Embedding Dashboard on Salesforce throws error when using RLS

Finally achieved this embedding!!! 🎉

Sharing solution in case someone's struggling with something similar.

My scenario was; I'm using a POST call to endpoint API GenerateTokenInGroup, my Dahsboard uses RLS, so it is required to include "identities" in the "Request Body" json, seems like I was not including all the required data on each section of the HttpRequest.

Important!

• Now I included Content-Type: application/json to the header of request
• Request Body is now composed with accessLevel: View, and identities using Service Principal Id (Application Client Id) as the username.
• I created a new Role with no filters and assigned to Service Principal
  • (This allows me to apply ReportLevelFilters for dynamically filtering from Salesforce)
• Provided the required API permissions on App Registration (Service Principal) on Azure.
  • Delegated Permissions, Power Bi Service; Report.ReadWrite.All, Dataset.ReadWrite.All, Content.Create

Full HttpRequest code

// Call to Power BI Service API to get embed token for report        
        HttpRequest reqGetEmbedToken = new HttpRequest();
        reqGetEmbedToken.setMethod('POST');
        String urlGetEmbedToken = 'https://api.powerbi.com/v1.0/myorg/groups/' + WorkspaceId + '/reports/' + ReportId + '/GenerateToken';
        reqGetEmbedToken.setEndpoint(urlGetEmbedToken);
        System.debug('setEndpoint = '+urlGetEmbedToken);
        reqGetEmbedToken.setHeader('Authorization', 'Bearer ' + access_token);
        reqGetEmbedToken.setHeader('Content-Type', 'application/json');
        system.debug('setHeader = '+reqGetembedToken.getHeader('Authorization'));
        reqGetEmbedToken.setBody(
            '{'
                +'"accessLevel":"View"'
                +',"identities":['
                    +'{"username":"1eac8b84-11a3-4f67-b308-c9ab0a7b8da0","roles":["noRlsFilters"],"datasets":["'+powerBiReport.datasetId+'"]}'
                +']'
            +'}');
        System.debug('setBody = '+reqGetEmbedToken.getBody());
    
        HttpResponse responseEmbedToken;
        try {                        
            responseEmbedToken = http.send(reqGetEmbedToken);
            System.debug('http send successfully');
            system.debug(responseEmbedToken);
        } catch (Exception error) {
            system.debug('Error Catched');
            System.debug(error);
        }

Response code is now 200 and Token is successfully generated,

Dashboard is displaying and filtering is correctly applying.

Hooray!