Azure Functions connects to data by using input bindings. The runtime uses these bindings to load data from external resources and pass them as function arguments. Here’s an example of how this might look in practical implementation.
module.exports = async function(context) {
const content = context.bindings.inputBlob;
context.log(content);
}
In the code sample above, inputBlob is the input binding and data from it is read into the content variable. The runtime binds the ‘inputBlob’ to the Blob Storage specified in the function.json bindings.
{
"bindings": [
{
"name": "inputBlob",
"type": "blobTrigger",
"direction": "in",
"path": "example/{name}",
"connection": "AzureWebJobsStorage"
}
]
}
Given above is the function.json that defines the inputBlob input binding that was used in the earlier function code. The “direction” parameter specifies that this is an input binding.
Understanding Output Bindings
Output bindings, on the other hand, can be used to send data from your function to an external resource. This is done by adding output data to the data place specified by the output binding.
Below is an example of an output binding. In this case, the Azure function creates a new document in an existing Azure Cosmos DB collection.
module.exports = async function(context, req) {
context.bindings.outputDocument = {
id: new Date().toISOString(),
text: req.body.text
};
context.res = {
status: 200,
body: "Success! A new document has been added."
};
}
Its corresponding function.json is as follows:
{
"bindings": [
{
"authLevel": "function",
"type": "httpTrigger",
"direction": "in",
"name": "req",
"methods": [
"post"
]
},
{
"type": "http",
"direction": "out",
"name": "res"
},
{
"type": "cosmosDB",
"direction": "out",
"name": "outputDocument",
"databaseName": "testDatabase",
"collectionName": "testCollection",
"createIfNotExists": true,
"connectionStringSetting": "AzureWebJobsCosmosDBConnectionString"
}
]
}
In this function.json, the “direction” parameter specifies that this is an output binding. The Azure function code writes a new document to the Azure Cosmos DB using the context.bindings.outputDocument binding.
Input and output bindings help to achieve modular code structure, allowing effective management of code, as well as better testability and version control. It serves as a highly useful tool in preparing for your AZ-204 Developing Solutions for Microsoft Azure exam and in efficiently leveraging Azure functions in your day-to-day development tasks.
Practice Test
True or False: Input and output bindings are a way to declare the data that your Azure function is going to connect with.
- True
- False
Answer: True.
Explanation: Bindings in Azure Function are a way of declaring and connecting the data within your Azure functions. They connect your function with another data source and can be used to move data into and out of your function.
What is the purpose of Input bindings in Microsoft Azure?
- A. To store output information
- B. To store data information
- C. To read data from an external source
- D. To perform the operation on data
Answer: C. To read data from an external source
Explanation: Input bindings are used in Azure to read data from an external source.
True or False: Only a single type of binding can be implemented in an Azure function.
- True
- False
Answer: False.
Explanation: An Azure function can have multiple types of bindings.
Which type of binding is used to write data to an external system?
- A. Input binding
- B. Output binding
- C. Function binding
- D. Process binding
Answer: B. Output binding
Explanation: Output bindings are used to write data to an external system from an Azure function.
True or False: Bindings in Azure Functions are optional and you can still write Azure Functions that read from and write to data sources directly.
- True
- False
Answer: True.
Explanation: While bindings in Azure Functions provide a declarative way to connect to data, reading from and writing to data sources can also be performed directly.
Which of the following are types of bindings in Azure Functions? Select all that apply.
- A. Input binding
- B. Output binding
- C. Trigger binding
- D. Database binding
Answer: A. Input binding, B. Output binding, C. Trigger binding
Explanation: There are three types of bindings: trigger, input, and output.
True or False: Each Azure Function must have a trigger, and it may also have multiple input and output bindings.
- True
- False
Answer: True.
Explanation: Triggers cause the function to run and a function must have exactly one trigger. Input and output bindings are optional and a function can have multiple of these.
Select the correct sequence for implementing input and output bindings in Azure functions:
- A. Create binding > Deploy function > Test function
- B. Deploy function > Create binding > Test function
- C. Test function > Create binding > Deploy function
- D. Create binding > Test function > Deploy function
Answer: D. Create binding > Test function > Deploy function
Explanation: The correct sequence is to create the bindings, then test the function, and finally, deploy it.
True or False: Azure Function Bindings provide support for Blob Storage, Azure Cosmos DB, SignalR, and more.
- True
- False
Answer: True.
Explanation: Azure Functions support a wide variety of data source types through bindings including Azure Blob Storage, Azure Cosmos DB, SignalR, and more.
What is an output binding in Azure Functions?
- A. It is a method to consume data.
- B. It is a declarative way to connect to data from the function.
- C. It is a method to write data.
- D. It is a way to trigger function.
Answer: C. It is a method to write data.
Explanation: Output Bindings are used as a method to write data to an external data source.
True or False: Input and Output Bindings in Azure Functions can only be configured in the function.json file.
- True
- False
Answer: False.
Explanation: Bindings are usually defined in the function.json file, but they can also be defined in the code.
Which type of binding provides data to an Azure Function?
- A. Input binding
- B. Output binding
- C. Trigger binding
- D. Transformation binding
Answer: A. Input binding
Explanation: An input binding is a source of data that provides data to a function.
True or False: Only one output binding can be created per Azure Function.
- True
- False
Answer: False.
Explanation: We can create multiple output bindings for a function in Azure Functions.
What type of binding causes a function to run?
- A. Input binding
- B. Output binding
- C. Trigger binding
- D. Transformation binding
Answer: C. Trigger binding
Explanation: A trigger is a type of binding that causes the function to run.
True or False: An Azure Function can have multiple Trigger bindings.
- True
- False
Answer: False.
Explanation: A single function must have exactly one trigger but can have multiple input and output bindings.
Interview Questions
What is Azure Active Directory?
Azure Active Directory (Azure AD) is Microsoft’s cloud-based identity and access management service. It helps employees sign in and access resources in external resources, such as Microsoft Office 365, the Azure portal, and internal resources.
What is the purpose of using Azure AD for authentication and authorization?
Azure AD handles authentication, and it ensures only verified users and applications can access your organization’s resources. It provides single sign-on, multi-factor authentication, social identity, self-service password, and more to ensure only authentic users access your resources.
How does OAuth work with Azure AD for application authorization?
OAuth 2.0 is a protocol that allows applications to request authorization to access resources from a server. An application can request an access token from Azure AD by providing its Client ID, Secret Key, and Scope. The access token can be used to access resources from the server.
How is user authorization achieved in Azure AD?
User authorization in Azure AD is achieved by defining roles and assigning them to users or groups. Roles define what actions a user can perform on a resource. Once a role is assigned to a user, the user can perform the activities defined in the role.
How do you register an application with Azure AD?
You register an application in the Azure portal. After registering, Azure AD assigns a unique Application ID to the app and enables it to receive tokens.
What is the role of a Service Principal in Azure AD?
The service principal is a security identity used by applications or services to access specific Azure resources. You can think of it as a user identity (username and password or certificate) for an application.
What are scopes in Azure AD?
In Azure AD, scopes are permissions that are defined by the application and exposed to other applications. These permissions define the actions an application can do, and when assigned to a service principal, define what actions the application can take.
How does SSO work in Azure AD?
Single Sign-On (SSO) in Azure AD enables users to sign in once with one account to access any other cloud or on-premises web app that also uses Azure AD for authentication. SSO provides a seamless user experience, reducing the need for users to remember multiple usernames and passwords.
What is a tenant in Azure AD?
A tenant in Azure AD represents an organization. It is a dedicated, isolated instance of Azure AD that an organization receives and owns when it signs up for a Microsoft cloud service like Azure, Microsoft Intune, or Microsoft 365.
What is multi-factor Authentication in Azure AD?
Multi-factor Authentication in Azure AD is a security feature whereby users are required to authenticate through two or more verification methods to gain access to resources. This may include a combination of passwords, phone verification, fingerprint scanning, facial recognition, or security questions.
extutorials.com