I love Power Apps

No self respecting technologies/programmer/ex-programmer likes simple solutions.  I still chose C# as my go to problem solver (I learnt to use a hammer 18 years ago and now all my problem look like a nail).  Don't tell anyone under 30 I still love C#, they think you are weird if you don't use Javascript for everything.  And 15 years ago I was arguing the same with the C++ golden oldies.  So the circle of life goes on.  Enter Simba, the Lion King...  Well not really but Power Apps is just making programmers look ridiculous.

Power Apps can do a lot...

MS have announce that components and PCF’s are part of Power Apps.  I've been using this for awhile and it's awesome.

https://powerapps.microsoft.com/en-us/blog/announcing-the-public-preview-of-canvas-components-and-power-apps-component-framework/ 

This diagram outlines extending Power Apps using Components:  Developers often say you can’t extend Power Apps so it is not a real language, my answer is really… 

The other argument for PowerApps is if you need to do any complex programming.....  Use an Azure Function (this allows C#, PowerShell, JS, …).  Simple to build in your own language, expose using an http endpoint and you can call the end point using a custom connector.  

So if you need: 

• Complex UI = go PCF, 
• Reusable UI e.g. menu's = use Components, 
• Complex processing or secure code logic = Azure Functions.

Here are some PCF examples that we can use that are already built:

https://powerusers.microsoft.com/t5/Canvas-Apps-Components-Samples/bd-p/ComponentsGallery

So what is stopping Power Apps:

1. Licencing - the licencing is expensive so you need to choose selectively when it is appropriate.  If MS change it's going to just go crazy the usage. IMHO. 
2. Functionality:  MS have introduced automated testing to the Power Apps platform but there are improvements scheduled.  For me the biggest issue is code reuse.  I wish there was a function library that you could write functions to and call in a single line of code, my individual field logic can be insane and tough to amend on complex large Power App UI's.   

Excellent blog on Power Apps

Top 10 Power Apps Articles Of 2021 - Matthew Devaney

Catch Error in Power Apps and App Insight Logging

Error Handling:
App Insights logging: https://sharepains.com/2019/01/24/powerapps-experimenting-with-error-handling/  Replaced as Microsoft have built in telemetry as of 3 Feb 2020.
https://powerapps.microsoft.com/en-us/blog/log-telemetry-for-your-apps-using-azure-application-insights/

Example Error capturing and tracing to Azure AppInsights:
IfError( // Perform API Call , // Fallback so log here! ,

    Trace("Pauls Unique PowerApp",TraceSeverity.Error, {UserName:User().Email,         Role:gblRole, ErrorMsg:ErrorInfo.Message, ErrorControl:ErrorInfo.Control,         ErrorProperty:ErrorInfo.Property});     Notify("Err message ..." & ErrorInfo.Message); // Display the error on the UI

More detail..

Possible Canvas Apps Error Handling Pattern:

1. Ensure AppInsights key is added to each canvas app
2. Use IfError() to check calls and logic
3. Use the Trace method to write info to App Insights
4. Do I want to enable the Experimental error handling features (great to trace by correlationId)
5. Consider all Power Automate that use Power Apps (ensure you use the V2 Connector)
6. Never use IfError to handle business logic

To Review your App Insights Logging:
Open you Azure Portal > Open your App Insights blade >
Click the "Search" navigation option > Free text entry e.g. "Loyalty PowerApp"

App Insights, finding Traces generated in Power Apps

Monitoring Tool within Power Apps
The Monitor tool in Power Apps is great for debugging and tracing.

Start a monitor on the open Power App.

Monitor Tool - Showing a GET via a custom Connector and the returned response

Function/Code Logging:

Server-side code should log to App Insights or you logging framework.

It is ideal with the Trace within Power Apps explained above to be used in conjunction with 3rd party API calls.

Overview: C# code needs to have logging. If an error occurs an appropriate response must be bubbled up for the next lay

Possible C# Error Handling Pattern:

1. All catch write exception to Log analytics or App insights 
2. Calls to data sources, Azure Services and third party API's and complex logic ideally should be wrapped in a try catch and log the error to App insights using the C# App Insights SDK 
3. The catch blocks ideally return the failed information so the caller code can deal with the logic using the output.  If you don't deal with the returned message, simply log the exception and rethrowing the error (this needs to be a conscious decision on each catch) 
4. Catch specific errors: log, if you don't pass info to caller rethrow the error if applicable (bubble), respond accordingly i.e. catch the specific error and lastly use a catch all. - Heavy, but only add to existing code where this happens often or we are having problems, i.e. be specific
5. Don't use Try, Catch to deal with business logic

Thought: Bubble up means: Code must log exceptions and returns appropriate reply to the caller, if you don't send the appropriate reply rethrow the exception after logging it so the caller has to deal with it.

Power Apps Component bug fixed

Problem:  Creating a new component with Input parameters.  When using the component and setting the custom input parameter with a global variable, the value passes thru, as the variable is reset, the control does not update with the variable.  Replication Steps are recorded  in the 2 min 20 sec recording showing the issue.


Initial Hypothesis: I have a large Power App project that uses this technique a lot.  The global variable were working until Fri 14 Feb 2020.  I believe the Power Apps version has been updated and is causing the issue.  I have tried the work on multiple environments and tenants.  It is happening across them all.

https://powerusers.microsoft.com/t5/Building-Power-Apps/Power-App-Components-not-working-with-Global-variables-used-with/m-p/473414

Warning: This affects Power Apps release 3.200221.27 (rolled out to me on Fri 14 Feb 2020), I think 3.20014.23 (latest release as of 13 Feb 2020) was still working correctly.  Don't change your app if it published on the lower versions until Microsoft release a new version.  This only affects Power Apps using Components and using Global variables on the component's input parameters.

Resolution: Power Apps release 3.20022.17 as of 20 Feb 2020 (UK tenant) has been fixed.  Quickly identified and corrected.

Power Apps - DTAP Azure diagram

Overview:  A sample architecture for DTAP in a highly controlled environment.  There are a lot of variations and the ability to use Power Apps publishing.

There are a few ways to manage environment deployments.

1. Simple: Create in unmanaged solutions and Export and Deploy Managed solutions manually using the Power Platform Ux.
2. Enterprise: Build Azure DevOps pipelines to add unpacked code to Github and deploy solutions using Azure pipelines.
3. 3rd party ALM tooling, some is specific to Dynamics.
4. Nov 2022 - Microsoft announce Power Platform Pipelines 

Custom Connectors:  As you step thru the DTAP environments using ALM to deploy you need to point the custom connector to the appropriate APIM (API):

Environment Variables are extremely useful for ALM

Lean UX for SaaS - Consider Removing

I am not an expert in UI design ( I am a big fan on keep it simple and consistent) - these are my notes and LEAN UX from workshops, and an expert I have worked with.  They have help me understand LEAN UX as a concept.  A lot of Agile pragmatic teams are already using a lot of LEAN UX without realising. 

Ux is how our users interact with our products.  Using LEAN UX to provide your users interaction design is a good approach. LEAN UX needs to meet their expectations, and help them meet there needs.  User Experience Design over-arches the Interactive design that we normally identify as key when developing SaaS software.  LEAN UX's goal is to reduce the UI development time with a great overall experience.

This book is Gospel for Lean UX.

LEAN UX Definition: Lean UX is focused on the experience under design and is less focused on deliverables than traditional UX.  The core objective is to focus on obtaining feedback as early as possible so that it can be used to make quick decisions. The nature of Agile development is to work in rapid, iterative cycles and Lean UX mimics these cycles to ensure that data generated can be used in each iteration.  from the Interaction Design Org.

Miro is commonly used for Design in LEANUX.

Low-Fidelity Tooling such as Balsamic is great for the actual design phase.  Anyone should be able to use, there is no over intricate detail.  Allows for validation from all people on the team immediately.  To gain common understanding and convergence on the target.

Key Principles to follow

1. Collaboration - no hero's, we all work together
2. Focus on Outcomes
3. Share Understanding
4. Permission to fail - Fail fast, learn, and it accepted
5. Talk to you customers, show people early PoC
6. Avoid analysis paralysis

Concepts:

• ME-NTERFACE - Personalised & Customised user Experience
• GAMIFICATION - Rewards to intensify a users experience (includes gratifications, such as badges and celebrations)
• PLACE-ONAS - User Voice interactions
• Problem Statements - Help frame what we are try to solve.
• Story Maps - Useful to get a flow and feature understanding.

References:

https://www.interaction-design.org/literature/article/a-simple-introduction-to-lean-ux

Notes: Miro is great for drawing, sharing, it's useful for big enterprises.  It's pretty expensive unless you use it heavily and their is a free edition.  Good integration with Jira and Confluence.  A lot of templates and can share your own templates easily, good for brainstorming, similar to Lucidchart with more collaboration.

Microsoft Teams Thoughts

Teams is pretty similar to Slack (which I use heavily for nearly 18 months).  The teams and channels concept make software development a pleasure even more so for teams with remote people which is pretty much all the software teams i work with for the past few years.
Teams brings multiple different functions under a single application.  Has all the feature of Zoom and Skype for Business for calling and meetings.
Note: Skype is being depreciate.  Teams supports also supports large meetings.  Allows you to add your own apps and approved ISV apps such as planners, Shifts.
Teams has a great calendar inside teams and you can use outlook to arrange Team meetings.
Each channel has Posts, files and Wiki (I love and use Wiki's in teams a lot, but you can remove the Wiki tabs easily)
Teams chat has the ability to share code snippets and the give control function is great for support and peer working.  The activity notifications work better than using email as your notification system which a lot of people tend to still do in large enterprise software projects.
Chats can now pop out into it's own window so it is separate from you MS teams client.  Very useful.
The reactions (e.g. like, surprise) within channels  are useful to build a strong team spirit.
Easy to add Canvas Power Apps, and work great with the Power Platform.
Teams native app is available on Mac, iOS, Android and Windows 10.

Zoom is more like Skype: Has meetings and chats, no file collaboration, apart from attachments in chats.  Files not 1st class citizen.  A small sub set of what Teams does.

Issues:
It's busy and users often don't like it for a few weeks.
Need to orientate yourself - the functionality is there, you just need to find it.
Apps don't keep session state when you change apps or focus.  MS I believe are going to offer popups and keep persistence shortly.

Updated: 20 May 2020: Who is a Chat/Conversation bot app that utilities MS Graph data:

Power Apps Quick Tips

Some of my Power Apps notes:

Licencing:
Determine your Power Apps licence using Power Apps Web user interface:
Power Apps > Settings > Plans

Note:  Microsoft changed how Power Apps licencing works circa Nov 2019.  The Power Apps licence with O365 E3/E5 does not have the connectors so is useful only for simple apps, and using flow, the apps can get more advanced.

Testing:
I saw a preview of the Power Apps Test Framework as the Microsoft Ignite Tour in mid Jan 2020.  The framework allows for recording UI tests and inserting asserts.  The tests are stored alongside the project inside Power Apps.  PowerApps Testing is in beta, it will be release by region so presumably it's already available in some US regions on the public beta.  The CI/CD pipeline integration was not shown but I'm sure some smart fella will look at this shortly.  I'd use Selenium for automated web testing at this stage, but that may change especially for mobile app development.

Updated 28 Jan 2020: Test Studio for Power Apps released today.  Here is the announcement.  Here is another recording outlining testing of Power Apps.

In the Power App > File > Settings > Advanced Settings > Scroll down to "Formula-level Error Management" and turn on the feature.
Open the "Advanced tools"

Accessing Test Studio in Power Apps

Power Apps Development Standards:
Error Handling - Should an unexpected event occur, log so the issue can be traced, as of 3 Feb 2020, PowerApps has App Insight integration.
Naming standards - Label visual controls and variables
Approved Colours - Digital branding standards
Reuse - Control reuse with shared branding
Roles - AAD connector allows me to figure out the user group the current user belongs too so they get appropriate menus, screens, and actions.
Menus -  @Laura-GB https://www.youtube.com/watch?v=5G-gVWRItmc  Build a menu component, input allows one to combine with AAD roles to create dynamic menus for users.
Copy and pasting OOB controls - such as a textbox, if you use a formula, the values are persist and passed around.  So if you have a color set by a variable, copy and paste results in the new text box referencing the colour.  Taking this further, if you put in the position X and Y a formula e.g. X=66*1 and Y=100*1, the control will inherit the parent controls property rather than reset the property.

Steps to setup and Use a Custom Connector:

Get the http response from a custom connector and add to a collection

Common Functions:
DateTimeValue() - Convert string into a date
Text() - Format a string
Value()- Format a string into a numeric
Text(DateTimeValue(TextInput1.Text), "dd-mmm-yyyy")
An approach I like to advanced Power App Input Validation.

Lookup() - Finds the first record in a table, closely related to Filter() and Search()

I.e. Fx> Set(Lookup(<DataverseTblName>,<UniqueRowId>=GUID("1234-1234-111...") 

Patch() - Update or add new, best way to save as it handle collections

Patch() function used to update an existing "Appeal" record.  Also note that a json string is saved- This is how to escape quotes.

Error Handling and Logging:
PowerApps has pretty basic error handling IfError(Try, if fail fall back)
Error Handling for Power Apps
The is a built in mechanism to log from Power Apps into App Insights.

Components:
Build a common UI element such as a menu or header.  The component has input and output parameters so you need to pass in the data to be used and return the output.  This allow the component to be re-used.  Obviously it makes sense that you can't use global variable within components, you need to pass the global variables in using input parameters.
Great example from @Laura-GB https://www.youtube.com/watch?v=5G-gVWRItmc