A #dataOp ramblings

As a data enthusiast, I’m always on the lookout for ways to streamline my workflow and make my life easier. In this post, I’ll be sharing two Tabular Editor scripts that have saved me countless hours of manual formatting in my Power BI projects.

There are two versions of this software. To use the scripts below you only need version two. This version is free and open source: https://tabulareditor.github.io/TabularEditor/

If you have the money for the license you can support the author (Daniel Otykier) by buying the license for version 3: https://tabulareditor.com

I got an assignment the other day to produce documentation to send to a customer. The extraction of the table names required to execute a certain Databricks notebook was part of the task. The plan was to build an object dependency tree.

The query spanned 279 lines. How can you extract only the table names from a file without having to manually look for them? Can we make use of this technique again in the future?

During data engineering projects I tend to try and minimize the tools being used. I think it’s a good practice. Having too many tools causes sometimes for errors going unnoticed by the teams members.

One of the advantages of having a tool like Databricks is that it allows us to use all the power of python and avoid, like I did in the past, to have something like Azure Functions to compensate for the limitations of some platform.

I’m currently working on a project where I’m adapting a code base of Databricks notebooks for a new client. There are a few errors to hunt but the Web UI is not really friendly for this purpose.

Just wanted a quick and easy way to not have to click around to find the issues.

Here’s a quick script to just do that:

import os, json
import configparser
from databricks_cli.sdk.api_client import ApiClient
from databricks_cli.runs.api import RunsApi


def print_error(nb_path, nb_params, nb_run_url, nb_error="Unknown"):
    error = nb_error.partition("\n")[0]
    params = json.loads(nb_params) if nb_params != "" else {}
    print(
        f"""
Path:	{nb_path}
Params:	{json.dumps(params,indent=2)}
RunUrl:	{nb_run_url}
Error:	{error}
"""
    )


databricks_cfg = "~/.databrickscfg"

conf = configparser.ConfigParser()
conf.read(os.path.expanduser(databricks_cfg))

api_client = ApiClient(
    host=conf["DEFAULT"]["host"],
    token=conf["DEFAULT"]["password"]
)

runs_api = RunsApi(api_client)

for x in range(1, 101, 25):
    x = runs_api.list_runs(
        job_id=None,
        active_only=None,
        completed_only=None,
        offset=x,
        limit=25,
        version="2.1",
    )
    if len(x["runs"]) > 0:
        for y in x["runs"]:
            if y["state"]["result_state"] == "FAILED":
                z = runs_api.get_run_output(run_id=y["run_id"])

                if "error" in z:
                    print_error(
                        z["metadata"]["task"]["notebook_task"]["notebook_path"],
                        z["metadata"]["task"]["notebook_task"]["base_parameters"][
                            "Param1Value"
                        ],
                        z["metadata"]["run_page_url"],
                        z["error"],
                    )
                else:
                    print_error(
                        z["metadata"]["task"]["notebook_task"]["notebook_path"],
                        z["metadata"]["task"]["notebook_task"]["base_parameters"][
                            "Param1Value"
                        ],
                        z["metadata"]["run_page_url"],
                    )

Follow this documentation to install the requirements. There’s a lot more you can do with databricks-cli to make your life easier. It’s a great tool to add to your toolbox.

There’s not an official function to calculate workdays in Databricks. Here are some solutions.

Having a DimCalendar with holidays and at least Databricks Runtime 12

If you have a DimCalendar in the system you can now do LEFT LATERAL JOIN without the correlated subquery errors when using non-equality predicates. Check SPARK-36114 for more details.

Calculating working days is then as simple as run a query like:

SELECT mt.StartDate,
       mt.EndDate,
       dc.Workdays
 FROM myTable mt
  LEFT JOIN LATERAL
    (SELECT COUNT(DateKey) - 1 AS Workdays
     FROM dimCalendar dc
     WHERE mt.StartDate <= dc.DateKey
        AND mt.EndDate >= dc.Datekey
        AND dc.IsDayWeekDay = TRUE
        AND dc.IsDayHoliday = FALSE
    )

If this query is slow, please check if the data types for the dates columns match. All are DATE or all are TIMESTAMP. If the sluginess remains check if any of the fields are not part of the statistics of the table.

A while ago I’ve received an email from Jason Alvarez asking me if I knew a way to change Power Query connections inside an Excel file. The problem is similar to my previous post on Mass changing pivot table connection strings in Excel using PowerShell. Turns out you can and he was able to find this solution:

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#root path to the collection of excel docs:
$rootPath = "C:\Temp\PowerQueryDemo\"

#Current query file path:
$currentPath = "C:\Temp\PowerQueryDemo\"
#Updated query file path:
$newPath = "C:\Temp\PowerQueryDemo\PowerQueryNewSource"

Get-ChildItem -Path $rootPath -Recurse -Include *.xlsx | ForEach-Object{
    $docPath = $_.FullName

    ## Create an instance of excel:
    $ExcelAppInstance = New-Object -ComObject "Excel.Application"
    $ExcelAppInstance.Visible = $false

    ## Open the workbook object within our Excel instance:
    $workbook = $ExcelAppInstance.workbooks.Open($docPath)

    ##iterate the list of queries embedded in the workbook,
    ##updating the file path to our new one:
    $workbook.Queries | ForEach-Object{
        Write-Output $_.Formula
        Write-output $_.Formula.replace($xPath,$tPath)
        $_.Formula = $_.Formula.replace($xPath,$tPath)
    }

    $workbook.Save()
    $workbook.Close()
    $ExcelAppInstance.Quit()
}

The key here is the Queries property inside the Workbook object.

Yesterday I had the pleasure to be back to in-person to give a small fun presentation about bending Power BI to help us solve Wordle puzzles.

The content is in Portuguese but I will upload an English version during this week.

Here’s the link on GitHub where you can download the file:

https://github.com/fpvmorais/presentations

If you have any questions please reach me.

Have fun!

While creating a new machine to be the Integration Runtime for Purview and after I have installed the mandatory JRE that allows the connection to Snowflake I kept getting this error:

Error: (3913) JavaException: Must have Java 8 or newer installed.

This puzzled me because I had installed version 17. Started troubleshooting and followed this guide to check if the installation was correct. Everything seemed alright but the error was still there.

Here are some tips of the things I’ve learned while creating them.

App Plan

If you already have an Windows ‘App Service Plan’ you’ll need a different one for running Python.

You can’t host Linux and Windows apps in the same resource group. If you have an existing resource group named AzureFunctionsQuickstart-rg with a Windows function app or web app, you must use a different resource group.

Python version

If you need to use ‘azure-identity’ you’ll need to use python 3.8 instead of the 3.9 otherwise you’ll get:

There’s a lot to chew while unit testing Azure Functions. I going to be quite liberal with the terminology because technically some of this will be in fact integration testing and not unit testing per se.

Either way, Azure Functions load the local.settings.json on startup, creating several environment variables that then we can use in our code. In C# we would access them like so:

tenantId = configRoot["TenantId"];
appId = configRoot["AppId"];

or in Python: