API Reference for Azure Functions Bindings
This document provides a detailed reference for the various bindings available in Azure Functions. Bindings simplify your code by allowing you to connect to other Azure services and external data sources without complex integration code.
Input Bindings
Input bindings allow you to read data from a service or storage into your function.
Blob Storage Input
Reads a blob from Azure Blob Storage.
{name} : blob : path
Example: myBlob : blob : container/{name}.txt
Cosmos DB Input
Reads a document from Azure Cosmos DB.
{name} : cosmosDB : databaseName : collectionName : id
Example: myDocument : cosmosDB : MyDb : Items : {id}
Event Hubs Input
Reads a single event from an Azure Event Hub.
{name} : eventHub : path
Example: myEvent : eventHub : myEventHub
Queue Storage Input
Reads a message from an Azure Queue Storage queue.
{name} : queue : queueName
Example: myQueueItem : queue : myQueue
Table Storage Input
Reads an entity from Azure Table Storage.
{name} : table : tableName : PartitionKey : RowKey
Example: myTableEntity : table : MyTable : Partition1 : Row1
Service Bus Queue Input
Reads a single message from a Service Bus queue.
{name} : serviceBusQueue : queueName
Example: myServiceBusMessage : serviceBusQueue : myQueue
Service Bus Topic Input
Reads a single message from a Service Bus topic subscription.
{name} : serviceBusTopic : topicName : subscriptionName
Example: myServiceBusTopicMessage : serviceBusTopic : myTopic : mySubscription
Output Bindings
Output bindings allow you to write data to a service or storage from your function.
Blob Storage Output
Writes data to a blob in Azure Blob Storage.
{name} : blob : path
Example: outputBlob : blob : container/{name}.txt
Cosmos DB Output
Writes a document to Azure Cosmos DB.
{name} : cosmosDB : databaseName : collectionName
Example: outputDocument : cosmosDB : MyDb : Items
Queue Storage Output
Writes a message to an Azure Queue Storage queue.
{name} : queue : queueName
Example: outputQueueMessage : queue : myQueue
Table Storage Output
Writes or updates an entity in Azure Table Storage.
{name} : table : tableName
Example: outputTableEntity : table : MyTable
Service Bus Queue Output
Sends a message to a Service Bus queue.
{name} : serviceBusQueue : queueName
Example: outputServiceBusMessage : serviceBusQueue : myQueue
Service Bus Topic Output
Sends a message to a Service Bus topic.
{name} : serviceBusTopic : topicName
Example: outputServiceBusTopicMessage : serviceBusTopic : myTopic
Trigger Bindings
Trigger bindings start your function execution in response to an event.
Blob Trigger
Triggered when a blob is created or updated.
{name} : blobTrigger : path
Example: myBlobTrigger : blobTrigger : container/{name}.txt
Cosmos DB Trigger
Triggered when documents are created or updated in a Cosmos DB collection.
{name} : cosmosDBTrigger : databaseName : collectionName
Example: myCosmosDbTrigger : cosmosDBTrigger : MyDb : Items
Event Grid Trigger
Triggered by events published to Azure Event Grid.
{name} : eventGridTrigger
Example: myEventGridTrigger : eventGridTrigger
Event Hubs Trigger
Triggered by events sent to an Azure Event Hub.
{name} : eventHubTrigger : path
Example: myEventHubTrigger : eventHubTrigger : myEventHub
HTTP Trigger
Triggered by an HTTP request.
{name} : httpTrigger : methods : authLevel
Example: myHttpTrigger : httpTrigger : POST,GET : function
Queue Trigger
Triggered when a new message is available in an Azure Queue Storage queue.
{name} : queueTrigger : queueName
Example: myQueueTrigger : queueTrigger : myQueue
Service Bus Queue Trigger
Triggered by messages arriving in a Service Bus queue.
{name} : serviceBusTrigger : queueName
Example: myServiceBusQueueTrigger : serviceBusTrigger : myQueue
Service Bus Topic Trigger
Triggered by messages arriving on a Service Bus topic subscription.
{name} : serviceBusTrigger : topicName : subscriptionName
Example: myServiceBusTopicTrigger : serviceBusTrigger : myTopic : mySubscription
Timer Trigger
Triggered on a schedule defined by a CRON expression.
{name} : timerTrigger : schedule
Example: myTimerTrigger : timerTrigger : '0 */5 * * * *'
Binding Configuration
Bindings are configured in the function.json file for each function. The configuration specifies the binding type, direction (in, out, or trigger), name, and service-specific properties.
Here's a simplified example of a function.json for a function that reads from a blob and writes to a queue:
{
"scriptFile": "run.py",
"bindings": [
{
"name": "myBlob",
"type": "blobTrigger",
"direction": "in",
"path": "input-container/{name}.txt",
"connection": "AzureWebJobsStorage"
},
{
"name": "outputQueueItem",
"type": "queue",
"direction": "out",
"queueName": "output-queue",
"connection": "AzureWebJobsStorage"
}
]
}
Common Binding Properties
name: The name of the parameter in your function code.type: The type of the binding (e.g.,blob,queue,httpTrigger).direction: Indicates whether the binding is for input (in), output (out), or a trigger.connection: The name of an app setting that contains the connection string for the service.path: For storage bindings, the path to the resource (e.g., container/blob name, queue name).
For detailed configuration options for each binding type, please refer to the specific service documentation.