Data Visualisation · External Tools · Power BI · Power BI Desktop

VisOps For Power BI With PBI Inspector

This week, one of my colleagues at Microsoft, Nat Van Gulck, showed me a cool new open-source tool he’s been working on to make VisOps for Power BI much easier: PBI Inspector. What is VisOps? I’ll admit I didn’t really know either, so being lazy I asked Nat to write a few paragraphs describing the project and why it will be useful:

Great progress has been made over the years with software development CI\CD tooling and processes (aka DevOps), just not so much with BI report visualisations and charts where we’ve come to accept only manual checks before publishing to production.  PBI Inspector is a rules-based visual layer testing tool for Power BI which aims to fill this tooling gap. It runs on either the report author’s desktop or as part of a CI\CD pipeline. The latter follows naturally from the recent Power BI Desktop Developer mode announcement which marks a step change in providing Pro developers with much improved source control capabilities. PBI Inspector reads report files in the PBIP format (currently in Preview) although it also accepts PBIX files. Test results can be presented in several formats including HTML, JSON and Azure DevOps logging commands

PBI Inspector’s rules combine Greg Dennis’s JsonLogic .NET implementation, which allows for the definition of expressive rule logic, with the querying abilities of JsonPath and JsonPointer libraries to select nodes from the Power BI report’s JSON layout definition for testing purposes.  As an illustrative example, here’s a rule that tests if charts are wider than tall in each report page and returns an array with the names of visuals that fail the test: 

{ 

        "name": "Charts wider than tall", 

        "description": "Want to check that your charts are wider than tall?", 

        "disabled": false, 

        "logType": "warning", 

        "forEachPath": "$.sections[*]", 

        "forEachPathName": "$.name", 

        "forEachPathDisplayName": "$.displayName", 

        "path": "$.visualContainers[*].config", 

        "pathErrorWhenNoMatch": false, 

        "test": [ 

        	        { 

                     "map": [ 

                     	{ 

                                    "filter": [ 

                                        { 

                                            "var": "visualsConfigArray" 

                                        }, 

                                        { 

                                            "<=": [ 

                                                { 

                                                    "var": "layouts.0.position.width" 

                                                }, 

                                                { 

                                                    "var": "layouts.0.position.height" 

                                                } 

                                            ] 

                                        } 

                                    ] 

                                }, 

                                { 

                                    "var": "name" 

                                } 

                            ] 

                        }, 

                        { 

                            "visualsConfigArray": "." 

                        }, 

                        [] 

                    ] 

} 

Here’s an example result wireframe depiction of a report page (provided as part of the HTML output) highlighting two visuals that failed the test because they are taller than wide: 

For additional rule examples, see PBI-Inspector/DocsExamples/Example rules.json at main · NatVanG/PBI-Inspector (github.com). For further details see NatVanG/PBI-Inspector: A rules-based Power BI Desktop file inspection or testing tool. (github.com)

I think this is a great example of the kind of community innovation that Power BI Desktop Developer Mode allows (see also the recent announcement of PBI Explorer). A lot of organisations that use Power BI don’t, and will never, care about this kind of thing – but those who do have been very vocal about Power BI’s previous limitations in the area of DevOps and DataOps. Thanks to the work of people like Mathias Thierbach (of pbi-tools fame), John Kerski and Nat we can see how quickly Power BI is catching up.

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