重要的应用设计模式。 Angular 有自己的 DI 框架,在设计应用时常会用到它,以提升它们的开发效率和模块化程度。 Dependency injection (DI), is an important application design pattern. dotnet add package Canduits. Azure Functions supports the dependency injection (DI) software design pattern, which is a technique to achieve Inversion of Control (IoC) between classes and their dependencies. Dependency Injection Containers There are hundreds of dependency injection containers available, from large, general-purpose frameworks to tiny containers that meet a specific need related to dependency injection. Justin on Introducing Swagger UI on Azure Functions; Indulis Misiņš on Introducing Swagger UI on Azure Functions. The reasons for dependency injection. A Dependency Manager for PHP Latest: 1. Azure Functions provides an intuitive, browser-based user interface allowing you to create scheduled or triggered pieces of code implemented in a variety of programming languages 0 1. If Azure Functions were an entrée, I’d say the dish layers executable code over unspecified hardware in the cloud with a sprinkling of input and output bindings on top. Once you're done setting up your IoC and logging, you can use any piece of code which is using the log4net ` ILog ` implementations and still see the results in your Azure Functions tooling!. The non generic logger instances will automatically get the right naming for the logging instances. Getting started with Swift Language. Download the code for this blog post. Please see my follow up post where you learn how to implement proper dependency injection with support for scoped services. Tutorials and snippets for programming languages, frameworks, tools, etc. Dagger is a new dependency injection framework for Java and Android. Services , directives , filters , and animations are defined by an injectable factory method or constructor function, and can be injected with "services", "values", and "constants" as dependencies. Lets see how we can take advantage of Guice in Functional Test automation frameworks. posted on February 19, 2018 by long2know in ASP. Developers can now create loosely coupled applications that are e. However, we still use existing private assemblies as long as we introduce the service locator pattern for dependency management. Objects usually do not work on their own. Your Function App is up and running. Below I will show a simple example. Hidden under all the major unveilings was the news that a mechanism for handling dependency injection in Azure Functions is now available. A special thanks to Symfony which was a great inspiration and example for this project. Why use AutoFac? I won't talk about the benefits of Dependency Injection or Inversion of Control because I'm sure if you've found an article about using Autofac in an Azure Function you are already familiar with them. When you're done, remember to run the command Azure Functions: Stop Streaming Logs to disable logging for the function app. In this article we will walk through using the Azure "Service Fabric". The Dependency Injection (DI) pattern uses a builder object to initialize objects and provide the required dependencies to the object, meaning that it allows developers to "inject" a dependency from outside the class. Samples default to using the built-in dependency injection since it does not require any external NuGet packages. NET Core it has become easier to do dependency injection. The sample project contains a single application with multiple services demonstrating the basic concepts needed to get you started building highly-available, scalable, distributed applications. Auditing with EF Core and Sql Server – Part 2: Triggers, Session context and dependency injection In part 1 I looked at using temporal tables to cover auditing requirements. NET ecosystem again and have jumped back in with Azure Functions (similar to AWS Lambda) to get my blog onto 99% static hosting. Adding Dependency Injection support for Service Fa Adding Dependency Injection support for Service Fa Adding Azure Active Directory OAuth 2. Sure, we would hide and abstract away the tools chosen—which logging or tracing library would be used—but in no way would it really de-couple the design. We are using Nlog for logging the details of our tasks. Getting Composer and all content on this site are released under the MIT license. We'll take a look at what Dependency Injection (DI) is, when we should use it, and what design patterns we can use to help us implement it. We'll start with the basics to see what Dependency Injection is, why we want to use it, and how we can add it to our applications. NET Core, Dependency Injection Dependency Injections on Azure Functions are not very intuitive. Durable Functions use Azure Storage queues, tables and blobs to manage state and messages. • Implemented model view controller (MVC) architecture with ASP. Sample Application. In a previous article we discovered in an advanced scenario how to implement Dependency Injection and Dependency Scope per job in Azure WebJobs with Unity. Trigger your functions in Azure. Instead of loading the respective class and instantiating the dependency right away, a proxy object is injected which automatically replaces itself with the real dependency once a method is called on it. many dependencies. NET Azure C#. 0 CDI targets Java SE and Java EE platforms. Dependency Injection in ASP. ILogger is a logger that is named after a type T. Newport Pagnell, England. Dependency Injection and ILogger in Azure Functions. The string argument will automatically be passed and runtime. What is Play Dependency Injection (DI) Play Framework supports DI, which is one of the popular Design Patterns used to decouple Application components behavior from Application components dependencies resolution. These are just some of the reasons why support for dependency injection was added to serverless functions targeting. NET Core) and then Blob Triggered. Mock winston in the logger. Fancy learning dependency injection? Chief Technology Officer (CTO) Simon Gilbert discusses the art of decoupling Azure Table Storage in C# Asp. One of the things which I noticed right away was that there does not seem to be any built-in support in the Azure WebJobs SDK for dependency injection. In a web app or hosted service, get an ILogger from dependency injection (DI). When you're done, remember to run the command Azure Functions: Stop Streaming Logs to disable logging for the function app. A special thanks to Symfony which was a great inspiration and example for this project. When starting to play around with Azure Functions, the lack of dependency injection support was pretty annoying. For the last 10 months I’ve been working with Azure Functions and mulling over the implications of computing without servers. Lets see how we can take advantage of Guice in Functional Test automation frameworks. While it's still in the works (the current version is 0. Introduction to Serverless computing using Azure Functions Ceate First Azure Function App Create Azure Timer Function using C# After creating the Azure Function App, I noted that an Azure Storage Account got created as shown below in the Resource Group contents. These are just some of the reasons why support for dependency injection was added to serverless functions targeting. SDI is a simple dependency injection engine, inspired from Angular. There are differences like no support for direct injection through function arguments (ASP. Here’s the sample function code:. Within the past week, I’ve written about dependency injection for Azure Functions and also dependency injection for. cs in the ConfigureServices. So far, we have a brief look how the service locator pattern works for our Azure Functions to manage dependencies. I've written many blog posts about dependency management on Azure Functions to improve testability and this was my latest one. This is also known as ‘injection’. Usage: import { DI } from 'tractor-dependency-injection'; DI. a lightweight, small, high level dependency injector with support for object lifetime management. A special thanks to Symfony which was a great inspiration and example for this project. 1 function you’ll first need to install the “Azure development” workload into Visual Studio if you haven’t done so already as part of the initial installation. Dependency Injection in Javascript 101 JSON and the MongoDB Driver for the. The core features of the DI container have been abstracted out to the. The route handler is a factory function which uses dependency injection to inject the logger into the route handler. How to create an Azure Function in Visual Studio How to connect to a database from an Azure Function Deploy an Azure… April 5, 2018 By benjaminperkins Accessing a. Which is a whole different pattern entirely. Angular is a platform for building mobile and desktop web applications. NET Core and C# When writing software using Azure Functions V2 in C#, you'll definitely want to follow well-established software best practices. Azure Functions major version 2. The latest update to Azure Functions v2 now has support for registering services w. Dependency Injection vs. Like Azure WebJobs, Azure Functions, that works very well at the low level like replacing very simple workload, has now evolved to provide more sophisticated features and better development. Functions are (usually) small pieces of code that run in Azure and are, just like WebJobs, triggered at a certain event, including an HTTP trigger. Just another reason to give them a go. Executed: 'Functions. DI is a great way to reduce tight coupling between software components. A Beginner's Guide to Dependency Injection. Due to the static nature of Azure Function triggers, it’s not easy to manage dependencies. Adding an ILogger interface as a new dependency for multiple classes is going to be a burden. Therefore, I created a few videos about Dependency Injection on my YouTube channel. Learn how to easily add in official dependency injection into your Xamarin apps with Microsoft. This is not dependency injection. Instead of loading the respective class and instantiating the dependency right away, a proxy object is injected which automatically replaces itself with the real dependency once a method is called on it. NET: Web API, SignalR, and MVC. This post refers specifically to Azure Function V2. Azure Function Dependency Injection with AutoFac: Autofac on Functions Azure Function Dependency Injection with AutoFac: Autofac on Functions. environment) So the SimpleApplicationLoader definition looks like :. However with the dependency injection container (DI) you have great possibility to automate this. Serverless Functions provide a simple, single-purpose method signature. This article might not be able to cover all the features of Guice. Back Forward Menu Home. NET Core dependency injection framework. The problem with the dependency injection approach, aside from its cumbersomeness, is that it did not sufficiently decouple what was a business concern from what was a generic library. Justin on Introducing Swagger UI on Azure Functions; Indulis Misiņš on Introducing Swagger UI on Azure Functions. NET developers have using Dependency Injection to better architect the applications in a way that simplifies management of application services, such as connections as well as an easier way for testing. On the other hand, if you really do have an optional or multivalued injection point, you should change the type of your injection point to Instance, as we’ll see in Section 4. It is based on the Dependency Inversion Principle (DIP) which is part of a greater design principle of Inversion of Control (IOC). This opens up new opportunities for building better architected C# applications with Serverless Azure Functions. According to this concept a class should not configure its dependencies statically but should be configured from the outside. This abstract class contains a single abstract method Load where we bind the interfaces with concrete types. A Dependency Manager for PHP. This post refers specifically to Azure Function V2. The latest update to Azure Functions v2 now has support for registering services with DI. Choose “Azure Function v2 (. Adding an ILogger interface as a new dependency for multiple classes is going to be a burden. Azure Functions is an event-based serverless compute experience to accelerate your development. Adaptive network hardening in Azure Security Center is generally available · 1 comment. Returning HTTP Status Codes Manually. This has been another little thing, that I always forget – so better document it somewhere! How to get application settings in different runtime versions of Azure Functions?. Then I trigger my function through an HTTP request and go to the Function's portal on Azure DevOps to see if the logs is actually printed: I only see the logs indicating that the function ran successfully however I do not see my log. Executed: 'Functions. and precisely use these IHostedServices for background tasks. Currently, it is not possible to use swashbuckle with azure functions either. Guice – Binding:. 2019 September 2019 Adding Environment Variables to an ARM template for Azure App Services (Azure, Azure DevOps, Azure Pipelines, C# tip) Create an Azure Key Vault using ARM templates, Resource Functions, and Azure Pipelines (Azure, Azure DevOps, Azure Pipelines) Healthcheck endpoints in C# in MVC projects using ASP. ⛔️ DO NOT depend on concrete logging, dependency injection, or configuration technologies (except as implemented in the com. It uses the storage account which is created when you create a new Function App through the Azure portal. NET - Channel 9, free! No signup or install needed. At the time of writing I also have a live demo if you want to just see the result in action. A Java class has a. However, they also wanted a sort of over-engineering including dependency injections, SOLID principles, unit testing, etc. This means that all HttpClientFactory dependencies are fulfilled and using it should be simple. The Problem.