[enhancement]: Update the Azure Functions App V2 Task to improve validation for the DevOps Service Tag Scenarios and also for Private IP Endpoints that are publicly accessible.

[FinVamp1]

Task name

AzureFunctionApp@2

Describe your feature request here

The current validation endpoints just check and block if the Function App is on a Private endpoint. There are some scenarios where the app could still be deployed to from Microsoft hosted agents.

Scenario 1 App is on Private endpoint but has used the Azure DevOps Service Tag to allow access.
Scenario 2 App is on a Private Endpoint but has allowed public access.

[github-actions]

This issue is stale because it has been open for 180 days with no activity. Remove the stale label or comment on the issue otherwise this will be closed in 5 days

[imdex-brett-debeer]

This has been broken since #16949 added these checks.

If no one is going to fix this problem in the near future, then it would be good to add a note not to use this task if they have private endpoints to azure-devops-yaml-schema/task-reference/azure-function-app-v2.md.

Adding something like the below to Tasks/AzureFunctionAppV2/operations/AzureAppServiceUtilityExt.t should work.

    public async getFuntionAppNetworkingCheck(isLinuxApp): Promise<void> {
        let success = true;

        try {
            let isFuncPrivate = await this.isFuncWithPrivateEndpoint();
            let isFuncAccessible = await this.isFuncWithAllowAgentIpRule();

            if (isFuncPrivate == "true" && isFuncAccessible != "false") {
                //will NOT be able to reach kudu site if isFuncPrivate and !isFuncAccessible
                tl.error("Function app has private endpoint(s). But you are not running this pipeline from a self-hosted agent that has access to the Functions App. Relevant documentation: "
                    + "https://learn.microsoft.com/en-us/azure/devops/pipelines/agents/agents?view=azure-devops&tabs=browser#install");
                success = false;
            }
            else if (isFuncPrivate == "true") {
                //just FYI
                console.log("NOTE: Function app has private endpoint(s). Therefore, make sure that you are running this pipeline from a self-hosted agent that has access to the Functions App.");
            }

            let isFuncVNet = await this.isFuncVnetIntegrated();
            if (isFuncVNet == "true") {
                //just FYI
                console.log("NOTE: Function app is VNet integrated.");
            }

            //network validation only avaliable for Windows (NOT Linux)
            if (!isLinuxApp) {
                let errormessage = await this.isAzureWebJobsStorageAccessible();

                if (errormessage) {
                    //AzureWebJobsStorage connection string is NOT accessible from Kudu
                    tl.error(errormessage);
                    success = false;

                    //can be because function app is outside VNet
                    if (isFuncVNet == "false") {
                        console.log("NOTE: Function app is NOT VNet integrated.");
                    }
                }
            }
        }
        catch (error) {
            tl.debug(`Skipping networking check with error: ${error}`);
        }

        if (!success) {
            throw Error("Networking validation for the Function app and Storage account has failed. Please review all error messages.");
        }
    }

    public async isFuncWithAllowAgentIpRule(): Promise<string> {
        try {
            let agentIp: string = await this.getAgentIpAddress();
            let siteConfig = await this._appService.getSiteConfig();
            let ipRestrictions = siteConfig.scmIpSecurityRestrictionsUseMain === true
                ? siteConfig.ipSecurityRestrictions
                : siteConfig.scmIpSecurityRestrictions;
            let defaultAction = siteConfig.scmIpSecurityRestrictionsUseMain === true
                ? siteConfig.ipSecurityRestrictionsDefaultAction
                : siteConfig.scmIpSecurityRestrictionsDefaultAction;
            let agentIpRule = ipRestrictions.find(x => x.ipAddress.split('/')[0] === agentIp );
            if (defaultAction === 'Allow' && !(agentIpRule?.action === 'Deny')) {
                return "false";
            }
            if (defaultAction === 'Deny' && !(agentIpRule?.action === 'Allow')) {
                return "false";
            }
            return "true";
        }
        catch (error) {
            tl.debug(`Skipping private endpoint check: ${error}`);
            return null;
        }
    }

[github-actions]

This issue is stale because it has been open for 180 days with no activity. Remove the stale label or comment on the issue otherwise this will be closed in 5 days