Voltmeter

A graphical overview of system health status.

Build status:

This application was built to quickly visualise the current state of services in any particular environment. It leverages simple service status endpoints (SE4) as defined by Beamly to provide this information.

Depending on how you can discover environments and services, the overview will be updated automatically when services appear or disappear in your running landscape.

Currently this has a hard coded set of providers that will just generate services and dependencies that can be used as a demonstration version of Voltmeter. To actually to make this work you will need to impement the ports you will need to make it work for your use case.

Running with the SE4 adapter

Do demonstrate how Voltmeter works it comes with an adapter that supports retrieving status from services that support the simple service status endpoints. Discovery is handled through the configuration file appsettings.<environment>.json. Configuration looks like so:

{
    "Voltmeter": {
        "Environments": [ "prod", "qa", "test" ],
        "Services": [
            {
                "Name": "user",
                "LocationPattern": "https://user.{environment}.tempuri.org"
            },
            {
                "Name": "session",
                "LocationPattern": "https://sessions.{environment}.tempuri.org"
            }
        ]
    }
}

• Environments is a list containing the names of the environments.
• Services is a list of known services
  • Name is the name of the service
  • LocationPattern is the URI of the service, {environment} will be replaced with values from Environments

When you run the application you should see a diagram similar to the one below:

You'll note the database and messagebus nodes in the diagram which are not in the configuration. Voltmeter will automatically add nodes to the diagram that it finds in the service dependencies and don't yet exist as known services.

Making this your own

The Voltmeter UI needs an adapter that must be configured to provide evironments, services and dependencies that will be used to visualise your landscape.

Start with by adding a new class library to contain the implementation you will created. You will create a class to register you port implementations to wire up the ports.

Create a class that you supply a IServiceCollection to register the ports. You will need to register the store as a singleton to share state in the application.

Then the fun part starts, you will need to implement the following ports:

• IEnvironmentProvider to discover environments
• IServiceDiscovery to discover services in a particular environment
• IServiceStatusProvider to get status of the service
• IServiceDependenciesProvider to determine the dependencies of a service

Building

Voltmeter uses Cake to build, test and package. You can run this on both Windows, Linux and macOS.

On Windows:

> .\build.ps1 -Target Build-Release -Configuration Release

On Linux/macOS:

> ./build.sh --target=Build-Release --configuration=Release

Note that on Linux, the build.sh script automatically installs dependencies through apt-get so YMMV on other Linuxes. The dependencies it looks for are: curl, unzip, dotnet and git. If you already have them on your system you'll be fine.

You can also run the build inside a docker container if you want. In that case do:

> docker run --rm -it -v c:\git\Voltmeter:/tmp/repo -w "/tmp/repo" ubuntu:18.04 ./build.sh --target=Build-Release --configuration=Release

This will create a binary release of Voltmeter in /artifacts

Models

Model	Purpose
Environment	Contains a set of services particular for that environment
Service	A logical service, specific to a particular environment
ServiceStatus	The state of a service in an environment
Dependency	The name of a dependency of a service
DependencyStatus	The state of a dependency of a service