Skip to main content

How to configure an Expectation store to use Azure Blob Storage

By default, newly profiled Expectations are stored in JSON format in the expectations/ subdirectory of your great_expectations/ folder. This guide will help you configure Great Expectations to store them in Azure Blob Storage.

Prerequisites: This how-to guide assumes you have:

Steps#

  1. Configure the config_variables.yml file with your Azure Storage credentials

    We recommend that Azure Storage credentials be stored in the config_variables.yml file, which is located in the uncommitted/ folder by default, and is not part of source control. The following lines add Azure Storage credentials under the key AZURE_STORAGE_CONNECTION_STRING. Additional options for configuring the config_variables.yml file or additional environment variables can be found here.

    AZURE_STORAGE_CONNECTION_STRING: "DefaultEndpointsProtocol=https;EndpointSuffix=core.windows.net;AccountName=<YOUR-STORAGE-ACCOUNT-NAME>;AccountKey=<YOUR-STORAGE-ACCOUNT-KEY==>"
  1. Identify your Data Context Expectations Store

    In your great_expectations.yml , look for the following lines. The configuration tells Great Expectations to look for Expectations in a store called expectations_store. The base_directory for expectations_store is set to expectations/ by default.

    expectations_store_name: expectations_store
    stores:    expectations_store:        class_name: ExpectationsStore        store_backend:            class_name: TupleFilesystemStoreBackend            base_directory: expectations/
  1. Update your configuration file to include a new store for Expectations on Azure Storage account

    In our case, the name is set to expectations_AZ_store, but it can be any name you like. We also need to make some changes to the store_backend settings. The class_name will be set to TupleAzureBlobStoreBackend, container will be set to the name of your blob container (the equivalent of S3 bucket for Azure) you wish to store your expectations, prefix will be set to the folder in the container where Expectation files will be located, and connection_string will be set to ${AZURE_STORAGE_CONNECTION_STRING}, which references the corresponding key in the config_variables.yml file.

    expectations_store_name: expectations_AZ_store
    stores:    expectations_AZ_store:        class_name: ExpectationsStore        store_backend:          class_name: TupleAzureBlobStoreBackend          container: <blob-container>          prefix: expectations          connection_string: ${AZURE_STORAGE_CONNECTION_STRING}
    note

    If the container is called $web (for hosting and sharing Data Docs on Azure Blob Storage) then set container: \$web so the escape char will allow us to reach the $webcontainer.

  1. Copy existing Expectation JSON files to the Azure blob. (This step is optional).

    One way to copy Expectations into Azure Blob Storage is by using the az storage blob upload command, which is part of the Azure SDK. The following example will copy one Expectation, exp1 from a local folder to the Azure blob. Information on other ways to copy Expectation JSON files, like the Azure Storage browser in the Azure Portal, can be found in the Documentation for Azure.

    export AZURE_STORAGE_CONNECTION_STRING="DefaultEndpointsProtocol=https;EndpointSuffix=core.windows.net;AccountName=<YOUR-STORAGE-ACCOUNT-NAME>;AccountKey=<YOUR-STORAGE-ACCOUNT-KEY==>"az storage blob upload -f <local/path/to/expectation.json> -c <GREAT-EXPECTATION-DEDICATED-AZURE-BLOB-CONTAINER-NAME> -n <PREFIX>/<expectation.json>example :az storage blob upload -f great_expectations/expectations/exp1.json -c <blob-container> -n expectations/exp1.json
    Finished[#############################################################]  100.0000%{"etag": "\"0x8D8E08E5DA47F84\"","lastModified": "2021-03-06T10:55:33+00:00"}
  1. Confirm that the new Expectations store has been added by running great_expectations --v3-api store list

    Notice the output contains two Expectation stores: the original expectations_store on the local filesystem and the expectations_AZ_store we just configured. This is ok, since Great Expectations will look for Expectations in Azure Blob as long as we set the expectations_store_name variable to expectations_AZ_store, which we did in the previous step. The config for expectations_store can be removed if you would like.

    great_expectations --v3-api store list
     - name: expectations_store   class_name: ExpectationsStore   store_backend:     class_name: TupleFilesystemStoreBackend     base_directory: expectations/
     - name: expectations_AZ_store   class_name: ExpectationsStore   store_backend:     class_name: TupleAzureBlobStoreBackend     connection_string: DefaultEndpointsProtocol=https;EndpointSuffix=core.windows.net;AccountName=<YOUR-STORAGE-ACCOUNT-NAME>;AccountKey=<YOUR-STORAGE-ACCOUNT-KEY==>     container: <blob-container>     prefix: expectations
  1. Confirm that Expectations can be accessed from Azure Blob Storage by running great_expectations --v3-api suite list.

    If you followed Step 4, the output should include the Expectation we copied to Azure Blob: exp1. If you did not copy Expectations to the new Store, you will see a message saying no Expectations were found.

    great_expectations --v3-api suite list
    Using v2 (Batch Kwargs) API1 Expectation Suite found:- exp1