Trigger Specification

This specification describes the azure-blob trigger for Azure Blob Storage. It scales based on the count of blobs in a given blob storage container and assumes the worker is responsible for clearing the container by deleting/moving the blobs once the blob processing completed.

triggers:
- type: azure-blob
  metadata:
    blobContainerName: functions-blob
    blobCount: '5'
    activationBlobCount: '50'
    connectionFromEnv: STORAGE_CONNECTIONSTRING_ENV_NAME
    accountName: storage-account-name
    blobPrefix: myprefix
    blobDelimiter: /example
    cloud: Private
    endpointSuffix: blob.core.airgap.example # Required when cloud=Private
    recursive: false
    globPattern: glob-pattern

Parameter list:

• blobContainerName - Name of container in an Azure Storage account.
• blobCount - Average target value to trigger scaling actions. (Default: 5, Optional)
• activationBlobCount - Target value for activating the scaler. Learn more about activation here. (Default: 0, Optional)
• connectionFromEnv - Name of the environment variable your deployment uses to get the connection string.
• accountName - Name of the storage account that the container belongs to.
• blobPrefix - Prefix for the Blob. Use this to specify sub path for the blobs if required. (Default: "", Optional)
• blobDelimiter - Delimiter for identifying the blob prefix. (Default: /, Optional)
• cloud - Name of the cloud environment that the blob belongs to. Must be a known Azure cloud environment, or Private for Azure Stack Hub or Air Gapped clouds. (valid values: AzurePublicCloud, AzureUSGovernmentCloud, AzureChinaCloud, AzureGermanCloud, Private; default: AzurePublicCloud)
• recursive - Indicates whether or not blobs should be counted recursively. (Values: true, false, Default: false, Optional, Equivalent to setting blobDelimiter as "")
• globPattern - Glob pattern for blob names. The scaler will count all blobs whose names match the pattern as metric value. (Default: "", Optional, The blobPrefix, blobDelimiter and recursive parameters are ignored when this is specified.)

When cloud is set to Private, the endpointSuffix parameter is required. Otherwise, it is automatically generated based on the cloud environment. endpointSuffix represents the storage blob endpoint suffix of the cloud environment that the blob belongs to, e.g. blob.core.cloudapi.de for AzureGermanCloud.

Authentication Parameters

You can authenticate by using pod identity or connection string authentication.

Connection String Authentication:

• connection - Connection string for Azure Storage Account.

Pod Identity Authentication

Azure AD Pod Identity or Azure AD Workload Identity providers can be used.

• accountName - Name of the Azure Storage Account.

Example

apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: azure-blob-auth
spec:
  podIdentity:
    provider: azure | azure-workload
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: azure-blob-scaledobject
  namespace: default
spec:
  scaleTargetRef:
    name: azureblob-function
  triggers:
  - type: azure-blob
    metadata:
      # Required
      blobContainerName: functionsblob
      # Optional, required when pod identity is used
      accountName: storage-account-name
      # Optional, connection OR authenticationRef that defines the connection
      connectionFromEnv: STORAGE_CONNECTIONSTRING_ENV_NAME # Reference to a connection string in deployment
      # or authenticationRef as defined below
      #
      # Optional
      blobCount: "5" # default 5
      blobPrefix: blobsubpath # Default : ""
      blobDelimiter: "/" # Default: "/"
      # Optional, default: AzurePublicCloud
      cloud: AzureChinaCloud
    authenticationRef:
        name: azure-blob-auth # authenticationRef would need either podIdentity or define a connection parameter