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How Service Connector helps Azure Functions connect to services

  • Article

Azure Functions is one of the compute services supported by Service Connector. We recommend using bindings to connect Azure Functions with other services, although you can also use client SDKs. This article aims to help you understand:

  • The relationship between Service Connector and Functions bindings.
  • The process used by Service Connector to connect Functions to other Azure services using bindings or the SDK.
  • The responsibilities carried by Service Connector and the users respectively in each scenario.

Prerequisites

Service Connector and Azure Functions bindings

Bindings in Azure Functions

A binding is a concept used by Azure Functions, aiming to provide a simple way of connecting functions to services without having to work with client SDKs in function codes.

Binding can support inputs, outputs, and triggers. Bindings let you configure the connection to services so that the Functions host can handle the data access for you. For more information, see Azure Functions triggers and bindings concepts.

Function binding supports both secret/connection string and identity based authentication types.

Service Connector

Service Connector is an Azure service that helps developers easily connect compute services to target backing services. Azure Functions is one of the compute services supported by Service Connector.

Compared to a function binding, which is more like a logically abstracted concept, Service Connector is an Azure service that you can directly operate on. It provides APIs for the whole lifecycle of a connection, like create, delete, validate health and list configurations.

Service Connector also supports both secret/connection string and identity based authentication types.

Connection in an Azure Functions binding

In Functions bindings, connection is a property defined in a binding file (usually the function.json file) in your function folder. It defines the app settings name or prefix that will be used by the binding runtime to authenticate to target services.

Connection in Service Connector

A connection in Service Connector refers to a specific Azure resource that belongs to Service Connector.

The connection used by Azure Functions bindings corresponds to the configuration name used by Service Connector. The configuration name refers to the app setting key names that Service Connect saves into the compute services' configurations.

Connecting Azure Functions to other cloud services using Service Connector

Service Connector reduces the amount of effort needed to connect Azure Functions to cloud services using bindings or SDKs. It takes over cloud resource configurations like App Settings, network, identity and permission assignment, so that users can focus on function business logics. The following sections describe how Service Connector helps simplify function connections with different connection mechanisms and authentication methods.

Binding

  • Secret/connection string
Scenario Operation Description Without Service Connector With Service Connector
Local project Add binding Add a binding in a function according to the target service type and binding type (in/out/trigger). User User
Consume binding Set a connection string for authentication in local.settings.json, and change the function code to consume the variable defined in the binding. User User
Cloud resource Configure app settings Configure connection string as an app setting in function resource's configurations. User Service Connector
Configure network Make sure the target service's network configuration allow access from function resource. User Service Connector
  • Identity based authentication
Scenario Operation Description Without Service Connector With Service Connector
Local project Add binding Add a binding in a function according to the target service type and binding type (in/out/trigger). User User
Consume binding Set a connection string for authentication in local.settings.json, and change the function code to consume the variable defined in the binding. User User
Cloud resource Configure app settings Configure the Azure Function's identity settings, such as service endpoints. User Service Connector
Configure network Make sure the target service's network configuration allows access from the function resource. User Service Connector
Configure identity Make sure system identity is enabled when using system identity to authenticate. User Service Connector
Permission assignment Assign the identity necessary roles so that it can access the target service. User Service Connector

When using Service Connector with function bindings, pay special attention to the function's key name configured by Service Connector. Make sure it's the same key name as the one defined in connection property in the binding file. If it's different, change the name in the binding file or use Service Connector's customize keys feature to customize Service Connector's default configuration names.

SDK

  • Secret/connection string
Scenario Operation Description Without Service Connector With Service Connector
Local project Add dependency Add dependency package according to the target service and your runtime. User User
Initiate SDK client Set connection string for authentication in local.settings.json. Initiate the target service SDK using a connection string. User User
Cloud resource Configure app settings Configure a connection string as an app setting in the function's configuration. User Service Connector
Configure network Make sure the target service's network configuration allow access from function resource. User Service Connector
  • Identity based authentication
Scenario Operation Description Without Service Connector With Service Connector
Local project Add dependency Add dependency package according to the target service and your runtime. User User
Initiate SDK client Set connection string for authentication in local.settings.json. Initiate the target service SDK using a connection string. User User
Cloud resource Configure app settings Configure a connection string as an app setting in the function's configuration. User Service Connector
Configure network Make sure the target service's network configuration allows access from the function resource. User Service Connector
Configure identity Make sure system identity is enabled when using system identity to authenticate. User Service Connector
Permission assignment Assign the identity necessary roles so that it can access the target service. User Service Connector

Next steps

Learn how to integrate different target services and read about their configuration settings and authentication methods.

Learn about how to integrate storage blob