Power Change Alerter

Summary

This is a Windows Service project that will send an email alert as the host powers on/off and drops in/out of battery power.

Backstory

Having UPS systems in the house to keep things alive during brown- or blackouts is great. However, excessive outtages that happen while away from the house can lead to unexpected consequences. For example, several hundred dollars worth of food in a refrigerator can become spoiled while you are away for a weekend.

The immediate need was to write an application to send notices to my cell phone. I happened to have a spare laptop laying around, so it made sense to rely on its internal message pump as it changed from wall power to battery (and vice-versa). Combine that with a free email address service and how a cell provider can translate SMTP messages to cellular text messages, and I had a working concept. The first implementation was done as a Windows Service as a quick means to an end.

Technologies

• C# Windows Service
• .NET + .NET Framework
• SMTP Communication
• PowerShell
• MSI Installer
• Unit + Integration Tests

NuGet Packages

• Microsoft Extension
• Newtonsoft JSON
• NUnit
• Serilog
• Trinet.Core.IO.Ntfs

Development Environment Setup

Ensure the following is installed:

• .NET Framework runtime version 4.8.1
• .NET version 6 runtime
• PowerShell (at least version 5)
• Visual Studio (Community Edition is fine)
• Windows Installer XML (aka WiX)
• WiX Toolset extension for Visual Studio

Aside from WiX, the installations listed above are available from the Visual Studio Installer app.

Once the above packages have been installed, load the PowerChangeAlerter.sln file in Visual Studio and do a complete rebuild of the solution. This will also cause any NuGet packages to be pulled down.

Before Running or Debugging

If this is your first time downloading the repo, then you will need to do an extra step. Browse to the $/PowerChangeAlerter.Common directory, and you will find a file called settings.runtime.TEMPLATE. Make a copy of this JSON file, and name it settings.runtime. Doing this will also resolve a Visual Studio error for missing a file in the CSPROJ file's manifest. You would then need to file in the appropriate fields in the JSON file.

If you do not do the above step, you will get an exception when you debug or run the application. This also applies for generating a MSI file.

Source Code Overview

The solution file has references to a few projects:

• PowerChangeAlerter - Primary starting point (i.e. startup project)
• PowerChangeAlerter.Common - Shared classes and functionality, the guts of the application
• PowerChangeAlerter.Install - Creates MSI installer files
• PowerChangeAlerter.Sandbox - Just a dummy console app used for ad-hoc testing of functionality
• PowerChangeAlerter.Tests - NUnit project for unit + integration tests

The primary worker (PowerChangeAlerter.csproj) is designed to run as a Windows Service. Since those cannot be natively debugged, there is an extra commandline option for running the project from Visual Studio or a command prompt -- just add the switch -cli to the project's properties window in the Debug --> Command line arguments section. Or just open a command prompt and run this:

PowerChangeAlerter.exe -cli

This will dump out some generalized information and ensure that the necessary event listeners are working.

(Re-)Building the solution will cause almost all projects to compile. There is one project that is excluded from the normal (re-)build process -- PowerChangeAlerter.Install. This was done to keep the normal build times as short as possible, by omitting the MSI installer file creation. See the next section for details.

Create Installer

Right-clicking on the PowerChangeAlerter.Install project in Visual Studio's Solution Explorer will open options to rebuild that project and generate a MSI file. For convenience, the generated MSI file is copied to the root of the repo, and will remove any other MSI files found there to eliminate confusion. This happens as a post-build step that runs the following PowerShell script: copy-msi-with-rename.ps1.

Installing

Run the generated MSI file, and click through the few prompts. If an existing copy of the service exists already, the installer will stop and remove the existing service, then replace it with the installer's version.

Logging

Serilog is used for capturing and routing log messages. By default, it is setup to use a rolling log file system. Additional features can be bolted into the settings.serilog file.

Where the log files are written depends on how the application is started:

• Visual Studio Debugging or Command-line - Look for a logs directory under the runtime's EXE location, usually in the bin directory
• Registered as a Windows Service - C:\ProgramData\Power Change Alerter\logs

Running the Service

The host machine will need the following:

• Windows 7 or higher (64-bit only)
• .NET Framework version 4.8.1

The service itself is setup to run with the following options:

• Start automatically
• Run as Local System
• Desktop interactive is turned off

Starting the service will dump several lines of initialization information. If you get any failures during startup, check the log files written to the location specified in the Logging section above. After the service has been running for a while, you will periodically see some "uptime minutes" messages being written to the log file.

Tests

The PowerChangeAlerter.Tests project contains all of the unit and integration tests. When you load the solution, look for a Solution Folder called Test Projects.

Certain catagories have been made for future filtering/exclusions of tests. See the CategoryNames.cs file for those values.

Notes

Use DebugView app to listen for additional Debug level messages that are scattered through the application. If you have Visual Studio running at the same time, then look at its Output window for the debug messages -- they are not redirected back to the debug stream when caught there.

If you get service startup failures and do not see a log file (or new log lines), check Windows Event Viewer for errors.

If the installer raises an error about insufficient privileges or permissions, then try one of the following:

• Copy the file locally, and ensure the file is not blocked (more info)
• Ensure that the "Services" window is not open (i.e. from Run dialog --> services.msc)

Future

In no particular order...

• Improved parameterization of Serilog options with Serilog.Settings.Configuration and Serilog.Sinks.Map;
• Expose REST API from for querying state, returning metrics, etc.;
• Create base class for declaring/discovering new functionality, detect and inject with IoC library;
• Capture instrumentation metrics;
• Track internet uptime, send outtage notice after service is restored.