I have try to define the azure WAF custom rule via Bicep in vs code (installed bicep plugin).
Such as

resource appGatewayFirewall 'Microsoft.Network/ApplicationGatewayWebApplicationFirewallPolicies@2022-09-01' = {
  name: firewallName
  location: location
  properties: {
    customRules: [
      {
        name: 'grafanaazuremonitordatasource'
        action: 'Allow'
        priority: 15
        ruleType: 'MatchRule'
        matchConditions: [

          { 
            matchVariables: [
              {
                variableName: 'RequestUri'
              }
            ]
          
            operator: 'Contains'   
            negationConditon: true
            matchValues: [
             '/api/ds/query?ds_type=grafana-azure-monitor-datasource'
            ]           
          }
        ]
      }
    ]
    policySettings: {
      requestBodyCheck: true
      maxRequestBodySizeInKb: 128
      fileUploadLimitInMb: 100
      state: 'Enabled'
      mode: 'Prevention'
    }
    managedRules: {
      managedRuleSets: [
        {
          ruleSetType: 'OWASP'
          ruleSetVersion: '3.2'
          ruleGroupOverrides: [
            // If necessary and safe, you can disable necessary rules. e.g. like this
            // {
            //   ruleGroupName: 'REQUEST-913-SCANNER-DETECTION'
            //   rules: [
            //     {
            //       ruleId: '913100'
            //       state: 'Disabled'
            //       action: 'AnomalyScoring'
            //     }
            //   ]
            // }
          ]
        }
      ]
      exclusions: [
        // If necessary and safe, you can disable checking specific arguments or parameters. e.g. like this:
        // {
        //   "matchVariable": "RequestArgNames",
        //   "selectorMatchOperator": "Equals",
        //   "selector": "repairForm"
        // }
      ]
    }
  }
}

In the matchConditions block,there is no parameter to define the Operation value “is” or “is not” according following image.

After I deploy the Bicep script successfully, the Operation value is “is not”,in fact I hope it is “is”. I dont know how to define this parameter name or format.

Thanks.

I have looked for the method in google,but failed.