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Tutorial: Calculate container statistics by using Databricks

  • Artikkeli

This tutorial shows you how to gather statistics about your containers by using Azure Blob Storage inventory along with Azure Databricks.

In this tutorial, you learn how to:

  • Generate an inventory report
  • Create an Azure Databricks workspace, cluster, and notebook
  • Read the blob inventory file
  • Get the number and total size of blobs, snapshots, and versions
  • Get the number of blobs by blob type and content type

Prerequisites

Generate an inventory report

Enable blob inventory reports for your storage account. See Enable Azure Storage blob inventory reports.

Use the following configuration settings:

Setting Value
Rule name blobinventory
Container <name of your container>
Object type to inventory Blob
Blob types Block blobs, Page blobs, and Append blobs
Subtypes include blob versions, include snapshots, include deleted blobs
Blob inventory fields All
Inventory frequency Daily
Export format CSV

You might have to wait up to 24 hours after enabling inventory reports for your first report to be generated.

Configure Azure Databricks

In this section, you create an Azure Databricks workspace, cluster, and notebook. Later in this tutorial, you paste code snippets into notebook cells, and then run them to gather container statistics.

  1. Create an Azure Databricks workspace. See Create an Azure Databricks workspace.

  2. Create a cluster. See Create a cluster.

  3. Create a notebook and choose Python as the default language of the notebook. See Create a notebook.

Read the blob inventory file

  1. Copy and paste the following code block into the first cell, but don't run this code yet.

    from pyspark.sql.types import StructType, StructField, IntegerType, StringType
import pyspark.sql.functions as F  
   storage_account_name = "<storage-account-name>"
   storage_account_key = "<storage-account-key>"
   container = "<container-name>"
   blob_inventory_file = "<blob-inventory-file-name>" 
   hierarchial_namespace_enabled = False

if hierarchial_namespace_enabled == False:
  spark.conf.set("fs.azure.account.key.{0}.blob.core.windows.net".format(storage_account_name), storage_account_key)
  df = spark.read.csv("wasbs://{0}@{1}.blob.core.windows.net/{2}".format(container, storage_account_name, blob_inventory_file), header='true', inferSchema='true')

 else:
  spark.conf.set("fs.azure.account.key.{0}.dfs.core.windows.net".format(storage_account_name), storage_account_key)
  df = spark.read.csv("abfss://{0}@{1}.dfs.core.windows.net/{2}".format(container, storage_account_name, blob_inventory_file), header='true', inferSchema='true')

  2. In this code block, replace the following values:

    • Replace the <storage-account-name> placeholder value with the name of your storage account.

    • Replace the <storage-account-key> placeholder value with the account key of your storage account.

    • Replace the <container-name> placeholder value with the container that holds the inventory reports.

    • Replace the <blob-inventory-file-name> placeholder with the fully qualified name of the inventory file (For example: 2023/02/02/02-16-17/blobinventory/blobinventory_1000000_0.csv).

    • If your account has a hierarchical namespace, set the hierarchical_namespace_enabled variable to True.

  3. Press the SHIFT + ENTER keys to run the code in this block.

Get blob count and size

  1. In a new cell, paste the following code:

    print("Number of blobs in the container:", df.count())
print("Number of bytes occupied by blobs in the container:", df.agg({'Content-Length': 'sum'}).first()['sum(Content-Length)'])

  2. Press SHIFT + ENTER to run the cell.

    The notebook displays the number of blobs in a container and the number of bytes occupied by blobs in the container.

    Screenshot of results that appear when you run the cell showing the number of blobs and the size of blobs in the container.

Get snapshot count and size

  1. In a new cell, paste the following code:

    from pyspark.sql.functions import *

print("Number of snapshots in the container:", df.where(~(col("Snapshot")).like("Null")).count())
dfT = df.where(~(col("Snapshot")).like("Null"))
print("Number of bytes occupied by snapshots in the container:", dfT.agg({'Content-Length': 'sum'}).first()['sum(Content-Length)'])

  2. Press SHIFT + ENTER to run the cell.

    The notebook displays the number of snapshots and total number of bytes occupied by blob snapshots.

    Screenshot of results that appear when you run the cell showing the number of snapshots and the total combined size of snapshots.

Get version count and size

  1. In a new cell, paste the following code:

    from pyspark.sql.functions import *

print("Number of versions in the container:", df.where(~(col("VersionId")).like("Null")).count())
dfT = df.where(~(col("VersionId")).like("Null"))
print("Number of bytes occupied by versions in the container:", dfT.agg({'Content-Length': 'sum'}).first()['sum(Content-Length)'])

  2. Press SHIFT + ENTER to run the cell.

    The notebook displays the number of blob versions and total number of bytes occupied by blob versions.

    Screenshot of results that appear when you run the cell showing the number of versions and the total combined size of versions.

Get blob count by blob type

  1. In a new cell, paste the following code:

    display(df.groupBy('BlobType').count().withColumnRenamed("count", "Total number of blobs in the container by BlobType"))

  2. Press SHIFT + ENTER to run the cell.

    The notebook displays the number of blob types by type.

    Screenshot of results that appear when you run the cell showing the number of blob types by type.

Get blob count by content type

  1. In a new cell, paste the following code:

    display(df.groupBy('Content-Type').count().withColumnRenamed("count", "Total number of blobs in the container by Content-Type"))

  2. Press SHIFT + ENTER to run the cell.

    The notebook displays the number of blobs associated with each content type.

    Screenshot of results that appear when you run the cell showing the number of blobs by content-type.

Terminate the cluster

To avoid unnecessary billing, make sure to terminate the cluster. See Terminate a cluster.

Next steps